Ascorbic Acid (Vitamin C)

Ascorbic acid is the form of vitamin C that has been the subject of the most research when it comes to skin. It is actually a natural antioxidant that is very abundant in our skin. Concentrations between 5% and 20% can improve many signs of aging, including discoloration, wrinkles, and loss of firmness due to sun damage. Lower concentrations, such as 0.3% to 2%, also offer benefits, such as improving uneven skin tone, fine lines, and increasing the skin’s supply of antioxidants.

Vitamin C is also very effective when combined with other antioxidants, particularly vitamin E, and is especially effective at evening out skin tone when used alone at higher concentrations, such as 15%, 20%. Vitamins C and E work together to stabilize each other and allow their benefits to be applied to the skin for longer.

To be most effective at higher concentrations, the pH of any water-based vitamin C formula should be less than or equal to 3.5. This helps improve the stability and permeability of ascorbic acid, allowing it to do more than just function as an antioxidant.

Ascorbic acid is an antioxidant that is particularly vulnerable when exposed to UV rays and air, so it should be packaged in a way that protects it from these elements during regular use. Otherwise, its effectiveness will gradually diminish to the point where it no longer works at all. You will notice this as discoloration due to oxidation that turns the product a coppery to brownish color. For this reason, avoid vitamin C products that come in transparent bottles.

Considered safe in cosmetics, ascorbic acid can also be used alongside retinol and niacinamide without either ingredient causing the other to degrade or lose its effectiveness beyond what would normally occur due to exposure to air and light, which is why ingredients like these should be applied regularly.