What is Humanin and what does it do?
Humanin is a 21-amino-acid mitochondria-derived peptide with neuroprotective, cardioprotective, and metabolic effects. Levels decline with age.
Updated May 11, 2026 · 3 min read
Humanin is a 21-amino-acid peptide encoded entirely within mitochondrial DNA — not nuclear DNA — making it unusual among biologically active peptides. It has documented neuroprotective, cardioprotective, and insulin-sensitizing effects in cell and animal models, and its circulating levels decline with age. In the biohacking and longevity community, it's used as a supplemental peptide to counter some of the metabolic and cellular aging signals that rising with time.
Where Humanin comes from
Humanin was discovered in 2001 by Nishimoto and colleagues, who found it by screening a cDNA library built from neurons that had survived in an Alzheimer's patient's brain — neurons that resisted the neurotoxic signals causing the surrounding cells to die. The peptide they identified, which they named Humanin, protected neurons from Alzheimer's-related toxins in vitro.
The unusual origin: Humanin is encoded in the 16S rRNA region of mitochondrial DNA. This makes it a "mitochondria-derived peptide" (MDP) — a class that also includes MOTS-c and SS-31. MDPs are increasingly recognized as important mediators between mitochondrial function and the broader cellular environment.
What Humanin does
Pre-clinical research has identified several overlapping mechanisms:
Neuroprotection
- Protects neurons from Alzheimer's-associated amyloid-beta toxicity
- Anti-apoptotic signaling via the STAT3 and PI3K/Akt pathways
- Studied in ischemic stroke models with positive results in reducing infarct size
Cardioprotection
- Reduces ischemia-reperfusion injury in cardiac tissue
- Attenuates cardiomyocyte apoptosis during oxidative stress
Metabolic effects
- Improves insulin sensitivity in animal models of diabetes
- Reduces hepatic glucose production
- Interacts with IGF-1 binding protein-3 (IGFBP-3), which modulates how IGF-1 signaling works in tissue
Anti-aging signal
- Circulating Humanin levels decline with age in humans
- Studies in the offspring of centenarians show they have significantly higher Humanin levels than age-matched controls — suggesting Humanin may be part of what makes long-lived families resilient
- Exogenous Humanin administration in aged animal models improved mitochondrial function and metabolic markers
HNG — the more potent variant
S14G-Humanin, often written HNG, is a single amino-acid substitution (glycine replaces serine at position 14) that increases potency roughly 1,000-fold in some assays. Most research peptide preparations of "Humanin" are actually HNG. If a vendor doesn't specify, assume they're selling HNG — ask for clarity.
What human data exists
The honest answer: limited. Most Humanin research is in cell cultures and rodents. Small observational human studies support the idea that higher Humanin levels correlate with better metabolic health and longevity signals. But there are no large randomized clinical trials of exogenous Humanin as a therapeutic intervention. Users are extrapolating from compelling but incomplete biology.
How the biohacking community uses it
Typical reported protocols:
| Parameter | Common approach |
|---|---|
| Compound | Humanin or HNG |
| Dose | 4–10 mg per injection |
| Frequency | 1–2x per week, SubQ |
| Cycle | 8–12 weeks, then reassess |
Most users combine Humanin with other mitochondrial/metabolic peptides — MOTS-c is the most frequent pairing, since the two have complementary mechanisms (MOTS-c focuses more on nuclear gene expression and exercise metabolism, Humanin on cellular protection and insulin signaling).
The safety reality
There is no long-term human safety dataset. Users are working from rodent toxicology data and a small collective of self-experimentation reports. The injection-site reaction profile appears mild based on community reports, and no serious adverse events have been widely documented. That's not the same as "safe" — it reflects the limits of the available data.
If you're considering Humanin, verify your source is selling what it claims using a COA from an accredited lab. See what does a COA show.