The short version of this quarter's MOTS-c news: in July, an FDA advisory panel recommended adding MOTS-c to the list of raw ingredients pharmacies may compound from, going against the agency's own reviewers. FDA hasn't turned that advice into a rule. The World Anti-Doping Agency (WADA) kept MOTS-c on its prohibited list for 2027. Every new study this quarter used cells, mice or measurements of the MOTS-c people already make; none gave the peptide to people.

As of September 22, 2026, the day this article was written, no proposed rule on MOTS-c had appeared in the Federal Register, where new federal rules are published, and the one treatment trial of the peptide listed on ClinicalTrials.gov had posted no results.

Changelog

September 22 — FDA still hadn't acted on the July vote. FDA's page on that ingredient list, known as the 503A bulks list still reads "Content current as of: 05/14/2026." The July meeting page, last updated August 6, has briefing documents, slides and webcast links, but no minutes or written vote record.

September 21 — WADA kept MOTS-c on its 2027 list. WADA published its 2027 Prohibited List, which takes effect January 1, 2027. MOTS-c is still named in section S4.4.1 among activators of AMPK, an energy sensor inside cells. That class is prohibited at all times, in and out of competition. WADA added other examples to the section for 2027; the MOTS-c entry didn't change.

August 25 — a review gathered the exercise studies. A systematic review in Physiology International, which gathers every study that meets set criteria, found nine studies, published from 2016 to 2025, on exercise and mitochondrial-derived peptides, the small family MOTS-c belongs to. Most reported a trend toward higher levels after exercise. The authors called the evidence limited, especially in people, and asked for controlled trials.

August 18 — the immune-defense paper reached its final version. Changhan Lee's lab at USC published the final version of work proposing that MOTS-c is a host defense peptide, one of the body's own germ-fighting molecules. In lab tests it attacked bacteria including MRSA (a drug-resistant staph germ), and it neutralized an MRSA infection in mice. That's bacteria, cells and mice, not a treatment trial in people.

July 23 — the advisory committee voted. FDA's Pharmacy Compounding Advisory Committee, a panel of outside experts, considered two forms of MOTS-c for the 503A bulks list: ingredients a pharmacy may compound from when a substance isn't part of an approved drug and has no official quality standard. In a briefing memo dated May 11, FDA staff proposed leaving both off. They found the ingredient poorly characterized, identified no clinical studies or human exposure data by any route, and said the risk of an immune reaction couldn't yet be assessed. The panel recommended adding MOTS-c anyway.

FDA hasn't published minutes, so its webcast recording is the record of the vote. A law firm's summary published July 27 reports the vote as 7 in favor, 5 against and 2 abstaining. The vote is advice, not a rule; the FDA peptide decision covers the whole meeting.

June 25 — a human study measured MOTS-c around a run. Researchers at the Karolinska Institute took blood from 43 people, 13 adults with cerebral palsy, 17 typically developing adults and 13 adolescents, before and an hour after a 45-minute run. Circulating MOTS-c and its relatives showed no or only modest change afterward, and resting levels were similar across groups. Nobody was given MOTS-c. A 2021 study found levels rose with hard cycling intervals, one reason MOTS-c exercise claims are more tangled than they look.

June 22 — a Mayo Clinic cell study found a trade-off. Researchers treated repair cells called mesenchymal stromal cells, taken from the belly fat of six people with obesity and six lean donors. MOTS-c switched on AMPK signaling, but it also slowed the cells' growth and raised markers of cell aging and inflammation. In mice with a narrowed kidney artery, the treated cells didn't help the kidney. It's a lab finding, but a fair check on the idea that switching on an energy pathway is always good.

What the MOTS-c news means now

MOTS-c is a peptide, a short chain of 16 amino acids, whose instructions sit in mitochondrial DNA, the small genome inside the cell's energy-making parts. A USC team reported it in 2015, and the story of who discovered MOTS-c starts there.

It's studied for insulin sensitivity, body weight, exercise and aging, but nearly all the treatment results come from mice and cells, as the MOTS-c benefits evidence table lays out species by species. Human studies so far mostly measure the MOTS-c the body makes.

One trial listed on ClinicalTrials.gov gives it to people. The MOTS-MET study plans to assign 120 adults with prediabetes and overweight or obesity, at random, to a daily injection or a placebo for 12 weeks, with insulin sensitivity as the main outcome. Its record, last updated April 1, lists it as recruiting at one site in Shenzhen, China, with main data collection estimated to finish in February 2027. No results are posted.

The same gap leaves MOTS-c side effects largely unmeasured: FDA's review found no human safety data to count.

Why SS-31 is a different story

People often ask about SS-31 in the same breath, since both peptides are tied to mitochondria. Their regulatory paths differ sharply.

SS-31, also called elamipretide, is dispensed here as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved. An FDA-approved elamipretide product, Forzinity, carries accelerated approval to improve muscle strength in people with Barth syndrome, a rare inherited condition, who weigh at least 30 kg. Accelerated approval means the agency accepted an early measure, here knee-muscle strength, while a confirmatory trial checks the benefit.

That approval doesn't extend to compounded SS-31, and it says nothing about MOTS-c. MOTS-c's review this year asked whether pharmacies may use it as a compounding ingredient, a different question from whether a finished medicine works for a specific use.

MOTS-c and FDA in 2026: where things stand

No MOTS-c product has ever been FDA-approved in the United States. Through Promise, MOTS-c is dispensed as a compounded medication, which is different from an FDA-approved product: the formulation offered here is not FDA-approved.

The July vote doesn't approve MOTS-c, remove it from anything or change a prescription. Advice becomes a rule only through a proposed rule, a public comment period and a final rule. FDA's page for its next compounding advisory meeting, due before the end of February 2027, lists five other substances, not MOTS-c.

A licensed provider may still prescribe a compounded formulation when they judge it appropriate; that decision is between the patient and the doctor.

For athletes who are tested, sport is a separate question: a prescription doesn't change WADA's list.

What a provider considers in September 2026

The first question is what someone hopes MOTS-c will do, and whether any evidence speaks to it. Much of what circulates online is a mouse result retold as a human one.

Then come history and medicines: insulin or a sulfonylurea (an older diabetes pill), because a peptide studied for insulin sensitivity raises an obvious blood-sugar question; pregnancy or breastfeeding, where no studies exist; a cancer history, with no long-term safety data to lean on; past reactions to injections; and whether the person competes in a tested sport.

At Promise, a licensed provider reviews every request and may prescribe or decline; not everyone qualifies. If MOTS-c is prescribed, the provider sets the dose and schedule, and a licensed U.S. compounding pharmacy prepares it.

What to watch next

Four things would change the next edition. A proposed rule in the Federal Register would be FDA's real answer to the committee. Written minutes or a transcript would put the vote on paper. Results from MOTS-MET would be the first controlled data on giving MOTS-c itself to people. And any study that doses people would matter more than another mouse paper.

Until then, the summary is short: advice given, no decision made, and the human evidence waiting on one trial.