SS-31: research protocol, dosing & reconstitution
Also known as: Elamipretide, MTP-131, Bendavia
Quick answer
What is SS-31?
SS-31 (elamipretide) is a four-amino-acid peptide that concentrates inside mitochondria — the structures that generate a cell's energy — and binds a fat called cardiolipin in their inner membrane. It is the most clinically advanced compound in this category, with real trial data in rare mitochondrial disease.
What SS-31 is
SS-31 is a synthetic tetrapeptide developed as elamipretide by Stealth BioTherapeutics. Its unusual chemistry lets it cross cell membranes and accumulate at high concentration in the inner mitochondrial membrane — a targeting property most peptides do not have.
Unlike most compounds on this site, elamipretide has been through registered clinical trials. It is still investigational and not approved for general use; research-vendor SS-31 is a Research Use OnlyRUO (Research Use Only)A regulatory classification meaning a product is sold strictly for laboratory research and is not approved, labeled, or intended for human or veterinary use.See glossary → chemical.
Mechanism of action
Cardiolipin is a lipid unique to the inner mitochondrial membrane, and its structure determines how efficiently the electron transport chain — the cell's energy production line — is organised. SS-31 binds cardiolipin and stabilises that structure, which a 2025 review describes as improving electron transfer efficiency and reducing reactive oxygen species [1].
The clinical evidence is narrow but genuine. A 168-week open-label extension in patients with Barth syndrome, a rare inherited cardiolipin disorder, reported long-term efficacy and safety data [2] — a far stronger evidence position than most research peptides hold.
What researchers study SS-31 for
- Mitochondrial dysfunction and cardiolipin biology
- Rare mitochondrial disease (Barth syndrome, primary mitochondrial myopathy)
- Cardiac ischemia-reperfusion models
- Age-related mitochondrial decline
What dose of SS-31 do researchers use?
Research literature commonly references doses of Clinical trials used 40 mg daily; research references are lower. This is not a recommendation — the table below summarizes protocols as they appear in published literature and trial designs.
| Context | Dose | Frequency | Duration |
|---|---|---|---|
| Clinical trial reference (Barth syndrome) | 40 mg | Once daily, subcutaneous | Long-term, in trial settings |
| Research literature reference | Lower than the trial dose | Once daily | Cycles referenced; no established schedule |
← Swipe to see the full table
Half-life and dosing timing
Half-life: ~2–3 hours. Route referenced in research: Subcutaneous. Half-lifeHalf-lifeHow long it takes for half of a compound to be eliminated from the body. Half-life determines how often researchers dose a compound in protocols.See glossary → is roughly 2–3 hours, and clinical dosing was once daily by subcutaneousSubcutaneous (SubQ)An injection into the fatty tissue just below the skin. The most commonly referenced administration route in peptide research literature.See glossary → injection. The trial schedule is the only well-documented pattern; anything below it in research protocols is extrapolation, not evidence.
Titration: start low, go slow
Trials did not use a graded titrationTitrationStarting at a low dose and increasing gradually on a schedule. Research protocols titrate to assess tolerance — 'start low, go slow.'See glossary → in the way GLP-1GLP-1 (glucagon-like peptide-1)A gut hormone that stimulates insulin release, slows stomach emptying, and reduces appetite. GLP-1 receptor agonists such as semaglutide are studied and prescribed for metabolic regulation.See glossary → programs do — the dose was established and maintained. Research protocols that start lower do so for tolerance and cost reasons rather than following a published schedule.
Skip the SS-31 math
Enter vial size, water volume, and target dose — the free calculator returns concentration, injection volume, and exact U-100 syringe units.
How is SS-31 reconstituted?
| Vial size | BAC water | Concentration | Worked example |
|---|---|---|---|
| 50 mg | 2 mL | 25 mg/mL | 10 mg = 0.4 mL = 40 units on a U-100 syringe |
| 20 mg | 2 mL | 10 mg/mL | 5 mg = 0.5 mL = 50 units on a U-100 syringe |
Add 2 mL of bacteriostatic waterBAC water (bacteriostatic water)Sterile water containing 0.9% benzyl alcohol, which suppresses bacterial growth. It is the standard diluent used to reconstitute lyophilized peptides for multi-dose research vials.See glossary → to a 50 mg vialVialThe small sealed glass container peptides are supplied in, topped with a rubber septum that a syringe needle can pass through.See glossary →: 50 ÷ 2 = 25 mg/mL. A 10 mg dose is 10 ÷ 25 = 0.4 mL — 40 units on a U-100 syringeU-100 syringeAn insulin syringe calibrated so that 100 units equal 1 mL. The standard syringe referenced in peptide research; each unit equals 0.01 mL.See glossary →.
New to the process? Read the full step-by-step reconstitution guide.
How long does reconstituted SS-31 last?
LyophilizedLyophilizedFreeze-dried. Peptides are shipped as a lyophilized powder ('puck') because the dry form is far more stable than a solution. It must be reconstituted before use in research.See glossary →: refrigerate. ReconstitutedReconstitutionThe process of mixing a freeze-dried (lyophilized) peptide powder with bacteriostatic water to create a solution of known concentration.See glossary →: refrigerate at 2–8°C, protect from light, and use within weeks.
What is SS-31 stacked with in research?
Referenced alongside NAD+ in mitochondrial research protocols. The rationale is that they act at different points of the same system — SS-31 on the structure of the inner membrane, NAD+ on the coenzyme supply that the electron transport chain runs on.
Side effects observed in research
Injection-site reactions were common in the clinical program and are the most consistently reported effect. Headache and nausea also appear in trial data. Because elamipretide has been through registered trials, its side-effect profile is better characterised than almost anything else in this category.
- Injection-site reactions (common in trials)
- Headache
- Nausea
Frequently asked questions
Is SS-31 the same as elamipretide?
Yes. SS-31 is the research designation; elamipretide is the drug name used in clinical development, and it has also appeared as MTP-131 and Bendavia.
What dose was used in clinical trials?
40 mg once daily by subcutaneous injection in the Barth syndrome program. This describes trial design, not a recommendation.
How does SS-31 differ from other longevity peptides?
Evidence. Most compounds in this category rest on cell-culture or animal work; elamipretide has multi-year clinical trial data in a defined patient population, including a 168-week extension study.
Is SS-31 approved anywhere?
No. It remains investigational. Research-vendor SS-31 is a Research Use Only chemical with no regulatory approval.
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References
- 1.Tung C, et al. Elamipretide: A Review of Its Structure, Mechanism of Action, and Therapeutic Potential. Int J Mol Sci. 2025. PubMed ↗
- 2.Thompson WR, et al. Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results. Genet Med. 2024. PubMed ↗