About StackRatings

Anecdotal, not medical evidence

Ratings are self-reported by a self-selected group of people. They show how a supplement felt to raters, not whether it works. Placebo effects, expectations, brand loyalty and who chooses to rate all shape the numbers. Use them as a starting point for questions, never as proof.

Not medical advice. Nothing on this site is a diagnosis, treatment or personal recommendation. Talk to a doctor or pharmacist before you start a supplement, especially if you take medication, are pregnant or breastfeeding, or have a health condition.

How scores are computed

Every rating has an effect score (0–10) and a side-effect score (0–10). A supplement only gets scores once it has at least 10 ratings. When you filter by a goal, only ratings given for that goal count, and the supplement needs 10 ratings for that goal.

The ranking uses a Bayesian average. Instead of the plain mean, every supplement starts as if it already had 10 "typical" ratings, and real ratings pull it away from there:

score = (10 × m + sum of effect ratings) / (10 + number of ratings)

m is the average effect across all ratings in the current view (all goals, or the selected goal). Until that view has at least 100 ratings, m is fixed at 5. This stops a supplement with three enthusiastic ratings from outranking one with three hundred good ones.

The side-effects column is a plain average, and "would take again" is the share of raters who answered yes. Histograms show raw counts and start at zero.

Evidence levels

The research column is an editorial rating per goal, based on published human studies (sources are listed on each supplement page).

• Strong: consistent meta-analyses of RCTs for this goal.
• Moderate: several RCTs, mostly consistent.
• Limited: few or small RCTs, or mixed results.
• Anecdotal: mostly mechanism, animal studies or user reports.

Each level has a direction: evidence of benefit evidence of no benefit evidence it makes this worse. A goal with no entry shows No research rating.

Who runs it

StackRatings is run by Nerd Protocols, a clinical and sports dietitian based in the EU, who writes the Nerd Protocols newsletter. The notes on each supplement page are written by Nerd Protocols; the ratings come from the community. There are no affiliate links, sponsors or ads.

Data license

The anonymous ratings are available as /data.csv (one row per rating, month only, no comments) under CC BY 4.0. Please credit "StackRatings (stackratings.org)". Stack ratings are in a separate file, /stacks.csv (one row per stack submission, month only, no free text, only combinations with at least 5 submissions).

Privacy policy

Data controller: [CONTROLLER NAME, ADDRESS, EMAIL]

Ratings are anonymous

A rating stores only what you enter (supplement, scores, goal, dose, duration, "would take again", optional comment) and the date (day only, no time). We don't store your name, account, age, sex, IP address or any device identifier with a rating. A rating can't be linked to an email address: they are stored in separate tables, sent through separate forms and share no ID. The "I'm 18 or older" box is checked but not stored.

A stack rating ("Rate my stack") follows the same rules: it stores the combination, optional dose, unit and timing per item, the overall scores, goal, duration, "would take again", the item you think does the most work (optional) and the day. No free text, no IP, no session or device identifier. It is not linked to your single ratings. A combination is shown publicly only after 5 people have submitted the same set. One stack per day is enforced with the same hashed-IP counter described below.

Newsletter email

If you sign up, we process your email address to send the Nerd Protocols newsletter, based on your consent (GDPR Art. 6(1)(a)). The email provider (Buttondown or Kit) stores it as our processor and handles confirmation (double opt-in). Every email has an unsubscribe link, and you can withdraw consent at any time by unsubscribing or by writing to the contact above. Until a provider is connected, the address is kept in our own database (Cloudflare D1) together with the signup date, the page you signed up on and the consent version.

Abuse protection

To limit spam (at most 20 ratings per day and one rating per supplement per day), we compute a one-way hash of your IP address combined with a random value that changes every 24 hours, and keep a counter under that hash for 24 hours in Cloudflare Workers KV. The hash is never stored with your rating and expires automatically. Legal basis: our legitimate interest in keeping the data free of spam (Art. 6(1)(f)). Forms are also protected by Cloudflare Turnstile, which checks that a human is submitting; Cloudflare processes technical data for this check.

Hosting and analytics

The site is hosted on Cloudflare (Pages, D1, Workers KV). We use Cloudflare Web Analytics, which does not use cookies or track you across sites. Fonts are served from this site, not from third parties.

Cookies and local storage

We use no cookies, so there is no cookie banner. Your browser's localStorage keeps a list of supplements you've already rated on this device, only to warn you about duplicates. It never leaves your device; clear it in your browser settings at any time.

Your rights

You can ask for access to, correction or deletion of your email address, and you can complain to your data protection authority. Because ratings are anonymous, we can't identify which ratings are yours.