Is Your Supplement Any Good?
Most supplements have one of three problems: wrong form (magnesium oxide instead of glycinate), wrong dose (too little to match clinical evidence), or wrong price (10x more than equivalent products). Enter what you take below and we'll check all three.
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Common Problems We Find
| Supplement | Common Problem | What to Use Instead | Guide |
|---|---|---|---|
| Magnesium | Oxide form (~4% absorbed) | Glycinate (~80% absorbed) | Forms guide |
| Vitamin D | D2 instead of D3; 400 IU dose | D3 at 1,000-5,000 IU | D2 vs D3 |
| Fish Oil | Ethyl ester form; "1200mg" label hiding 360mg EPA+DHA | Triglyceride form; check actual EPA+DHA | TG vs EE |
| Creatine | HCl or buffered form (5-10x overpriced) | Plain monohydrate ($0.05/day) | Forms guide |
| Multivitamin | Folic acid + cyanocobalamin (synthetic B vitamins) | Methylfolate + methylcobalamin | Quality guide |
The evidence · Magnesium Glycinate
What the published reviews of Magnesium Glycinate concluded
- Minerals and Sarcopenia; The Role of Calcium, Iron, Magnesium, Phosphorus, Potassium, Selenium, Sodium, and Zinc on Muscle Mass, Muscle Strength, and Physical Performance in Older Adults: A Systematic Review. · Journal of the American Medical Directors Association, 2018
“Minerals may be important nutrients to prevent and/or treat sarcopenia. Particularly, magnesium, selenium, and calcium seem to be most promising. Most of the included studies, however, were observational studies.”
- Magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus. · The Cochrane database of systematic reviews, 2024
“The currently available evidence indicates that magnesium sulphate for women at risk of preterm birth for neuroprotection of the fetus, compared with placebo, reduces cerebral palsy, and death or cerebral palsy, in children up to two years' corrected age, and probably reduces severe intraventricular haemorrhage for infants.”
- The impact of essential fatty acid, B vitamins, vitamin C, magnesium and zinc supplementation on stress levels in women: a systematic review. · JBI database of systematic reviews and implementation reports, 2017
“The current review suggests that EFAs may be effective in reducing prenatal stress and salivary cortisol and may reduce anxiety during premenstrual syndrome and during menopause in the absence of depression.”
- Magnesium sulfate for postoperative complications in children undergoing tonsillectomies: a systematic review and meta-analysis. · Journal of evidence-based medicine, 2017
“Unlike the studies in adults, this review shows there is no statistically significant effect of perioperative use of magnesium in the postoperative pain control in children undergoing tonsillectomies.”
Method: PubMed searched in humans for systematic reviews and meta-analyses with Magnesium Glycinate in the title; these 4 of the 31 that qualified are shown with the authors’ own conclusion quoted rather than summarised. What it cannot tell you: whether Magnesium Glycinate will work for you — each of these reports an average across trials published 2017–2024, and null findings are shown here as readily as positive ones.
Frequently Asked Questions
How do I know if my supplement is good quality?
Check three things: form (glycinate > oxide for magnesium, D3 > D2 for vitamin D, triglyceride > ethyl ester for fish oil), dose (compare to clinical trial amounts), and third-party testing (USP or NSF). Our tool checks all three.
Am I overpaying for my supplement?
Probably. The key metric is cost per clinically-effective daily dose, not cost per bottle. A cheap bottle requiring 6 pills/day costs more than an expensive bottle requiring 2. Enter your product above to find out.