OpenSupplement.orgCondition-specific supplement research, objectively rated

Scoring Methodology

Last updated: April 13, 2026

Every supplement on OpenSupplement.org is rated on 5 standardized dimensions. Each dimension is scored 1–5. This page explains exactly what each score means.

Our goal is transparency: you should be able to look at any supplement’s scores and understand precisely how we arrived at them.

Dimension 1: Evidence Quality

This is the most important dimension — and the one most supplement sites get wrong. We rate the strength of the human clinical evidence, not the strength of the marketing.

  • 5 — Multiple randomized controlled trials (RCTs) or meta-analyses in humans with consistent positive results
  • 4 — A few solid human trials with generally positive results
  • 3 — Human trials exist but are small, limited in number, or show mixed results
  • 2 — Mostly animal studies, in vitro (cell) studies, or mechanistic data with limited human evidence
  • 1 — Traditional use, anecdotal reports, or preliminary data only

Dimension 2: Safety Profile

How safe is this supplement at commonly recommended doses for generally healthy adults?

  • 5 — No significant adverse effects reported at recommended doses
  • 4 — Minor, uncommon side effects possible (e.g., mild GI discomfort)
  • 3 — Moderate side effect profile; some people may experience noticeable effects
  • 2 — Notable side effects or contraindications for certain populations
  • 1 — Significant side effect risk, narrow therapeutic window, or serious adverse events reported

Dimension 3: Interaction Risk

How many known drug interactions does this supplement have? This score is inverted — a higher score means fewer interactions, which is better.

  • 5 — Very few or no known drug interactions
  • 4 — Some interactions with uncommon medications
  • 3 — Interacts with several commonly prescribed medications
  • 2 — Significant interaction profile; caution required with multiple drug classes
  • 1 — Interacts with many common medications; requires careful medical oversight

Dimension 4: Cost Accessibility

Based on the typical monthly cost at effective doses from mainstream retailers.

  • 5 — Under $10/month
  • 4 — $10–$20/month
  • 3 — $20–$35/month
  • 2 — $35–$60/month
  • 1 — Over $60/month

Dimension 5: Onset Speed

How quickly are effects typically noticed? This reflects published clinical data and commonly reported user experience.

  • 5 — Same day
  • 4 — Within 1 week
  • 3 — 2–4 weeks
  • 2 — 4–8 weeks
  • 1 — 8+ weeks of consistent use

How We Derive Scores

Scores are determined by the OpenSupplement Editorial Team based on our assessment of:

  • Peer-reviewed studies indexed in PubMed
  • Systematic reviews and meta-analyses
  • NIH Office of Dietary Supplements fact sheets
  • Established clinical pharmacology references for interaction data
  • Current retail pricing from major supplement retailers

We aim for consistency: the same evidence standard is applied to every supplement. Where we are uncertain, we err on the side of a lower evidence score and note the uncertainty in the supplement’s detail page.

Scores may be updated as new research is published. When a score changes, the supplement’s detail page will reflect the update date.

Limitations

No scoring system is perfect. Ours has inherent limitations:

  • Evidence quality is a spectrum, not a number. A score of “3” covers a range of situations.
  • Cost varies by retailer, form, and brand. Our cost score reflects typical pricing, not the cheapest or most expensive option.
  • Individual responses to supplements vary. A supplement with strong average evidence may not work for you, and vice versa.
  • We do not test products. Our ratings are based on the research literature for each ingredient, not on specific brands.

If you believe a score is inaccurate or a relevant study has been missed, contact us at suppguide@tojocu.com. We welcome evidence-based corrections.