What reduces disease risk?

Is associated with lower cardiovascular mortality

Finnish prospective cohorts following adults for decades found sauna frequency associated with substantially lower cardiovascular mortality, in a dose-dependent pattern, including after adjusting for fitness and conventional risk factors.

Improves outcomes in specific diagnosed conditions

Randomised trials have tested NR in defined patient groups, including a crossover trial in Werner syndrome and trials in cognitive impairment and hypertension.

Reduces cardiovascular events in statin-treated patients with high triglycerides

REDUCE-IT randomised 8,179 statin-treated patients with elevated triglycerides to 4 g/day icosapent ethyl (purified EPA) or placebo. Cardiovascular events fell significantly over a median 4.9 years.

Reduces cardiovascular events in adults with overweight or obesity and existing cardiovascular disease

SELECT randomised 17,604 adults with overweight or obesity and established cardiovascular disease — but no diabetes — to weekly semaglutide or placebo and found fewer major cardiovascular events over about three years. A landmark trial; the grade reflects our replication requirement, not doubt about its conduct. A mortality signal appeared among secondary outcomes, which is exactly the kind of result a dedicated trial should now test.

Improves outcomes as an adjunct treatment in chronic heart failure

Q-SYMBIO randomised 420 heart-failure patients to CoQ10 or placebo alongside standard therapy for two years and reported fewer major adverse cardiovascular events and lower cardiovascular mortality. A positive hard-endpoint trial — modest in size, awaiting modern replication, and about treating disease, not preventing ageing.

Combined with selenium, reduces cardiovascular mortality in elderly people with low selenium status

The Swedish KiSel-10 trial gave community-dwelling elderly people selenium plus CoQ10 or placebo for four years; cardiovascular mortality was lower in the treated group, with the difference still visible twelve years on. The catch for supplement buyers: it was a combined intervention in a low-selenium population — Sweden's soils are selenium-poor — so it cannot tell you what CoQ10 alone does, or what happens in selenium-replete people.

Reduces cardiovascular disease in type 2 diabetes

A meta-analysis of randomised trials found the evidence for metformin reducing cardiovascular events in type 2 diabetes to be inconclusive — surprising given how confidently this benefit is often described.

Improves injury recovery in humans

A 2025 systematic review searched for clinical evidence behind BPC-157's growing use in sports medicine and found no published randomised human trial. The confident dosing protocols circulating online are extrapolated from rodent work and anecdote, not from human data.

Deliberately changing sleep improves hard health outcomes

This is the claim that sleep optimisation products actually need — and no randomised trial has tested it against mortality or major disease events. Sleep interventions improve sleep and daytime measures; whether they move the outcomes the cohort associations describe is unknown.

Improves function or health outcomes in humans

No completed randomised trial has reported. The trials that will answer this are registered and running — a phase II in postmenopausal breast cancer survivors with reduced physical function among them — which makes fisetin one of the few supplements where 'wait' has a specific, checkable meaning.

Improves health and wellbeing

A 2025 systematic review and meta-analysis pooled the controlled research on cold-water immersion and found the evidence base thin: some short-lived effects on stress and sleep-adjacent measures, from mostly small, low-quality studies, with nothing on actual health outcomes. The honest summary of the world's most photographed longevity habit is: physiologically interesting, clinically unproven.

Prevents cardiovascular disease and cancer in generally healthy adults

The VITAL trial randomised 25,871 healthy US adults to 1 g/day marine omega-3 or placebo for a median 5.3 years. Neither major cardiovascular events nor invasive cancer was reduced.

Time-restricted eating produces greater weight loss than ordinary meal timing

TREAT randomised 116 adults with overweight or obesity to 16:8 time-restricted eating or three structured meals for 12 weeks. Weight loss did not differ significantly between groups.