In this article

The short answer: Some measurable markers of aging can move in the right direction, but nobody has shown that human aging itself is reversed. Epigenetic clock scores have dropped in a few small trials, and clearing senescent cells improves function in mice, with only early pilot data in people. The most defensible stance today: lifestyle changes can shift clock readings and function, drug-based "reversal" is experimental, and a lower clock number is not yet proof of a longer life.

  1. 01What Reversal Means
  2. 02Epigenetic Clocks
  3. 03Senescent Cells
  4. 04What You Can Do
  5. 05FAQ
  6. 06Key Takeaways
  7. 07References
Jump to key takeaways

What does "reversing aging" actually mean?

Aging is not one thing. The hallmarks of aging framework (López-Otín et al., 2023) lists twelve interlinked processes, including epigenetic change, cellular senescence, and loss of proteostasis. "Reversal" in a headline usually means one measured marker moved, not that the whole system was rewound. Ask three questions of any claim: what was measured, in whom, and for how long.

Marker

An epigenetic clock score or a biomarker. Can move without changing health.

Function

Walking speed, strength, fitness. Closer to what you feel day to day.

Outcome

Disease and lifespan. The slowest to measure and the least tested.

For the broader framework, see the hallmarks of aging guide.

What do epigenetic clocks show?

Epigenetic clocks estimate age from DNA methylation patterns. A widely cited one (Horvath, 2013) was built from thousands of samples across many tissues. Newer measures, such as DunedinPACE (Belsky et al., 2022), estimate the pace of aging instead of an age in years. Clocks are real research tools, but a clock score is a statistical estimate, and different clocks can disagree.

Age clocks
Estimate biological age in years from methylation at selected sites.
Pace clocks
Estimate how fast aging is proceeding, trained on decades of change in organ function.

Two small studies reported clock scores moving down. A pilot randomized trial of an eight-week diet and lifestyle program in 43 healthy men reported a lower methylation age than controls (Fitzgerald et al., 2021), though the authors called for larger and longer trials and the paper was later corrected. The TRIIM study, a nine-man single-arm trial of growth hormone with other drugs, reported a lower epigenetic age at the end of a year (Fahy et al., 2019); outside researchers noted it was very small and uncontrolled.

Caveat

Both studies are small, short, and measured a clock rather than disease or lifespan. They justify larger trials, not a claim that aging was reversed.

More on reading these scores in what epigenetic age means.

Can clearing senescent cells reverse aging?

Senescent cells stop dividing but stay metabolically active and release inflammatory signals. In a mouse model of accelerated aging, removing p16-positive senescent cells delayed the onset of age-related problems in several tissues and slowed some already established ones (Baker et al., 2011). That is a mouse result in a specialized model, and it did not apply to every tissue.

In mice

  • • Genetic clearance delayed some age-related disorders
  • • Effects varied by tissue

In people

  • • A 14-person open-label pilot of dasatinib plus quercetin in lung fibrosis (Justice et al., 2019)
  • • Mainly tested feasibility; no placebo group

The human pilot supported feasibility and the authors called for larger randomized trials. Senolytic drugs are not an approved anti-aging treatment, and supplement versions are not equivalent to the trial regimen. See senescent cells explained.

What can you do that has support today?

The practical levers are the unglamorous ones, and several have stronger outcome evidence than any anti-aging drug. Keeping muscle and aerobic fitness is tied to better long-term health, which is why muscle mass and VO2 max are worth tracking. Treat clock scores as one noisy input, not the goal.

1
Train strength and aerobic fitness. These are tracked directly and respond to effort.
2
Protect sleep and food quality. They sit behind most of the markers that move.
3
Track function and trends. Compare yourself with your own past results rather than one test.
4
Be skeptical of products. Ask what was measured, in whom, and whether it was replicated.

Common Misconception

"A lower biological age score means I am younger." It means one estimate changed. Whether that predicts longer or healthier life is still being studied.

Frequently asked questions

Has anyone reversed aging in humans?

Not in the sense of restoring a whole body to a younger state. A few small trials reported lower epigenetic clock scores, but they were short and did not measure disease or lifespan.

Can lifestyle change my epigenetic age?

One small pilot randomized trial reported a lower methylation age after eight weeks of diet and lifestyle changes in men (Fitzgerald et al., 2021). Larger, longer studies are needed to confirm it.

Are senolytic supplements proven to work?

No. Human data is limited to small early pilots of prescription drug combinations, and supplements are not shown to match them.

Are epigenetic clock tests worth buying?

They are useful for research, but a single consumer score is a noisy estimate that differs by clock. Trends in strength, fitness, and lab markers are easier to act on.

What should I track instead?

Strength, aerobic fitness, sleep, and routine blood markers over time. Compare with your own baseline.

What to remember

The short version.

  1. 1No human trial has shown whole-body aging reversed; claims usually rest on one marker.
  2. 2Epigenetic clock scores have dropped in a few small, short trials that need replication.
  3. 3Clearing senescent cells helps in mouse models; human data is early and uncontrolled.
  4. 4A lower clock number is not proof of a longer or healthier life.
  5. 5Strength, fitness, sleep, and food quality are the supported levers today.
  6. 6Track your own trends over time rather than a single score.

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ReferencesSources

Key Studies

  • Horvath (2013) Genome Biology. DNA methylation age of human tissues and cell types; the multi-tissue epigenetic clock.
  • Belsky et al. (2022) eLife. DunedinPACE, a DNA methylation biomarker of the pace of aging.
  • Fitzgerald et al. (2021) Aging (Albany NY). Pilot randomized trial of a diet and lifestyle program and DNA methylation age in men; later corrected.
  • Fahy et al. (2019) Aging Cell. Reversal of epigenetic aging and immunosenescent trends in humans; a small single-arm trial.
  • Baker et al. (2011) Nature. Clearance of p16Ink4a-positive senescent cells delays ageing-associated disorders in mice.
  • Justice et al. (2019) EBioMedicine. Senolytics in idiopathic pulmonary fibrosis: a first-in-human, open-label pilot study.

Reviews

  • López-Otín et al. (2023) Cell. Hallmarks of aging: an expanding universe.