Humectant

Magnesium PCA

INCI: MAGNESIUM PCA

Reviewed by Daisy · Last updated 14 Aug 2026

Also known as: Magnesium Pca

A magnesium salt that helps skin retain moisture and maintain hydration

Best For Skin Types

All, Dry, Combination, Sensitive

Addresses

Dryness, Hydration

Usage Frequency

Daily

What Is Magnesium PCA?

Magnesium PCA is the magnesium salt of pyrrolidone carboxylic acid (PCA), a naturally occurring compound found in skin. It functions as a humectant and skin conditioning agent, meaning it draws moisture into the skin and helps maintain hydration levels.

PCA is part of the skin's natural moisturising factor—the combination of compounds that keeps skin supple and hydrated. In skincare formulations, magnesium PCA works to support the skin's ability to absorb and retain water.

Benefits for Your Skin

How It Works

Magnesium PCA works as a humectant by attracting water molecules from the environment and deeper skin layers, drawing them to the outer layers of the skin. This helps maintain hydration and prevents transepidermal water loss.

The magnesium component may also contribute to skin conditioning benefits, though the majority of its functional role in cosmetics centres on its humectant properties.

Clinical Evidence & References

Magnesium PCA has been assessed for safety by the Cosmetic Ingredient Review Expert Panel and confirmed as safe for use in cosmetics at current concentrations. The ingredient is recognised as a legitimate skin conditioning agent and humectant.

However, specific clinical studies demonstrating its hydrating efficacy in human skin remain limited. It is used in approximately 0.2% of skincare products, suggesting its adoption in formulations is relatively modest compared to other humectants.

How to Use

Magnesium PCA is typically found in serums, moisturisers, and hydrating toners. For best results, apply to damp skin to maximise its water-binding capacity, then follow with an occlusive moisturiser to seal in hydration. It works well alongside other humectants and can be used daily.

Safety & Precautions

Magnesium PCA is well-tolerated and considered safe for use in cosmetic formulations at approved concentrations. It is not known to be a common irritant or sensitiser.

Frequently Asked Questions

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