Elamipretide the Mitochondrial Peptide
By Dr Andrew Crockett
Elamipretide (Forzinity) is the first therapy to step inside the mitochondria and attempt structural repair rather than symptom management. One of its functions is that it binds a key lipid, cardiolipin, to steady the inner architecture of the cell’s power stations and improve energy output. Approved for the ultra-rare Barth syndrome, it may signal a turning point: mitochondrial dysfunction might no longer be an inevitable feature of ageing, but a modifiable biological system. It is an elegant idea, with a good safety profile and significant promise, though proof of broad clinical benefit is still yet to be explored with outcome studies.
Background
Every cell in the human body depends on mitochondria to convert oxygen and nutrients into usable energy. When those engines sputter, the results ripple through muscle, brain, and heart. Fatigue, metabolic dysfunction, and accelerated ageing all trace some part of their pathology back to a faltering energy system.
In 2025, the U.S. FDA quietly approved Elamipretide (Forzinity) for Barth syndrome. The decision made few front-page headlines, but in scientific circles it was seismic: the first official recognition that mitochondrial structure can be pharmacologically repaired. For the longevity field, a domain often crowded with speculation, this was a hard-won moment of validation.
A Glimpse into Barth Syndrome
Barth syndrome is a rare genetic fault in TAZ, the gene responsible for crafting cardiolipin, a fat molecule that acts like rebar in the mitochondrial wall. Without it, the inner folds (cristae) collapse, and energy production falters.
Elamipretide is a short positively charged peptide which slips through cell membranes and latches onto cardiolipin, bracing the structure and restoring the geometry needed for efficient ATP generation [FDA, 2025]. Its licence covers only this single disorder, but its conceptual reach is far wider: proof that mitochondrial repair is not science fiction.
How It Works
Mitochondria hold a negative electrical charge inside their membranes, a quirk of chemistry that draws elamipretide inward. Once there, the peptide binds to cardiolipin, a lipid found nowhere else in the body, keeping the cristae tidy and the respiratory chain running smoothly [PMID: 17025271]. The result is better electron flow, higher ATP yield, and fewer stray electrons leaking out as reactive oxygen species (ROS) [PMID: 24134698].
In cell and animal studies, this leads to cleaner bioenergetics, higher energy output, lower oxidative debris, and improved performance in heart and skeletal muscle. The effect is less a turbo-boost and more a tune-up, subtle, stabilising, and mechanistically convincing.
Human Evidence
Barth Syndrome (TAZPOWER): In the randomized, placebo-controlled TAZPOWER trial with a 168-week open-label extension, daily subcutaneous elamipretide was generally well tolerated (injection-site reactions most common) and was associated with sustained improvements in 6-minute walk distance, fatigue scores, and 3D left-ventricular volumes [PMID: 38602181].
Heart Failure with reduced EF (HFrEF): In the PROGRESS-HF phase 2 trial ($n=71$), four weeks of daily subcutaneous elamipretide did not improve the primary endpoint (LV end-systolic volume by CMR) or LVEF versus placebo; study-drug-related adverse-event rates were similar across groups [PMID: 32068002].
Aging Muscle/“Efficiency”: In healthy older adults selected for impaired skeletal-muscle mitochondrial capacity, a single two-hour elamipretide infusion transiently increased ATPmax immediately post-dose without improving measured local fatigue; the effect was no longer evident by day seven (PMID: 34264994).
Strengths in the Design
Elamipretide stands out for its precision. It binds only to cardiolipin, a lipid found exclusively in mitochondria, leaving other cellular systems untouched. The result is a cleaner pharmacology than most molecules in its class. Mechanistically, it improves the central task of mitochondria oxidative phosphorylation allowing for more efficient energy production without flooding the system with unwanted by-products.
Equally important is its balance. Elamipretide reduces oxidative stress but doesn’t smother the mild redox signals that drive adaptation, repair, and resilience. Under the microscope, electron imaging shows something few drugs can claim, repaired mitochondrial folds, or cristae, visibly restored to structure.
These details give elamipretide an unusually coherent scientific story in a space often dominated by grand claims and thin evidence.
Where It Falters
Mechanistic beauty does not guarantee clinical transformation. Better electron flow on a microscope slide doesn’t always yield stronger legs or a more resilient heart. Most studies run only 12–36 weeks; we know little about what happens when the peptide is withdrawn, or when it is taken for years.
Cost and access remain barriers. And because mitochondria thrive on intermittent stress, the hormetic jolt of exercise, fasting, or cold, some scientists question whether chronic pharmacological support might blunt those natural signals. In other words, stabilise too much and you may sterilise adaptation.
A Growing Mitochondrial Toolkit
Elamipretide has reignited a field that once felt almost mythical, the idea of directly repairing the cell’s energy machinery. Around it, a new generation of mitochondrial drugs is quietly emerging. Researchers are refining SS-31 analogues for better tissue uptake, designing molecules that regulate the mitochondrial permeability transition pore to limit damage after ischaemia, and developing targeted antioxidants such as MitoQ and SkQ that deliver redox-active compounds straight into the organelle.
Different mechanisms, one shared ambition: to preserve the structure and stability of mitochondria, the architecture that underpins metabolic life.
Performance and Longevity
Ageing can be read as a slow unraveling of mitochondrial order. Energy dips, ROS rise, signalling falters. In that sense, mitochondria sit at the crossroads of physiology and philosophy: the point where metabolism meets mortality.
In healthy older adults, elamipretide’s effects are modest: a transient increase in ATPmax without improvement in volitional fatigue resistance (VO2max or maximal strength were not tested) [PMID: 34264994]; even in patient cohorts with mitochondrial myopathies, short-course treatment did not change CPET/VO2 outcomes [PMID: 29500292], and strength gains have been observed only after many months of continuous therapy in Barth syndrome [PMID: 33077895; PMID: 36056411]. Overall, its likely use is in recovery/resilience rather than peak enhancement.
For clinicians in the health-span and performance space, the message is restraint. Mitochondrial peptides are promising adjuncts, not replacements for the old triad of training, nutrition, and sleep. Resistance work, adequate protein, metabolic flexibility, and circadian regularity still drive the strongest improvements in mitochondrial density and efficiency. Pharmacology can support the orchestra, but lifestyle remains the conductor.
What We Still Don’t Know
Durability: Do the benefits persist once treatment stops?
Synergy: How does it interact with NAD⁺ boosters, fasting, or exercise mimetics?
Delivery: Can oral or transdermal forms reach therapeutic levels?
Range: Will results extend from rare syndromes to the metabolic mainstream?
The answers will decide whether mitochondrial peptides stay boutique or move into the core of preventive medicine.
Clinical Takeaway
Elamipretide is safe, elegant, and credible. Its approval signals the start of an era in which the mitochondrion is not merely a victim of ageing but a target for repair. For now, it functions as a proof of principle, a well-engineered molecule showing that cellular energy can, in fact, be stabilised.
Used wisely, mitochondrial-targeted therapies may complement the pillars of performance and longevity medicine rather than compete with them. The mitochondrion, once an obscure organelle in biology textbooks, is now a clinical frontier - small, complex, and charged with possibility.
References
U.S. Food and Drug Administration. FDA Approves First Therapy Targeting Mitochondrial Dysfunction for Barth Syndrome [Forzinity / Elamipretide]. FDA Press Release, 2025.
Szeto HH. Mitochondria-targeted peptide antioxidants: novel neuroprotective agents. AAPS J. 2006 Aug 18;8(3):E521-31. doi: 10.1208/aapsj080362. PMID: 17025271; PMCID: PMC2761060.
Butler J, Khan MS, Anker SD, Fonarow GC, Kim RJ, Nodari S, O'Connor CM, Pieske B, Pieske-Kraigher E, Sabbah HN, Senni M, Voors AA, Udelson JE, Carr J, Gheorghiade M, Filippatos G. Effects of Elamipretide on Left Ventricular Function in Patients With Heart Failure With Reduced Ejection Fraction: The PROGRESS-HF Phase 2 Trial. J Card Fail. 2020 May;26(5):429-437. doi: 10.1016/j.cardfail.2020.02.001. Epub 2020 Feb 14. PMID: 32068002.
Birk AV, Chao WM, Bracken C, Warren JD, Szeto HH. Targeting mitochondrial cardiolipin and the cytochrome c/cardiolipin complex to promote electron transport and optimize mitochondrial ATP synthesis. Br J Pharmacol. 2014 Apr;171(8):2017-28. doi: 10.1111/bph.12468. PMID: 24134698; PMCID: PMC3976619.
Reid Thompson W, Hornby B, Manuel R, Bradley E, Laux J, Carr J, Vernon HJ. A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome, a genetic disorder of mitochondrial cardiolipin metabolism. Genet Med. 2021 Mar;23(3):471-478. doi: 10.1038/s41436-020-01006-8. Epub 2020 Oct 20. PMID: 33077895; PMCID: PMC7935714.
Karaa A, Haas R, Goldstein A, Vockley J, Weaver WD, Cohen BH. Randomized dose-escalation trial of elamipretide in adults with primary mitochondrial myopathy. Neurology. 2018 Apr 3;90(14):e1212-e1221. doi: 10.1212/WNL.0000000000005255. Epub 2018 Mar 2. Erratum in: Neurology. 2018 Apr 3;90(14):669. doi: 10.1212/WNL.0000000000005461. Erratum in: Neurology. 2018 Nov 20;91(21):986. doi: 10.1212/WNL.0000000000006635. PMID: 29500292; PMCID: PMC5890606.
Sabbah HN, Taylor C, Vernon HJ. Temporal evolution of the heart failure phenotype in Barth syndrome and treatment with elamipretide. Future Cardiol. 2023 Mar;19(4):211-225. doi: 10.2217/fca-2023-0008. Epub 2023 Jun 16. PMID: 37325898.
Thompson WR, Manuel R, Abbruscato A, Carr J, Campbell J, Hornby B, Vaz FM, Vernon HJ. Long-term efficacy and safety of elamipretide in patients with Barth syndrome: 168-week open-label extension results of TAZPOWER. Genet Med. 2024 Jul;26(7):101138. doi: 10.1016/j.gim.2024.101138. Epub 2024 Apr 8. PMID: 38602181.
Reid Thompson W, Hornby B, Manuel R, Bradley E, Laux J, Carr J, Vernon HJ. A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome, a genetic disorder of mitochondrial cardiolipin metabolism. Genet Med. 2021 Mar;23(3):471-478. doi: 10.1038/s41436-020-01006-8. Epub 2020 Oct 20. PMID: 33077895; PMCID: PMC7935714.
Roshanravan B, Liu SZ, Ali AS, Shankland EG, Goss C, Amory JK, Robertson HT, Marcinek DJ, Conley KE. In vivo mitochondrial ATP production is improved in older adult skeletal muscle after a single dose of elamipretide in a randomized trial. PLoS One. 2021 Jul 15;16(7):e0253849. doi: 10.1371/journal.pone.0253849. PMID: 34264994; PMCID: PMC8282018.
