Magnesium for Hair: What the Research Shows
Magnesium is an essential mineral, and low intake is common, but we found only one trial that looked at a hair outcome: in women with polycystic ovary syndrome (PCOS), 10 weeks of magnesium did not significantly change alopecia scores. It did improve quality of life. The case for magnesium and hair is indirect.
Here's what that trial found, what magnesium does in the body, and how much supplemental magnesium is considered tolerable.
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Key Takeaways
- Magnesium is a cofactor in hundreds of enzyme reactions, and deficiency remains common worldwide because of low dietary intake, chronic disease, medications and lifestyle.
- In a 10-week trial in 64 women with PCOS, magnesium supplementation did not significantly change alopecia, acne or abnormal uterine bleeding, but improved quality of life.
- The US upper limit for supplemental magnesium in adults is 350 mg a day, based on diarrhea.
- We found no trial showing magnesium helps hair growth or hair loss.
What Is Magnesium?
Magnesium is the fourth most abundant cation in the human body. It's involved in energy metabolism, nerve and muscle function, cardiovascular health, bone integrity and immune defense.
Does Magnesium Help Hair?
Not shown. Low magnesium is common, so some people may be short, but whether correcting it changes hair hasn't been demonstrated. The only hair-outcome trial we found had a null result for alopecia.
Getting Magnesium
- Food first. A varied diet is the base. See your doctor if you suspect a deficiency.
- Supplements are common; watch the dose, because diarrhea is the main limiting side effect.
- Don't expect a hair effect from magnesium alone.
What The Research Shows
A Trial With A Hair Outcome
Sixty-four women with PCOS were randomized to magnesium or placebo for 10 weeks. Magnesium significantly improved quality of life, including physical functioning, emotional well-being and energy, compared with placebo. No significant effect was observed on acne, alopecia or abnormal uterine bleeding (Jaripur et al., 2022).
Magnesium Status
A review describes magnesium as a critical cofactor for hundreds of enzymes. It reports that deficiency is common worldwide, driven by inadequate dietary intake, chronic diseases, medication use and lifestyle, and that low magnesium status is associated with hypertension, type 2 diabetes, osteoporosis, migraines, depression and chronic inflammation (Matek Sarić et al., 2025).
How Much Supplemental Magnesium Is Tolerable
In 1997 the US Institute of Medicine set a tolerable upper intake level of 350 mg/day for adults from supplements alone, with diarrhea as the limiting factor. A 2023 perspective argued the level should be re-evaluated because seven studies using 128 to 1,200 mg/day found no significant difference in diarrhea between intervention and control groups (Costello et al., 2023).
Inositol is often taken alongside magnesium in the studies we reviewed; see inositol and hair.
See also: Boron for Hair: What the Research Actually Shows · Chromium for Hair: Blood Sugar, Insulin & What the Research Shows
To see how this fits with the other nutrients hair needs, read our guide to the best vitamins for hair growth.
Magnesium is one of the ingredients in FullyVital's Hair Skin Gut Collagen. For how the evidence for each ingredient in the line stacks up, see our evidence-tier breakdown.
Frequently Asked Questions
Does magnesium help hair growth?
We found no trial showing it does. In women with PCOS, 10 weeks of magnesium did not significantly change alopecia scores.
Can low magnesium cause hair loss?
We found no study showing that. Magnesium deficiency is common, and a doctor can check your levels if you're concerned.
How much magnesium can I take?
The US upper limit for supplements is 350 mg a day for adults, based on diarrhea. Talk to your doctor before taking more.
References
- Jaripur M, Ghasemi-Tehrani H, Askari G, et al. The effects of magnesium supplementation on abnormal uterine bleeding, alopecia, quality of life, and acne in women with polycystic ovary syndrome: a randomized clinical trial. Reprod Biol Endocrinol. 2022. PubMed
- Matek Sarić M, Sorić T, Juko Kasap Ž, et al. Magnesium: Health Effects, Deficiency Burden, and Future Public Health Directions. Nutrients. 2025. PubMed
- Costello R, Rosanoff A, Nielsen F, et al. Perspective: Call for Re-evaluation of the Tolerable Upper Intake Level for Magnesium Supplementation in Adults. Adv Nutr. 2023. PubMed
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