The Supplement Decision Framework
Why this guide exists — and how to use it
Supplements are not magic, and they don't compensate for the fundamentals — sleep, food, exercise — covered throughout this Archive. What they can do, when chosen well, is fill genuine gaps that diet alone often doesn't cover. This guide covers the handful with real evidence behind them, with honest evidence tiers rather than uniform confidence.
This guide draws on the International Society of Sports Nutrition's position stands, and cross-references the deeper mechanism discussions already built out elsewhere in this Archive — magnesium and L-theanine in the Sleep guide, zinc and vitamin D in the Hormones guide, NAD+ precursors in the Longevity guide — rather than repeating that ground. Read the quick-reference table in Start Here, then use the sections that follow for the evidence behind each entry.
Three Questions Worth Asking Before Any Supplement
| Question | Why it matters |
|---|---|
| Is this filling a genuine gap, or replacing a fundamental? | No supplement compensates for poor sleep, a poor diet, or a sedentary lifestyle — those come first. |
| What's the actual evidence tier? | "Studied in a handful of small trials" and "one of the most rigorously tested compounds in nutrition science" are very different claims, often marketed identically. |
| Does the label disclose exact doses? | Proprietary blends that don't disclose per-ingredient doses can't be evaluated against the evidence at all — that alone is a reason for scepticism. |