All about using vitamin C on your skin

Vitamin C is without a doubt one of the best skin care ingredients you can incorporate into your daily regimen, and we're not the only ones saying that. Dermatologists and beauticians sing the praises of vitamin C for its antioxidant power and ability to even out the skin.

How Vitamin C Benefits Your Skin

“Vitamin C is an essential part of skin health, both as an antioxidant and as a critical factor for collagen synthesis. It contributes to photoprotection, reduces photographic damage and is necessary for wound healing.”

Says Dr. Hadley King, a board-certified dermatologist based in New York City. By photoprotection, he means vitamin C's ability to ward off free radicals. In other words, it diminishes all signs of aging caused by the sun, such as UV-induced wrinkles and wrinkles, collagen degradation, and even sun spots and melasma.

“Studies have shown that using vitamin C in applications for at least 12 weeks has been shown to decrease wrinkles, reduce damage to protein fibers, decrease apparent skin roughness and increase collagen production. Additionally, vitamin C has also been shown to reverse some of the age-related changes in the epidermis.”

What to Look for in a Vitamin C Product

The thing about vitamin C is that it is considered an “unstable” ingredient in liquid form, meaning it degrades quickly if it is not formulated well or if the packaging is subpar. This is one of the reasons you often see vitamin C in small amounts and why bottles are airtight and opaque versus clear. To maximize effectiveness, it must be used quickly and not exposed to light or air.

“The stability of vitamin C in solution has been a concern because exposure to air, heat and light can slowly degrade the vitamin. Ascorbic acid has been shown to be the most effective form of vitamin C for topical administration, but it is the least stable in solution. Stability can be increased by adding other antioxidants. Therefore, look for ascorbic acid, combined with other antioxidants, and packaging that protects the solution from air and light.” says Dr. King.

There are some vitamin C derivatives that are also effective in skin care products. These include tetrahexyldecyl ascorbate (THD), sodium ascorbyl phosphate, 3-O-ethyl ascorbic acid, and ascorbyl glucoside.

Each of them must be formulated differently from each other (for example, some are water-soluble while others are oil-soluble), each has different concentrations of ascorbic acid and also penetrates the skin differently. Although ascorbic acid, in its purest form, is the most potent, the trade-off with these derivatives is that they tend to be more stable.

What concentration of Vitamin C should I look for?

Regarding the concentrations of vitamin C in a product, this depends on your needs and skin type.

“The strengths of vitamin C can range from 10% to 30%. If your skin is on the sensitive side, I would use a lower percentage. If you use vitamin C or if your skin is used to medical-grade products, you should use the higher strength of 30%,” says Bobbi Del Balzo, lead medical esthetician at New York's Deep Blue Med Spa.

Products that contain vitamin C derivatives tend to have a higher concentration, but this does not mean that they are as potent as the ascorbic acid equivalent. What's best for you is really a matter of preference and general wording.

Vitamin C: what to do and not to do

Before we wrap up, let's talk about applying vitamin C. Apply your vitamin C product in the morning.

“The best time is in the morning because vitamin C fights against environmental damage and UV/HEV rays. You can also use it at night, but it should not be mixed with certain products.” says Balzo.

Don't combine your vitamin C with retinol. The data is not entirely straightforward regarding whether or not some vitamin C formulations may contribute to retinoid degradation. For this reason, prefer to use vitamin C during the day and a retinoid at night. You also shouldn't mix vitamin C with AHAs or BHAs, as this can cause irritation.

Use SPF with your vitamin C products in the morning. The ingredient can make your skin more sensitive to the sun, plus applying sunscreen on top of your vitamin C product helps prevent the ingredient from oxidizing in your skin. Oxidation can make your vitamin C less effective and even lead to the formation of blackheads.

Do not use an oxidized product in the bottle. Vitamin C serum is generally light in color, that is, when it starts to turn yellowish/brown, it means that it has oxidized too much and the product is no longer effective. Store your product in a cool, dark and dry place. To prevent accelerated oxidation, keep the vitamin C serum out of light and in a cool, dark place. Also, make sure the lid is completely sealed. Obviously, this only applies to vitamin C in liquid form, not in cream or lotion form.

Use your vitamin C every day. Make applying vitamin C part of your daily routine and reap the rewards of this brilliant ingredient the Earth so graciously gave us.