SS-31 (Elamipretide)
Also referenced as: Elamipretide, Forzinity, MTP-131, Bendavia
A cardiolipin-targeting mitochondrial peptide with accelerated FDA approval for muscle strength in a defined Barth syndrome population; other uses remain investigational.
- Evidence grade
- CEarly Human Research
Early Human Research
- Regulatory status
- FDA Approved for Specific Indication
Forzinity received FDA accelerated approval on September 19, 2025 to improve muscle strength in adult and pediatric patients with Barth syndrome weighing at least 30 kg. Approval was based on knee-extensor strength; confirmation of clinical benefit remains required. Other proposed uses and research-vial products are not approved by this decision.
- Human data
- Yes
Registered clinical trials exist
- Last reviewed
- October 27, 2026
Overview
SS-31, developed as elamipretide, concentrates in the inner mitochondrial membrane where it interacts with cardiolipin. Unlike most compounds in this library, it has been studied in properly registered clinical trials.
Results have been mixed. Some trials in primary mitochondrial myopathy and Barth syndrome reported signals on secondary endpoints while missing primary ones — a pattern worth understanding rather than glossing over.
Why It's Being Studied
- Primary mitochondrial myopathy and rare mitochondrial disease.
- Barth syndrome and cardiolipin-related cardiomyopathy.
- Heart failure, ischaemia-reperfusion injury and dry age-related macular degeneration.
Mechanism of Action
It concentrates inside mitochondria and stabilises a key membrane fat, helping the energy-producing machinery work more normally.
Elamipretide is a cell-permeable tetrapeptide (D-Arg-dimethylTyr-Lys-Phe) that accumulates in the inner mitochondrial membrane through electrostatic and hydrophobic interaction with cardiolipin. It is proposed to stabilise cardiolipin-cytochrome c interaction, preserving cristae architecture, electron transport efficiency and reducing reactive oxygen species production.
How cells make energy
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Background: Mitochondrial Research
Mitochondria turn nutrients and oxygen into ATP, the cell's energy currency. Their function declines with age and in several diseases.
Compounds in this area target the inner mitochondrial membrane, NAD+ supply or signalling peptides encoded by mitochondrial DNA. Human outcome data remains sparse.
Research Areas & Routes Studied
- Mitochondrial myopathy
- Cardiomyopathy
- Heart failure
- Retinal disease
- Subcutaneous injection (approved Forzinity and clinical trials)
- Intravenous (clinical trials)
- Topical ophthalmic (trials)
Evidence Summary
FDA accelerated approval supports a narrow Barth syndrome indication based on an intermediate clinical endpoint. Confirmatory clinical benefit remains to be established, and other mitochondrial trials have had mixed or negative primary outcomes.
Higher tiers carry more weight. Filled tiers have evidence for SS-31 (Elamipretide); tap to read it.
- Randomised trials in primary mitochondrial myopathy reported inconsistent results on six-minute walk distance and patient-reported outcomes.
- Barth syndrome research reported functional signals in small populations.
- Forzinity received accelerated FDA approval based on knee-extensor strength in a defined Barth syndrome population; confirmation of clinical benefit remains required.
- Multiple registered trials across cardiac, ophthalmic and mitochondrial indications.
3 cited sources spanning 2025–2025.
- Regulatory document2
- Randomised controlled trial1
Human clinical evidence
- Randomised trials in primary mitochondrial myopathy reported inconsistent results on six-minute walk distance and patient-reported outcomes.
- Barth syndrome research reported functional signals in small populations.
- Forzinity received accelerated FDA approval based on knee-extensor strength in a defined Barth syndrome population; confirmation of clinical benefit remains required.
Clinical trials
- Multiple registered trials across cardiac, ophthalmic and mitochondrial indications.
Animal studies
- Extensive ischaemia-reperfusion and heart failure model data.
Reported Adverse Events in Research
- Injection-site reactions are the most commonly reported effect in trials.
- Gastrointestinal effects and headache reported.
- Serious hypersensitivity is an important risk in the approved label.
Limitations of Current Evidence
- Primary endpoints have not been consistently met.
- Rare-disease populations are small, limiting statistical power.
How to Read This Research
- Did the study show a functional change (exercise capacity, fatigue) or only a lab marker?
- Was the population healthy, elderly or living with a specific mitochondrial disease?
- Raising blood NAD+ levels does not confirm tissue-level benefit.
- Disease-specific trial results do not automatically apply to healthy people.
- ATP
- Adenosine triphosphate, the cell's energy currency.
- Cardiolipin
- A lipid unique to the inner mitochondrial membrane.
- NAD+
- A coenzyme central to energy metabolism and DNA repair.
Compare With Other Compounds
| SS-31 (Elamipretide) | MOTS-c | |
|---|---|---|
| Evidence grade | C — Early Human Research | D — Preclinical Research |
| Regulatory status | FDA Approved for Specific Indication | Research Use Only |
| Human data | Yes | Limited |
| Clinical trials | Registered trials exist | None identified |
| Research routes | Subcutaneous injection (approved Forzinity and clinical trials), Intravenous (clinical trials), Topical ophthalmic (trials) | Intraperitoneal (animal research), Subcutaneous (animal research) |
| Cited sources | 3 | 2 |
Frequently Asked Questions
Documented Research Protocols
Elamipretide (SS-31) — clinical trial protocols as registered
Summarise the administration structure used in registered trials in primary mitochondrial myopathy and related conditions.
View documented protocol
Why It Is Used
- Longevity
Energy and Mitochondrial Function
Fatigue that sleep does not fix is the entry point. Mitochondrial compounds are the most biologically interesting and least resolved category on this site.
Read the case study
Research References
- Regulatory document2025
FDA accelerated approval of Forzinity for Barth syndrome
- Randomised controlled trial
Elamipretide in primary mitochondrial myopathy: randomised trial
- Main finding
- Mixed results across functional and patient-reported endpoints.
- Regulatory document
Registered elamipretide trials