Every guide leads with a verdict.

Worth a short, cautious trial for stress and sleep — the evidence is decent — but a real (if rare) liver-injury signal means this is not the risk-free 'natural calm' it's marketed as.

Unsettled, and closer to a drug than a vitamin. Berberine genuinely moves blood-sugar and cholesterol markers in studies, but it's a potent plant alkaloid with real medication interactions — not the casual 'nature's Ozempic' its marketing implies, and not a substitute for treating any condition.

Worth it for a narrow job — high-intensity efforts in the 1–4 minute range — and pointless outside it. Well-evidenced buffer, harmless tingle, but not a general 'more energy' supplement.

Worth it — one of the few supplements with a genuinely large, reliable performance effect. The science is strong, the dose is modest, and the only real skill is respecting the daily ceiling and your own tolerance.

Get it from food first. Calcium is essential for bone, but supplements barely move fracture risk in healthy adults, carry a possible small heart signal, and cause GI grief — so they're worth it mainly for people who genuinely can't hit intake from diet.

Unsettled and mildly promising. A popular 'pump' ingredient with a sound mechanism but genuinely equivocal performance data — safe and cheap enough to try, but don't expect the label's promises.

Unsettled and probably oversold — the skin and joint studies look positive but are heavily industry-funded, and independent trials tend to shrink the effect. Low-risk to try; keep expectations modest and your money guarded.

Worth it — the most evidence-backed, lowest-risk sports supplement there is. Creatine monohydrate reliably adds strength and lean mass on top of training, it's safe long-term in healthy people, and the fancy forms are a waste of money.

Worth it for some with osteoarthritis pain, where it performs surprisingly like an NSAID short-term — but poorly absorbed on its own, and the very formulations that fix that (piperine-boosted, 'high-bioavailability') are the ones linked to rare liver injury.

Worth it for long, hot, sweaty sessions; oversold for everyone else. For most people most days, water and normal meals cover it — and drinking too much plain water is a bigger risk than running low on electrolytes.

Worth it — psyllium is one of the best-evidenced, cheapest supplements going. It reliably helps regularity, modestly lowers LDL cholesterol, and blunts blood-sugar spikes. Most people just under-eat fiber, and this closes the gap.

Oversold. The big independent trial found the combo no better than placebo for knee pain, and major guidelines don't recommend it. It's safe and some people feel better, so a time-limited trial is defensible — but keep expectations low.

Essential and clearly worth it when you're actually deficient — and a genuinely bad idea to take 'just in case.' Iron is the one common supplement where taking it without needing it can do real harm.

Worth it for some as a low-risk 'calm focus' aid, especially paired with caffeine to take the edge off jitters — but the effects are modest and short-term, not a treatment for an anxiety disorder.

Worth it for many adults — cheap, safe, and genuinely useful if you're low, but the form matters less than the marketing claims, and it's oversold as a sleep cure.

Worth it for circadian problems (jet lag, delayed sleep timing) at a low dose — not a sleeping pill for ordinary insomnia. It's a timing signal, most people take far too much, and the products are notoriously mislabeled.

Worth it for high triglycerides and for people who don't eat fish — but the heart-protection story is genuinely unsettled, and two landmark trials flatly disagree.

Worth it for specific, strain-matched uses — IBS symptoms and antibiotic-associated diarrhea have the best support — and oversold as a daily 'gut health' cure-all. The strain on the label matters more than the word 'probiotic.'

Total daily protein is worth getting right; a protein powder is a convenient way to hit it. Standalone amino-acid products are mostly oversold — EAAs beat BCAAs, but both are redundant if you already eat enough complete protein.

Essential and worth it for the groups who can't get enough — vegans, many older adults, and people with absorption problems — and close to pointless for well-fed omnivores who already have plenty.

Oversold for the thing people buy it for. Vitamin C is essential and easy to get from food; as a cold preventive it basically doesn't work, and megadosing mostly makes expensive urine.

Worth it for people who are actually low or at risk — but oversold for everyone else. The big trial evidence deflated most of the population-wide disease-prevention hype.

Worth it as a convenience, not a magic ingredient — whey only builds muscle insofar as it helps you hit your total daily protein target. It's a fast, leucine-rich, complete protein, but the powder isn't special; the daily total is.

Worth it in two narrow situations — correcting a shortfall and possibly shortening a cold if started fast — but easy to overdo. Chronic high-dose zinc quietly causes copper deficiency, so more is genuinely not better.