What the FDA's Own Scientists Wrote About MOTS-c, Semax, Epitalon and DSIP (July 2026)
We read all four FDA briefing documents from the July 2026 compounding meeting: no human studies for MOTS-c, two weak ones for Semax, a cancer question for Epitalon.
Important notice: This article summarises regulatory documents for scientific information only. MOTS-c, Semax, Epitalon and emideltide (DSIP) are research compounds, not intended for human consumption, and none holds a marketing authorisation in the EU or the United States. FDA's own briefing document records Semax as a registered drug in Russia, sold as 0.1% and 1% nasal drops, which is not an EU or a US approval. Nothing here is a dosing recommendation, a protocol, a safety assurance or legal advice. The process described is a United States compounding procedure and changes nothing about European classification.
TL;DR: the documents nobody read
What happened: On 23 and 24 July 2026 the FDA's Pharmacy Compounding Advisory Committee reviewed seven peptides. The headlines covered BPC-157, KPV and TB-500. Four others were on the same agenda: MOTS-c, Semax, Epitalon and emideltide, better known as DSIP. What we did: We downloaded and read all four FDA briefing documents, 260 pages in total, plus the agenda and the three documents from the first day. What they say: FDA staff proposed not adding any of the seven to the compounding list. For MOTS-c they found no human studies at all. For Semax the only two usable human references showed lack of effectiveness. For Epitalon they raised a mechanistic cancer question. For DSIP they found a human record going back to 1981 in which the trials contradict each other. The twist nobody reported: every one of the eleven nominations behind these seven substances had been withdrawn by the people who filed them. FDA carried on evaluating them anyway, on its own initiative. A recommendation is not an approval. In FDA's own words, advisory committees "make non-binding recommendations to the FDA, which generally follows the recommendations but is not legally bound to do so".
Why these four are worth more attention than the three that made the news
The reporting from that meeting followed the vote. BPC-157, KPV and TB-500 each cleared the committee 8 to 6 with one abstention, against the recommendation of FDA's own reviewers, and that conflict was the story.
But the same meeting produced something more useful than a vote tally: four detailed technical assessments of compounds that are sold worldwide as research peptides and about which almost nobody publishes an honest evidence summary. FDA's reviewers worked through the references the nominators submitted, except those published only in Russian or that could not be located, went looking for more, and wrote down exactly what they found and what they did not. That is a rarer document than it sounds.
We sell all four of these compounds. We think the FDA assessments are worth reading precisely because they are unflattering.
The detail that changes how you read all of it
Buried in footnote 1 of each document is a sentence that did not make a single headline. The nominations were withdrawn.
"These nominations were withdrawn, but because FDA is evaluating epitalon (free base) and epitalon acetate on its own initiative, FDA considered information submitted in these nominations as part of this evaluation."
The same construction appears in all seven documents. Eleven nominations, filed by Wells Pharmacy Network and by LDT Health Solutions on behalf of the International Peptide Society, were pulled by the nominators. FDA decided to evaluate the substances regardless, using the withdrawn packages as source material.
How FDA judges a bulk substance
Under 21 CFR 216.23(c), FDA weighs four factors for the Section 503A bulk drug substances list: the physical and chemical characterisation of the substance, any evidence of historical use in compounding, evidence of effectiveness, and safety. A substance can fail on any one of them. In these four documents, most of them failed on three or four at once, and the first factor, characterisation, failed more often than you might expect: for several substances FDA could not establish from the paperwork whether the free base or the acetate salt was even the thing being nominated.
MOTS-c: no human data of any kind
MOTS-c is a 16 amino acid peptide encoded in mitochondrial DNA, molecular weight 2174.6 g/mol for the free base. It was nominated for insulin resistance, obesity, osteoporosis, vascular calcification, muscle and fat metabolism, and longevity, as 5 mg and 10 mg subcutaneous injections.
Here is FDA's summary of the human evidence:
"We performed our own search of published medical literature and did not identify clinical studies evaluating administration of MOTS-c-related BDSs in human subjects."
That is not a criticism of study quality. It is the absence of studies. The document then works through each safety category in turn, and each one comes back empty: no in-vivo pharmacokinetic or toxicokinetic studies, no acute toxicity studies, no repeat-dose toxicity, no genotoxicity, no developmental or reproductive toxicity, no carcinogenicity. The Adverse Event Reporting System was searched twice, through February 2024 and again through March 2025. "The searches retrieved no reports."
The entire evidence base FDA could find is in vitro work plus rodent studies in mice, rats and rat bone marrow stem cells. The one pharmacokinetic-adjacent finding is an in vitro study in which MOTS-c incubated in human whole blood was rapidly cut apart by proteases into shorter fragments.
Two more things the MOTS-c document establishes
Nobody has been compounding it. "According to outsourcing facility (OF) reports submitted to FDA, OFs have not reported preparing single or multiple-API compounded drug products containing MOTS-c (free base) or MOTS-c acetate from January 2017 to December 2025." Nine years, zero reports. It is banned in sport. MOTS-c "appears as a prohibited substance in the Global Drug Reference Online (Global DRO) Database, which obtains information from the 2024 WADA (World-Anti-Doping Agency) Prohibited List of Hormone and Metabolic Modulators." It is not alone, although for that you have to read the other two documents: the BPC-157 briefing records BPC-157 on the WADA prohibited list under non-approved substances, and the TB-500 briefing records TB-500 under section S2.3.
FDA staff concluded: "Accordingly, we propose not adding MOTS-c (free base) or MOTS-c acetate to the 503A Bulks List."
The committee disagreed. On the afternoon of 23 July it voted 7 in favour, 5 against, with 2 abstentions: the weakest support of that day's four substances, with the fewest votes in favour and the most abstentions, though the margin was the same two votes as the other three.
Mitochondrial-derived signaling peptide (16 amino acids) that mimics the effects of exercise at the cellular level. Activates AMPK, improves glucose uptake, and enhances fat metabolism - a key tool in metabolic and longevity research.
Semax: two usable human references, both negative
Semax is a heptapeptide analogue of the ACTH 4-10 fragment, nominated for cerebral ischemia, migraine and trigeminal neuralgia. FDA's verdict on the effectiveness evidence is one sentence:
"Only two available references were available with insufficient details on the design and conduct of the studies, and the available references demonstrated lack of effectiveness and were limited by small sample size and lack of information about some relevant clinical endpoints."
What those two references contain, in FDA's reading: a 2002 meeting abstract in chronic ischemic brain disease with an unstated number of subjects, and a 1996 report covering 12 migraine subjects and 25 subjects with facial pain. In the migraine group, 4 of 12 reported that headache pain stopped 90 to 120 minutes after a single intranasal dose. In the 16 subjects with typical trigeminal neuralgia there were, in FDA's words, no changes in pain characteristics, sensation, pain thresholds or evoked potentials at all.
Nobody has ever injected it in a study
The nominations propose semax as an intranasal spray or a subcutaneous injection. FDA looked for human data by the injected route and found none: "We were unable to find literature that discussed administration via subcutaneous injection ROA. The only ROA discussed in the literature was intranasal." Nor is there human pharmacokinetic data by any route. In total, FDA counted human exposure across the literature at 33 to 47 healthy adults, 69 adults with medical conditions, and 451 children, all intranasal.
The safety section contains two signals worth knowing about, both from rodents rather than people. Rat studies found that intranasal Semax raises anticoagulant and fibrinolytic activity, which led FDA to write that this "raises concern about the risk of bleeding, particularly in certain populations at risk for bleeding or if combined with other medications that increase bleeding risk". Separately, in mice, Semax potentiated amphetamine-induced dopamine release in the striatum, which FDA calls "concerning" because that is the kind of response typically produced by drugs of abuse. No dedicated abuse-potential studies exist.
The Adverse Event Reporting System held exactly one Semax report, a consumer report describing ocular pain and burning after nasal drops bought online, with hospitalisation and the eye pain unresolved a year later.
FDA staff proposed not adding either form, citing poor characterisation on top of the missing evidence. For the free base there was no certificate of analysis in the nominations at all.
Brain-boosting nootropic peptide derived from ACTH. Increases BDNF (brain-derived neurotrophic factor), enhances focus, memory, and mental clarity. Widely used in Russian clinical practice for cognitive enhancement.
Epitalon: the telomerase question, turned around
Epitalon is a four amino acid peptide, Ala-Glu-Asp-Gly, nominated for insomnia as a subcutaneous injection. On effectiveness, FDA found two human references. One is a literature review of pineal gland ageing, not a trial. The other, from 2021, randomised 40 women aged 40 to 50 with low melatonin metabolite levels into placebo or peptide, 0.5 mg per day as a sublingual spray for 20 days. The metabolite rose 1.7-fold in the treated group.
Neither study measured sleep. Neither used the proposed injection route. FDA's wider literature search turned up three studies in which epitalon was given to humans at all: the two sublingual ones in night-shift workers, and one parabulbar injection study in congenital retinitis pigmentosa.
"Our search of published medical literature did not retrieve publications discussing efficacy of epitalon-related BDSs administered in patients with insomnia, or clinical studies reporting use of these substances via the proposed SC ROA."
The Adverse Event Reporting System returned no reports. The food and supplement complaint system returned no cases. There is no human pharmacokinetic data at all.
The mechanism cuts both ways
Epitalon is marketed on the strength of telomerase activation. FDA takes that claim seriously enough to turn it into a safety question: "This is concerning because, from the mechanistic standpoint, epitalon has the potential to be carcinogenic. Specifically, epitalon has been shown to activate telomerase and lengthen telomeres, and longer telomeres are generally associated with increased risk for cancer." The mouse carcinogenicity studies FDA reviewed actually reported fewer tumours, but they came from a single research group, used female mice only, a fixed dose, and intermittent dosing that exposed the animals for at most about 5.5 months against a standard two-year design. The honest summary is that the question is open in both directions, not that it has been answered reassuringly.
One historical detail the document records: Epitalon received an FDA orphan drug designation for retinitis pigmentosa on 2 September 2010, and that designation was withdrawn or revoked on 6 January 2016. A designation is not an approval, and retinitis pigmentosa is not the insomnia use under review here.
FDA staff proposed not adding either Epitalon form.
Tetrapeptide (Ala-Glu-Asp-Gly) that activates telomerase, the enzyme responsible for maintaining telomere length. One of the most studied peptides in longevity research, developed by Prof. Khavinson at the St. Petersburg Institute of Bioregulation.
DSIP (emideltide): the deepest human record, and the most contradictory
Of these four, emideltide has by far the longest human history. FDA reviewed six studies in chronic insomnia running from 1981 onward, plus one narcolepsy case and two opioid-withdrawal studies. Every single human study used intravenous administration. The nomination proposes subcutaneous injection.
The insomnia results do not converge. In FDA's account: a 1981 crossover in six subjects found a sleep-promoting effect from the second hour onward; a 1987 study in 14 subjects reported sleep-onset latency falling from 58.4 to 27.6 minutes, but had no placebo arm and used an external control group; a 1992 double-blind placebo-controlled study in 16 subjects found "no significant difference in objective sleep measures or subjective sleep quality between emideltide group and placebo group"; and a 1987 crossover in six subjects with severe chronic insomnia found no significant differences against baseline or placebo, with the authors themselves concluding the effects were of little clinical significance.
FDA's summary:
"There is insufficient evidence to make a conclusion on the effectiveness of IV emideltide for chronic insomnia. Although some studies showed that short-term IV emideltide appeared to exert an effect on disturbed sleep, the results appear inconclusive and at best preliminary."
The narcolepsy evidence is a single patient. The opioid withdrawal evidence is two uncontrolled open-label studies, in the larger of which 40 of 60 opioid subjects were assessed and reported as improved, while the authors of the smaller one wrote that nothing allows any conclusion about a maintenance treatment.
Two safety points from the DSIP document
A theoretical addiction question. Emideltide does not bind opioid receptors directly. It appears to work by facilitating the release of the body's own enkephalins, and naloxone blocks both its sleep effect and its analgesia in animals. FDA reasons from there: "by stimulating endorphin release in reward brain regions, emideltide-related BDSs could have reinforcing properties that could, in turn, contribute to the development of addiction." No abuse-potential studies exist. This is inference from animal data, not a human finding. The mouse tumour result is not what it looks like. The longevity and anti-tumour mouse data everyone cites used Deltaran, which is a lyophilised mixture of emideltide and glycine at a ratio of 1 to 10 by weight. Glycine is ten times the bulk of the product and has its own documented antimutagenic and anti-tumorigenic properties, which is exactly why FDA writes that it is unclear whether the reduced tumour incidence was due to emideltide at all.
FDA staff proposed not adding either emideltide form, adding a practical formulation objection: the free base dissolves in water at only 0.5 mg/mL, while the proposed product is 1,000 micrograms per millilitre.
DSIP (Delta Sleep-Inducing Peptide), a nonapeptide isolated in 1977. Research material for sleep, HPA-axis, and stress regulation. Research-grade lyophilized powder, laboratory use only.
The most transferable point in all 260 pages
Running underneath the four assessments is a problem that has nothing to do with efficacy: FDA repeatedly could not establish what the submitted substance actually was. The agenda gave a dedicated session on conflated bulk substances and common name challenges on both mornings. In the Epitalon document, FDA notes that the certificate of analysis submitted with each nomination "refers to one BDS by name in the title and a different BDS by the molecular weight/formula". For Semax there was no certificate of analysis for the free base at all.
That is the identity problem, and it is the same problem a researcher faces with any vial from any source. It is not solved by a purity percentage, because purity is a ratio that tells you how homogeneous the contents are, not what the contents are. Identity is a separate measurement, normally mass spectrometry, and a batch report that does not include it has not answered the question.
What this means for a research buyer in the EU
Nothing in these documents changes European classification, and nothing in them makes any of these four compounds an approved medicine in the EU or the United States. What they do provide is an unusually honest map of where the evidence stops for each one. If you work with these peptides, the useful takeaway is not the vote: it is that FDA, with full access to the nominators' own submissions, could not find human safety data for MOTS-c or Epitalon, could not find any injected human data for Semax or DSIP, and could not always establish substance identity from the paperwork. Our own supplier batch reports, from a third-party laboratory, are published per batch on our CoA page, and our guide to vetting a supplier explains what those reports do and do not certify.
What actually happened at the vote, and what did not
Day one: four substances, all four passed
BPC-157, KPV and TB-500 each passed 8 to 6 with one abstention. MOTS-c passed 7 to 5 with two abstentions. Each substance was voted separately rather than as a bundle, and NPR reports that each one drew two separate votes because two chemical variants were under review for each. That is why the seven could split.
Day two: emideltide, Epitalon and Semax
The three were taken in that order on 24 July, and the committee did not repeat the day-one pattern. Emideltide, for opioid withdrawal, chronic insomnia and narcolepsy, failed 6 in favour to 7 against: the only substance of the seven the committee declined to back. Epitalon, for insomnia, passed 7 to 4. Semax, for cerebral ischemia, migraine and trigeminal neuralgia, passed 8 to 5. Tallies as reported by STAT News on 24 July and corroborated by Fierce Pharma and Drug Topics.
Then: a rulemaking process, or nothing
A committee recommendation is advice. FDA still has to decide whether to open formal rulemaking, and it has published no timeline. One trade estimate puts a realistic rulemaking cycle at eight to twelve months; that is a journalist's estimate, not an agency commitment.
Why the committee's opinion diverged from its own agency's
This is worth stating plainly because it explains the whole meeting. In June 2026 the committee was expanded. According to NBC News, eight members had been recently appointed under Health Secretary Robert F. Kennedy Jr., including six who run clinics that offer peptides, and all eight of those new appointees voted yes on BPC-157, KPV and TB-500. The public docket on the question drew roughly 1,860 comments, with compounding pharmacies and peptide-medicine bodies in favour and PhRMA, the Partnership for Safe Medicines and the American Pharmacists Association opposed. A vote is a vote. It is not new evidence, and no new study appeared between the briefing documents and the show of hands.
The four compounds in our catalogue
Mitochondrial function, NAD+ metabolism, telomere maintenance
The four reviewed here
Mitochondrial-derived signaling peptide (16 amino acids) that mimics the effects of exercise at the cellular level. Activates AMPK, improves glucose uptake, and enhances fat metabolism - a key tool in metabolic and longevity research.
Brain-boosting nootropic peptide derived from ACTH. Increases BDNF (brain-derived neurotrophic factor), enhances focus, memory, and mental clarity. Widely used in Russian clinical practice for cognitive enhancement.
Tetrapeptide (Ala-Glu-Asp-Gly) that activates telomerase, the enzyme responsible for maintaining telomere length. One of the most studied peptides in longevity research, developed by Prof. Khavinson at the St. Petersburg Institute of Bioregulation.
DSIP (Delta Sleep-Inducing Peptide), a nonapeptide isolated in 1977. Research material for sleep, HPA-axis, and stress regulation. Research-grade lyophilized powder, laboratory use only.
The three from day one
Gastric pentadecapeptide (15 amino acids) known for exceptional tissue repair properties. Promotes wound healing, angiogenesis, and cytoprotection across tendons, muscles, gut, and nerves. Over 30 years of preclinical research.
Full-length 43-amino-acid Thymosin Beta-4, a naturally occurring repair protein, independently confirmed by a third-party CoA from Janoshik. Promotes cell migration and new blood vessel formation for systemic tissue healing. Especially researched for muscle, tendon, and cardiac repair.
Anti-inflammatory tripeptide derived from alpha-MSH (positions 11-13). Inhibits NF-kB signaling, supports gut barrier integrity, and shows antimicrobial activity. A targeted approach to inflammation research without broad immunosuppression.
FAQ
Sources
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FDA. "Briefing Document for MOTS-c-Related Bulk Drug Substances." Pharmacy Compounding Advisory Committee meeting, 23 and 24 July 2026, 44 pages. https://www.fda.gov/media/193347/download
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FDA. "Briefing Document for Semax-Related Bulk Drug Substances." Same meeting, 69 pages. https://www.fda.gov/media/193348/download
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FDA. "Briefing Document for Epitalon-Related Bulk Drug Substances." Same meeting, 64 pages. https://www.fda.gov/media/193345/download
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FDA. "Briefing Document for Emideltide-Related Bulk Drug Substances." Same meeting, 83 pages. https://www.fda.gov/media/193344/download
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FDA. Meeting page and final agenda, Pharmacy Compounding Advisory Committee, 23 and 24 July 2026, including the docket FDA-2025-N-6895 and the statement on non-binding recommendations. https://www.fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-compounding-advisory-committee-07232026
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Lovelace B Jr. "FDA panel recommends easing some peptide restrictions despite disapproval from scientists." NBC News, 23 July 2026. https://www.nbcnews.com/health/health-news/peptides-restrictions-ease-fda-panel-recommend-bpc-157-scientists-rcna588879
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Stone W. "FDA advisers vote to ease peptide restrictions, despite agency concerns." NPR, 23 July 2026. https://www.npr.org/2026/07/23/nx-s1-5903202/fda-peptides-restrictions
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Eglovitch JS. "FDA advisory committee backs two controversial peptides." Regulatory Focus (RAPS), 23 July 2026. https://www.raps.org/resource/fda-advisory-committee-backs-two-controversial-peptides.html
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Lawrence L, Todd S. "FDA advisory panel narrowly rejects compounding of one peptide, backs two others." STAT News, 24 July 2026. Day-two tallies for emideltide, Epitalon and Semax. https://www.statnews.com/2026/07/24/fda-peptide-compounding-panel-backs-epitalon-rejects-emideltide/
Research disclaimer: All content serves scientific information only. The compounds discussed are not intended for human consumption and are not approved as medicines in the EU or the United States. FDA records semax as a registered drug in Russia, which is not an EU or a US approval. Study details reported here are FDA's own characterisation of the underlying papers as set out in its briefing documents.
Research context for English-speaking buyers
Most of our English-speaking customers ship to the UK, Ireland, Malta or other English-as-second-language EU territories. The regulatory picture differs per country.
- Relevant authorities
- MHRA (UK, post-Brexit), HPRA (Ireland, EU-aligned), FDA Section 503A bulks list (US, restricted Cat 2 status of several peptides as of 2026)
- Customs and VAT
- EU shipments include 19% VAT; UK shipments after Brexit are now extra-EU and may attract UK VAT plus a handling fee at import
- Typical shipping window
- EU 2-4 working days, UK 4-7 working days, other international 7-14 working days, depending on customs
Research-grade peptides shipped from our EU warehouse are sold for laboratory use only and are not authorised for human or veterinary therapeutic application in any of the destination jurisdictions. US customers should be aware that the FDA Section 503A bulks list classification (and the April 2026 reclassification of twelve compounds) only governs compounding pharmacies, not direct-to-researcher imports for non-clinical work. UK buyers should declare the consignment on import and may be asked for a research justification by HMRC. We provide a CoA per batch identified by colour code rather than serial number; customs sometimes asks for this document when clearing the parcel.