The hallmarks of aging — and which peptides target which

A field map, drawn carefully — because the evidence is real in some lanes and thin in others.

TL;DR

• Researchers describe twelve “hallmarks” — biological processes that drive aging.
• Specific peptides have been studied for several of these, mostly in cells and animals.
• Human evidence for peptides as longevity tools is still early. Read the field as research, not settled medicine.

What it is

The hallmarks of aging are a framework biologists use to organize what changes inside cells and tissues as we get older. The original 2013 paper proposed nine hallmarks; the updated 2023 version describes twelve, including genomic instability, telomere shortening, mitochondrial dysfunction, cellular senescence, and chronic inflammation (López-Otín et al., 2023). Together they form a checklist of what longevity researchers are trying to slow, halt, or reverse.

How it works

Think of aging as a slow leak in many systems at once. Each hallmark is a different leak. Some peptides act on a single hallmark — MOTS-c (in plain English: a small peptide encoded in mitochondrial DNA) engages mitochondrial dysfunction. Others touch several. The honest framing: these peptides plug specific leaks in research models. Whether plugging those leaks meaningfully extends human healthspan is the open question of the field.

Who asks about it

People come to this topic when they’re past general longevity-product marketing and want to understand the actual biology. They’ve heard names — Epitalon, MOTS-c, Thymosin alpha-1 — and want to know which mechanism each one engages with, and which evidence to trust.

What the research says

A simplified map:

• Mitochondrial dysfunction → MOTS-c. Studied in animal models for metabolic and exercise-mimetic effects.
• Telomere attrition → Epitalon. Animal and limited human studies suggest telomerase activation; long-term outcome data is absent.
• Immunosenescence (in plain English: aging of the immune system) → Thymosin alpha-1. Most studied peptide for immune aging support.
• Loss of proteostasis and tissue repair → BPC-157, TB-500. Strong animal data; very limited human trials.
• Chronic inflammation (“inflammaging”) → KPV (Category 2), GHK-Cu in dermatology research.

Most of these compounds are not FDA-approved. BPC-157, TB-500, KPV, Epitalon, MOTS-c, Selank, and Semax are currently classified as Category 2 (in plain English: not available from 503A compounding pharmacies as of May 2026, pending regulatory updates).

What to know before considering it

Mechanism is not outcome. A peptide can engage a hallmark in a research dish without meaningfully changing how long or how well a person lives. Be skeptical of any product or clinic that promises lifespan extension. The honest position is curiosity, plus careful clinician oversight, plus willingness to wait for better data.

The Halftime POV

We respect the science and we respect the ceiling of the science. The hallmarks framework is genuinely useful for organizing the field. Some peptides hit some hallmarks in research. The leap from “engages a pathway” to “extends life” is a leap nobody has made yet. We say so.

Related reading:

• The hallmarks of aging: how the field maps biological decline
• MOTS-c: the mitochondria-derived peptide in the literature
• Epitalon and the telomere research

FAQ

Q: What are the hallmarks of aging? A: Researchers describe twelve cellular and systemic processes that drive aging — including mitochondrial dysfunction, telomere shortening, cellular senescence, and chronic inflammation.

Q: Which peptides target hallmarks of aging? A: MOTS-c is studied for mitochondrial dysfunction. Epitalon is studied for telomere biology. Thymosin alpha-1 is studied for immunosenescence. Most evidence is preclinical.

Q: Do peptides slow aging? A: Some peptides engage pathways involved in aging biology in research settings. Whether they meaningfully extend human healthspan is not yet established. Caution and clinician oversight matter.

Disclaimer

As of 2026-05-09, several peptides discussed in this article — including BPC-157, TB-500, KPV, Epitalon, MOTS-c, Selank, and Semax — are classified by the FDA as Category 2, which means they are not currently available from 503A compounding pharmacies. A February 2026 HHS announcement proposed returning these peptides to Category 1 pending formal FDA Federal Register notice. This article is educational and is not medical advice. Halftime Health only prescribes through licensed clinicians in states where our partner physicians are credentialed.

Get updates

Halftime Health is launching soon. We’ll share what we learn along the way — the research, the regulations, the real-world trade-offs. Join the waitlist and we’ll email you when we’re live.

Sources

• López-Otín C, et al. Hallmarks of aging: an expanding universe. (PubMed, 2023)
• López-Otín C, et al. The hallmarks of aging (original). (PubMed, 2013)

This article discusses compounds that are currently under FDA Category 2 review (see our FDA categorization explainer). These compounds are not currently part of Halftime Health’s published protocol catalog. This article is provided for educational purposes only and does not constitute medical advice or an offer to sell.