MC Metabolic Clarity

Independent supplement research

Weight-Loss Supplements: How to Read the Evidence

A statistically significant result can still be small, uncertain or irrelevant to the exact product you are considering.

Health note: Dietary supplements can have side effects and interact with medicines. This page is educational and does not diagnose, treat or replace advice from a qualified clinician.

Start with effect size, not the headline

The 2025 resveratrol umbrella review is illustrative: it reported statistically significant changes, but average reductions were small. “Significant” in statistics does not automatically mean dramatic or personally meaningful.

Separate ingredient from formula

A multi-ingredient supplement should not inherit every favorable finding ever published about each ingredient. Dose, formulation and interactions between ingredients matter.

Treat safety as first-class evidence

NIH notes that some weight-loss supplement ingredients can cause adverse effects or interact with medications. Green tea extract, for example, has uncommon reports of liver injury.

Use claims as questions

Instead of asking “Is this miracle claim true?”, convert it into testable questions: What outcome? In humans? Compared with what? At what dose? For how long? How large was the effect?

Sources & further reading