HNG (S14G-Humanin)

What it is

HNG is humanin with one amino acid swapped, which made it about a thousand times stronger in the original cell tests and turned it into the version most humanin research actually uses. People run it a few times a week as the 'protect the cells' piece of a mitochondrial or longevity stack. Every result so far is in cells or rodents, so you are buying a mechanism, not an outcome you will feel.

HNG belongs to a specific kind of user: the person building a mitochondrial stack with MOTS-c and SS-31 who wants the survival-signal arm, and the person with Alzheimer's or heart disease in the family who has read the rodent neuroprotection papers and would rather do something than nothing. A few run it after a cardiac event or during a hard training block hoping for the stress-resistance effect. It is not a beginner's peptide and not a peptide that fixes a symptom.

What you will notice: in most cases, nothing at all, and that is expected. Humanin's job in the rodent studies is to keep stressed cells alive, under amyloid, oxygen loss or metabolic strain, and a healthy person has no way to feel that. Some users report steadier energy or better sleep over a few weeks; that is the same thing people say about every mitochondrial peptide. If you are expecting a focus effect like Semax or an energy lift like NAD+, you will be disappointed by week two and tempted to double the dose, which is the common mistake.

Dosing is guesswork anchored to the Humanin record: 100, 250 or 500 mcg subQ two to three times a week for 8 to 12 weeks, then a few weeks off. That break is caution, not a reset: with no human data, nobody knows whether steady use is a problem or whether the effect fades. Because HNG is far more potent than native humanin in the dish, the tiers sit at or below humanin's rather than above. Start at 100 mcg, hold for two weeks, then settle at 250 mcg if nothing odd happens. A 5 mg vial mixed with 1 ml gives 20 doses at 250 mcg, which is 7 to 10 weeks, so one vial is one cycle. Keep it as the only new peptide for the first cycle so a reaction can be attributed.

Evidence sits at animal 3, human 0. The rodent literature is real and consistent: less neuron death in Alzheimer's-type and stroke models, smaller heart damage after blocked-then-restored blood flow, better insulin sensitivity in some metabolic models. The thousand-fold potency claim is from cell assays and tells you nothing about a human dose. There are no human trials of HNG at any dose, so the whole case rests on mechanism and animals.

Not worth it as a first longevity peptide: SS-31 has human trials under the name elamipretide and NAD+ at least has human tolerability data. Not worth it if a specific symptom is the goal; HNG does not treat anything you can measure at home. If you want the native signal rather than the analog, the Humanin record covers the same ground at higher doses. HNG makes sense as the third or fourth piece of a mito stack for someone who has already run the better-proven pieces and accepts that this one is a bet.

What people use it for

Safety, in brief

The full picture — stop signs and who should talk to a doctor first — is on the dosing guide.

Sources

The labels and studies behind this page. Each link opens the original on PubMed, DailyMed or ClinicalTrials.gov.

1. A humanin derivative, S14G-HN, prevents amyloid-beta-induced memory impairment in miceTajima et al., J Neurosci Res 2005 · Study
2. Acute humanin therapy attenuates myocardial ischemia and reperfusion injury in miceMuzumdar et al., Arterioscler Thromb Vasc Biol 2010 · Study
3. Neuroprotective Action of Humanin and Humanin Analogues: Research Findings and PerspectivesKarachaliou et al., Biology (Basel) 2023 · Review