Biohacking: what survives a serious reading

Biohacking is not the problem. The problem is the inverted hierarchy: men fine-tuning NAD, fasting windows and the temperature of their shower while sleeping six hours, lifting nothing and not having checked their glucose in three years.

This article sorts fifteen common practices into three categories, with the level of evidence attached to each. The rule is the same one I use across the longevity section: robust evidence means human clinical trials, replicated, with outcomes that matter; preliminary evidence means small, short or surrogate-outcome human studies; preclinical evidence means cells and animals, which explain mechanisms and do not authorize conclusions about people.

What carries the weight

1. Strength training

Clinical consensus. A meta-analysis of 16 cohort studies published in the British Journal of Sports Medicine in 2022 (Momma and colleagues) linked strength training to 10 to 17 % lower all-cause mortality, with the largest benefit around 30 to 60 minutes a week. And handgrip strength, the simplest marker of muscle reserve, predicted mortality and cardiovascular events in the PURE study (The Lancet, 2015) across 17 countries.

Two to four weekly sessions with progressive overload. Nothing that comes after compensates for its absence.

2. Aerobic base plus intervals

Clinical consensus. In 122,007 patients who underwent exercise testing at the Cleveland Clinic (JAMA Network Open, 2018), low cardiorespiratory fitness carried a higher risk of death than diabetes, smoking or coronary disease, and the benefit showed no ceiling: the fittest kept dying less than the step below them. An analysis of more than 750,000 veterans (Journal of the American College of Cardiology, 2022) confirmed the gradient at every age.

Conversational volume most of the week, plus one or two short high-intensity blocks to push the aerobic ceiling.

3. Sleep hygiene

Clinical consensus. One week of five-hour nights lowered daytime testosterone by 10 to 15 % in young, healthy men (JAMA, 2011). And in more than 60,000 UK Biobank participants measured with accelerometers (Sleep, 2024), the regularity of the schedule predicted mortality better than its duration.

Stable timing, darkness, temperature, and control of alcohol and caffeine. It is the cheapest multiplier there is, and the first one men drop.

4. Enough protein

Clinical consensus. The meta-analysis by Morton and colleagues (British Journal of Sports Medicine, 2018), with 49 trials and nearly 2,000 participants, found that additional protein increases the lean mass and strength gained with training, with the effect plateauing around 1.6 g per kilogram of body weight a day (about 0.7 g per pound). In a man who trains and ages, protein spread across the day is the nutrient that decides whether muscle gets built or lost.

5. Creatine

Clinical consensus. It is the supplement with the most human trials. The International Society of Sports Nutrition position stand (2017) summarizes decades of data on strength and lean mass with creatine monohydrate at 3 to 5 grams a day, with an excellent safety profile in healthy kidneys. In older adults, meta-analyses show more lean mass and strength when combined with resistance training, and there are signals in memory, especially after 60.

Cheap, safe and boring. Which is why almost nobody sells it with enthusiasm.

What helps, with caveats

6. Sauna

Observational evidence. In 2,315 Finnish men followed for two decades (JAMA Internal Medicine, 2015), using the sauna four or more times a week was associated with less cardiovascular and all-cause death than using it once. These are observational data, from one culture, in a population that already used the sauna routinely: not a trial, and nobody has shown that sauna replaces exercise. As a complement, it is reasonable.

7. Cold immersion

Preliminary evidence. Cold improves mood and the feeling of recovery in the short term in small studies. But applied right after strength training, it blunts part of the muscle adaptation: Roberts and colleagues showed it in the Journal of Physiology in 2015, with less hypertrophy and less anabolic signaling in those who got into cold water after lifting. If you enjoy it, keep it away from the strength session.

8. Fasting and eating windows

Preliminary evidence. In the trial by Liu and colleagues (New England Journal of Medicine, 2022), restricting the eating window added no weight loss or metabolic improvement to calorie restriction alone. And in the TREAT trial (JAMA Internal Medicine, 2020), an eight-hour window produced minimal weight loss, part of it lean mass. Much of the effect is explained by eating less and eating less late. It is an adherence tool for those it works for, not a magic mechanism; and if you lift, watch the protein that no longer fits in the window.

9. Vitamin D and omega-3

Mixed evidence. The VITAL trial (New England Journal of Medicine, 2019), with nearly 26,000 adults, found no reduction in cancer or cardiovascular events with vitamin D or omega-3 in the general population. The D-Health trial in Australia (2022) found no effect on mortality either. Correcting a documented deficiency does improve markers and symptoms; taking them with normal levels extends nothing. Measure first.

10. Watches and rings

Preliminary evidence. They are useful for trends: how many steps, what time you go to bed, how your resting heart rate is doing. They diagnose nothing, and the sleep literature describes a phenomenon called orthosomnia (Journal of Clinical Sleep Medicine, 2017), in which the obsession with the wearable's score worsens the very sleep it is meant to measure. When the morning number weighs more than how you feel, the watch stopped helping.

What is sold above its evidence

11. Supplement stacks

Preclinical evidence. The long lists are built on cell and mouse studies. The 2022 US Preventive Services Task Force review (JAMA) found no benefit from vitamin and mineral supplements for preventing cardiovascular disease or cancer in healthy adults, and specifically advised against beta-carotene and vitamin E. Most stacks correct a deficiency you don't have and empty a wallet you do. More than five bottles in the kitchen is a signal, not a protocol.

12. NAD+ precursors and resveratrol

Preclinical evidence. NMN and NR raise NAD in the blood; that much is shown. What nobody has shown is that raising it extends life or improves a relevant clinical outcome in people: the human trials are small, short and measure markers. Resveratrol carries two decades of promises in yeast and mice, and in humans it has not produced a clinical result to back them. Interesting as science; premature as a purchase.

13. "Anti-aging" drugs in healthy men

Preclinical evidence. Metformin and rapamycin have data in animals and in patients with disease, and the trials meant to test them for aging in healthy people have no results yet. Meanwhile there is an uncomfortable signal: in healthy older adults, metformin blunted the improvement in aerobic capacity and insulin sensitivity that exercise produces (Aging Cell, 2019). They are prescription medications with side effects of their own, not supplements. In a healthy man there is no trial that justifies taking them to "live longer."

14. Continuous glucose monitor without diabetes

Preliminary evidence. In diabetes it changes lives. In a healthy man it turns normal post-meal spikes into anxiety, absurd restrictions and, at times, less carbohydrate than he needs to train. No trial shows that wearing one improves outcomes in people without diabetes. One HbA1c a year, a lipid profile and a waist measurement say more and cost less.

15. "Moderate alcohol is healthy"

Robust evidence against. For years the J-curve suggested that a drink a day was protective. Once the biases were corrected, it disappeared: the meta-analysis by Zhao and colleagues (JAMA Network Open, 2023), with 107 cohorts and nearly five million people, showed that the supposed benefit came from comparing drinkers against abstainers who were already sick or had quit. The Global Burden of Disease study (The Lancet, 2018) concluded that the amount that minimizes harm is zero. You can drink; what you cannot do is call it health.

What I'd like you to take away

My clinical opinion. The list above has a shape: what carries the weight is boring, cheap and demands consistency; what sells for a lot is new, comfortable and weak on evidence. That is no accident. The market needs you to do something different every month; your physiology needs you to do the same thing for years.

Before buying the next bottle, answer three questions: do I train strength at least twice a week? Do I sleep seven hours on a stable schedule? Do I know my waist measurement and my HbA1c? If any answer is no, that is your biohacking. The rest is marketing.