Vitamin C in Skin Care Products

Vitamin C is an essential and important antioxidant that you should incorporate into your skin care routine.

It is essential because our body cannot synthesize it. It must be obtained from the diet. And, because Vitamin C has a very short period of activity, it must be replenished daily, both nutritionally and topically.

Key Benefits:

• Stops Free Radicals (Antioxidant)
• Increases Collagen
• Reduces Pigmentation

Vitamin C performs many functions in the body. Most importantly, Vitamin C builds and strengthens tissues (connective tissues such as collagen, and vascular tissues such as blood vessel walls). A lack of Vitamin C makes connective tissues weak, which slows down wound healing and accelerates aging.

You may have heard of scurvy, a disease that long ago affected sailors who did not have access to fresh fruit on long sailing expeditions. Scurvy is a deficiency of Vitamin C.

Vitamin C also plays a role in the metabolism of folic acid and some hormones.

In skin care, Vitamin C is an effective antioxidant at quenching free radicals. Skin is significantly less damaged when Vitamin C is applied to skin before and after sun exposure.

Vitamin C also boosts collagen levels, as it is a required nutrient for collagen production. Collagen requires Vitamin C and iron to form healthy protein fibers. In the absence of Vitamin C, collagen forms abnormal fibers. This leads to skin lesions, fragile skin and blood vessels.

Vitamin C also inhibits melanin formation (it is a tyrosinase inhibitor). Melanin is the pigment that gives skin and hair its color. And excess melanin leads to hyperpigmentation. More about Vitamin C as a brightening ingredient here.

Another benefit of Vitamin C is its complementary role to Vitamin E. It is an essential companion to Vitamin E. Vitamin E can neutralize only one free radical at a time. It becomes inactive after neutralizing a single radical. Vitamin C regenerates Vitamin E, by converting the inactive Vitamin E back into an active antioxidant form. This is why it is good to have both Vitamin C and Vitamin E together in a product.

Vitamin C is also a naturally mild exfoliator that cleanses the pores. So while it’s not as exfoliating as an AHA, it does makes skin smoother and more radiant.

Finally, Vitamin C increases ceramide synthesis, which improves dry skin and the skin’s barrier function.

There are different forms of Vitamin C, and it is important to choose the right form. First, because they have varying levels of effectiveness and stability. Second, a form that is unsuitable for your skin can irritate it.

Pure Vitamin C is Ascorbic Acid, also called L-ascorbic acid. The “L” refers to the chirality of the molecule. All Ascorbic Acid in skin care products is in the “L” chiral form. Manufacturers know to use the L chiral form, so the use of the L chiral form is assumed. You should see “ascorbic acid” denoted without the “L” on an ingredient list because designating the chirality on ingredient labels is prohibited. But sometimes the “L” is shown anyway.

L-ascorbic acid is the acidic form of Vitamin C, and it is water-soluble. Ascorbic Acid is the bioavailable form needed for collagen synthesis. All other forms of Vitamin C need to be converted to Ascorbic Acid inside cells.

In skin care products, it is more common to see derivatives of Vitamin C, which are salts (water-soluble) or esters (oil-soluble) of Ascorbic Acid.

Note: A skin care product will never list the word “Vitamin” on the ingredient list (it is a labeling law). Instead, it will show the formal chemical name (INCI). To recognize a Vitamin C ingredient, look for the word “ascorbyl” or “ascorbate.”

Common Forms of Vitamin C:

• Ascorbic Acid (L-Ascorbic Acid)
• Ascorbyl Palmitate
• Sodium Ascorbate
• Sodium Ascorbyl Phosphate
• Magnesium Ascorbyl Phosphate (MAP)
• Tetrahexyldecyl Ascorbate (THDA) (also denoted Ascorbyl Tetraisopalmitate)
• Ascorbyl Glucoside
• Ascorbyl Glucosamine
• Ascorbyl Methylsilanol Pectinate

Important Precautions About Ascorbic Acid

Ascorbic acid is the most irritating and least stable form of Vitamin C.

It oxidizes extremely fast, which means that if it has started oxidizing while still in its bottle, it will actually generate free radicals instead of stop them.

To be effective, Ascorbic Acid must be stabilized. The shelf life of unstabilized Ascorbic Acid is at most 6 months. Once it has oxidized, it will actually cause your skin harm instead of helping it. And even when formulated correctly, it STILL oxidizes.

How Ascorbic Acid Is Stabilized

Keep Vitamin C products away from sunlight. Vitamin C is easily oxidized by sunlight. Store your skin care products in a dark, cool, dry place.

You shouldn’t buy a Vitamin C serum that is packaged in a clear bottle. Clear bottles that allow light to penetrate aren’t good for any kind of skin care products. Sunlight and heat degrade skin care ingredients. Look for opaque bottles, preferably airtight containers with a pump. The one exception is a high percentage Ascorbic Acid serum (i.e. it has a high concentration of Vitamin C). These acids needs to be packaged in glass bottles (but dark colored ones) because the acid can react with plastic material (acids don’t react with glass).

If your Vitamin C serum or cream has changed color and turned TAN OR BROWN (starting from a clear or light color), throw it out. The browning of the color means it has oxidized. The oxidized ingredients in the product will generate free radicals in your skin (instead of stopping them). Any product that has oxidized will harm your skin. There are a few exceptions though. Some products are expected to change color slightly without affecting the efficacy of the product, but the manufacturer will state that upfront.

• If your skin is NOT sensitive, use a Vitamin C serum or serum that contains Vitamin C at least once daily. You can also apply it twice daily (once in the morning and once at night before bed). Apply it under your moisturizer.

• If you plan to spend an extended time in the sun, apply Vitamin C BEFORE you go into the sun and AFTER you return indoors. Especially after. Being in the sun depletes your antioxidants. Your skin will need the Vitamin C to quench the free radicals generated from your time in the sun.