The quick verdict
Strong consistent evidence for longer, healthier life Unproven plausible, but not shown in humans Avoid little benefit, or real risks
| Intervention | Grade | Bottom line |
|---|---|---|
| Not smoking | Strong | The single biggest controllable factor. Quitting at any age helps. |
| Exercise: cardio fitness & strength | Strong | Among the strongest predictors of how long and how well you live. |
| Blood pressure, LDL & blood sugar control | Strong | Proven to prevent heart attacks, strokes, and early death. |
| Sleep, diet, weight, alcohol, relationships | Strong | Consistent evidence, and the effects stack. |
| Screening & vaccines | Strong | Prevents deaths from the diseases they target. |
| Rapamycin | Unproven | Extends life in animals. Human evidence is thin, and it suppresses immunity. |
| Metformin | Unproven | Not shown to extend life in healthy people. |
| NAD+ boosters (NMN, NR) | Unproven | Raise NAD+ levels, but no proven health benefit. |
| Fasting & time-restricted eating | Unproven | Works for weight loss about as well as other diets. |
| Biological age tests | Unproven | Research tools, not reliable for individual decisions. |
| HGH for anti-aging | Avoid | Illegal to prescribe for this purpose in the U.S., with real side effects. |
| Unapproved peptides | Avoid | Little human data and uncertain product quality. |
| Stem cells, young plasma, IV drips | Avoid | Expensive, unproven, and the subject of FDA warnings. |
What's proven
None of this is new, but it's what the evidence consistently supports, and the effects are large. In large population studies, people who combine several healthy habits (not smoking, being active, eating well, keeping a healthy weight, and drinking little or no alcohol) live about a decade longer on average than people who have none of them, with more of those years free of chronic disease.
Not smoking Strong
Lifelong smoking takes roughly a decade off life expectancy. Quitting before 40 recovers most of that, and quitting at any age helps. Vaping is less harmful than smoking but not harmless, and nicotine still raises blood pressure.
Cardio fitness & strength Strong
Cardiorespiratory fitness (VO₂ max) is one of the strongest predictors of lifespan ever measured. In large studies, moving from the least-fit group to even a moderate level is associated with a large drop in mortality risk. Muscle strength and grip strength show the same pattern. Muscle also protects against falls, frailty, and loss of independence later in life.
The numbers Strong
Controlling blood pressure, LDL cholesterol, and blood sugar is one of the few "longevity interventions" backed by large randomized trials showing fewer heart attacks, strokes, and deaths. For many men, the most effective longevity drugs are a generic blood pressure pill and a statin. Check your numbers →
Sleep, diet, weight & alcohol Strong
- Sleep 7+ hours, and treat sleep apnea. Sleep guides →
- Eat mostly minimally processed food: vegetables, fruits, legumes, whole grains, nuts, fish, and olive oil. Mediterranean-style diets have the strongest evidence.
- Keep visceral fat down. Waist size is a better guide than weight.
- Drink less. The idea that moderate drinking protects the heart has weakened with better research. Less is better, and none is fine.
Relationships & purpose Strong
Social isolation and loneliness are associated with mortality risk comparable to other major risk factors. Men are especially prone to losing friendships in midlife. Maintaining close relationships, community, and a sense of purpose is consistently linked with longer life, even though it's harder to study in trials.
Screening & vaccines Strong
Colorectal and lung cancer screening, blood pressure checks, and vaccines like Shingrix and pneumococcal have proven benefits. Build your checklist →
Promising but unproven
Rapamycin Unproven
Rapamycin (sirolimus) is an immune-suppressing drug used after organ transplants. It consistently extends lifespan in mice and other animals, which has made it popular in longevity circles, usually taken in low weekly doses. But human evidence is limited to small, short studies measuring surrogate markers, not lifespan or disease. Risks include mouth sores, higher infection risk, and effects on blood sugar and cholesterol. If you're considering it, do so only under a physician who monitors you, and understand you're experimenting.
Metformin Unproven
Early observational data suggested people with diabetes on metformin might outlive people without diabetes. That finding hasn't held up well in later analyses. A large trial to test metformin as an anti-aging drug (TAME) has been proposed but not completed. Metformin may also blunt some of the fitness gains from exercise. It's an excellent diabetes drug, but not a proven longevity drug for healthy people.
NAD+ boosters (NMN, NR) & NAD+ infusions Unproven
NAD+ is a molecule involved in cellular energy that declines with age. Supplements like NMN and nicotinamide riboside do raise NAD+ levels in the blood, but human trials haven't shown meaningful improvements in health, fitness, or aging. NAD+ IV infusions at clinics are expensive, often uncomfortable, and have even less evidence.
Fasting & time-restricted eating Unproven
Calorie restriction extends lifespan in many animals, and intermittent fasting has been promoted as an easier way to get the same benefits. In human trials, time-restricted eating produces about the same weight loss and metabolic improvements as simply eating less. Use it if it helps you eat less. Keep protein up and keep lifting so you don't lose muscle.
Resveratrol, sauna, cold plunges & more Unproven
Resveratrol's early promise hasn't held up in human studies. Frequent sauna use is linked with lower cardiovascular risk in Finnish observational studies, but that doesn't prove cause and effect. Cold exposure has little long-term evidence. These are fine if you enjoy them, but they don't replace the basics. More on recovery tools →
Longevity tests & trackers
Biological age tests Unproven
Epigenetic "clocks" estimate your biological age from DNA methylation patterns in blood or saliva. They're valuable research tools, but consumer tests can give different results from the same sample, and they aren't validated for guiding individual decisions. Whether "lowering" your biological age score improves your actual health is unknown. Blood pressure, lipids, A1c, waist size, fitness, and grip strength are cheaper and better understood.
VO₂ max testing Useful
A lab VO₂ max test, or a reasonable estimate from a fitness watch, is one of the more meaningful longevity metrics you can track, because fitness is so strongly tied to lifespan and it responds to training.
Coronary calcium scans Situational
Useful for men in their 40s and beyond who are on the fence about statins. More on CAC scans →
Full-body scans & multi-cancer blood tests Not yet
Popular at longevity clinics, but not proven to reduce deaths, and prone to incidental findings. Why we don't recommend them yet →
What to avoid
HGH for anti-aging Avoid
Human growth hormone is approved for specific medical conditions, such as adult growth hormone deficiency diagnosed with proper testing. Distributing it for anti-aging or athletic purposes is illegal under U.S. federal law. Studies in healthy older men showed small increases in lean mass without meaningful gains in strength or function, along with side effects: joint pain, fluid retention, carpal tunnel syndrome, and higher blood sugar. Clinics offering "HGH therapy" or HGH-releasing peptides as anti-aging treatment are a red flag.
Unapproved peptides Avoid
Peptides like BPC-157, TB-500, and various growth-hormone secretagogues are widely sold through clinics and "research chemical" websites. Most have little or no human safety or effectiveness data. The FDA has flagged several as raising safety concerns for compounding, and gray-market products may be mislabeled or contaminated. The fact that a clinic prescribes one doesn't mean it's been shown to work.
Stem cells, young plasma & IV drips Avoid
- ✕Stem cell clinics: outside of approved uses (mainly blood and immune disorders), the FDA has repeatedly warned about unapproved stem cell products, which have caused serious injuries including blindness and infections.
- ✕Young plasma infusions: the FDA has warned that they have no proven benefit for aging and carry transfusion risks.
- ✕IV vitamin drips: no evidence of benefit for healthy people, and any IV carries infection and vein risks. Your gut absorbs vitamins fine.
Supraphysiological testosterone Avoid
Some longevity and "optimization" clinics push testosterone toward the top of the range or beyond it for men with normal levels. TRT for genuinely low testosterone is legitimate medicine. Above-normal dosing adds risk (thick blood, blood pressure, fertility loss) without proven longevity benefit. Read the testosterone guide →
Evaluating a longevity clinic
Longevity clinics range from excellent preventive medicine practices to expensive sales operations. Signs of a good one:
- ✓It focuses first on the proven basics: blood pressure, lipids including ApoB and Lp(a), blood sugar, fitness, sleep, and screening.
- ✓It's upfront about which recommendations are proven and which are experimental.
- ✓It works with your primary care doctor, or offers true primary care itself.
Red flags:
- ✕A standard package of hormones, peptides, or IVs for everyone, regardless of labs.
- ✕Big-ticket scans and tests with little plan for what happens after an abnormal result.
- ✕Selling supplements or treatments they profit from directly.
- ✕Promises to "reverse aging" or lower your biological age by years.
Several of the providers in our TRT directory are longevity-style clinics. Our reviews note pricing and red flags for each.