Mitochondrial cardiolipin-binding tetrapeptide
Elamipretide (SS-31)
aka SS31 · MTP-131 · Bendavia · Forzinity
Grade note: revised from B to C on independent review. The FDA accelerated approval (September 2025) is for Barth syndrome only, an ultra-rare genetic disease that is not what the peptide is marketed for, so the 'narrow approval' route to B does not apply.
User reports
approximate — combined from two independent Reddit reads
Men 45–60
0 men aged 45–60
No reports in this group yet.
All men
1 man
small sample · n = 1Outcome mixed 1 of 1
Benefits energy 1 of 1
Side effects other 1 of 1
Why stopped side effects 1 of 1
Everyone
21 people
- Positive: 11 of 21 (52%)
- Mixed: 6 of 21 (29%)
- Negative: 1 of 21 (5%)
- No effect: 2 of 21 (10%)
- Unclear: 1 of 21 (5%)
| Item | Reports |
|---|---|
| Energy | 11 of 21 (52%) |
| Endurance | 4 of 21 (19%) |
| Focus / cognition | 4 of 21 (19%) |
| Recovery | 2 of 21 (10%) |
| Mood / anxiety | 1 of 21 (5%) |
| Other | 1 of 21 (5%) |
| Item | Reports |
|---|---|
| Anxiety | 2 of 21 (10%) |
| Heart rate up | 2 of 21 (10%) |
| Insomnia | 2 of 21 (10%) |
| Other | 2 of 21 (10%) |
| Blood pressure | 1 of 21 (5%) |
| Fatigue | 1 of 21 (5%) |
| Flushing | 1 of 21 (5%) |
| Item | Reports |
|---|---|
| Side effects | 2 of 21 (10%) |
User reports are anecdata, not evidence: self-selected, unverified, often combined with other compounds.
In their words
“Very quickly noticed that it was helping, however it raised my fasting blood sugar 20 to 30 points.”
“At 500mcg we both had tons of energy. Couldn’t nap. Had extra endurance for our workouts.”
“I ran 2mg a day for 28days. I noticed that about 2 weeks into it my endurnace for physical work was exceptional.”
“Why is SS-31 helping me so much?”
“SS-31 raised my resting heart rate by 5, and a lot more (translated from a German page view)”
Read summaries and method notes
Read 1. No man aged 45–60; the only explicit man was over 70 (mixed: quick benefit but fasting glucose up 20–30 points, reversed after stopping). Across 19 users in seven threads, energy and endurance were the clearest benefits, with less brain fog and better recovery. Adverse: anxiety, insomnia, dizziness or cardiovascular changes, flushing, fatigue; two noticed nothing. Onset immediate to about two weeks; many stacked with NAD+ or MOTS-c.
Read 2. No stated sex or age. Two users from two accessible threads: one positive ("Why is SS-31 helping me so much?"), one negative (resting heart rate up 5 bpm, among other effects). Four seed threads could not be read. Too small to draw conclusions.
Note 1. No men aged 45-60; the only explicit male was over 70. NAD+/MOTS-c co-use common. Raised fasting glucose counted as 'other'.
Note 2. Four seed threads were unavailable, leaving two threads with minimal detail.
Each read counted people independently. Overlap between the two reads is estimated from shared threads and removed; counts are approximate. How we count.
Summary
Synthetic aromatic-cationic tetrapeptide, D-Arg-dimethylTyr-Lys-Phe, MW ~640. Formerly Bendavia / MTP-131.
Mechanism is well characterised and independently replicated — the sharpest contrast with the Khavinson family. It concentrates in the inner mitochondrial membrane and binds cardiolipin through electrostatic and hydrophobic interaction, preserving cardiolipin's association with cytochrome c and the electron transport chain, stabilising cristae, and cutting ROS at source rather than scavenging downstream (JASN 2013; PNAS 2020 interaction landscape).
Safety
- Frequent injection-site reactions
- Serious hypersensitivity contraindication
- Eosinophil elevations
- Renal impairment affects dosing
- Benzyl alcohol formulation must not be used in neonates
From labels, regulators and trials. No signal in small studies ≠ safe.
Legal status
US FDAApproved for Barth syndrome only
Approved (improve muscle strength in Barth syndrome, weight at least 30 kg). Accelerated approval on September 19, 2025; confirmatory clinical benefit remains required. Not an anti-aging approval. Not on the July 23-24, 2026 PCAC agenda. Source
checked 2026-11-13WADA 2026Not named
Not listed by name; FDA approval means an automatic S0 classification is inappropriate; compound-specific anti-doping determination not found. Source
checked 2026-11-13EU
EMA orphan designation EU/3/21/2430 for Barth syndrome; marketing authorization not found, and orphan designation is not authorization. Source
checked 2026-11-13Evidence C mitochondrial support / anti-ageing in people without Barth syndrome
Changed B to C. The FDA accelerated approval (September 2025) is for Barth syndrome only, an ultra-rare genetic disease that is not what the peptide is marketed for, so the 'narrow approval' route to B does not apply. For the marketed use the only direct evidence is one 39-person RCT in older adults with an acute biomarker signal that was gone by day 7. Every randomized trial in a wider population missed its primary endpoint (primary mitochondrial myopathy phase 3, heart failure, the Barth crossover itself). That is 'small, early, unconfirmed' and sits closer to F than to B. B would be correct only for Barth syndrome.
Human trials · 4
- PMID 330778952021Randomized double-blind placebo-controlled crossover plus open-label extension 12 people
Barth syndrome
Both randomized primary endpoints failed; eight extension participants improved walking and fatigue at 36 weeks. Source
- PMID 372684352023Phase 3 RCT 218 people
Primary mitochondrial myopathy
At 24 weeks, walking difference was -3.2 m (95% CI -18.7 to 12.3; p=0.69); fatigue endpoint also failed. Source
- PMID 342649942021Double-blind placebo-controlled RCT 39 people
Adults aged 60-85 selected for low muscle mitochondrial function
Acute ATP-production biomarker signal; no sustained between-group ATPmax difference at day 7 or significant prespecified fatigue-resistance improvement. Source
- PMID 320680022020Phase 2 RCT 71 people
Stable heart failure with reduced ejection fraction
Neither 4 mg nor 40 mg daily improved the primary left-ventricular end-systolic-volume endpoint at four weeks. Source
Bar length = trial size on a log scale.
Dose ranges
Reported ranges from labels and studies, with context. Not a recommendation.
Editorial ratings EDITORIAL
Editors’ judgement, 0–5. Opinion, not data; separate from grade and user score.
Sources
- pubmed.ncbi.nlm.nih.gov/33077895/
- pmc.ncbi.nlm.nih.gov/articles/PMC10382259/
- pmc.ncbi.nlm.nih.gov/articles/PMC8282018/
- pubmed.ncbi.nlm.nih.gov/32068002/
- fda.gov/drugs/drug-trials-snapshots/drug-trials-snapshots-forzinity
- wada-ama.org/sites/default/files/2025-09/2026list_en_final_clean_september_2025.pdf
- ema.europa.eu/en/medicines/human/orphan-designations/eu-3-21-2430
- accessdata.fda.gov/drugsatfda_docs/label/2025/215244s000lbl.pdf
- fda.gov/advisory-committees/advisory-committee-calendar/july-23-24-2026-meeting-pharmacy-c
- euclinicaltrials.eu/ctis-public/view/2025-523837-25-00
- clinicaltrials.gov/study/NCT07275424
Reddit threads read · 9
2 further sources on commercial or non-primary hosts not listed.
Research checked 2026-11-13.