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Ingredient Insider: Vitamin C

Vitamin C, also known as Ascorbic Acid, is an essential nutrient for the body. It stimulates production of immune system cells, and increases levels of circulating antibodies within the blood. It further helps to maintain blood vessel walls and thus prevents cardiovascular disease. Vitamin C also helps the body deal with stress. Ascorbic Acid aids the production of collagen, a protein that supports cell growth and gives skin its firmness and strength. Vitamin C helps the skin repair itself and thus aids the creation of scar tissue, as well as the diminishment of acne scars, and the treatment of hyper-pigmentation by slowing down the production of melanin.

A Powerful Antioxidant

Vitamin C is a powerful antioxidant: it slows the rate of free-radical damage. Free radicals are unstable molecules with an unpaired electron. They look to bond with other molecules destroying their health and creating new free radicals in the process.

Environmental insults such as ultraviolet (UV) rays, cigarette smoke and pollutants expose the body to free radicals that attack cells – even DNA - and can thus cause photo-aging of the skin, collagen damage, skin dryness, wrinkles, disease and even the formation of cancerous cells. The skin relies on antioxidants such as Vitamin C for protection: antioxidants scavenge free radicals and neutralize them.

The body cannot produce Vitamin C. Therefore it is essential to ensure a diet adequate in Vitamin C, by eating citrus fruits and vegetables such as bell peppers, cauliflower, broccoli, spinach, collard greens and tomatoes. Unfortunately, ingested Vitamin C cannot necessarily deliver an adequate amount of Ascorbic Acid to the skin.

The application of topical L-Ascorbic Acid, the purest form of Vitamin C, will help fight free radicals and increase the antioxidant protective reservoir of the skin.

Photo-Protection And Photo-Repair

The skin receives the most intense free-radical assault from UV rays. Increasing the antioxidant defense of the skin therefore becomes an attractive strategy for photo protection and photo repair. Vitamin C will not only act as an antioxidant to fight free radicals, but it also increases the effectiveness of sunscreen. (This does not mean you can skip the sunscreen)

Vitamin C is a Fickle Friend. Check The Ingredient List as formulation characteristics are critical for the penetration of L-Ascorbic Acid and its effectiveness.

The Molecular Structure Of The Vitamin C

L-Ascorbic Acid is the only molecular structure proven to penetrate into the skin and neutralize free radicals. Just because a vitamin C derivative is in a product does not mean it is effective—unless it is L-Ascorbic Acid.

Concentration And pH Of The L-Ascorbic Acid

To maximize activity and penetration into the epidermis, L-Ascorbic Acid should come in 15%-20% free acid concentration with a pH of 3.0 and be contained in a light-protected package. This highlights one of the problems of vitamin C products on the market today. Many products lack a sufficient concentration to be effective.

Saturation is generally achieved after three consecutive days of application at L-Ascorbic Acid concentr­ation at 20%, and these levels are maintained for three days in the skin after the application is stopped. Preparations of more than 15% may be irritating to the skin. It is advisable to start with a lower percentage concentration when using a Vitamin C treatment for the first time. A little stinging and tingling might occur, which is acceptable and will go away when skin gets used to the treatment. Over time concentration may be increased. If irritation persists, downgrade to a less potent concentration.

Tissue levels were enhanced only for formulations with a pH less than 3.5. Preparations with a pH higher than 4.0, will oxidize the L-Ascorbic Acid in the product. A product where the pH is too low, particularly less than 2.5, will result in skin irritation. An appropriate pH of 3.0 will maximize biologic activity, penetration and effectiveness. 

Check the packaging!

Proper packaging of a L-Ascorbic Acid product is important. Vitamin C lacks stability when exposed to air and light. It can begin oxidizing within minutes, which renders it ineffective. Product packaging should be air-tight and block out UVA and UVB rays. Lids should not be left off products any longer than necessary.

Know the limits of L-Ascorbic Acid and stay with professionally formulated products.


As discussed previously, the instability of L-Ascorbic Acid poses its biggest challenge. It quickly degenerates and loses its effectiveness when exposed to air and light. This oxidation process can lead to creation of additional free radicals and thus further aging.

To deliver L-Ascorbic Acid in the most effective way, choose a mix-before-use product.  


L-Ascorbic Acid is the primary water-soluble antioxidant in human tissue. It acts as first defense against free radicals generated in plasma, but cannot scavenge lipophilic (fat-soluble) free radicals within the membranes. Lipophilic antioxidants, particularly Vitamin E, suppress oxidative damage efficiently in membranes and should be added to the skincare regimen. Vitamin C, however, plays a vital role in reactivating vitamin E.

Newer types of lipid-(fat-) soluble Vitamin C, such as ascorbyl tetraiso­palmitate, have shown an enhanced penetration rate into skin, and are more stable.

Side Effects

Vitamin C has low toxicity and is not believed to cause serious adverse effects at high intakes, as the body will simply excrete any superfluous Vitamin C.  A high concentration of L-Ascorbic acids in topical products might irritate the skin. Do not use highly acidic natural ingredients known to be high in Vitamin C directly on your skin - think lemon juice. Stick with professionally formulated products as the ensure proper delivery and penetration.

Side effects can also occur when Ascorbic Acid is used too soon on fresh skin after microdermabrasion or a chemical peel. It is not recommended to use a strong Vitamin C serum after a chemical peel for a week or longer, and at least a few days following a microdermabrasion. A mild Vitamin C cream or lotion can however soothe fresh skin and possibly let it heal faster.

The Bottom Line

Only 25%-30% of skin aging process is genetically determined. This means we actually have a lot of control over our aging: diet and exercise, avoiding sun and other free radical attacks, and the use of proper cleansing routine are all big levers for skin health.

Vitamin C is one of the best researched, most effective and important ingredients available to the esthetician to treat a number of skin problems, including aging skin, acne scars and pigmentation disorders. It can help achieve younger, healthier and more radiant skin. It also brightens while toning pores, and aids the healing of scars both old and new.

A series of Vitamin C treatments provides the best results when coupled with at-home product use. You should see results with consistent use over 3-4 weeks depending on skin type and pre-existing damage.

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