How to Lower Your Biological Age: What Works

If a biological age calculator told you your body is running older than your birth certificate, the obvious next question is: can I change that? The honest answer is probably, at least somewhat, but the field is young, the best studies are small, and the marketing around “age reversal” runs miles ahead of the data.

This is educational information, not medical advice. Nothing below is a treatment plan; talk to a clinician before changing diet, exercise, or supplements, above all if you have a medical condition.

First, what “lowering biological age” even means

Biological age is a model output, a number derived either from blood markers (like the blood PhenoAge from Liu, Levine, and colleagues) or from DNA methylation patterns (epigenetic “clocks”). To lower it, you have to move the inputs: the blood chemistry, or the methylation marks the clock reads. If you’re fuzzy on how those clocks work, start with our primer on how epigenetic clocks measure biological age.

That framing matters because it sets a fair bar. “Lowering your biological age” means improving the underlying physiology (inflammation, metabolic health, immune function) enough that the score reflects it. The interventions that reliably improve those systems are, unsurprisingly, the ones with the best evidence.

Biological age isn’t fixed, but the human trial evidence for lowering it is early, small, and best read cautiously.

What the randomized trials show

Two human randomized studies get cited constantly.

Caloric restriction: the CALERIE trial. This is the strongest randomized evidence to date. Researchers randomized 220 healthy, non-obese adults to a caloric-restriction target (roughly 25%) or to eat normally, for two years. Waziry and colleagues (2023, Nature Aging) then measured several DNA-methylation aging clocks. The result was nuanced: caloric restriction produced a small but statistically significant slowing of the DunedinPACE clock (a measure of the pace of aging), but it did not significantly change the PhenoAge or GrimAge clocks. So even the best trial shows a real-but-modest effect on one measure, not a dramatic reversal across the board.

Diet and lifestyle: the Fitzgerald pilot. A 2021 pilot randomized trial (Fitzgerald et al., Aging) put 43 healthy men aged 50–72 through an eight-week program: a plant-centered, methylation-supporting diet, at least 30 minutes of exercise most days, seven-plus hours of sleep, twice-daily breathing exercises, and probiotic/phytonutrient supplements. The treatment group tested an average of 3.23 years younger on the Horvath DNAmAge clock than controls (p = 0.018). That’s an eye-catching number, but it’s a pilot: small, short, one sex, and awaiting replication in larger trials before anyone should treat it as settled.

Intervention	Trial	Design	Effect on an aging clock
~25% caloric restriction, 2 yr	CALERIE (Waziry 2023)	RCT, 220 adults	Small, significant slowing of DunedinPACE; no significant change in PhenoAge/GrimAge
Diet + lifestyle, 8 wk	Fitzgerald 2021	Pilot RCT, 43 men	~3.23 yr lower DNAmAge vs. control (p = 0.018)

The takeaway across both: effects are real but modest, and the enthusiastic headlines outrun the evidence.

The levers most likely to help

Rather than chase a specific clock, aim at the systems that drive the blood markers behind your score: inflammation, glucose regulation, and immune and metabolic health (the nine inputs are broken down in the nine blood markers behind your biological age). These are the same fundamentals that decades of research link to healthier aging:

• Sort out metabolic health. Blood glucose is a direct PhenoAge input, and it’s highly modifiable. Losing excess visceral fat, cutting refined carbohydrate spikes, and staying active all push it down. If caloric restriction feels extreme, note that CALERIE’s participants weren’t even obese. A modest, sustainable energy deficit for those carrying extra weight targets the same biology.
• Lower chronic inflammation. C-reactive protein weighs heavily in the score. Regular exercise, adequate sleep, not smoking, and treating hidden sources of inflammation (poor oral health, untreated conditions) all help. See inflammation markers, hs-CRP, and aging.
• Train, both cardio and strength. Exercise improves glucose handling, inflammation, immune profile, and body composition simultaneously. It’s the closest thing to a single lever that moves several of the nine markers at once.
• Protect sleep. Short and disrupted sleep worsen glucose control and inflammation. The Fitzgerald protocol built in a seven-hour minimum for a reason.
• Eat mostly whole, plant-rich food. Both trials leaned on nutrient-dense, mostly plant-based eating. You don’t need an exotic supplement stack; you need the dietary pattern the trials used.

None of these is a shortcut. They’re the same durable habits that address the underlying biology of aging, which is exactly why they show up in the results. For the mechanisms they’re acting on, see the hallmarks of aging explained.

What to be skeptical of

• “Reverse your age by X years” products. The one trial that produced a headline reversal number was a small pilot of an entire lifestyle program, not a pill. No supplement has replicated that on its own in larger human trials.
• Single-clock claims. As CALERIE showed, an intervention can move one clock and not others. A product citing a change in one obscure measure isn’t proof of broad benefit.
• One-off score chasing. A single test is noisy. Chasing a good number on one draw, by testing right after a fasting-and-exercise stretch, improves the reading, not your biology.

A sensible way to run it

1. Establish a clean baseline. Test fasting, healthy, and hydrated, and note which of the nine markers are driving your score.
2. Pick the modifiable inputs. For most people that’s glucose, CRP, and body composition, all downstream of diet, activity, and sleep.
3. Give it real time. Both trials ran for months to years. Re-test after a meaningful interval, not weeks.
4. Watch the trend, and loop in a clinician. The direction of your acceleration over time is the signal; a professional can put it against the rest of your health picture. For the wider set of measures worth following, see biomarkers of aging worth tracking.

The takeaway

Yes, biological age appears to be at least partly movable. The CALERIE and Fitzgerald trials show real, if modest, effects from caloric restriction and a structured diet-and-lifestyle program. But the evidence is early, the effect sizes are small, and no shortcut has earned the hype. The reliable play is unglamorous: improve the metabolic, inflammatory, and immune health that the nine markers measure, then re-check the trend on your biological age calculator over time. The habits that lower the number are the same ones worth having anyway.