SS-31 (Elamipretide)
Also known as: Elamipretide · MTP-131 · Bendavia
A four-amino-acid peptide that homes to the inner mitochondrial membrane and stabilises cardiolipin. Currently the most clinically advanced mitochondrial peptide in trials.
Overview
SS-31 (elamipretide, formerly Bendavia) is unusual among 'longevity' peptides in that it has a clear biophysical mechanism and a real clinical-trial pipeline. The peptide concentrates in the inner mitochondrial membrane by an unusual electrostatic mechanism and binds cardiolipin, the phospholipid that organises the electron transport chain. Stabilising cardiolipin tightens the chain, reduces electron leak, and cuts reactive-oxygen-species production at source. The Phase 2 trials in Barth syndrome (a rare cardiolipin-deficiency disease), primary mitochondrial myopathy, and dry AMD have shown signal but not approval-grade effect sizes; the program continues. Outside trials, users dose for general mitochondrial-energy improvement and report subjective gains that are hard to measure objectively — typical for anything operating below the level of perceived performance.
Evidence quality
Multiple Phase 2 trials have been completed and ongoing in Barth syndrome (TAZPOWER), primary mitochondrial myopathy (MMPOWER series), and dry age-related macular degeneration (ReCLAIM). Effect sizes have been mixed — clear pharmacodynamic signal, less consistent clinical-endpoint improvement. The 2014 Szeto group review established the mechanism. Stealth BioTherapeutics has been the primary sponsor. No approved indication yet, but the regulatory dossier is the most developed in the mitochondrial-peptide space.
Benefits & timeline
Benefits
- Mitochondrial-targeted antioxidant effect via cardiolipin binding — operates at the source of ROS production rather than scavenging downstream
- Subjective energy improvements, particularly in users with age-related mitochondrial decline
- Active development pipeline for Barth syndrome and mitochondrial myopathy — the closest thing to a 'real' mitochondrial drug
- Cardiac and renal protective signals in animal ischemia-reperfusion models
Timeline
Week 1
Most users feel nothing yet. Mitochondrial turnover is slow and the signal accumulates rather than spikes.
Week 2–3
Subjective energy and recovery improvements begin — particularly mid-afternoon, when mitochondrial function tends to be the rate-limiter for older users.
Week 6–8
If anything is going to work, it's clear by here. Objective metrics — exercise tolerance, HRV, time-to-fatigue on familiar workouts — are the honest read.
Week 12
Plateau. Continuing past 12 weeks rarely improves the response further.
Off-cycle
4 weeks off lets you read whether the gains hold without ongoing dosing. Many users find a fraction of the benefit persists, suggesting the mitochondrial pool got 'cleaner' even after stopping.
Dosage protocols
Advanced
5 mg
once daily
Beginner
1 mg
once daily
Standard
3 mg
once daily
Titration & adjustment
Start at 1 mg once daily for the first week. Escalate to 3 mg once daily for the rest of the cycle if energy improvement is felt. Maximum 5 mg daily. Cycle off for 4 weeks every 12 weeks to allow for objective re-assessment.
Injection timing
Once daily, morning preferred — energy improvements feel most useful when dosed early in the day.
Side effects & contraindications
- mildInjection-site reaction — small bump or redness for under 24 hours.
- mildHeadache in the first few days, usually resolving on its own as the dose is held steady.
- mildTransient nausea at higher doses (5 mg), particularly on an empty stomach.
- moderateLong-term safety data is still being generated through the Phase 2 trials. Years of dosing have not flagged major issues, but the safety envelope is narrower than for fully approved drugs.
Contraindications
- Active cancer — tumours rely on mitochondrial metabolism too, and a peptide that protects mitochondrial function may be doing the wrong thing in this context
- Pregnancy or breastfeeding — no human reproductive data
- Severe renal impairment without specialist guidance, given the clearance route
- No pediatric data outside the Barth-syndrome trials, which are conducted under specialist supervision
Reconstitution & injection
A 10 mg vial reconstituted with 2 ml bacteriostatic water gives 5 mg per ml. A 3 mg dose is 0.6 ml, which is 60 units on a U-100 insulin syringe; a 1 mg dose is 20 units, a 5 mg dose is 100 units (the full insulin syringe — use a 1 ml syringe if available). Subcutaneous into abdomen or thigh; rotate sites. The peptide is reasonably stable in solution but refrigerate after reconstitution and use within 30 days. Morning dosing is the convention because the energetic effect is most usefully felt early in the day.
Open calculator pre-filledStorage after reconstitution
Refrigerate at 2–8 °C after reconstitution. Do not freeze. Light-protected. SS-31 (elamipretide) reconstituted in BAC water is stable for 28 days at fridge temperature. The molecule targets cardiolipin in the inner mitochondrial membrane and is reasonably robust in solution.
Common mistakes
Expecting a stimulant-like jolt.
Better approach: SS-31 is not caffeine. The effect is a gradual lift in the energetic floor over weeks, not a same-day boost. If you're benchmarking against a pre-workout, you'll dismiss the peptide before it has time to work.
Dosing in the evening to 'support recovery.'
Better approach: Most users find the energetic effect mild but noticeable enough that late dosing disrupts sleep onset. Morning is the default for a reason. If recovery is the goal, the daytime effect on training capacity matters more than the bedtime timing.
Stacking with high-dose antioxidants.
Better approach: Heavy oral antioxidant doses (high-dose vitamin C, NAC) may blunt the exercise-adaptation signal that SS-31's milder ROS modulation preserves. The peptide operates at the source; ramming in scavengers downstream tends to be redundant or counterproductive.
Tracking it on energy alone.
Better approach: Energy is subjective and drifts. Pick an objective marker — time-to-fatigue on a familiar steady-state effort, HRV trend over 2 weeks, recovery time between hard sessions. If those don't move by week 6, the peptide isn't doing what you hoped.
Real-world tips
- Morning dosing pairs well with fasted cardio — the mitochondrial substrate-handling effect is most usefully felt during fat-oxidation work.
- Reconstituted vials hold well at fridge temperature for 30 days. Don't freeze — the peptide tolerates 2–8°C but the unfolding from a freeze cycle is hard to detect visually.
- If you train heavily and notice the gains plateau at week 6, that's likely the ceiling for your current mitochondrial pool. Pushing the dose higher rarely helps.
- Pair with mitochondrial-stress training (zone-2 endurance, sprint intervals) — the peptide protects mitochondria, but you still need to give them a reason to upregulate. SS-31 isn't a substitute for the work.
- Track HRV (chest strap, not wrist) over a 4-week baseline before starting. The most reliable signal SS-31 sends is a small but durable HRV improvement, and you can't see it without a baseline.
When something else is the better tool
MOTS-c
Use instead when: Metabolic and exercise-capacity focus rather than direct membrane stabilisation. MOTS-c acts through a different mitochondrial axis (mitochondrial-encoded peptide signalling) and is the better fit if metabolic flexibility is the primary target.
NAD+ precursors (NMN, NR) or NAD+ injections
Use instead when: Substrate-pool depletion is the suspected bottleneck rather than membrane damage. Cheaper, oral options exist for NAD+; SS-31 is the right pick when the question is membrane integrity, not coenzyme supply.
Standard zone-2 training
Use instead when: You haven't yet done the boring work of building mitochondrial density through endurance training. The peptide protects what you have; it doesn't substitute for not having built it. Run a 12-week zone-2 block first, then re-evaluate.
- Is SS-31 a longevity drug?
- Mechanistically it touches a longevity-relevant pathway (mitochondrial integrity drops with age, contributes to a long list of age-related diseases). Whether that translates to a measurable lifespan effect in humans is unknown — there is no longevity trial. Take the longevity framing as plausible mechanism, not demonstrated outcome.
- Why is it called both SS-31 and Elamipretide?
- SS-31 is the research designation from the original Szeto group; Elamipretide is the generic name assigned for clinical development. They are the same molecule. MTP-131 and Bendavia were earlier development names. The label drift is messy but the peptide is one.
- Will I feel it on day one?
- Almost certainly not. The mechanism is membrane stabilisation, not receptor activation. The signal accumulates over days to weeks. If you feel something dramatic on day one, that's likely either placebo or an irritation reaction.
- Can I stack with CoQ10?
- Yes — they operate on adjacent layers of the same system. CoQ10 supplies a redox-active substrate within the electron transport chain; SS-31 stabilises the membrane that organises it. Many users on mitochondrial protocols run both, alongside zone-2 work.
- What about hair, skin, or weight effects?
- Not the right peptide. SS-31 acts at the cellular energetics level; visible cosmetic effects are not its target. Users sometimes report skin-quality improvements as a secondary effect of better cellular energy, but if cosmetics are the primary goal, look at GHK-Cu or the GLOW/KLOW stacks instead.