Longevity Peptides
Healthspan, mitochondrial, and immune compounds, separated by whether the data is human or rodent.
Longevity is the hardest category to evidence, because the endpoint takes decades to measure. What studies actually report are surrogates: NAD+ levels, mitochondrial function, telomerase activity, immune markers. Some compounds here have genuine clinical footing, elamipretide reached late-stage trials and thymosin alpha-1 is approved in dozens of countries. Others rest on mouse lifespan curves. The grades below tell you which is which.
Thymosin Alpha-1
A-gradeA 28-amino-acid thymic peptide approved in 35+ countries as Zadaxin for immune support, but never FDA-approved in the United States.
Oxytocin
B-gradeA naturally occurring nonapeptide, FDA-approved as Pitocin for labor, and separately studied off-label (intranasal) for social bonding and stress research.
SS-31 (Elamipretide)
B-gradeA mitochondria-targeting tetrapeptide, FDA-approved in September 2025 for Barth syndrome, a real approval in one narrow rare disease, not a general muscle or longevity drug.
Humanin
C-gradeA mitochondrial-derived peptide discovered protecting neurons from Alzheimer's-linked toxicity, cell and rodent data only, no human trial exists.
MOTS-c
C-gradeA mitochondrial-derived peptide that supports metabolic flexibility, insulin sensitivity, and exercise capacity.
VIP (Vasoactive Intestinal Peptide)
C-gradeA 28-amino-acid neuropeptide with broad vasodilator, anti-inflammatory, and immunomodulatory effects, cleared from plasma within about a minute.
Epithalon
D-gradeA synthetic tetrapeptide analog of a natural pineal gland peptide, studied for telomerase activation and circadian regulation.
SLU-PP-332
D-gradeA pan-ERR agonist nicknamed the 'exercise pill', reduced fat mass and raised fatty-acid oxidation in obese mice, with zero human trials as of 2026.
SLU-PP-915
D-gradeThe first orally-active pan-ERR agonist, raised exercise capacity in mice even when dosed orally, where its predecessor SLU-PP-332 needed injection.
Adamax
F-gradeA synthetic nonapeptide analog of Semax with N-terminal acetylation and adamantyl C-terminal modification, studied for enhanced BDNF signaling and blood-brain barrier penetration.
Pinealon
F-gradeA Khavinson-group tripeptide bioregulator, studied preclinically for neuroprotective and cognitive-aging effects.
Guides in this category
Best Peptides for Anti-Aging
Compare the best anti-aging peptides for longevity, skin health, cognitive function, and cellular repair. Evidence-based rankings.
Best Peptides for Sleep
Compare the best peptides for sleep quality: DSIP, ipamorelin, CJC-1295, Selank, epithalon. Evidence-based rankings with dosing.
Best Peptides for Cognitive Enhancement
Compare the best nootropic peptides for focus, memory, and neuroprotection. Evidence-based rankings of Semax, Selank, and more.
Best Peptides for Sexual Health
Compare peptides for libido, arousal, and hormonal support. Evidence-based rankings of PT-141, kisspeptin-10, and more.
Best Peptides for Immune Support
Compare peptides for immune modulation and antimicrobial defence. Evidence-based rankings of thymosin alpha-1, LL-37, and more.
Epithalon vs SS-31 (Elamipretide)
Epithalon vs SS-31 (Elamipretide): mechanism, dosing, evidence grade, and side effects compared side by side, with citations.
Longevity peptide questions
How many longevity peptides are there?
This library covers 11 longevity compounds, each graded from S (regulatory approval) to F (no usable evidence).
Which longevity peptide has the strongest evidence?
Thymosin Alpha-1 carries the highest research grade in this category at A. A 28-amino-acid thymic peptide approved in 35+ countries as Zadaxin for immune support, but never FDA-approved in the United States.
What does the research grade mean?
The grade describes how well a compound has been measured in humans, not how well it works. S means regulatory approval; D means animal data only. Popularity and anecdote do not affect it.