Verified Supplement Data

Evidence-based supplement comparisons. We chain clinical trial evidence to specific products, third-party certifications, and cost per clinically-effective daily dose.

How we're different: Most supplement sites compare products by price per pill. We compare by cost per clinically-effective dose — the price to take the amount actually studied in clinical trials. A cheap product that underdoses the active ingredient isn't a good deal.

Magnesium Supplements

Magnesium Supplement Guide

Complete hub for magnesium comparisons — which form for which goal, product rankings, and cost analysis.

All Magnesium Forms Compared

8 forms ranked: glycinate, citrate, oxide, threonate, taurate, malate, chloride, sulfate. Bioavailability, use cases, side effects, cost.

Best Magnesium for Sleep (2026)

6 glycinate products compared. Clinical dose: 320–400mg/day. Best value: $0.24/day. Based on systematic review of 9 studies (n=7,582) + meta-analysis (-17 min sleep onset latency).

Magnesium Glycinate vs Citrate

The most common comparison question. Head-to-head evidence, absorption, side effects, cost, and which to choose.

Our Data Sources

Clinical Evidence: PubMed systematic reviews and meta-analyses with direct links to source studies
Product Labels: NIH Dietary Supplement Label Database (DSLD) — 207,000+ verified labels
Quality Verification: NSF Certified for Sport, USP Verified, ConsumerLab Approved status
Pricing: Current retail pricing from Amazon and brand websites, updated regularly

Methodology

Read our full methodology for details on how we collect, verify, and normalize supplement data.