11/08/2025
Magnesium: The Truth Behind the Absorption Debate
Magnesium myths circulate widely, and one of the most common is that most oral magnesium supplements have less than 25 percent absorption, while transdermal magnesium oils supposedly reach 85 percent. The science does not support that claim.
Oral magnesium is typically absorbed at 20 to 50 percent, depending on the form and individual physiology. Forms such as magnesium citrate, glycinate, and malate are significantly more bioavailable than oxide or sulfate. The human body regulates absorption based on need, increasing uptake when stores are low and decreasing it when levels are sufficient.
Transdermal or topical magnesium has become popular through marketing claims, yet peer-reviewed studies have not confirmed high absorption through the skin. The most comprehensive reviews describe the evidence as scientifically unsupported. Small pilot studies show only modest increases in serum magnesium levels, not the dramatic effects that are often promoted.
In orthomolecular medicine, oral magnesium remains the most reliable and evidence-based method to restore cellular magnesium. The key is using well-absorbed forms, dividing doses throughout the day, and maintaining synergy with nutrients such as vitamin C, vitamin B3, and adequate hydration.
When absorption seems low, the issue is usually the supplement form, digestive pH, or tissue saturation not wasted nutrients. Magnesium functions optimally when supported by a whole-nutrient environment that includes the cofactors needed for its transport and retention.
(References: Magnesium bioavailability, PMC6683096; BMC Nutr 2016; PLOS One 2017; PMC5579607)
