Magnesium chloride (topical)
What it is
Magnesium chloride hexahydrate applied as a 'magnesium oil' spray or bath flake — popular for local muscle cramp relief and as an adjunct when oral magnesium is poorly tolerated. Transdermal absorption is real but small and highly variable — insufficient to fully replace oral magnesium for systemic repletion, despite marketing claims. Best positioned as a local comfort tool and mild adjunct rather than a primary route. Skin stinging on broken skin is common. Oral remains the primary evidence-based route.
Dose
10–20 sprays (200–400 mg) to limbs, or 1–2 cups flakes in bath
Time of day & tips
Apply after showering to clean skin; some stinging is normal and decreases with use; do not rely on transdermal alone for correcting deficiency; excellent for localised cramps
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