Four that are worth it. The rest is theater.
Four supplements clear the bar for a man’s cabinet: creatine, vitamin D when your level is genuinely low, magnesium, and omega-3. Everything else in the aisle — boosters, burners, “test support,” proprietary blends — is marketing wrapped around a Supplement Facts panel.
Creatine is the one with nothing to argue about
Creatine monohydrate, 5 g a day, has the deepest evidence base of any performance supplement, and the mechanism is settled: your muscles store it as phosphocreatine and draw on it to regenerate ATP during short, hard efforts. More phosphocreatine means a rep or two more before the tank empties, and over months that compounds into measurable gains in strength and lean mass — provided you actually train. The weight you gain in the first week is water pulled into muscle, not fat. It does not harm kidneys in men with normal kidney function; that myth traces to creatine mildly raising serum creatinine, a lab marker, without touching the kidney itself.
Two things people get wrong. Monohydrate is the only form worth buying — the “buffered,” “HCl,” and liquid versions charge more to solve problems monohydrate doesn’t have. And loading is optional: 5 g daily reaches the same muscle saturation in about three weeks. The genuinely open question is cognition. Smaller trials hint at a benefit under sleep deprivation, but whether that holds in well-rested men is unproven (tier 2).
Vitamin D: fix a low number, don’t chase a high one
Vitamin D is worth taking if a blood test shows you’re low — common in men who work indoors — and close to pointless if you’re not. It behaves like a hormone precursor, and correcting a real deficiency restores normal bone and muscle function. What it does not do, and this is now settled: supplementing men who aren’t deficient has not lowered cardiovascular events or cancer risk in large prevention trials. So chase a number, not a feeling — check 25-hydroxyvitamin D, supplement 2,000 IU/day if you’re under about 40 ng/mL, and recheck in 12 weeks. Adding K2 is low-risk and reasonable, but the evidence behind it is thin (tier 3), so don’t pay a premium for the combo.
Magnesium and omega-3: real, but oversold
Magnesium glycinate, 300–400 mg in the evening, is defensible: magnesium is a cofactor in hundreds of enzymatic reactions, and the glycinate form absorbs better than the oxide that fills cheap tablets. Its effects on sleep and blood pressure are modest, and clearest in men who are actually deficient (tier 2) — not dramatic for everyone.
Omega-3 (EPA + DHA) is where marketing outruns data. The strong cardiovascular evidence is narrow: high-dose, purified prescription EPA in people with elevated triglycerides. That does not automatically transfer to a 2 g drugstore softgel in a healthy man (tier 2). It’s still a reasonable supplement, especially if you rarely eat fish — just buy on the EPA + DHA totals printed on the label, not the headline “fish oil” number, and don’t expect it to offset a bad diet.
What to skip, and why
- Testosterone boosters. Almost universally junk. If your energy, libido, and morning erections have dropped, get a real testosterone level rather than a proprietary herb blend — and if it’s low, treat low T directly, not with a supplement pretending to.
- BCAAs. If you eat enough protein, you already have them; isolated BCAAs add nothing.
- Fat burners. Caffeine plus a label. And to be blunt: no supplement in this article moves body weight the way a GLP-1 does — semaglutide produced −14.9% mean weight loss versus −2.4% on placebo at week 68 in STEP 1, an effect no pill in this aisle approaches. If fat loss is the actual goal, start there.
- Proprietary pre-workouts. If the panel says “blend,” you can’t know your dose. Plain caffeine plus creatine does the same job for less.
When something else earns a spot
Berberine has a real glucose-lowering signal, but it is not “nature’s Ozempic” (tier 2). Ashwagandha has small trials for stress and sleep (tier 2–3). A plain fiber supplement helps if you can’t hit fiber from food. Any of these can interact with prescription medication, so clear them with your clinician before stacking.
The takeaway
- Buy: creatine at 5 g/day; vitamin D only to correct a documented low level; magnesium glycinate; omega-3 chosen on EPA + DHA totals.
- Skip: boosters, burners, BCAAs, and proprietary blends.
- Creatine is settled; the rest sit at tier 2 — labeled so you know which is which.
