SS-31 / Elamipretide
Elamipretide, originally known as SS-31, binds cardiolipin, a specialized lipid found in the inner membrane of mitochondria.
By targeting mitochondrial structure rather than simply adding another antioxidant, SS-31 has become an important research platform for cellular energy, muscle function, mitochondrial disease, cardiovascular biology, and healthy aging.
What Is SS-31?
SS-31 is a synthetic four-amino-acid peptide now known clinically as elamipretide.
Unlike many compounds that circulate throughout a cell, elamipretide has an unusual affinity for the inner mitochondrial membrane.
Its primary molecular target is cardiolipin—a specialized phospholipid that helps organize the mitochondrial membrane and the machinery involved in cellular energy production.
Why Mitochondria Matter
Mitochondria convert energy from food into ATP, the usable energy currency that powers cells.
But healthy mitochondria also influence cellular signaling, oxidative balance, muscle performance, metabolism, and the ability of cells to respond to stress.
Cellular Energy
Mitochondria use the electron transport chain to convert fuel into ATP that powers muscle contraction and cellular function.
Membrane Structure
Healthy mitochondrial membranes help organize the machinery required for efficient energy production.
Oxidative Stress
Dysfunctional mitochondria can produce excessive reactive oxygen species and create additional cellular stress.
Cellular Resilience
Maintaining mitochondrial function may help cells better tolerate physical, metabolic, and disease-related stress.
How Does SS-31 Work?
Cardiolipin is concentrated within the inner mitochondrial membrane.
It helps organize the curved folds of the membrane—called cristae—where much of the machinery responsible for energy production is located.
Healthy Mitochondrial Membrane
Well-organized cardiolipin helps maintain mitochondrial structure and supports proper organization of respiratory proteins involved in ATP production.
Mitochondrial Stress
Oxidative stress and disease can disrupt membrane organization, impair mitochondrial function, and reduce energy efficiency.
SS-31 Is More Than a Traditional Antioxidant
The central idea is not simply to “scavenge free radicals.” Elamipretide physically localizes to the inner mitochondrial membrane and interacts with cardiolipin-associated mitochondrial biology.
FDA-Approved Use: Barth Syndrome
Forzinity™ — Elamipretide
In September 2025, FDA granted accelerated approval to Forzinity™ to improve muscle strength in adult and pediatric patients with Barth syndrome weighing at least 30 kg.
The approval was based on improvement in knee-extensor muscle strength, which FDA considered reasonably likely to predict meaningful clinical benefit.
What Is Barth Syndrome?
Barth syndrome is a rare genetic mitochondrial disorder involving abnormal cardiolipin metabolism.
It can affect the heart, skeletal muscle, exercise tolerance, energy levels, growth, and other body systems.
Accelerated Approval Has a Specific Meaning
FDA’s accelerated-approval pathway allows earlier approval based on an intermediate endpoint reasonably likely to predict clinical benefit.
Continued approval may depend on confirmatory studies verifying that improved muscle strength translates into meaningful benefit for patients.
FDA-Approved Use vs. Broader SS-31 Research
FDA-Approved
Forzinity™ is approved to improve muscle strength in eligible patients with Barth syndrome weighing at least 30 kg.
This indication has actual FDA-reviewed clinical evidence, standardized manufacturing, prescribing information, and safety labeling.
Broader Research
SS-31/elamipretide has also been investigated in heart failure, primary mitochondrial disease, aging biology, skeletal muscle, kidney disease, and other conditions.
These broader uses are not FDA-approved indications.
FDA-Labeled Forzinity™ Administration
Approved Pharmaceutical Dosing
Forzinity prescribing information recommends 40 mg subcutaneously once daily for eligible patients weighing at least 30 kg.
Adult patients with severe renal impairment require a reduced dose according to the FDA prescribing information.
This Is Not a General “Mitochondrial Wellness Protocol”
The FDA-approved dose is specific to Forzinity and its approved Barth syndrome indication. It should not automatically be extrapolated to experimental longevity, performance, or wellness use.
Human Research in Barth Syndrome
The TAZPOWER clinical program included a randomized, placebo-controlled crossover phase followed by a long-term open-label extension.
Muscle Strength
Improvement in knee-extensor muscle strength became the intermediate clinical endpoint supporting FDA accelerated approval.
Functional Capacity
During the long-term extension, participants demonstrated improvement in six-minute walking distance compared with the start of the extension.
Long-Term Exposure
Some patients were followed for more than three years, providing important longer-term safety and clinical information in this rare disease population.
Small Rare-Disease Trial
The FDA clinical program involved only 12 patients with Barth syndrome, reflecting the extreme rarity of the disease.
That makes the evidence meaningful but very different from a large cardiovascular or metabolic drug trial involving thousands of patients.
SS-31 & Heart Mitochondria
Heart muscle depends continuously on mitochondrial ATP production. Mitochondrial abnormalities are therefore an important area of cardiovascular research.
Failing Human Heart Tissue
Laboratory research using freshly explanted failing human heart tissue found that exposure to elamipretide improved several measures of mitochondrial respiratory function.
Mitochondrial Respiration
Research has examined effects on oxygen flux, respiratory-chain activity, and mitochondrial supercomplex organization.
Cardiolipin Biology
Cardiolipin abnormalities occur in several models of cardiac dysfunction and remain a central mechanistic reason for studying elamipretide.
Clinical Heart Failure Research
Elamipretide has undergone human heart-failure trials, but it has not been established or FDA approved as a general heart failure therapy.
Important Translation Point
Improving mitochondrial function in failing human heart tissue in the laboratory is biologically important, but it is not the same as demonstrating improved survival, hospitalization rates, or long-term heart-failure outcomes in patients.
SS-31 & Healthy Aging Research
Mitochondrial dysfunction, altered energy production, and oxidative stress are frequently studied as contributors to age-related changes in muscle and cardiovascular function.
The Famous “8-Week Cardiac Aging” Study
In a 2020 study, researchers treated 24-month-old mice with SS-31 for eight weeks.
Treatment improved age-related diastolic dysfunction, myocardial performance, exercise capacity, mitochondrial proton leak, and oxidative stress.
This Does Not Mean SS-31 Reverses Human Aging
The cardiac-aging reversal experiment was performed in mice. It does not demonstrate that eight weeks of SS-31 reverses cardiac aging, biological age, or aging itself in humans.
Muscle, Energy & Physical Capacity
Muscles require ATP every time they contract.
When mitochondrial energy production is impaired, symptoms can include reduced endurance, fatigue, poor exercise tolerance, and muscle weakness.
Muscle Strength
Muscle-strength improvement is the clinical endpoint that ultimately supported Forzinity’s accelerated FDA approval in Barth syndrome.
Exercise Tolerance
Exercise capacity has been evaluated in both human mitochondrial-disease research and aging-animal studies.
ATP Production
Mitochondrial protein-interaction research supports effects on proteins involved in oxidative phosphorylation and energy metabolism.
Healthy Aging
Preservation of muscle and mitochondrial function is an important research target in aging, but human longevity benefits have not been established.
Related Mitochondrial Strategies
SS-31 targets mitochondrial membrane biology, but other strategies influence mitochondrial function through different pathways.
MOTS-c
A mitochondrial-derived peptide being studied for metabolic signaling, exercise adaptation, insulin sensitivity, and cellular stress responses.
Exercise
Regular exercise is one of the strongest physiologic signals for mitochondrial biogenesis, turnover, and metabolic adaptation.
Nutrition & Metabolism
Adequate micronutrients, protein, glucose regulation, and metabolic health all influence mitochondrial performance.
Sleep & Recovery
Cellular repair, metabolic regulation, and recovery from physical stress are strongly influenced by sleep quality.
Complementary Biology ≠ Proven Synergy
SS-31, MOTS-c, supplements, exercise, and other mitochondrial strategies may influence different pathways, but that does not mean combinations have been clinically proven to produce synergistic effects.
What Does the Evidence Actually Show?
Evidence Rating: Established for a Specific Rare Disease
SS-31 is unusual among peptides because an elamipretide drug has crossed into FDA-approved medicine.
That approval should not be generalized to every proposed mitochondrial or longevity application.
Safety & Important Considerations
Injection-Site Reactions
The most common adverse effects include redness, pain, firmness, itching, bruising, and urticaria at the injection site.
Hypersensitivity
Serious allergic reactions have been reported and can include skin and respiratory symptoms.
Renal Function
Adults with severe renal impairment require dosage adjustment under the FDA-approved prescribing information.
Neonates
Forzinity contains benzyl alcohol and is not approved for use in neonates because of the risk of benzyl-alcohol toxicity.
Approved Product Matters
FDA-reviewed Forzinity has standardized identity, concentration, manufacturing, sterility, and prescribing information.
Other Uses
Safety and benefit in healthy adults using elamipretide for general energy, performance, or anti-aging purposes are not established by the FDA approval.
Serious Hypersensitivity Can Occur
FDA labeling reports serious allergic reactions requiring emergency medical treatment in some patients.
Frequently Asked Questions
Are SS-31 and elamipretide the same thing?
Yes. SS-31 is the research name commonly used for the peptide later developed clinically as elamipretide.
What is Forzinity?
Forzinity™ is the FDA-approved elamipretide drug product used to improve muscle strength in eligible patients with Barth syndrome.
What does SS-31 target?
Elamipretide is classified by FDA as a mitochondrial cardiolipin binder that localizes to the inner mitochondrial membrane.
Does SS-31 increase ATP?
Its mechanism involves mitochondrial membrane and respiratory biology related to energy production. It is more accurate to say it may improve mitochondrial function than to promise a specific increase in ATP in every patient.
Does SS-31 reverse aging?
No human evidence establishes that SS-31 reverses aging. An important eight-week study improved several age-related cardiac abnormalities in old mice, which is promising preclinical research rather than proof of human age reversal.
Is SS-31 FDA approved?
Elamipretide is FDA approved as Forzinity for a specific Barth syndrome indication. General mitochondrial, longevity, performance, and other broader uses are not FDA-approved indications.
Is SS-31 the same as MOTS-c?
No. Both are discussed in mitochondrial health, but they are completely different peptides. SS-31 primarily targets mitochondrial membrane biology, while MOTS-c is a mitochondrial-derived signaling peptide involved in metabolic regulation.
The Bigger Picture
Mitochondrial health is influenced by physical activity, metabolic health, sleep, nutrition, cardiovascular fitness, muscle mass, inflammation, and exposure to physiologic stress.
A mitochondrial-targeted medication may influence one important part of this system, but it cannot replace the foundational signals that keep mitochondria healthy.
Better Energy Starts Inside the Cell
Mitochondria need intact membranes, efficient energy machinery, healthy metabolic signaling, adequate nutrients, and regular demand from movement and exercise.
Healthy mitochondria help create resilient cells.Interested in Mitochondrial & Metabolic Health?
Schedule a personalized wellness consultation to discuss energy, exercise capacity, metabolic health, muscle function, recovery, and strategies that support mitochondrial health.
Book a Wellness ConsultationSelected Scientific & Clinical References
FDA accelerated approval of Forzinity™ as the first treatment for Barth syndrome.
View FDA Approval →
FDA-approved indication, dosing, mechanism, safety, contraindications, and clinical-study information.
View Prescribing Information →
168-week open-label extension of the TAZPOWER study evaluating long-term elamipretide treatment in Barth syndrome.
View on PubMed →
Elamipretide and mitochondrial function in freshly explanted failing human heart tissue.
View on PubMed →
Mitochondrial protein-interaction landscape of SS-31 and proteins involved in oxidative phosphorylation and metabolic pathways.
View on PubMed →
Eight-week SS-31 treatment and age-related cardiac dysfunction, exercise capacity, mitochondrial proton leak, and oxidative stress in old mice.
View Study →
Phase 2 PROGRESS-HF trial evaluating elamipretide in patients with heart failure and reduced ejection fraction.
View on PubMed →