Magnesium Chloride: Uses, Benefits, Dosage & Safety
Last updated: August 2026 · Reviewed by the FactoWiki Editorial Team for clarity and source accuracy
Quick summary
Magnesium chloride is well absorbed orally and is the form used in topical magnesium oils and flakes. The oral evidence is reasonable; the claim that it absorbs meaningfully through skin is not well supported.
What is Magnesium Chloride?
Magnesium bound to chloride, around 12% elemental magnesium by weight. Highly soluble and well absorbed when taken by mouth. It is also the form used in magnesium oil sprays and bath flakes.
What Magnesium Chloride is commonly used for
Oral magnesium repletion, and topically for muscle soreness — the latter with weaker justification than the marketing suggests.
How Magnesium Chloride works
Orally it behaves like other soluble magnesium salts. The topical claim rests on transdermal absorption, and the skin is a genuinely effective barrier to charged mineral ions. Studies attempting to demonstrate meaningful transdermal magnesium uptake have been small and largely unconvincing.
What the evidence says
Each claim below is tied to the specific study behind it, rather than to a general reading list.
- Magnesium chloride is well absorbed orally relative to inorganic forms. Firoz & Graber, Magnesium Research, 2001 — comparative bioavailability study. (PubMed)
- Evidence for meaningful transdermal magnesium absorption is limited. Gröber et al., Nutrients, 2017 — review of transdermal magnesium. (PubMed)
- The stratum corneum is an effective barrier to ionic minerals. Dermatological absorption literature. (PubMed)
Typical dosage used in studies
200–400 mg elemental daily orally. Topical products do not have an established effective dose because the absorption question is unresolved.
Side effects and safety
Well tolerated orally, with a moderate laxative effect between citrate and glycinate. Topically it commonly causes tingling or itching, particularly on broken skin.
Medication interactions and who should avoid Magnesium Chloride
Medication & safety check
Standard magnesium interactions — separate from levothyroxine, bisphosphonates and certain antibiotics by two hours. Caution in reduced kidney function.
General information, not personal medical advice. If you take any medication, confirm it is safe to combine with Magnesium Chloride with your doctor or pharmacist first.
Sources & further reading
The claim-level citations above are drawn from these sources:
- Firoz & Graber, Magnesium Research, 2001 — comparative bioavailability study — find on PubMed
- Gröber et al., Nutrients, 2017 — review of transdermal magnesium — find on PubMed
- Dermatological absorption literature — find on PubMed
- NIH Office of Dietary Supplements
- NIH National Center for Complementary and Integrative Health
Frequently asked questions
Does magnesium oil work through the skin?
The evidence is weak. The skin barrier resists charged mineral ions and the studies claiming transdermal uptake are small and methodologically limited. A warm bath is relaxing regardless.
Is oral magnesium chloride good?
Yes, it is well absorbed. Whether it beats glycinate or citrate for your purpose comes down to bowel tolerance.
Can I use it on broken skin?
It stings considerably. Avoid it.
Part of a wider guide
Magnesium Chloride is one form of Magnesium. This page covers what is specific to this form — absorption, tolerability, dosing and who it suits. For the underlying nutrient itself, its overall evidence base and general safety, read the Magnesium guide.
Where you'll find Magnesium Chloride
Magnesium Chloride appears in Minerals formulas. Browse the supplement guides to see the products we review, each with a full breakdown of formula, pricing and safety.
Related ingredients to explore
Ingredients often studied or formulated alongside Magnesium Chloride.
General information, not medical advice.