Terms of Use
Use the site freely. Cite our research with a link. Do not treat any of it as medical advice. Prices and label data change, and we do not warrant that any figure is current at the moment you read it.
Using this site
You may read, share and link to anything here. The site is provided as-is, for informational purposes, and access may change or be interrupted without notice.
You may not scrape the site at a rate that degrades it for other readers, misrepresent our figures as your own original research, or present our content in a way that implies we endorse a product, brand or clinician. We do not accept payment for placement, rankings or coverage.
Citing our data
Our research is free to cite, quote and embed with attribution and a link back to the page it came from. Several datasets are published deliberately for that purpose — see Cite Our Data and the open evidence database.
If you quote a figure, please quote it with the sample size and retrieval date attached. Our label figures are snapshots of a market that changes; a percentage lifted without its denominator and its date stops being accurate quite quickly, and we would rather not be the source of that.
Accuracy, and what we do not warrant
We take accuracy seriously — every figure traces to a stated source, published findings are validated before they appear, and mistakes are logged publicly on the corrections page rather than quietly edited.
That said, we do not warrant that any price, dose, certification status or availability is correct at the moment you read it. Prices change daily. Products are reformulated. Certifications are granted by batch and can lapse. The retailer's own listing at the time of purchase is authoritative, not ours. If you spot something wrong, tell us.
Our tools
The calculators and analysers on this site run in your browser. They apply published reference ranges and trial doses to the values you enter; they do not know your medical history, and they are not diagnostic. Values you type into them are not sent to us or stored on our servers.
Affiliate links
Some outbound product links are affiliate links, and we may earn a commission on qualifying purchases at no extra cost to you. As an Amazon Associate we earn from qualifying purchases. Products are ranked by cost per effective dose, independent verification and published evidence; commission does not influence the order, and the rate does not vary by which product you choose.
Medical disclaimer
This site is not medical advice and is not a substitute for a clinician. The full statement, including the situations where you should speak to a professional before acting on anything here, is on the medical disclaimer page.
Third-party content
We link to external sources — PubMed, the NIH Dietary Supplement Label Database, certifier registries and retailers — and we do not control what those sites publish or how they change. Advertising served on this site is provided by third parties whose data practices are described in our privacy policy.
Changes
These terms may be updated. The date at the top reflects the most recent change.