Only what works: five supplements with real evidence behind them

The supplement industry is enormous, loosely regulated, and very good at storytelling. The honest starting point: most supplements do little or nothing, and no supplement outperforms the basics, food, training, sleep. That said, a small handful have accumulated genuine, mainstream evidence. Here they are, with the caveats attached.

Protein powder: food in convenient form

Protein powder isn't magic, it's simply protein, the same nutrient in chicken, eggs, yogurt, and lentils. Its value is convenience: it makes hitting a reasonable daily protein intake dramatically easier for busy people. If your meals already cover your protein needs, powder adds nothing. If they don't, it's one of the most practical tools available. Whey, casein, and quality plant blends all work.

Creatine monohydrate: the most studied supplement in sports science

Creatine monohydrate has hundreds of studies behind it. The consistent findings: modest but real improvements in high-intensity, repeated-effort performance (like strength training), which over time supports greater strength and muscle gains. It is inexpensive, and long-term use in healthy adults has a strong safety record in the research. Plain monohydrate is the studied form, fancier versions add price, not evidence. Some people notice slight water-weight gain early on.

Vitamin D: for the many people who are actually low

Vitamin D is produced in skin from sunlight, and insufficiency is common in people who live at higher latitudes, spend most time indoors, or have darker skin. It matters for bone health and plays roles across many systems. The honest caveat: supplementing helps people who are low; piling more on top of adequate levels shows little benefit. This is the one item on this list where a blood test through your healthcare provider is genuinely useful before committing.

Omega-3s: cover it with fish first

Long-chain omega-3 fatty acids (EPA and DHA) support cardiovascular health markers such as triglycerides, and mainstream dietary guidance already recommends eating fatty fish (salmon, sardines, mackerel) regularly. If you eat fish a couple of times a week, a supplement likely adds little. If you rarely or never do, a fish-oil or algae-based omega-3 is a reasonable way to cover the gap.

Caffeine: the one you're already taking

Caffeine is the most reliable performance supplement known, it measurably improves alertness, perceived effort, and endurance performance. It's also easy to misuse: too much or too late in the day degrades the sleep that your progress actually depends on, quietly borrowing tomorrow's energy. Used deliberately, modest amounts, earlier in the day, occasionally before harder sessions, it earns its place.

What didn't make the list

Fat burners, detox teas, testosterone boosters, most greens powders, and the supplement-of-the-month generally lack meaningful evidence, and some carry real risks. A useful filter: the stronger the promise, the weaker the data usually is.

A final note on quality: supplements are loosely regulated, so favor products carrying third-party testing certifications, which verify that what's on the label is what's in the container.

What to try this week

Before buying anything, run the basics audit: protein at most meals, two-plus strength sessions, seven-plus hours of sleep, fish or another omega-3 source in the week. Whatever line item is missing is worth more than any purchase. If the basics are genuinely covered and you train hard, plain creatine monohydrate is the most evidence-backed next consideration.

When to see a professional

Supplements can interact with medications and conditions, blood thinners, blood pressure medication, pregnancy, kidney concerns, and more. Check with a qualified healthcare provider or pharmacist before starting anything new, and use a blood test through your provider to guide vitamin D decisions.