Ascorbic Acid

Technical name for pure vitamin C

Proven to reduce wrinkles and discolorations

Helps boost the effectiveness of sunscreens

The most abundant antioxidant in skin

Very sensitive to light and air exposure

Ascorbic acid - also known as L-ascorbic acid - has the most research of any form of vitamin C when it comes to skin, and in fact is the most abundant naturally occurring antioxidant in our skin. Concentrations between 5-20% can improve numerous the appearance of signs of aging, including discolorations, wrinkles, and loss of firmness due to sun damage. Lower concentrations such as those between 0.3-2% also offer benefits, such as improvement of uneven skin tone, fine lines, and boosting skin’s antioxidant supply.

Ascorbic acid is also a powerhouse when mixed with other antioxidants, especially vitamin E, and is particularly great for evening out skin tone when used alone in higher concentrations, such as 15%, 20%, or greater. Vitamins C and E work together to keep each other stabilized and able to exert their benefits in skin longer.

In order to be most effective in higher concentrations, any water-based vitamin C formula’s pH should be 3.5 or lower. This helps improve stability and permeability of ascorbic acid, allowing it to do more than work as an antioxidant.

Ascorbic acid is a particularly vulnerable antioxidant when exposed to UV light and air, so it must be packaged to protect it from these elements during routine use. If not, its effectiveness will gradually become diminished to the point of not working at all. You will see this as discoloration from oxidation which causes the product to turn a copper to brownish color. For this reason, avoid any vitamin C (ascorbic acid) products packaged in traditional, open-mouthed jars or clear bottles.

Dropper-based dispenser-type packaging should also have air-restrictive capabilities to improve stability. And for maximum potency, it’s best to use a water-based vitamin C treatment within 3 months of opening. With once-daily usage, most people will find they go through their vitamin C product within a couple months.

Considered safe as used in cosmetics, ascorbic acid is also fine to use with retinol and niacinamide without any of these ingredients causing the other to break down or lose effectiveness beyond what would normally occur due to air and light exposure, which is why ingredients like these need to be routinely applied.

See: Vitamin C