Longevity peptides are compounds marketed to slow aging, protect mitochondria or lengthen telomeres, but none has been shown to extend human lifespan. The most discussed are epitalon, MOTS-c, SS-31 and NAD+, along with GHK-Cu and thymosin alpha-1. Their best results come from cells and mice; SS-31 is FDA-approved, but only for a rare genetic disease.[1][6][11][12]

What are longevity peptides?

Longevity peptides are short amino-acid chains promoted to target the biology of aging rather than one disease. Sellers group them by the aging process they claim to address: mitochondrial energy (SS-31, MOTS-c), telomeres (epitalon), skin and tissue repair (GHK-Cu) and immune function (thymosin alpha-1).

NAD+ is usually sold alongside them, but it is a coenzyme made from vitamin B3, not a peptide.[3] The category also overlaps with others: see metabolic peptides for MOTS-c’s effects on blood sugar, skin peptides for GHK-Cu, and immunity peptides for thymosin alpha-1.

Browse all longevity peptides

See all 19 longevity peptides ↓

How anti-aging peptides work

Each compound targets a different piece of aging biology, and most of the evidence for each mechanism comes from the lab:

  • NAD+: a coenzyme that powers energy reactions and is consumed by DNA-repair and sirtuin enzymes. NAD+ appears to fall with age in some tissues,[3] but a 2026 study found whole-blood NAD+ stayed stable with age.[2]
  • Epitalon: switched on telomerase and lengthened telomeres, the protective caps on chromosomes, in human cell cultures.[4][5]
  • MOTS-c: a signal from mitochondria that activates the energy sensor AMPK. In mice it prevented diet-induced obesity and improved physical performance at every age.[9][10]
  • SS-31: binds cardiolipin inside mitochondria.[13] One dose restored muscle energy production in old mice within an hour.[14]
  • GHK-Cu: stimulated collagen production by skin cells in lab dishes.[16]
  • Thymosin alpha-1: an immune-activating peptide; it is grouped here because of interest in immune aging, but its trials tested infections and cancer, not aging.[18][28]

Do any peptides extend human lifespan?

No. The lifespan claims trace back to animals and to old Russian cohort studies:

  • Epitalon and epithalamin: a Russian study of 266 older adults reported 1.6 to 1.8-fold lower mortality in the group given the pineal extract epithalamin (not epitalon); other groups received a thymus extract. Details on randomization and blinding are limited, and an Alzheimer’s research foundation review noted there has been no independent confirmation.[7][23]
  • MOTS-c: treatment late in life improved strength and walking in old mice, but the increase in lifespan was not statistically significant. No human trial of MOTS-c itself has been published.[10][11]
  • SS-31: in 39 adults aged 60 to 85, a single infusion produced only a borderline improvement in muscle energy production and no change in fatigue.[13] Its largest trial, in 218 adults with mitochondrial myopathy, missed its main goals.[15]
  • NAD+: a 2026 systematic review found no trials testing IV or injected NAD+ for aging or wellness outcomes.[1] Oral precursors such as NMN and NR do raise blood NAD+,[1] but in a year-long trial of 410 people with early Parkinson’s disease, NR did not slow the disease.[29]

Mitochondrial peptides: SS-31 vs MOTS-c

SS-31 and MOTS-c are both sold as “mitochondrial peptides”, but their evidence is very different.

SS-31MOTS-c
OriginLab-designed drug (elamipretide)Natural peptide made by mitochondria[9]
Human trialsSeveral, including the trial behind its Barth syndrome approval[12][15]None published for MOTS-c itself[11]
Aging dataMice; one single-dose study in older adults[13][14]Mice only[10]

An improved MOTS-c analog, CB4211, reached a small phase 1 trial in people with fatty liver disease. In 20 people with fatty liver disease, CohBar reported lower liver enzymes (ALT and AST) after four weeks, but liver fat fell by a similar amount on placebo.[26] Neither peptide has been tested as an anti-aging treatment in a long-term human trial.

Skin and immune aging: GHK-Cu and thymosin alpha-1

GHK-Cu’s anti-aging reputation comes mainly from skincare. It boosts collagen in lab dishes,[16] but peer-reviewed human evidence for visible results is limited, and there are no published human studies of the injections now sold for “systemic” anti-aging.[17] Thymosin alpha-1 is sold as a medicine in other countries, mainly for hepatitis B,[28] but it has never been tested as an aging treatment, and its largest recent trial, in sepsis, found no survival benefit.[18]

Telomere claims vs evidence

Telomere length is the most common selling point for epitalon. Here is what has and has not been shown:

ClaimEvidence
Epitalon lengthens telomeresTrue in human cell cultures, in a 2003 Russian study and an independent 2025 UK study[4][5]
It lengthens telomeres in peopleNever tested in a published human study[6]
Longer telomeres mean a longer lifeNot established; a large genetic study linked longer telomeres to higher risk of several cancers but lower risk of heart disease[8]
Telomerase activation is harmlessUnknown; in the UK study, breast cancer cells also lengthened their telomeres, and FDA raised a theoretical cancer concern[5][6]

The genetic study is worth understanding. Using inherited gene variants across more than 400,000 cases, researchers found that people genetically inclined to longer telomeres had higher odds of cancers such as glioma, lung adenocarcinoma and melanoma.[8] That does not prove epitalon causes cancer, but it shows why longer telomeres are not automatically better.

Safety, legality and sports rules

  • FDA approval: only SS-31 is FDA-approved, as Forzinity, under accelerated approval for Barth syndrome in patients weighing at least 30 kg, in September 2025.[12] The others are not FDA-approved for any use, although GHK-Cu is a legal cosmetic ingredient and thymosin alpha-1 is sold as a medicine in other countries.[28]
  • Compounding: FDA advisers reportedly voted 7 to 5 in July 2026 to recommend compounded epitalon (for insomnia) and MOTS-c, against FDA staff advice; FDA had not acted on either vote at our last review.[6][11][24][27] NAD and non-injectable GHK-Cu are still under FDA evaluation.[21] Advisers voted 17 to 4 against compounded thymosin alpha-1 in 2024.[19]
  • Unknown long-term safety: FDA found no human study of epitalon that reported safety data, found no human exposure data for MOTS-c, and it has flagged immune reactions and impurities as risks of injected peptides.[6][11][20] FDA has also warned that some compounded IV NAD+ was made from ingredients not suitable for sterile use.[25]
  • Gray-market SS-31 is not the approved product, and “research use only” vials are not tested for identity, purity or dose. GHK-Cu injections have never been studied in people.[17]
  • Sports: WADA names MOTS-c as a prohibited AMPK activator, and limits IV infusions such as NAD+ drips to 100 mL per 12 hours outside hospital care. Epitalon is not named, but in our reading, as an unapproved substance it falls under category S0.[22]

This is general information, not medical or legal advice.