StackGuide

The short list that earns its shelf space

Supplements

Most supplements don't do much, and the industry is built on hoping you won't check. We graded each one honestly: a few are genuinely worth it, several are situational, and some are here mainly so we can tell you to save your money. The grade and the dose are on every entry.

15 entries · roughly 7% of what moves the needle

Supplements

Caffeine

The best-evidenced legal ergogenic and alertness aid there is — powerful, cheap, and safe within limits, with a real cost to your sleep if you mistime it.

A Strong evidence Maybe

Supplements

Creatine

Creatine monohydrate — the most evidence-backed, cheapest, best-studied performance supplement there is. Boring, and it works.

A Strong evidence Worth it

Supplements

Psyllium

A cheap soluble fiber that lowers LDL, steadies blood glucose, and fixes bowel regularity — one of the better-evidenced supplements most people ignore.

B Moderate evidence Worth it

Supplements

Iron

The definitive treatment for iron-deficiency anemia — powerful when you're genuinely low, and genuinely risky to take when you're not.

B Moderate evidence Maybe

Supplements

Melatonin

A hormone that shifts your body clock — genuinely useful for jet lag and delayed sleep timing, and often mistaken for a knockout pill it isn't.

B Moderate evidence Maybe

Supplements

Vitamin B12

Essential to correct if you're actually deficient — vegans, older adults, long-term metformin or PPI users — and inert if you're already replete.

B Moderate evidence Maybe

Supplements

Omega-3

Fish-oil capsules do far less for the average healthy person than the bottle implies — the real cardiovascular signal lives in specific high-risk contexts.

C Suggestive evidence Maybe

Supplements

Vitamin D

Worth taking if you're actually low; largely inert for hard outcomes if you're already replete. A fix for a deficiency, not a longevity lever.

C Suggestive evidence Maybe

Supplements

Ashwagandha

An adaptogenic herb with small-but-consistent trials for stress and anxiety — and rare, genuine reports of liver injury that make the risk more than theoretical.

C Suggestive evidence Maybe

Supplements

Magnesium

A reasonable low-stakes add-on when intake is low or sleep quality is mildly off — wildly over-marketed, and not a substitute for fixing the basics.

C Suggestive evidence Maybe

Supplements

Zinc

Genuinely useful for shortening a cold if started early and for correcting real deficiency — but chronic high-dose supplementation quietly depletes copper, so more is not better.

C Suggestive evidence Maybe

Supplements

Berberine

A plant alkaloid with genuine but modest effects on glucose and lipids — and a 'nature's Ozempic' reputation it comes nowhere near deserving.

C Suggestive evidence Maybe

Supplements

Curcumin

Turmeric's active compound, with a modest anti-inflammatory and joint-pain signal — and a serious absorption problem that most products don't solve.

C Suggestive evidence Maybe

Supplements

Glycine

An inexpensive amino acid with a thin but real signal for better subjective sleep quality when taken before bed — nothing dramatic, and studied only in small trials.

C Suggestive evidence Maybe

Supplements

L-theanine

An amino acid from tea associated with a calm, focused state — mildly promising for acute stress and, paired with caffeine, for attention. Effects are small and the stakes are low.

C Suggestive evidence Maybe