Supplement Guides, Graded by Evidence

Quick answer

Each guide covers one ingredient: what it does, how much the studies used, and who should ask a doctor first. Every benefit carries a grade of strong, moderate or early, and a source we opened. Creatine's strength entry, for example, is graded strong at 3 to 8 g a day, while its lean mass entry is graded moderate.^1,2

Key facts

A strong grade needs consistent results from meta-analyses or several randomized trials in people. Creatine's strength entry rests on a 2025 meta-analysis of 69 randomized trials.¹
A moderate grade also covers a well-established nutrient function, such as magnesium's role in normal muscle and nerve function. Those entries describe getting enough, not taking more.^3,4
An early grade means a few small studies or mostly animal and laboratory work. Magnesium and sleep is one example, and it is labeled early wherever it appears.^5,6
Facts come first from the NIH Office of Dietary Supplements, then from trials and reviews on PubMed. Each source was opened on the date its guide shows.^7,8

How to read the grades

Every benefit in a guide is shown with one of three grades. The grade describes the research behind the wording, not the product, and the amount the studies used is always shown beside it.

The three grades, with one example each^1,3,5
Grade	What it needs	Example
Strong	Consistent results from meta-analyses or several randomized trials in people, at an amount a product provides	Creatine and strength, from a 2025 meta-analysis of 69 trials
Moderate	Several human trials that mostly agree but are small, short or mixed, or a well-established nutrient function	Magnesium and normal muscle and nerve function, a long-established role of the mineral
Early	A few small human studies, or mostly animal and laboratory work	Magnesium and sleep, from small trials of self-rated sleep

Where one of our products has a different amount or form from the one studied, the guide says so. A moderate grade is not a weak one when it describes a nutrient's normal job. It means the wording is about getting enough.

Where the facts come from

The first source is the NIH Office of Dietary Supplements, which publishes a fact sheet for most nutrients. After that come systematic reviews, position stands and randomized trials on PubMed. For medicines, the sources are DailyMed labels, MedlinePlus medicine pages and LiverTox.

Brand sites, supplier copy, news articles and AI summaries are not used. Every source in a guide is a page that was opened, and the guide shows the date.

What the guides leave out

The guides do not make medical claims or promise outcomes. They describe how a nutrient works in the body, and where the research is thin or mixed, they say so. A guide can end with no benefit at all, which is a valid answer.

Where to start

Start with the guide for an ingredient you already take. If you are starting from a goal instead, try the goal pages, such as supplements for strength training or what supplements to take every day. The calculators turn the studied amounts into numbers for your weight and your products.

See what we make

Every product shows its whole label and what its lab report covers. The store opens soon.

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Sources

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.