MOTS-C, DSIP, Epitalon & Semax: PCAC Docket Research Summary
Mini-profiles of the four less-covered compounds in the July 2026 FDA PCAC 503A docket — MOTS-c, DSIP, Epitalon, and Semax — covering mechanism, preclinical evidence, and what the hearing means for each.
Research reference only. The information in this article is a summary of peer-reviewed scientific literature. It does not constitute medical advice and is not intended to guide human use. See our full disclaimer.
title: "MOTS-C, DSIP, Epitalon & Semax: PCAC Docket Research Summary" description: "Mini-profiles of the four less-covered compounds in the July 2026 FDA PCAC 503A docket — MOTS-c, DSIP, Epitalon, and Semax — covering mechanism, preclinical evidence, and what the hearing means for each." date: "2026-06-13" category: "Regulatory & Policy" tags: ["MOTS-c", "DSIP", "Epitalon", "Semax", "PCAC", "503A", "FDA", "compounding", "mitochondria", "neuropeptide", "telomere", "longevity"] slug: "mots-c-dsip-epitalon-semax-pcac-docket-summary" heroImage: "/blog-images/fda-pcac-july-2026-full-docket-guide.png" readingTime: 8 author: "ClinicalPeptide Research Team"
The FDA Pharmacy Compounding Advisory Committee (PCAC) convenes July 23–24, 2026 to re-evaluate the 503A bulk drug substance status of seven peptide compounds. BPC-157 and TB-500 have received the most media coverage, but four compounds on the same docket — MOTS-c, DSIP, Epitalon, and Semax — are equally significant for the research community that relies on the 503A channel.
This article provides a single-page research reference for all four: mechanism of action, the core preclinical evidence, current 503A status, and what the PCAC is specifically evaluating. For the full compound-by-compound breakdown of all seven peptides, see the complete PCAC docket guide.
Research reference only. Content summarizes peer-reviewed preclinical literature and regulatory documentation. Not medical or legal advice.
MOTS-c: The Mitochondria-Derived Metabolic Peptide
Current 503A status: Under Review
MOTS-c (Mitochondrial Open Reading Frame of the 12S rRNA-c) is a 16-amino-acid peptide encoded within the mitochondrial genome — the only known peptide hormone produced directly from mitochondrial DNA. It was characterized in research published by Lee et al. (2015, Cell Metabolism) as a regulator of cellular metabolism acting through AMPK (AMP-activated protein kinase) signaling.
What preclinical research has studied
Rodent studies have examined MOTS-c across metabolic and aging contexts. In mouse models, exogenous MOTS-c administration has been reported to improve insulin sensitivity, reduce diet-induced obesity, and increase exercise capacity. A subset of studies has investigated its role in healthspan and longevity through mitochondrial regulation of NAD+ metabolism. Because MOTS-c is endogenously produced and its circulating levels decline with age, researchers have explored whether exogenous supplementation can restore youthful metabolic function in aged animal models.
The NAD+ and MOTS-c mitochondrial research overview covers the specific mechanistic connections in greater detail.
What the PCAC is evaluating
MOTS-c presents the committee with an unusual circumstance: it is an endogenously synthesized peptide with no FDA-approved equivalent, documented metabolic activity in preclinical models, and an emerging body of mechanistic research. The compounding case rests on unmet metabolic-disease need and the absence of any commercial alternative. The committee will assess whether the preclinical evidence base supports positive listing.
DSIP: The Delta Sleep-Inducing Peptide
Current 503A status: Under Review
DSIP (Delta Sleep-Inducing Peptide) is a nonapeptide (9 amino acids: Trp-Ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu) first isolated in 1974 from rabbit cerebral perfusate. Its molecular formula is C₃₅H₄₈N₁₀O₁₅ (MW 848.8 g/mol, CAS 62568-57-4). The name reflects the circumstances of its isolation: administration to rabbits produced characteristic slow-wave (delta) sleep in EEG recordings.
What preclinical research has studied
Early research documented DSIP's ability to influence sleep architecture and circadian rhythm in animal models, as well as its apparent modulation of the hypothalamic-pituitary axis — specifically, influences on cortisol and LH secretion patterns. Subsequent studies have examined neuroendocrine stress-attenuation effects and antioxidant activity in rodent models. The preclinical profile is heterogeneous: DSIP appears to have multiple biological actions beyond sleep modulation, though the mechanistic clarity of each is variable.
The human clinical evidence for DSIP is limited. Small trials have examined its effects on sleep and stress parameters, but no large randomized controlled trials exist. This evidentiary gap is the central issue at the PCAC hearing.
What the PCAC is evaluating
DSIP's historical use in compounding for sleep and neuroendocrine indications constitutes the clinical-need argument. The committee will evaluate whether the documented preclinical and limited human evidence supports positive 503A listing, and whether the absence of an approved equivalent justifies continued compounding access.
Epitalon: The Telomere and Pineal Research Peptide
Current 503A status: Under Review
Epitalon (also Epithalon or Epithalamin) is a synthetic tetrapeptide (Ala-Glu-Asp-Gly, 4 amino acids) developed from research by Vladimir Khavinson at the St. Petersburg Institute of Bioregulation and Gerontology. It is designed to replicate the proposed bioactive core of epithalamin, a natural pineal polypeptide extract studied in Russian longevity research since the 1980s.
What preclinical research has studied
The most cited preclinical finding for Epitalon is its proposed role in telomerase activation. Studies published by the Khavinson group report that Epitalon administration induced telomerase activity in human cell lines and extended replicative lifespan of cultured cells. A 2025 correction to a published paper (PMID 41240216) addressed earlier Epitalon telomere-length research, reflecting the ongoing scientific scrutiny of this work.
Animal longevity studies in rodents and Drosophila models have reported extended lifespan and reduced tumor incidence in Epitalon-treated groups. Neuroendocrine studies have examined its effects on melatonin secretion from pineal tissue, with some rodent studies reporting restoration of age-related decline in nocturnal melatonin output. Immunological studies have looked at thymic function restoration in aged animals.
An important caveat: the majority of Epitalon research originates from a single research group in Russia. Independent replication in Western academic institutions is limited, which affects the evidentiary weight the PCAC is likely to assign.
What the PCAC is evaluating
Epitalon has regulatory approval in Russia but not in the US. The committee will examine whether the available evidence — primarily from one research group, largely in animal models — meets the threshold for 503A positive listing. The longevity and telomere rationale faces the challenge that its primary evidence source has limited independent replication. However, there is no approved US equivalent, and the compounding nomination rests on the clinical demand from anti-aging and longevity research contexts.
Semax: The Neuropeptide With Partial Regulatory Precedent
Current 503A status: 503A Withdrawn
Semax occupies a distinct regulatory position among the July 2026 docket compounds: its 503A status is listed as Withdrawn, meaning a prior PCAC or FDA action has removed it from favorable 503A consideration. This makes the July 2026 review specifically a re-evaluation — the committee is assessing whether grounds exist to restore or otherwise revise its withdrawn status.
Semax is a synthetic heptapeptide (Met-Glu-His-Phe-Pro-Gly-Pro) derived from the ACTH 4-10 sequence. It has regulatory approval in Russia and Ukraine for neurological indications including stroke recovery and cognitive impairment, though it has not received FDA approval or IND designation in the United States.
What preclinical research has studied
The Russian clinical and preclinical literature documents Semax's effects on BDNF (brain-derived neurotrophic factor) expression and neuroprotection in ischemia models. In rodent stroke models, Semax administration has been reported to reduce infarct volume and promote functional recovery. Its ACTH-derived structure provides mechanistic plausibility for neuroendocrine and cognitive effects, and animal studies have examined attention, memory, and neuroprotective endpoints.
The Selank vs. Semax comparison article covers the relative research profiles of the two Russian neuropeptides in detail.
What the PCAC is evaluating
For Semax, the PCAC is deciding whether the existing Russian approval and the available preclinical/clinical literature from Russian regulatory trials constitutes sufficient evidence for restoring 503A access. The "Withdrawn" status creates a higher bar: the committee's prior finding was that Semax did not meet positive-listing criteria, and nominators must present evidence sufficient to reverse that determination.
The PCAC will likely scrutinize: (1) whether Russian regulatory approval constitutes meaningful clinical evidence under FDA evidentiary standards; (2) the quality of available human study data; and (3) whether there is demonstrable clinical need that is unmet by approved alternatives.
Shared Factors Across All Four Compounds
Despite their mechanistic diversity, MOTS-c, DSIP, Epitalon, and Semax share several features relevant to the PCAC evaluation:
No FDA-approved equivalent exists for any of the four. This is the single most favorable factor in the compounding case for all of them. The 503A framework was designed to permit access to compounds that cannot be redirected to a commercial product — and none of these four has one.
All four have primarily preclinical or limited human evidence. This is the shared evidentiary gap. The committee must evaluate whether the research record for each compound meets the positive-listing threshold absent large RCT data.
All four have established compounding use histories. Nominator submissions will document prescribing patterns and clinical-need populations, which supports the "clinical use" criterion in the PCAC's four-factor analysis.
Frequently Asked Questions
What does the PCAC hearing mean for MOTS-c, DSIP, Epitalon, and Semax?
The July 2026 PCAC hearing will determine whether each compound is recommended for positive listing on the 503A Bulks List (Category 1), maintained in an unfavorable holding category, or restricted. For MOTS-c, DSIP, and Epitalon, it is a first formal evaluation. For Semax, it is a re-evaluation of a prior Withdrawn status.
Does preclinical evidence alone qualify a compound for 503A positive listing?
The 503A framework does not require human RCT data for positive listing. It requires documented clinical use, a reasonable basis for expecting safety and effectiveness for the nominated indication, and the absence of a suitable commercially available alternative. Preclinical evidence can support positive listing when combined with compounding use history and clinical-need documentation.
Why is Semax's status listed as "Withdrawn" rather than "Under Review"?
Semax previously underwent PCAC evaluation and the committee's finding resulted in withdrawal from 503A positive listing. The July 2026 review gives nominators the opportunity to present new evidence or arguments to reverse this determination.
Where can I find the full PCAC docket for all seven compounds?
The FDA PCAC July 2026 full docket guide covers all seven compounds — BPC-157, TB-500, KPV, MOTS-c, DSIP, Epitalon, and Semax — in a single reference article.