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, GHK-Cu in dermatology research.
Most of these compounds are not FDA-approved. FDA removed KPV, Epitalon, MOTS-c, and Semax from Category 2 on April 22, 2026, after their nominations were withdrawn. FDA removed Selank from Category 2 on September 27, 2024, after the nomination was withdrawn. As of September 14, 2026, none of these five peptides is in any FDA 503A category or on the 503A bulks list. As of September 2026, FDA has not made a final decision on BPC-157 or TB-500. At its July 23–24, 2026 meeting, FDA's Pharmacy Compounding Advisory Committee voted separately on each. Both votes were 8 yes, 6 no, and 1 abstention to recommend adding the peptide to the Section 503A bulk drug substances list. The committee is advisory, and formal addition to the list requires further FDA action.
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 physician 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 physician oversight matter.
Disclaimer
Several peptides discussed in this article — including KPV, Epitalon, MOTS-c, Selank, and Semax — were previously in FDA's Category 2. FDA removed them from Category 2 (September 2024 or April 2026, depending on the peptide). As of September 14, 2026, they are not in any FDA 503A category and are not on the 503A bulks list. In February 2026, HHS Secretary Robert F. Kennedy Jr. said in a podcast interview that FDA would soon make more peptides accessible. That was not a formal proposal; the formal step was FDA's April 2026 change to its category list. As of September 2026, FDA has not made a final decision on BPC-157 or TB-500. At its July 23–24, 2026 meeting, FDA's Pharmacy Compounding Advisory Committee voted separately on each. Both votes were 8 yes, 6 no, and 1 abstention to recommend adding the peptide to the Section 503A bulk drug substances list. The committee is advisory, and formal addition to the list requires further FDA action. This article is educational and is not medical advice. Halftime Health only prescribes through licensed physicians in states where our partner physicians are credentialed.
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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 whose FDA compounding status has been under review (see our FDA categorization explainer). Halftime Health protocols are prescribed by licensed physicians and prepared by licensed 503A compounding pharmacies. Compounded drugs are not FDA-approved and have not been evaluated by FDA for safety or effectiveness. This article is provided for educational purposes only and does not constitute medical advice or an offer to sell.
Frequently asked questions
What are the hallmarks of aging?
Researchers describe twelve cellular and systemic processes that drive aging — including mitochondrial dysfunction, telomere shortening, cellular senescence, and chronic inflammation.
Which peptides target hallmarks of aging?
MOTS-c is studied for mitochondrial dysfunction. Epitalon is studied for telomere biology. Thymosin alpha-1 is studied for immunosenescence. Most evidence is preclinical.
Do peptides slow aging?
Some peptides engage pathways involved in aging biology in research settings. Whether they meaningfully extend human healthspan is not yet established. Caution and physician oversight matter.
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