Neither peptide sold for mitochondrial health has shown a benefit in a healthy person. SS-31 (elamipretide) is the one with an FDA approval, and that approval is accelerated, limited to the rare inherited disorder Barth syndrome in patients weighing at least 30 kg, and rests on a knee strength measurement from an uncontrolled extension; the label itself states the drug was not superior to placebo on the randomized trial's primary endpoints [[4]]. Tested more broadly, in 218 adults with mitochondrial myopathy at 40 mg a day for 24 weeks, it missed both primary endpoints [[3]]. MOTS-c, the peptide most discussed for healthy optimization, has never completed a human trial; its first one, a Phase 2a in 120 adults with prediabetes and overweight or obesity, began enrolling in February 2026 and will not report before 2027. The human evidence that does exist points at exercise, which raises the MOTS-c your own body makes [[2]].
Peptides commonly discussed for mitochondrial health
Safety: MOTS-c is not approved by the FDA for any human use, and it is not eligible for compounding either: a bulk substance can be used by a compounding pharmacy only if it has a US Pharmacopeia monograph, is a component of an FDA-approved drug, or appears on FDA's 503A bulks list, and MOTS-c is none of the three [[8]]. It is sold labelled for laboratory research use only and not for human consumption, and no completed human study means there is no human safety data of any kind. SS-31 (elamipretide) is approved only as Forzinity for Barth syndrome under accelerated approval; its label warns of hypersensitivity (severe allergic) reactions that can require emergency treatment and can appear minutes to months after starting, serious hypersensitivity to the drug or any ingredient is a contraindication, it contains benzyl alcohol at 20 mg/mL, injection-site reactions were near universal in its pivotal trial, and the dose is reduced below an eGFR of 30 in patients not on dialysis, with insufficient information for patients on dialysis [[4]]. Anyone with an active or recent cancer, and anyone pregnant or breastfeeding, should treat both compounds as off the table pending a clinician's judgment. Persistent fatigue and exercise intolerance deserve a medical workup for thyroid disease, sleep apnea, anemia, inflammation and genuine mitochondrial disease before any research compound enters the conversation. PeptidesDNA publishes education and genetics reports; we are not a licensed healthcare provider, we do not diagnose, prescribe or treat, and we do not sell or supply any compound discussed here. Nothing on this page is medical advice, a diagnosis, or a protocol.
Where to buy
Where to get peptides for mitochondrial health
MOTS-c
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Two peptides are sold for the compartments inside your cells that turn food and oxygen into ATP, the molecule that pays for every muscle contraction and every thought, and the evidence behind each is weaker than the marketing. SS-31 (elamipretide) ran the largest controlled trial of any mitochondrial-targeted peptide, 218 adults with mitochondrial myopathy, and missed both endpoints it set out to move 3. MOTS-c has never completed a trial in a human being.
What declines with age
Muscle mitochondria make less ATP every decade, and the decline is measurable rather than inferred. Short and colleagues took muscle biopsies from 146 healthy adults aged 18 to 89 and measured mitochondrial ATP production directly. Production fell steadily across adulthood, alongside falling mitochondrial DNA abundance and rising oxidative damage to DNA, and the ATP production rate tracked with aerobic capacity and glucose tolerance 5. That is the decline every mitochondrial compound is aimed at, and it is descriptive biology rather than proof that anything reverses it. If you are reading this because you are past 50 and noticing it, peptides after 50 covers the wider picture.
What is MOTS-c peptide used for, and has it been tested in people?
MOTS-c is a 16-amino-acid peptide encoded inside mitochondrial DNA rather than in the nucleus, which makes it one of the few peptides your mitochondria write themselves 2. It is sold and discussed for insulin sensitivity, exercise capacity, fatigue and general metabolic health. Every one of those uses rests on animal work: MOTS-c given to mice three times a week improved physical performance in young, middle-aged and old animals, including when treatment started at 23.5 months of age 2. Both anchor MOTS-c papers carry the same conflict statement, that senior authors Pinchas Cohen and Changhan Lee are consultants and shareholders of CohBar, the company whose MOTS-c analog appears later on this page. That does not make the mouse data wrong, and it does help explain why the compound has more promotion than trials.
The registered trial's design differs from what circulates online. NCT07505745 enrols 120 adults aged 18 to 65 with prediabetes and overweight or obesity (BMI 27.0 to 40.0), gives a fixed dose under the skin once daily for 12 weeks, and has two co-primary endpoints: the Matsuda index from an oral glucose tolerance test (a measure of insulin sensitivity) at week 12, and treatment-emergent adverse events at week 16. The protocol people pass around in forums, roughly 10 mg twice a week on a 12 weeks on and 4 weeks off cycle, matches no trial, no dose-finding study, and not the one registered trial's schedule either. You can read the registry record at ClinicalTrials.gov.
Link · Lee C et al., Cell Metabolism 2015MOTS-c: the 2015 discovery paperThe paper that identified MOTS-c inside the mitochondrial 12S rRNA gene and worked out its route through AMPK, the cell's energy-sensing switch, and the folate cycle. Mouse and cell work throughout; it is the origin of nearly every claim made for the compound today.doi.orgWhat is SS-31 peptide, and what did the FDA approve?
SS-31 is the research name for elamipretide, a four-amino-acid peptide that concentrates in the inner mitochondrial membrane and binds cardiolipin, a fat found almost nowhere else in the cell. It received FDA accelerated approval on 19 September 2025 as Forzinity, for improving muscle strength in Barth syndrome in patients weighing at least 30 kg 4. That is the entire approved use.
FORZINITY was not superior to placebo on these primary endpoints.FDA prescribing information for Forzinity (elamipretide), NDA 215244, Section 14 Clinical Studies
The pivotal Barth syndrome study was a crossover trial in 12 patients, meaning each patient took both drug and placebo in turn. In the randomized portion, six-minute walk distance and fatigue did not separate from placebo. The approval rests on knee extensor strength recorded during the open-label extension, where everyone knew they were taking the drug, and it carries a required confirmatory trial that can withdraw the approval if it fails 4. An accelerated approval on an intermediate endpoint is a bet that the strength number will translate; it is not a finding that patients felt better.
Why SS-31 should work
What the 218-patient trial found
MMPOWER-3 (NCT03323749) randomized 218 adults with genetically confirmed primary mitochondrial myopathy, 109 to elamipretide at 40 mg a day under the skin and 109 to placebo, for 24 weeks. Mean age was 45.6 years and 74% carried a mitochondrial DNA alteration. The difference in six-minute walk distance was -3.2 meters (95% CI -18.7 to 12.3, p = 0.69) from a baseline of about 337 meters, and the fatigue score difference was -0.07 (p = 0.37) 3. In plain terms: the drug group and the placebo group walked the same distance and felt equally tired, and the small gap between them is what you would expect from chance alone. Dropout did not differ in a way that explains the null result, and tolerable is not the same as harmless: in the 12-patient Barth syndrome trial that supported approval, every patient on drug had an injection-site reaction 4.
This study provides Class I evidence that elamipretide does not improve the 6MWT or fatigue at 24 weeks compared with placebo in patients with primary mitochondrial myopathy.Karaa A et al., MMPOWER-3, Neurology 2023
Class I is the strongest evidence grade Neurology assigns, and the trial's registry record is now marked terminated, with the 24-week randomized phase completed and published. A 2024 post hoc analysis in Orphanet Journal of Rare Diseases, meaning a subgroup look taken after the trial ended, reported that participants with nuclear DNA variants did better on the walk test than those with mitochondrial DNA variants. That subgroup was prespecified, and the finding has already produced a designed follow-up Phase 3, NuPOWER, in patients with mtDNA-maintenance disorders. That is where the question gets answered, and it has not been answered yet. If you have a diagnosed mitochondrial disease, this is a conversation with your neurologist, not a reason to buy anything.
The compound with an FDA approval missed both endpoints in the largest controlled test of it. The compound without one has never been tested in a person at all.
The evidence, graded
| What it is | Best human evidence | What was measured | Result | US status |
|---|---|---|---|---|
| SS-31 (elamipretide), a synthetic peptide that binds cardiolipin | Phase 3, 218 adults with primary mitochondrial myopathy, 40 mg/day for 24 weeks 3 | Six-minute walk distance and a fatigue score | Missed both. Walk distance differed by -3.2 m, p = 0.69 3 | Approved only as Forzinity for Barth syndrome, at least 30 kg, accelerated approval with a required confirmatory trial 4 |
| MOTS-c, a 16-amino-acid peptide encoded in mitochondrial DNA 2 | None completed. One Phase 2a in 120 adults with prediabetes and overweight or obesity started enrolling in February 2026 (NCT07505745) | Nothing yet in humans. Mouse work measured running capacity and muscle metabolism 2 | Unknown in people | Not approved for any use, and not eligible for 503A compounding: no USP monograph, not a component of an approved drug, not on the bulks list 8 |
| NAD+ precursors (nicotinamide riboside, NMN), supplements feeding the NAD+ coenzyme | A 6-week crossover trial in healthy middle-aged and older adults (Martens and colleagues, Nature Communications 2018, linked below) | Blood NAD+ concentration | Blood NAD+ rose by roughly 60% at 1,000 mg a day. Muscle ATP production was not the endpoint | Sold as supplements, no efficacy review |
| Exercise training, not a compound | 12 weeks of supervised training in 72 adults randomized to interval, resistance, combined or sedentary control, with muscle biopsies before and after 7 | Skeletal muscle mitochondrial respiration and mitochondrial protein synthesis | Rose in the interval and combined arms; resistance training alone did not move them. The largest gene-expression response was in adults aged 65 to 80 7 | Free, and the only row here with a measured mitochondrial outcome in healthy people |
MOTS-c or SS-31, if you are trying to choose
Exercise is the part of the MOTS-c story with human data in it
Train, and your own muscle makes more MOTS-c. That half of the 2021 Nature Communications paper was done in humans; the half where MOTS-c was injected was done in mice 2. The genetics point the same way. Across three Japanese cohorts totalling 27,527 participants, men carrying the C allele of the MOTS-c K14Q variant (m.1382A>C) had a higher prevalence of type 2 diabetes and women did not. Within one of those cohorts, J-MICC, the excess sat in the least active third of men and was absent in the most active 1. That is a cross-sectional association, not risk measured over time.
Read together, the human epidemiology and the mouse work describe MOTS-c as part of the exercise adaptation signal. Nothing in either dataset supports taking it while sedentary, in any species. The comparator does have direct evidence: 12 weeks of supervised training in 72 adults raised skeletal muscle mitochondrial respiration and mitochondrial protein synthesis in the interval and combined arms, with the strongest transcriptional response in the 65 to 80 group 7. What training does to muscle itself is covered on peptides for muscle growth.
CB4211 is not MOTS-c
The most-cited piece of "human MOTS-c data" is not MOTS-c. CB4211 is a synthetic MOTS-c analog, a different molecule, tested by CohBar in an 88-participant Phase 1a/1b study in healthy adults and adults with fatty liver disease (NCT03998514). The registered endpoints were safety measures. The liver enzyme and glucose figures that circulate in marketing copy were company-reported, never posted to the registry, and never peer reviewed. Nasdaq notified CohBar in November 2023 and the delisting took effect on 8 January 2024; the company merged into Morphogenesis, whose merger materials state the combined company would not continue CohBar's candidates, and the program ended without a Phase 2. Citing it as evidence for MOTS-c gets both the molecule and the endpoint wrong. If a vendor page cites human data for MOTS-c, this is almost always what it is citing, and now you know what it is.
What your DNA can and cannot say here
Mitochondrial genetics is unusual in two ways. Mitochondrial DNA passes down only from your mother, and most variants that shape mitochondrial performance sit in your nuclear DNA anyway. Three variants come up constantly in this conversation, and none of them has ever been tested as a predictor of response to a peptide.
- **SOD2 rs4880 (Ala16Val)** affects manganese superoxide dismutase, the enzyme that clears superoxide inside mitochondria. In an import assay in the laboratory, the Val form of the human enzyme was imported less efficiently into isolated rat liver mitochondria 6. That is a protein-handling experiment rather than a measurement in a living person, and it has never been tested against any peptide.
- **PPARGC1A (PGC-1 alpha)** is the master switch for building new mitochondria. Variant associations with training response are inconsistent across cohorts and do not support individual-level prediction.
- **MOTS-c K14Q (m.1382A>C)** is a mitochondrial DNA position found mainly in Northeast Asian maternal lineages. Across 27,527 Japanese participants, men carrying it had a higher prevalence of type 2 diabetes, concentrated in the least active third of men in one cohort and absent in the most active 1. Most consumer genotyping files do not report this position in a usable form, and no study has tested whether carriers respond differently to injected MOTS-c.
Genetics sets context and directs your measurements here. It describes oxidative-stress handling and metabolic baseline, and in the K14Q case it nudges toward the one intervention with human data behind it. For what a consumer DNA file does and does not contain, see our SelfDecode peptide report review, and for how to weigh any of this against your own situation, our decision framework. For the wider longevity frame, our anti-aging page draws the same line on the extract sold as a peptide: "The marketing treats them as one product; the published record treats them as two substances." See also epithalon, and for the metabolic claims borrowed from MOTS-c biology, peptides for fat loss.
Side effects, and what is unknown
Elamipretide used outside Barth syndrome is off-label use of a prescription drug and belongs with a prescriber. MOTS-c has no label at all, so any use in a person sits outside the approval system entirely, and neither situation is covered by the safety information above. Anyone with an active cancer or a recent cancer history should treat mitochondrial-targeted compounds as a question for their oncology team, since the theoretical concern about supporting tumor cell metabolism has not been resolved either way. Pregnancy and breastfeeding have no safety data for either compound. No drug interaction study exists for MOTS-c, which is different from no interactions existing. And if the complaint is really tiredness, start with sleep: our peptides for sleep page puts it bluntly, "Get the sleep study before spending money on a research compound", and best peptides for sleep covers what has and has not been tested there.
Cost, storage, and how long studies ran before measuring anything
Elamipretide is a specialty prescription drug priced for an ultra-rare disease, and what a patient pays depends entirely on insurance, so we do not print a figure. MOTS-c reaches buyers as a lyophilized (freeze-dried) powder in 5 mg and 10 mg vials from research suppliers, at research-chemical rather than pharmacy prices. Those vials are sold for laboratory research use only and labelled not for human consumption; as our anti-aging page puts it, "Epitalon, MOTS-c and injectable GHK-Cu are sold labeled for research use only, which means no agency has checked what is in the vial." Buying one to inject puts a person outside that labelling, outside any pharmaceutical manufacturing standard, and outside the reach of any recall or adverse-event system. Suppliers state that sealed powder is kept cold and out of light and that reconstituted material is refrigerated with a working life measured in weeks rather than months; that is storage chemistry, not a suggestion to use it. Our reconstitution guide covers the laboratory mechanics and peptides for beginners covers sterile handling, and neither is an endorsement of human use.
Schedules that appear in the published record
On timelines: MMPOWER-3 measured at 4, 12 and 24 weeks and found no separation from placebo at any of them 3. The MOTS-c trial reads its primary endpoints at 12 and 16 weeks and will not report before 2027. Anyone judging either compound on how week two felt is working with a signal the trials could not detect over six months. If you came here tired, the sequence that actually has evidence behind it runs the other way round: a workup first for thyroid disease, sleep apnea and anemia, then aerobic training, which is the only input on this page with a measured mitochondrial result in healthy people 7, and only then a conversation about anything in a vial.
Link · Martens CR et al., Nature Communications 2018Chronic nicotinamide riboside supplementation is well-tolerated and elevates NAD+ in healthy middle-aged and older adultsThe 2 x 6-week crossover trial behind the NAD+ row in the table above: 1,000 mg a day raised blood NAD+ by about 60% in healthy adults aged 55 to 79. Raising the blood marker is the confirmed result. Blood NAD+ is not a measure of how much ATP your muscle mitochondria make.doi.orgYour DNA file already carries SOD2 and PPARGC1A, the variants behind oxidative-stress handling and mitochondrial building. Upload the raw data you have and see how the published genetics for all 39 peptides lines up with your file. The report is educational and is not a diagnostic test: no genetic variant has been validated as a predictor of response to any peptide, including the ones on this page, and nothing in it is a recommendation to take a compound.
Get your DNA report- An approval is not the same as a positive trial
SS-31 (elamipretide) is FDA approved, and its own label says the drug was not superior to placebo on the primary endpoints of the randomized trial that supported it. The approval is accelerated, covers Barth syndrome alone, rests on a knee strength measurement taken in an uncontrolled extension where everyone knew what they were getting, and requires a confirmatory trial that can withdraw it. Meanwhile the largest controlled test of the same drug in broader mitochondrial disease, 218 patients over 24 weeks, was negative on both endpoints.
Frequently asked questions
When did research protocols dose MOTS-c, and does exercise timing matter?
The only registered human trial of MOTS-c, NCT07505745 in 120 adults with prediabetes and overweight or obesity, gives a fixed dose under the skin once daily for 12 weeks and reads insulin sensitivity at week 12 and adverse events at week 16. It began enrolling in February 2026 and will not report before 2027. The twice-weekly cycled schedule traded in forums, described earlier on this page, matches no study. On timing around training, no trial has compared before-workout with after-workout dosing in any species, so any rule you read on that point was invented. The exercise link in the data runs the other direction: training raises the MOTS-c your own body makes [[2]], and the K14Q diabetes association was concentrated in the least active men [[1]].
How is MOTS-c taken in studies, and what does it ship as?
MOTS-c is a peptide, so the registered trial gives it by injection under the skin; swallowing it would break it down in the stomach. Research suppliers ship it as a lyophilized powder in 5 mg and 10 mg vials that must be reconstituted with bacteriostatic water and refrigerated afterward, and those vials are labelled for research use only and not for human consumption. MOTS-c is not FDA approved, and no compounding pharmacy may legally prepare it either: a bulk substance qualifies for 503A compounding only if it has a US Pharmacopeia monograph, is a component of an approved drug, or appears on FDA's 503A bulks list, and MOTS-c is none of the three [[8]]. Handling mechanics are covered in our reconstitution guide; the decision itself belongs with a clinician.
What are the claimed SS-31 benefits, and which ones held up?
SS-31 (elamipretide) is marketed for fatigue, exercise capacity, heart function, kidney protection, eye disease and general mitochondrial support. In the largest controlled test, 218 adults with primary mitochondrial myopathy taking 40 mg a day for 24 weeks, neither walking distance nor fatigue improved against placebo, and Neurology graded that as Class I evidence [[3]]. The one endpoint that supported an approval is knee extensor muscle strength in Barth syndrome, measured in an open-label extension rather than against placebo [[4]]. Nothing on the marketing list has been demonstrated in a healthy adult.
Is SS-31 the same thing as elamipretide?
Yes. SS-31 was the research designation, elamipretide is the drug name, and Forzinity is the brand approved by the FDA on 19 September 2025 under accelerated approval for Barth syndrome in patients weighing at least 30 kg [[4]]. Because it is now an approved prescription drug, research-chemical SS-31 is an unapproved copy of a licensed medicine, made under no pharmaceutical standard. If SS-31 is indicated for a diagnosed condition, that is a specialist prescription conversation.
Sources8
- Zempo H, Kim SJ et al. A pro-diabetogenic mtDNA polymorphism in the mitochondrial-derived peptide, MOTS-c. Aging (Albany NY) 2021 (three Japanese cohorts, 27,527 participants)
- Reynolds JC, Kim SJ et al. MOTS-c is an exercise-induced mitochondrial-encoded regulator of age-dependent physical decline and muscle homeostasis. Nature Communications 2021
- Karaa A et al. Efficacy and Safety of Elamipretide in Individuals With Primary Mitochondrial Myopathy: The MMPOWER-3 Randomized Clinical Trial. Neurology 2023 (n=218, both primary endpoints missed)
- FDA prescribing information for Forzinity (elamipretide), NDA 215244, accelerated approval 19 September 2025 for Barth syndrome
- Short KR et al. Decline in skeletal muscle mitochondrial function with aging in humans. PNAS 2005 (146 adults aged 18 to 89)
- Sutton A et al. The Ala16Val genetic dimorphism modulates the import of human manganese superoxide dismutase into rat liver mitochondria. Pharmacogenetics 2003 (in vitro import assay)
- Robinson MM et al. Enhanced Protein Translation Underlies Improved Metabolic and Physical Adaptations to Different Exercise Training Modes in Young and Old Humans. Cell Metabolism 2017 (12 weeks, 72 adults, muscle biopsies)
- US Food and Drug Administration. Bulk drug substances that can be used to compound drug products under section 503A of the FD&C Act (the 503A Bulks List)
This article is for informational and educational purposes only. It is not medical advice and does not diagnose, treat, cure, or prevent any disease. Consult a qualified healthcare professional before starting any peptide protocol. Individual results vary. Some outbound links are affiliate links, at no extra cost to you.
This page is educational and is not medical advice. Peptides are not intended to diagnose, treat, cure, or prevent any disease, and most are not FDA-approved. Talk to a qualified healthcare provider before starting anything. Availability and legal status of peptides vary by jurisdiction.
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