How to Read Supplement Studies Without Being Misled

Most supplement claims quote "science," but the decision quality depends on study design, effect size, and external validity.

Annotated clinical study page with evidence quality notes
Move from headline-level evidence to method-level interpretation.

1. Start with the exact question

Before reading results, define population, intervention, comparator, and outcome. If the paper answers a different question, the claim is already overstated.

  • Population: age, risk profile, baseline status.
  • Intervention: dose, formulation, timing, adherence.
  • Comparator: placebo, standard care, or active control.

2. Check design before outcomes

Randomized and blinded designs reduce major bias, but execution still matters. High dropout or poor adherence can distort the apparent effect.

  • Was allocation concealed?
  • Were assessors blinded for subjective outcomes?
  • Was intention-to-treat analysis reported?

3. Read effect size, not only p-values

Statistical significance does not guarantee clinical relevance. A small but "significant" change may have negligible real-world impact.

Reviewer note

Prefer absolute change, confidence intervals, and baseline-adjusted results over isolated p-values.

4. Assess applicability and harms

If participants are highly selected, extrapolation can fail. Review adverse event reporting and interaction risks before translating findings into practice.

Evidence quality is not a badge. It is a chain of method decisions, each of which can weaken or strengthen inference.

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