MOTS-c and SS-31: Sport Rules and US Legal Status

Who Sets the Rules for MOTS-c and SS-31

Two separate sets of rules apply to mitochondrial peptides, and they answer different questions. Anti-doping rules decide whether a tested athlete can be sanctioned. WADA writes the main list, and sports leagues and the NCAA adopt or adapt it. Drug law, enforced in the US by the FDA, decides whether a product can be sold for human use. A compound can be clearly banned under one and sit in a gray zone under the other.

An earlier version of this page said WADA bans MOTS-c and SS-31 "under catch-all categories" for non-approved substances. That was wrong for both. As of October 2026, MOTS-c is named on WADA's list in its own right. SS-31 (elamipretide) has been an FDA-approved prescription medicine since September 2025, which takes it outside the catch-all as written.

The sections below go through each row. How WADA's testing and sanctions work in practice is covered on our page about MOTS-c and SS-31 in tested sport.

WADA and USADA

WADA's 2026 Prohibited List has been in force since January 1, 2026. It names MOTS-c in full ("mitochondrial open reading frame of the 12S rRNA-c") under S4.4.1, activators of AMP-activated protein kinase (AMPK), next to AICAR and BAM15. Substances in S4.4 are non-Specified and prohibited in and out of competition. USADA, which tests US Olympic and Paralympic athletes, reads the list the same way. Its explainer, updated in August 2026, says MOTS-c is "prohibited at all times" and that a therapeutic use exemption is "highly unlikely" because the peptide has no approved medical use.

SS-31 is the harder case, because it isn't named anywhere on the 2026 list. It used to fall under S0, which covers any pharmacological substance not addressed elsewhere on the list "and with no current approval by any governmental regulatory health authority for human therapeutic use." On September 19, 2025, the FDA granted accelerated approval to Forzinity (elamipretide), so the drug now has a current approval and no longer meets that condition. Whether WADA would place it in another class, such as the S4.4 metabolic modulators, is unverified as of October 2026. We found no WADA or USADA statement on it since the approval. For a tested athlete, that is a question to put to their anti-doping organization in writing, not a sign that SS-31 is allowed.

USADA's advisory on the 2027 List, which takes effect January 1, 2027, adds a warning that covers both peptides. The S0 examples now include "peptides" in general, and USADA cautions that a peptide can be prohibited even if it isn't named on the list or on Global DRO, its substance lookup.

For comparison, here is where the 2026 list puts the peptides most often sold alongside MOTS-c and SS-31. All are prohibited at all times.

• BPC-157: S0, named
• TB-500 and thymosin beta-4: S2.3, growth factors
• AOD-9604 and other growth hormone fragments: S2.2.3
• GHRH analogues (CJC-1295, sermorelin, tesamorelin) and GH secretagogues (ipamorelin, MK-677, the GHRPs): S2.2.4
• IGF-1 and its analogues: S2.3

The NCAA and Professional Leagues

Leagues outside the Olympic system write their own lists. None of the ones we could open names either mitochondrial peptide.

NCAA. The NCAA bans drugs by class and says its classes align with WADA's except for glucocorticoids and cannabinoids. BPC-157 and TB-500 appear among its peptide hormone examples, and it bans hormone and metabolic modulators as a class. MOTS-c isn't among the examples. The NCAA also states that any substance "chemically/pharmacologically related" to a banned class is banned too, and that there is no complete list. On our reading, an AMPK activator like MOTS-c would fall inside the metabolic modulator class. SS-31 is less clear. The NCAA has a medical exception process for athletes with a documented condition that needs a banned drug.

NFL. The league's 2026 Policy on Performance-Enhancing Substances names BPC-157 under protein and peptide hormones, along with the GH-releasing peptides and secretagogues. MOTS-c isn't named. The policy's gene-doping section prohibits "PPARδ-AMP-activated protein kinase (AMPK) axis agonists (e.g. AICAR)," the same pathway WADA cites for MOTS-c. Whether the league would apply that line to MOTS-c is our inference, not a stated rule.

MLB. The 2022 Joint Drug Prevention and Treatment Program, the most recent major-league text we could open, names TB-500 and AOD-9604 among its peptides and lists metabolic modulators including AICAR. It also treats peptide hormones that can't lawfully be obtained in the US as banned even when they aren't listed. Neither MOTS-c nor SS-31 is named.

US Legal Status

MOTS-c isn't approved by the FDA for any use. USADA's August 2026 explainer adds that it isn't approved for use in compounded medications either. What's sold online is labeled "for research use only."

SS-31 comes in two forms that the law treats differently. Forzinity is a prescription medicine, approved for patients with Barth syndrome, a rare inherited mitochondrial disease, who weigh at least 30 kg. It's given by subcutaneous injection once daily, and FDA has required a confirmatory randomized trial as a condition of the accelerated approval. A prescription for Forzinity is the only lawful US route to elamipretide. Vials sold online as "SS-31" are not that product. In an August 24, 2026 warning letter to the seller Tex Peptides, one of several FDA sent to online peptide sellers in 2026, the agency listed "SS-31 (Elamipretide)" among products it called unapproved new drugs.

The research-use-only label. The same letter takes on the label directly. Despite statements such as "research use only" and "not for human or veterinary use," FDA wrote, evidence on the website showed the products were intended as drugs for human use. It counted the sale of bacteriostatic water for reconstituting the peptides as part of that evidence. As of October 2026, these actions have targeted sellers. For a buyer, the label means no regulator has checked what's in the vial. US law for athletes, including compounding rules, is covered in more depth in our page on legal and ethical considerations for athletes.

Outside the US

Health Canada's April 9, 2026 advisory lists MOTS-c and SS-31 among unauthorized injectable peptide drugs it has seized, and tells consumers not to buy or use them. Drugs authorized for sale in Canada carry an 8-digit Drug Identification Number on the label. We didn't check how other regulators, such as the UK's MHRA or Australia's TGA, treat these two peptides specifically.

Tested vs. Untested Athletes

For an athlete tested under WADA rules or a league policy, the anti-doping question comes first. MOTS-c is named on WADA's list as a non-Specified substance, the class with the heavier default sanctions. On our reading, the NCAA and league wording on metabolic modulators and AMPK agonists points the same way, even though none names it. SS-31 adds uncertainty rather than safety: until an anti-doping body says otherwise, an athlete has no ruling to rely on. Someone with Barth syndrome who is prescribed Forzinity is in a different position, and the exemption route for that case is covered on our tested-sport page linked above.

For lifters in untested federations, or who don't compete at all, sanctions drop out of the picture. What's left is drug law, which as of October 2026 has been enforced against sellers, and the product itself. The seller's own certificate of analysis is usually the only quality evidence a buyer sees. Our page on peptide synthesis and purity testing explains what those certificates can and can't show. Federations that do test set their own banned lists, so for those competitors the federation's rulebook is the one to check.

What We Still Don't Know

• How WADA classifies elamipretide now that it's an approved drug, and whether Global DRO lists it.
• Whether the NCAA and the pro leagues would treat MOTS-c as a banned metabolic modulator in a contested case, since none names it.
• How leagues we didn't check, such as the NBA and NHL, handle either peptide.
• Whether the broader S0 wording in the 2027 List changes how anti-doping bodies treat approved peptides in practice.