Peptides, explained without a single instruction.
Fifteen compounds people ask about constantly, each one written the same way: what it is, what it is claimed to do, what has actually been measured in humans, where it stands with the FDA, what the safety signals are, and whether it is banned in sport. No dosing. No routes. No protocols. No sourcing. No vendors. Not now, not later.
Read this first. It is the condition of the section existing at all.
Education only
Everything below is general education about pharmacology and regulation. It is not medical advice, not a diagnosis, not a treatment plan, and not a recommendation that you take anything. It does not establish a clinician–patient relationship with anyone at RYLOME.
No instructions, by design
You will not find a dose, a route, a cycle length, a reconstitution method, a stack, a supplier or a product link anywhere in this section. That is a permanent editorial rule, not an oversight. FDA has treated dosing instructions supplied alongside a “research use only” product as evidence that human use was intended see the enforcement record below.
No endorsement
Listing a compound is not an endorsement of it. Several entries exist mainly so you can see how thin the human evidence is. Nothing here is sold by RYLOME, and RYLOME does not prescribe, dispense, compound, source or refer for any compound named on this page.
Talk to your own clinician
Decisions about any prescription drug belong to you and a licensed prescriber who knows your history, your medications and your labs. If you are considering something on this page, the useful outcome of reading it is a better conversation with that person — not a purchase.
These statements have not been evaluated by the Food and Drug Administration. The compounds discussed here are not intended by RYLOME to diagnose, treat, cure or prevent any disease. Regulatory status changes; every status below is dated and linked to its primary source so you can check it yourself. Last reviewed August 2026.
Eleven status labels, and what each one really tells you.
Most confusion about peptides is a vocabulary problem. “Approved”, “legal”, “available”, “studied” and “safe” are five different claims, and marketing copy routinely swaps one for another. Every compound below carries the labels that apply to it.
Approved by FDA for one or more specific medical indications. Approval is always for a named use in a named population, never for wellness generally.
Was approved by FDA at one time. No currently marketed approved product was identified for the uses discussed in wellness settings.
Studied in registered human trials but not approved by FDA for any use.
FDA has not identified significant safety risks at this stage of its review and does not intend to act against compounding while evaluation continues. Category 1 is not a finding of safety or effectiveness.
No FDA approval for any indication, in any population.
Not on any FDA bulk-substances list that would permit a pharmacy to compound it from raw substance.
FDA stated it identified no human clinical studies and no human exposure data by any route.
A trade or vendor name for a multi-ingredient blend. FDA does not define or recognise it. No blend-level approval, trial, or standard of identity exists.
Commonly grouped with peptides in wellness marketing, but chemically it is not one.
FDA's strongest labelled warning, reserved for risks that can lead to serious injury or death.
Prohibited at all times under the WADA Prohibited List. A tested athlete who uses it commits an anti-doping rule violation.
Six sentences that sound like facts and are not.
If you only take one thing from this section, take this list. It is the difference between reading a vendor page critically and being sold to.
“It is FDA approved”
Approval is always for a named indication in a named population. Tesamorelin is approved for abdominal fat in HIV lipodystrophy and its label says it is not indicated for weight loss EGRIFTA WR prescribing information. Bremelanotide is approved for premenopausal women and its label says it is not indicated for men VYLEESI prescribing information. “Approved” and “approved for what you want it for” are different sentences.
“It is not on any FDA list, so it is unregulated”
Absence from a bulk-substances list is not permission. It usually means no one successfully made the case for it. The practical consequence is that there is no lawful route for a pharmacy to compound it from raw substance FDA interim policy on bulk drug substances.
“It is Category 1, so FDA says it is safe”
Category 1 means only that FDA has not identified significant safety risks at this stage of its review and does not intend to act while it keeps evaluating. It is an interim procedural posture, not a safety finding FDA interim policy on bulk drug substances.
“FDA banned it in 2023”
This is the single most common factual error on this topic, and it now cuts both ways. BPC-157, TB-500, CJC-1295, KPV, MOTS-c and injectable GHK-Cu did receive Category 2 designations dated 29 September 2023, but those nominations were withdrawn and the substances now sit in a separate withdrawn-nominations table FDA, bulk substances that may present significant safety risks. FDA then re-evaluated them on its own initiative and in July 2026 proposed not adding BPC-157, KPV, TB-500 or MOTS-c to the 503A bulks list FDA PCAC overview, July 23–24 2026; FDA advisory committee meeting page. The bottom line is unchanged — still no lawful compounding route — but the reasoning matters, because the withdrawal did not create a pathway.
“It says research use only, so it is legal to sell”
That disclaimer has essentially no protective effect once the seller's own marketing shows human use is intended. FDA's wording is nearly identical across letters: “Despite statements on your product labeling marketing your products, ‘FOR RESEARCH USE ONLY’ and ‘NOT INTENDED FOR HUMAN USE,’ evidence obtained from your website establishes that your products are intended to be drugs for human use” FDA warning letter, Xcel Research LLC, Dec 10 2024.
“There are studies on it”
There is a wide gap between a study and evidence. A rat study, an in-vitro assay, a conference abstract, a 13-patient trial with negative objective endpoints and a 2,539-patient phase 3 trial are not the same tier of knowledge, and this page labels which one you are looking at for every compound.
Fifteen entries, grouped by what they act on.
Open any one to see the full breakdown. Grouping is for orientation only — sitting in the same group says nothing about a compound’s evidence or its legal status.
Growth-hormone axis
These act upstream on the pituitary rather than replacing growth hormone directly. Two have been through FDA review. One never has, and its defining property is that a single exposure keeps IGF-1 elevated for weeks.
Sermorelin
GHRH(1-29) · formerly marketed as Geref
Formerly approvedBanned in tested sport
Sermorelin
GHRH(1-29) · formerly marketed as GerefWhat it is
Synthetic 29-amino-acid analogue of growth hormone-releasing hormone (GHRH).
What it is claimed to do, and what is established
Binds GHRH receptors on pituitary somatotrophs and stimulates the synthesis and pulsatile release of the body's own growth hormone Prakash & Goa, BioDrugs 1999. Because it works upstream on the pituitary rather than replacing growth hormone directly, its effect depends on that axis being intact — which also means a normal response to it cannot rule out growth hormone deficiency arising higher up in the hypothalamus same review.
Best human evidence
The strongest human evidence is a one-year multicentre open-label study in 110 previously untreated prepubertal growth-hormone-deficient children (86 evaluable): mean height velocity rose from 4.1 cm/yr at baseline to 8.0 cm/yr at six months, with no adverse biochemical changes Geref International Study Group, JCEM 1996. A review notes height-velocity gains were lower with sermorelin than with growth hormone itself at equivalent dosing, and that the effect on final adult height had not been determined Prakash & Goa, BioDrugs 1999. For adult body-composition, energy or anti-ageing endpoints, no human trial evidence was identified.
Regulatory status
Geref (sermorelin acetate), NDA 020443, received marketing approval on 26 September 1997 for short stature in a preselected subgroup of children with idiopathic growth hormone deficiency FDA orphan drug designation record, sermorelin. FDA's own 2024 review refers to that approval in the past tense FDA PCAC briefing document, October 29 2024. Sermorelin acetate sits in Category 1 of the 503B nominated bulk-substances list FDA 503B nominated bulk substances list. No approved sermorelin product has ever existed for adult wellness, body composition or growth-hormone “optimisation”.
Safety signals
Reported effects in the paediatric literature were mild — transient facial flushing and injection-site pain Prakash & Goa, BioDrugs 1999. FDA has issued a warning letter to a seller marketing sermorelin online as an unapproved new drug FDA warning letter, Xcel Research LLC, Dec 10 2024, and has separately flagged internet promotion of sermorelin/ipamorelin combinations advertising a “3-5 fold increase in growth hormone release,” while raising safety concerns about sustained stimulation of the GH/IGF-1 axis FDA PCAC briefing document, October 29 2024.
Sport and competition
Prohibited at all times, named under WADA S2.2.4 growth hormone releasing factors WADA 2026 Prohibited List.
Tesamorelin
EGRIFTA WR
FDA approvedBanned in tested sport
Tesamorelin
EGRIFTA WRWhat it is
Synthetic GHRH analogue. An approved prescription drug.
What it is claimed to do, and what is established
Binds and stimulates growth-hormone-releasing-factor receptors with similar potency to the body's own GRF, raising endogenous growth hormone and downstream IGF-1; the resulting visceral lipolysis is the basis for its approved indication EGRIFTA WR prescribing information.
Best human evidence
The strongest human evidence of any GHRH-type peptide here. A randomised, double-blind, placebo-controlled phase 3 trial in 412 patients over 26 weeks plus a 26-week extension found visceral adipose tissue fell 15.2% on tesamorelin versus a 5.0% rise on placebo (p<0.001) Falutz et al., NEJM 2007.
Regulatory status
Approved 2010; label revised March 2025. Indicated for the reduction of excess abdominal fat in HIV-infected adults with lipodystrophy. The label states two limitations plainly: long-term cardiovascular safety has not been established, and it is not indicated for weight loss EGRIFTA WR prescribing information.
Safety signals
No boxed warning. Contraindicated in disruption of the hypothalamic-pituitary axis, active malignancy, hypersensitivity to tesamorelin or mannitol, and pregnancy. Labelled warnings include increased neoplasm risk, elevated IGF-1 (47% of patients above +2 SD at 26 weeks), fluid retention, glucose intolerance and new diabetes, and increased mortality in acute critical illness EGRIFTA WR prescribing information. In the pivotal trial, anti-tesamorelin antibodies developed in 48.6% of treated patients versus 2.7% on placebo Falutz et al., NEJM 2007.
Sport and competition
Prohibited at all times under WADA S2.2.4 WADA 2026 Prohibited List.
CJC-1295
Long-acting GHRH analogue · sold with and without DAC
Not approved for human useNo lawful compounding routeBanned in tested sport
CJC-1295
Long-acting GHRH analogue · sold with and without DACWhat it is
Long-acting synthetic analogue of growth hormone-releasing hormone.
What it is claimed to do, and what is established
Stimulates pituitary GHRH receptors to raise endogenous growth hormone and IGF-1. Its distinguishing feature is duration: in humans, a single injection raised growth hormone two- to ten-fold for six days or more and IGF-1 one-and-a-half to three-fold for nine to eleven days, with an estimated half-life of 5.8–8.1 days Teichman et al., JCEM 2006. The commonly marketed distinction between with-DAC and without-DAC forms could not be confirmed from a primary source, so we do not state it.
Best human evidence
Two randomised, placebo-controlled, double-blind ascending-dose trials of 28 and 49 days in healthy adults aged 21–61. After multiple doses IGF-1 remained above baseline for up to 28 days, and the peptide was described as well tolerated Teichman et al., JCEM 2006. Note the limit precisely: these are pharmacodynamic studies showing that growth hormone and IGF-1 go up. They are not clinical-outcome trials for body composition, recovery, sleep or longevity, and no phase 3 programme was identified.
Regulatory status
Not approved for any human use. CJC-1295 appears in the withdrawn-nominations table of FDA's significant-safety-risk page FDA, bulk substances that may present significant safety risks and is absent from the 503A Category 1 list FDA 503A nominated bulk substances list, updated May 14 2026 and the 503B lists FDA 503B nominated bulk substances list. There is no lawful route to compound it from bulk substance.
Safety signals
FDA's stated concern is specific: “FDA has identified serious adverse events associated with CJC-1295 including increased heart rate and systemic vasodilatory reaction. Available clinical data are limited” FDA, bulk substances that may present significant safety risks. Multi-week IGF-1 elevation from a single dose Teichman et al., JCEM 2006 is the clearest reason why prolonged stimulation of this axis is not a trivial intervention. FDA has also documented online marketing of CJC-1295 with ipamorelin claiming a “3-5 fold increase in growth hormone release” FDA PCAC briefing document, October 29 2024.
Sport and competition
Prohibited at all times, named explicitly under WADA S2.2.4 WADA 2026 Prohibited List.
Repair and tissue peptides
This is the category with the widest gap between how confidently it is marketed and what has actually been measured in people. Read the evidence rows carefully — in three cases FDA states outright that no human data exists.
BPC-157
Bepecin · PL-14736 · pentadecapeptide BPC 157
Not approved for human useNo lawful compounding routeBanned in tested sport
BPC-157
Bepecin · PL-14736 · pentadecapeptide BPC 157What it is
Synthetic 15-amino-acid peptide. Not a component of any FDA-approved drug FDA BPC-157 briefing document, May 2026.
What it is claimed to do, and what is established
Investigated as a cytoprotective and mucosal-healing agent; the use FDA actually evaluated was ulcerative colitis FDA BPC-157 briefing document, May 2026. The honest statement about mechanism is that it is not established in humans: FDA reported that BPC-157 was not detected in plasma after rectal administration, and that no human pharmacokinetic data exists for the oral, subcutaneous, nasal or transdermal routes at all same evaluation.
Best human evidence
FDA identified five human studies in total. The strongest is a conference abstract: a randomised, double-blind, placebo-controlled trial in 53 patients with mild-to-moderate ulcerative colitis given a two-week course by enema, where the disease-activity index fell 3.2 points versus 1.6 on placebo FDA BPC-157 briefing document, May 2026. The other four are a 32-patient phase 1 tolerability study, a 17-patient retrospective chart review, a 12-patient single-arm study and a two-subject pilot all per FDA's review. There is no adequately powered, published, peer-reviewed phase 3 trial for any indication. The strongest positive human result comes from a route and a disease unrelated to the tendon, joint and gut-healing claims made for it in wellness marketing. A phase 2 hamstring-strain trial began in February 2026 and is recruiting ClinicalTrials.gov NCT07437547.
Regulatory status
Not approved. BPC-157 sits in the withdrawn-nominations table of FDA's significant-safety-risk page FDA, bulk substances that may present significant safety risks, and at the July 2026 advisory committee meeting FDA proposed not adding it to the 503A bulks list, citing inadequate chemical characterisation, inadequate impurity and endotoxin data, immunogenicity concerns for injectables, insufficient evidence of effectiveness, insufficient clinical safety information, and the availability of approved alternatives FDA BPC-157 briefing document, May 2026; FDA PCAC overview, July 23–24 2026.
Safety signals
FDA stated it “lacks sufficient information to know whether the drug would cause harm when administered to humans” FDA, bulk substances that may present significant safety risks. In its 2026 evaluation FDA also identified possible clotting- and liver-related signals in non-clinical repeat-dose studies FDA BPC-157 briefing document, May 2026.
Sport and competition
Prohibited at all times. Named explicitly in WADA S0, non-approved substances WADA 2026 Prohibited List.
TB-500
Thymosin beta-4 fragment (LKKTETQ) — not full-length thymosin β4
Not approved for human useNo human dataNo lawful compounding routeBanned in tested sport
TB-500
Thymosin beta-4 fragment (LKKTETQ) — not full-length thymosin β4What it is
Synthetic N-acetylated heptapeptide corresponding to residues 17–23 of the 43-amino-acid protein thymosin β4 FDA TB-500 briefing document, May 2026. TB-500 and thymosin β4 are not interchangeable and should not be described as the same thing.
What it is claimed to do, and what is established
The sequence contains the actin-binding LKKTET motif, and TB-500 is hypothesised to bind globular actin, which is the proposed basis for effects on cell migration and repair FDA TB-500 briefing document, May 2026. This is hypothesised, not demonstrated. Notably, in vitro TB-500 free base did not induce fibroblast wound healing at all; only an N-acetylated metabolite produced a small effect same document.
Best human evidence
There is none in humans. FDA stated it identified no human data of any kind: an adverse-event database search returned no reports, the literature contained no cases, and there were no repeat-dose, genotoxicity or carcinogenicity studies FDA TB-500 briefing document, May 2026. The only pharmacokinetic data FDA identified was in thoroughbred geldings same document. A phase 1/2 trial in stable atherosclerotic cardiovascular disease began in February 2026 and is recruiting ClinicalTrials.gov NCT07487363.
Regulatory status
Not approved. Listed in the withdrawn-nominations table of FDA's significant-safety-risk page, where FDA recorded immunogenicity risk and that it “has not identified any human exposure data” FDA, bulk substances that may present significant safety risks. FDA proposed not adding it to the 503A bulks list in July 2026, and no outsourcing facility reported compounding it during the period FDA reviewed FDA TB-500 briefing document, May 2026; FDA PCAC overview, July 23–24 2026.
Safety signals
Because no human safety database exists, the accurate characterisation is that the safety profile is unknown — not that it is well tolerated FDA TB-500 briefing document, May 2026. FDA identified immunogenicity risk and no human exposure data FDA, bulk substances that may present significant safety risks.
Sport and competition
Prohibited at all times under WADA S2.3 growth factors, named as a thymosin-β4 derivative WADA 2026 Prohibited List.
GHK-Cu
Copper tripeptide-1 · glycyl-L-histidyl-L-lysine-Cu²⁺
Not approved for human use503A Category 1Investigational
GHK-Cu
Copper tripeptide-1 · glycyl-L-histidyl-L-lysine-Cu²⁺What it is
Copper(II) complex of a three-amino-acid peptide Miller et al., Arch Facial Plast Surg 2006.
What it is claimed to do, and what is established
Studied topically as a copper-carrying tripeptide supporting wound re-epithelialisation and dermal remodelling ClinicalTrials.gov NCT07437586. Human mechanistic confirmation is limited, and FDA has flagged limited human data for the injectable form specifically FDA, bulk substances that may present significant safety risks.
Best human evidence
The strongest published human trial is small and largely negative on objective measures: 13 completers after circumoral laser resurfacing, randomised to a skincare regimen with or without GHK-Cu and followed to 12 weeks. Computer analysis and blinded evaluators found no statistically significant difference in erythema resolution, wrinkle improvement or overall skin quality. The only significant result was on the patients' own questionnaire (p=0.04) Miller et al., Arch Facial Plast Surg 2006. A larger phase 2 topical wound-healing trial began in February 2026 and has posted no results ClinicalTrials.gov NCT07437586.
Regulatory status
The most route-dependent entry on this page, and the one most often misreported. GHK-Cu except for injectable routes currently sits in Category 1 of FDA's 503A nominated list; FDA removed it in April 2026 after nominations were withdrawn, then restored the non-injectable form in May 2026 once a nominator clarified that only the injectable route had been withdrawn, and FDA intends to consult its advisory committee before the end of February 2027 FDA 503A nominated bulk substances list, updated May 14 2026. Injectable GHK-Cu sits in the withdrawn-nominations table of the significant-safety-risk page, where FDA cited immunogenicity risk from aggregation and impurities FDA, bulk substances that may present significant safety risks.
Safety signals
For the injectable form, FDA identified immunogenicity risk due to peptide aggregation and impurities plus limited human data FDA, bulk substances that may present significant safety risks. No FDA safety communication specific to topical GHK-Cu was located.
Sport and competition
Not named on the WADA list WADA 2026 Prohibited List. Absence is not the same as permission — the S0 class sweeps in non-approved substances generally, so a tested athlete should not read this row as a green light.
GLOW
Vendor blend name, commonly GHK-Cu + BPC-157 + TB-500
Marketing name, not a drug substanceNot approved for human useNo lawful compounding route
GLOW
Vendor blend name, commonly GHK-Cu + BPC-157 + TB-500What it is
A marketing name for a multi-ingredient blend, not a defined drug substance. FDA does not recognise or define “GLOW” in any document we located. FDA has, however, documented internet promotion of exactly this kind of multi-ingredient peptide product FDA KPV briefing document and complaints involving blended TB-500 and BPC-157 FDA TB-500 briefing document, May 2026.
What it is claimed to do, and what is established
No blend-level mechanism has been characterised. Only component-level statements are defensible, and each component carries its own caveat — see GHK-Cu, BPC-157 and TB-500 above.
Best human evidence
None. We searched the clinical trials registry for the blend and found only single-agent studies; a literature search for the combination returned narrative reviews and one animal study in rat Achilles tendon BPC-157 and TB-500 in rat Achilles tendon healing. There is no human clinical trial, no systematic review and no regulatory approval for this blend.
Regulatory status
No lawful compounding route exists. BPC-157 and TB-500 were both the subject of FDA's July 2026 recommendation not to add them to the 503A bulks list, and injectable GHK-Cu sits in the withdrawn-nominations table FDA, bulk substances that may present significant safety risks; FDA PCAC overview, July 23–24 2026. A blend requiring BPC-157 and TB-500 cannot be lawfully compounded from bulk substances on any current FDA list.
Safety signals
Inherits every component risk: immunogenicity and impurity concerns for injectable peptides, no human exposure data for TB-500, and insufficient clinical safety information plus non-clinical clotting and liver signals for BPC-157 FDA TB-500 briefing document, May 2026; FDA BPC-157 briefing document, May 2026. FDA has separately warned that food-grade ingredients used in sterile compounding carry microbial and endotoxin contamination risk FDA reminder on ingredients suitable for sterile compounding.
Sport and competition
Prohibited for tested athletes, because BPC-157 (S0) and TB-500 (S2.3) are both banned at all times WADA 2026 Prohibited List.
KLOW
Vendor blend name, commonly KPV + GHK-Cu + BPC-157 + TB-500
Marketing name, not a drug substanceNot approved for human useNo human dataNo lawful compounding route
KLOW
Vendor blend name, commonly KPV + GHK-Cu + BPC-157 + TB-500What it is
A marketing name for a four-ingredient blend; not a defined drug substance in any FDA document we located. KPV itself is the tripeptide Lys-Pro-Val, a fragment of α-melanocyte-stimulating hormone, with no assigned unique ingredient identifier FDA KPV briefing document.
What it is claimed to do, and what is established
No blend-level mechanism exists. KPV's proposed mechanism derives from α-MSH anti-inflammatory signalling, and the nomination FDA reviewed was supported by eight animal studies plus one in-vitro cadaver-skin permeation study in which KPV did not permeate well FDA KPV briefing document.
Best human evidence
None, for KPV individually or for the blend. FDA stated there are no human clinical studies and no human exposure data for KPV by any route FDA KPV briefing document. Our registry search for the blend returned no matching record, and a literature search returned only reviews and animal work BPC-157 and TB-500 in rat Achilles tendon healing.
Regulatory status
No lawful compounding route. KPV appears in the withdrawn-nominations table where FDA stated it “has not identified any human exposure data… via any route” FDA, bulk substances that may present significant safety risks, and FDA proposed not adding it to the 503A bulks list in July 2026, noting that no outsourcing facility reported compounding it between January 2017 and June 2025 FDA KPV briefing document.
Safety signals
Component risks as above, plus FDA's finding of a complete absence of human exposure data for both KPV and TB-500 FDA KPV briefing document; FDA TB-500 briefing document, May 2026. Sterile-compounding contamination risk applies to any injectable version FDA reminder on ingredients suitable for sterile compounding.
Sport and competition
Prohibited for tested athletes via BPC-157 (S0) and TB-500 (S2.3) WADA 2026 Prohibited List.
Metabolic and incretin drugs
The best-evidenced group on this page by a wide margin, with phase 3 trials in the thousands. It is also the group where the difference between an approved product and a grey-market vial matters most.
Semaglutide
Ozempic · Wegovy · Wegovy HD
FDA approvedCarries a boxed warning
Semaglutide
Ozempic · Wegovy · Wegovy HDWhat it is
GLP-1 receptor agonist with 94% sequence homology to human GLP-1 OZEMPIC label, revised 05/2026.
What it is claimed to do, and what is established
Selectively activates the GLP-1 receptor, producing glucose-dependent stimulation of insulin secretion and suppression of glucagon, with a minor delay in gastric emptying. Albumin binding and resistance to enzymatic degradation are what make once-weekly dosing possible OZEMPIC label, revised 05/2026.
Best human evidence
STEP 1: phase 3, double-blind, randomised, placebo-controlled, 129 sites in 16 countries, 1,961 adults, 68 weeks. Mean body-weight change was −14.9% versus −2.4% on placebo; 86.4% lost at least 5% of body weight versus 31.5%, and 32.0% lost at least 20% versus 1.7% Wilding et al., STEP 1, NEJM 2021. The label additionally reports a 17,604-patient cardiovascular outcomes trial WEGOVY label, revised 02/2026.
Regulatory status
Approved since 2017 across several products and indications: type 2 diabetes glycaemic control, cardiovascular risk reduction, kidney-outcome reduction OZEMPIC label, revised 05/2026; long-term weight reduction in adults and in patients aged 12 and over with obesity, plus accelerated approval for non-cirrhotic MASH with moderate-to-advanced fibrosis WEGOVY label, revised 02/2026. FDA has also approved a higher 7.2 mg dose FDA approval of higher-dose semaglutide. It cannot be compounded from bulk substance — it is on neither the 503B bulks list nor the shortage list FDA, policies for compounders as GLP-1 supply stabilises, and FDA has proposed formally excluding it for lack of identified clinical need FDA proposes excluding semaglutide, tirzepatide and liraglutide from the 503B bulks list. FDA is also explicit that salt forms such as semaglutide sodium and semaglutide acetate are different active ingredients with no lawful basis for use in compounding FDA, concerns with unapproved GLP-1 drugs used for weight loss.
Safety signals
Boxed warning: risk of thyroid C-cell tumours. Dose- and duration-dependent tumours occurred in rodents at clinically relevant exposures; human relevance is undetermined; contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2 WEGOVY label, revised 02/2026. Labelled warnings include pancreatitis, diabetic retinopathy complications, hypoglycaemia with insulin or secretagogues, acute kidney injury and hypersensitivity OZEMPIC label, revised 05/2026. In STEP 1, gastrointestinal disorders occurred in 74.2% versus 47.9% on placebo Wilding et al., STEP 1, NEJM 2021. At the 7.2 mg dose FDA noted altered skin sensation was common and is under further investigation FDA approval of higher-dose semaglutide. Separately, FDA had received 990 adverse-event reports for compounded semaglutide as of 31 May 2026 and notes these are likely under-reported FDA, concerns with unapproved GLP-1 drugs used for weight loss.
Sport and competition
Not named on the WADA list WADA 2026 Prohibited List.
Tirzepatide
Mounjaro · Zepbound
FDA approvedCarries a boxed warning
Tirzepatide
Mounjaro · ZepboundWhat it is
Dual GIP and GLP-1 receptor agonist; a 39-amino-acid modified peptide with a fatty-diacid moiety MOUNJARO label, revised 01/2026.
What it is claimed to do, and what is established
Agonises both the glucose-dependent insulinotropic polypeptide receptor and the GLP-1 receptor, enhancing first- and second-phase insulin secretion and reducing glucagon in a glucose-dependent way MOUNJARO label, revised 01/2026.
Best human evidence
SURMOUNT-1: phase 3, double-blind, randomised, placebo-controlled, 119 sites in 9 countries, 2,539 participants, 72 weeks. Mean weight change was −15.0%, −19.5% and −20.9% across three dose groups versus −3.1% on placebo Jastreboff et al., SURMOUNT-1, NEJM 2022. The Zepbound label additionally reports sleep-apnoea studies showing significant reductions in the apnoea-hypopnoea index ZEPBOUND label.
Regulatory status
Approved since 2022. Mounjaro for glycaemic control in type 2 diabetes in adults and in patients aged 10 and over MOUNJARO label, revised 01/2026; Zepbound for long-term weight reduction and for moderate-to-severe obstructive sleep apnoea in adults with obesity ZEPBOUND label. Not compoundable from bulk substance — not on the 503B bulks list or the shortage list FDA, policies for compounders as GLP-1 supply stabilises, with formal exclusion proposed FDA proposes excluding semaglutide, tirzepatide and liraglutide from the 503B bulks list.
Safety signals
Boxed warning: risk of thyroid C-cell tumours; contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2, and FDA notes routine calcitonin or thyroid ultrasound monitoring is of uncertain value ZEPBOUND label. Labelled warnings include pancreatitis, hypoglycaemia with secretagogues, acute kidney injury, severe gastrointestinal disease and gastroparesis (not recommended), diabetic retinopathy and acute gallbladder disease MOUNJARO label, revised 01/2026. FDA had received more than 730 adverse-event reports for compounded tirzepatide as of 31 May 2026 FDA, concerns with unapproved GLP-1 drugs used for weight loss.
Sport and competition
Not named on the WADA list WADA 2026 Prohibited List.
Retatrutide
Triple agonist, investigational
InvestigationalNot approved for human useNo lawful compounding route
Retatrutide
Triple agonist, investigationalWhat it is
Single-molecule triple hormone-receptor agonist at the GIP, GLP-1 and glucagon receptors Jastreboff et al., NEJM 2023.
What it is claimed to do, and what is established
Agonises three metabolic receptors at once. Because there is no approved label, there is no FDA-reviewed mechanism statement — the mechanism here is attributed to the trial literature, not to a label Jastreboff et al., NEJM 2023.
Best human evidence
Phase 2, double-blind, randomised, placebo-controlled, 338 adults with obesity over 48 weeks: weight change at 24 weeks ranged from −7.2% to −17.9% across dose groups versus −1.6% on placebo Jastreboff et al., NEJM 2023. The phase 3 trial, TRIUMPH-1, enrolled 2,335 and completed in April 2026 but has posted no results ClinicalTrials.gov NCT05929066, so the strongest published human evidence remains phase 2.
Regulatory status
Investigational only — not approved for any human use. Retatrutide does not appear in FDA's 2026 novel drug approvals FDA novel drug approvals, 2026, and FDA states flatly that “retatrutide and cagrilintide cannot be used in compounding under federal law” FDA, concerns with unapproved GLP-1 drugs used for weight loss. FDA has warned telehealth companies marketing it, distributors selling it to compounders, and outsourcing facilities repackaging it same statement. It is also among the most frequently cited substances in recent warning letters to grey-market sellers FDA warning letter, Xcel Research LLC, Dec 10 2024; FDA warning letter, Summit Research Peptides, Dec 10 2024; FDA warning letter, Gram Peptides, Mar 31 2026.
Safety signals
In the phase 2 trial, adverse events occurred in 73–94% of retatrutide groups versus 70% on placebo, discontinuation for adverse events in 6–16% versus 0%, with dose-dependent heart-rate increases peaking at 24 weeks and cutaneous hyperesthesia in 7% versus 1% Jastreboff et al., NEJM 2023. FDA has warned about dosing-error hospitalisations associated with consumer-sold versions of these unapproved products FDA, concerns with unapproved GLP-1 drugs used for weight loss.
Sport and competition
Not named on the WADA list WADA 2026 Prohibited List.
MOTS-c
Mitochondrial open reading frame of the 12S rRNA-c
Not approved for human useNo human dataNo lawful compounding routeBanned in tested sport
MOTS-c
Mitochondrial open reading frame of the 12S rRNA-cWhat it is
Mitochondrial-derived 16-amino-acid peptide encoded within the mitochondrial 12S rRNA FDA MOTS-c briefing document.
What it is claimed to do, and what is established
Classified by WADA among AMP-activated protein kinase activators WADA 2026 Prohibited List, and studied for insulin sensitivity — the current trial's primary pharmacodynamic endpoint is an oral-glucose-tolerance-derived insulin sensitivity index ClinicalTrials.gov NCT07505745. Human pharmacokinetics are unknown, and in vitro MOTS-c underwent rapid proteolysis in human whole blood FDA MOTS-c briefing document.
Best human evidence
None in humans. FDA stated there are no human clinical studies, no human exposure data and no clinical pharmacokinetic data for MOTS-c, that potential safety risks are unknown, and that adverse-event database searches returned no reports FDA MOTS-c briefing document. Evidence to date is animal and in-vitro only. A phase 2a trial in prediabetes and overweight began in February 2026 with no results posted ClinicalTrials.gov NCT07505745.
Regulatory status
Not approved and not compoundable. Listed in the withdrawn-nominations table of FDA's significant-safety-risk page, where FDA cited significant immunogenicity risk and no human exposure data by any route FDA, bulk substances that may present significant safety risks. FDA proposed not adding it to the 503A bulks list in July 2026, and no outsourcing facility reported compounding it between January 2017 and December 2025 FDA MOTS-c briefing document.
Safety signals
FDA: significant immunogenicity risk, no human exposure data, unknown safety profile FDA, bulk substances that may present significant safety risks; FDA MOTS-c briefing document.
Sport and competition
Prohibited at all times under WADA S4.4.1, AMPK activators, named explicitly WADA 2026 Prohibited List.
Hormones and other compounds
Grouped here because they are frequently discussed alongside peptides even though they are pharmacologically unrelated to each other, and in one case not a peptide at all.
NAD+
Nicotinamide adenine dinucleotide
Not a peptideNot approved for human use503A Category 1
NAD+
Nicotinamide adenine dinucleotideWhat it is
A coenzyme, not a peptide. NAD⁺ is a pyridine nucleotide. It contains no amino acids and no peptide bonds, so it does not belong in a peptide taxonomy at all. It is included on this page only because wellness marketing routinely groups it with peptides FDA 503A nominated bulk substances list, updated May 14 2026.
What it is claimed to do, and what is established
Functions as a redox coenzyme in cellular metabolism. Because no FDA-approved NAD⁺ drug exists, there is no FDA-reviewed mechanism statement to cite; the clinical literature administers it intravenously and compares it against the precursor nicotinamide riboside Frontiers in Aging 2026;7:1652582.
Best human evidence
Human evidence is pilot-scale and tolerability-focused. The most recent primary study we located is a retrospective tolerability pilot in a commercial wellness setting with 14 clients across two arms and 30-day follow-up Frontiers in Aging 2026;7:1652582. No adequately powered randomised controlled trial supporting clinical benefit of intravenous NAD⁺ for wellness, longevity, cognition or addiction endpoints was identified.
Regulatory status
No approved NAD⁺ drug product was identified FDA novel drug approvals, 2026. It is, however, the one compound on this page with a currently permissive compounding posture: nicotinamide adenine dinucleotide is in Category 1 of the 503A nominated list FDA 503A nominated bulk substances list, updated May 14 2026 and beta-nicotinamide adenine dinucleotide is in Category 1 of the 503B list FDA 503B nominated bulk substances list. Category 1 means only that FDA has not identified significant safety risks at this stage of its review and does not intend to act while evaluation continues. It is not a finding of safety or effectiveness FDA interim policy on bulk drug substances.
Safety signals
Two things belong side by side here. In the 2026 retrospective pilot, all six intravenous NAD⁺ participants reported moderate-to-severe abdominal cramping, diarrhoea, nausea, vomiting, increased heart rate and throat symptoms Frontiers in Aging 2026;7:1652582. And FDA has stated: “FDA has received adverse event reports following use of NAD+ injectable drugs, including severe chills, shaking, vomiting and fatigue with some requiring medical treatment,” and that “these reactions are consistent with excessive levels of endotoxins” — in the context of reminding compounders that food-grade ingredients are not suitable for making sterile drugs FDA reminder on ingredients suitable for sterile compounding. If you are considering an intravenous NAD⁺ product anywhere, that is the question to ask about it.
Sport and competition
Not named on the WADA list WADA 2026 Prohibited List.
PT-141
Bremelanotide · VYLEESI
FDA approved
PT-141
Bremelanotide · VYLEESIWhat it is
Synthetic melanocortin receptor agonist peptide; an approved prescription drug VYLEESI prescribing information.
What it is claimed to do, and what is established
A non-selective melanocortin receptor agonist, with MC1 and MC4 binding considered most relevant at therapeutic doses. The label is unusually candid: “the mechanism by which VYLEESI improves HSDD in women is unknown” VYLEESI prescribing information. We do not assert a confident central mechanism that FDA's own label declines to state.
Best human evidence
RECONNECT: two identical phase 3, randomised, double-blind, placebo-controlled 24-week trials, 1,267 randomised. Change in the desire domain versus placebo was +0.30 and +0.42 across the two studies (p<0.001), with a small reduction in associated distress Kingsberg et al., RECONNECT, Obstet Gynecol 2019. Read that plainly: statistically significant but numerically modest changes on desire and distress scales in premenopausal women — and not evidence in men.
Regulatory status
Approved 2019 for premenopausal women with acquired, generalised hypoactive sexual desire disorder. The label states explicitly that it is not indicated for postmenopausal women, not indicated for men, and not for enhancement of sexual performance VYLEESI prescribing information. Male use is the dominant marketing context for “PT-141” in the wellness space and it is not an approved indication. FDA's position on compounded bremelanotide was not located in the sources we reviewed, so compounded PT-141 should not be described as FDA-sanctioned FDA 503A nominated bulk substances list, updated May 14 2026.
Safety signals
No boxed warning, but contraindicated in uncontrolled hypertension or known cardiovascular disease. Labelled effects include a transient blood-pressure rise of roughly 6 mmHg systolic peaking two to four hours after dosing, nausea in 40% of patients, and focal hyperpigmentation in about 1% at up to eight doses per month but 38% with daily dosing for eight days — which may not resolve. More than eight doses per month is not recommended VYLEESI prescribing information.
Sport and competition
Not named on the WADA list WADA 2026 Prohibited List.
HCG
Human chorionic gonadotropin · PREGNYL
FDA approvedBanned in tested sport
HCG
Human chorionic gonadotropin · PREGNYLWhat it is
Glycoprotein gonadotropin hormone produced by the human placenta FDA, questions and answers on HCG products for weight loss.
What it is claimed to do, and what is established
Its action is “virtually identical to that of pituitary LH,” with slight FSH activity. In males it stimulates Leydig cells to produce androgens; in females it supports corpus luteum progesterone production and triggers ovulation PREGNYL label, NDA 017692.
Best human evidence
For the approved undescended-testis indication, a systematic review with meta-analysis found testicular descent in 25% with hCG versus 18% with an alternative, concluded there was no evidence supporting larger doses or longer intervals, and cautioned that hormonal treatment cannot be recommended for everyone given few trials, small samples and moderate risk of bias Pediatr Surg Int 2004;20(5):357–9. For weight loss, FDA states: “There is no substantial evidence that HCG increases weight loss” FDA, questions and answers on HCG products for weight loss.
Regulatory status
Approved, with narrow indications: prepubertal cryptorchidism not due to anatomical obstruction, selected cases of hypogonadotropic hypogonadism in males, and induction of ovulation in anovulatory infertile women PREGNYL label, NDA 017692. FDA states approved hCG products are available only as injections, require a prescription, and that “FDA has not approved prescription HCG for any other uses, including weight loss.” FDA and the FTC have issued seven joint warning letters over over-the-counter “homeopathic” hCG weight-loss products, and FDA's position is that “all drug products claiming to include ‘homeopathic’ HCG are illegally marketed” FDA, questions and answers on HCG products for weight loss.
Safety signals
The approved label carries an unusual all-capitals efficacy disclaimer: “HCG HAS NOT BEEN DEMONSTRATED TO BE EFFECTIVE ADJUNCTIVE THERAPY IN THE TREATMENT OF OBESITY…” and “HCG HAS NO KNOWN EFFECT ON FAT MOBILIZATION, APPETITE OR SENSE OF HUNGER, OR BODY FAT DISTRIBUTION” PREGNYL label, NDA 017692. Warnings include anaphylaxis with urinary-derived product, ovarian hyperstimulation syndrome which may be life-threatening, pulmonary and thromboembolic complications including death, ovarian torsion and multi-fetal gestation same label. FDA also warns that the very-low-calorie diets bundled with these products raise the risk of gallstones, electrolyte imbalance and cardiac arrhythmias FDA, questions and answers on HCG products for weight loss.
Sport and competition
Prohibited at all times in males under WADA S2.2.1, testosterone-stimulating peptides. The male-only qualifier is the List's own wording WADA 2026 Prohibited List.
“Research use only” is a marketing phrase, not a legal shield.
This is the single most misunderstood thing in the peptide market. The label does not change what a product legally is, and FDA has said so repeatedly in writing. Here is the reasoning it actually uses, step by step.
Marketing establishes intended use
Website copy and labelling are what determine a product's intended use, under FDA's intended-use regulation at 21 CFR 201.128 FDA warning letter, USApeptide.com, Feb 26 2025.
Intended use makes it a drug
Anything intended to prevent, treat or cure disease, or to affect the structure or function of the body, is a drug under section 201(g)(1) of the Federal Food, Drug, and Cosmetic Act FDA warning letter, Xcel Research LLC, Dec 10 2024.
Not generally recognised as safe and effective makes it a new drug
Because these products are not generally recognised as safe and effective for the uses being marketed, they are “new drugs” under section 201(p) same letter.
Selling a new drug without an approved application is illegal
Introducing a new drug into interstate commerce without an approved application under section 505 violates sections 301(d) and 505(a) same letter.
Missing directions add a misbranding charge
FDA has additionally charged misbranding under section 502(f)(1) for inadequate directions for use, holding that the products were dispensed without a prescription and were not exempt FDA warning letter, USApeptide.com, Feb 26 2025.
The enforcement record
A sample of FDA warning letters issued to firms selling peptides labelled for research use. Every one of these firms used the phrase. None of them were protected by it.
| Firm | Date | Substances cited | Source |
|---|---|---|---|
| Summit Research Peptides | 10 Dec 2024 | Semaglutide, retatrutide, cagrilintide, tirzepatide, mazdutide, labelled “research use only” and “intended as a research chemical only” | Warning letter |
| Xcel Research LLC | 10 Dec 2024 | Retatrutide, cagrilintide with semaglutide, mazdutide, semaglutide, survodutide, sermorelin | Warning letter |
| USApeptide.com | 26 Feb 2025 | Semaglutide, tirzepatide, bacteriostatic water and syringes; “research use only,” “not for human consumption”; misbranding also charged | Warning letter |
| Pinnacle Peptides | 12 Dec 2025 | Andarine, ligandrol and ostarine, labelled “for research only” and “not for human use” | Warning letter |
| Gram Peptides | 31 Mar 2026 | Retatrutide, tirzepatide and bacteriostatic water — FDA held the water itself to be a drug when sold alongside injectable peptides | Warning letter |
| Wholesale Peptide | 17 Jun 2026 | Products marketed as “Prostamax” and “Gonadorelin” | Warning letter |
FDA has also treated bacteriostatic water as an unapproved drug when it was sold alongside injectable peptides, on the reasoning that the intended use of the accompanying products established the intended use of the diluent USApeptide.com warning letter.
The compounded GLP-1 window has closed.
For roughly two years, a genuine drug shortage created a narrow lawful path for pharmacies to compound semaglutide and tirzepatide. That path is gone, and a large amount of marketing has not caught up. If you are being offered a compounded version today, this timeline is the context.
Tirzepatide shortage resolved
FDA determined the tirzepatide shortage was resolved on 2 October 2024, re-decided the matter on 19 December 2024, and set the end of its enforcement discretion at 18 February 2025 for pharmacies and 19 March 2025 for outsourcing facilities FDA, policies for compounders as GLP-1 supply stabilises.
Semaglutide shortage resolved
The semaglutide shortage was resolved on 21 February 2025, with discretion running to 22 April 2025 for pharmacies and 22 May 2025 for outsourcing facilities FDA, policies for compounders as GLP-1 supply stabilises.
Court challenges denied
Compounders challenged the determinations in the Northern District of Texas. Preliminary injunctions were denied on 5 March 2025 for tirzepatide and 24 April 2025 for semaglutide FDA, policies for compounders as GLP-1 supply stabilises.
FDA moves to make the exclusion permanent
Neither drug appears on the 503B bulks list or the shortage list, and FDA has proposed formally excluding semaglutide, tirzepatide and liraglutide on the basis that it “did not identify a clinical need” FDA, policies for compounders as GLP-1 supply stabilises; FDA proposes excluding semaglutide, tirzepatide and liraglutide from the 503B bulks list.
Salt forms and newer molecules
FDA states semaglutide sodium and semaglutide acetate are different active ingredients with no lawful basis for use in compounding, and that retatrutide and cagrilintide cannot be used in compounding under federal law at all FDA, concerns with unapproved GLP-1 drugs used for weight loss.
Counterfeits inside the legitimate supply chain
FDA has warned three times about counterfeit Ozempic reaching the US drug supply chain, naming specific lots. In one case the needles were confirmed counterfeit and sterility could not be verified FDA counterfeit Ozempic consumer warning.
What this section will and will not ever do.
What you get
- Mechanism in plain language, with the honest caveat where mechanism is unproven in humans
- The best human evidence that exists, described at its real size — including when that is a 13-person trial or a conference abstract
- Current FDA status, dated, linked to the primary document
- Known safety signals and boxed warnings, quoted rather than summarised away
- Anti-doping status, so competitive athletes are not blindsided
- Better questions to bring to your own prescriber
What you will never get
- Doses, units, routes, cycles, titration schedules or reconstitution instructions
- Sources, suppliers, vendors, pharmacies, affiliate links or product recommendations
- Stacking or combination guidance of any kind
- Interpretation of your labs, symptoms or results, or advice on whether a compound suits you
- A claim that any compound will produce a specific outcome for you
- Sale, dispensing or referral for any compound named here
This section is elective, and it stays that way.
No RYLOME track routes you here. It exists because adults ask the question anyway, and the alternative is a vendor answering it for them.