Magnesium Aspartate

Magnesium aspartate is a magnesium salt of an amino acid, typically used at low concentrations as a skin-conditioning/ionic supplement and is generally well tolerated in leave-on and rinse-off products. Available irritation and patch-test experience with magnesium and amino-acid salts suggests a low irritation profile, with occasional stinging possible on very compromised or fissured skin due to electrolyte load rather than true causticity. Given the limited dedicated topical clinical data and my focus on high-sensitivity populations, I rate it as very gentle but not completely inert. Safety Notes: Magnesium aspartate is an uncommon cosmetic magnesium salt, but when used it typically appears in multi-mineral/skin-conditioning blends and barrier-support creams at low levels around 0.01–0.2% as a trace electrolyte/conditioning agent. Higher-strength consumer products marketed for “magnesium skincare” (leave-on lotions/creams and some serums) can push magnesium salts into the ~1–3% range before solubility, crystallization, tackiness, and potential irritation become limiting; rinse-off formats generally stay toward the low end because contact time is short and electrolytes can destabilize surfactant systems.