Aspartic Acid

What is Aspartic Acid?

Aspartic acid is one of the amino acids your body uses to build proteins. Cosmetic aspartic acid is usually made by fermentation or chemical synthesis, and the label name doesn’t tell you which.

On a label it usually appears in a group with other amino acids, such as glycine, alanine, serine and proline. You’ll find it in serums, moisturizers, toners and some hair products. A related salt, magnesium aspartate, shows up in similar formulas.

What does Aspartic Acid do?

• Conditions skin. The safety review describes amino acids as working mainly as skin and hair conditioning agents.
• Helps hold water. Amino acids are also listed as humectants, which means they help a product hold moisture at the skin’s surface.
• Supports the formula’s feel. In a blend with other amino acids and humectants, it adds to a soft, hydrated finish.

It’s a supporting ingredient. Reported use levels in cosmetics are low, at most about 1% in the safety review, so it isn’t a reason to buy a product on its own.

Who is Aspartic Acid for?

It suits most skin types, including dry and sensitive skin. In the human patch tests the safety panel reviewed, leave-on products containing aspartic acid caused no irritation or sensitization. The panel concluded it is safe as used in cosmetics.

The “acid” in the name sometimes worries people with sensitive skin. It isn’t an exfoliating acid. If a product with aspartic acid stings, other ingredients in the formula, such as fragrance or an exfoliating acid, are more likely to be responsible.

What to pair Aspartic Acid with, and what to avoid

It already sits alongside other amino acids and humectants such as glycerin and hyaluronic acid in most formulas. There’s nothing you need to avoid with it.