The Ultimate Derm’s Guide to Vitamin C: Benefits, Tips, and Safer Alternatives

Vitamin C is a well-known and well-studied active ingredient with multiple benefits. The benefits of Vitamin C have been demonstrated for decades by extensive research, and that is why this ingredient is included in numerous skincare products worldwide. To learn how to best use vitamin C, it’s important to learn about its different forms, how they work and potential side effects. We checked in with Skincare Junkie® founder and board-certified dermatologist Dr. Murphy-Rose. 

Vitamin C in Skincare 

Vitamin C is one of the most common active ingredients in skincare due to its many proven benefits. Dr. Murphy-Rose explains, “Vitamin C is one of the most powerful antioxidants and has well-known anti-aging, collagen-boosting, and skin-brightening benefits. It is pregnancy-safe and effective as part of a skincare regimen for treating and preventing hyperpigmentation, improving melasma and post-inflammatory hyperpigmentation, and preventing fine lines and wrinkles.”

Why Do We Need Vitamin C? 

“Vitamin C is an essential vitamin that humans cannot synthesize in our bodies. We rely on supplementation to get sufficient vitamin C, but dietary vitamin C does not efficiently reach our skin. So, we require topical application to get the active form of vitamin C working best on our skin. And make no mistake, of course we want to consume adequate daily dietary vitamin C to reap its many benefits to our bodies,” says Dr. Murphy-Rose.  

Types of Vitamin C in Skincare 

Did you know there are six types of vitamin C used in skincare? Check the ingredients list on your products to find out which one you are using. Below is a brief summary of each type and some pros and cons:

L-Ascorbic Acid 

The most-studied, well-known, and purest form of vitamin C. Dr. Murphy-Rose says, “L-ascorbic acid is a potent form of vitamin C that provides excellent antioxidant benefits to our skin. This is the most frequently used form in skincare products. Ascorbic acid can cause skin irritation, so its concentration and the way it is formulated will be variably tolerated by consumers.” Those with sensitive skin should avoid high concentrations of ascorbic acid. 

Because ascorbic acid is unstable and prone to oxidation (which stops it from working well), it is often formulated with other acids to reduce its pH level and with tocopherol (vitamin E) which is highly comedogenic (pore-clogging). Lastly, ascorbic acid is water-soluble, which reduces its ability to penetrate the skin. This means it will treat surface hyperpigmentation, not the deeper levels. 

Sodium Ascorbyl Phosphate

A more stable form of vitamin C that is less irritating to the skin. However, it is also less potent than ascorbic acid and does not absorb into the skin well.

Ascorbyl-6-Palmitate, Ascorbyl Glucoside, Magnesium Ascorbyl Phosphate

Water- and fat-soluble forms of vitamin C, which are more stable, better able to penetrate the skin, and less irritating. However, they are less potent than ascorbic acid and take longer to work. 

Tetrahexyldecyl Ascorbate (or THD vitamin C)

A newer form of vitamin C that is Dr. Rose’s favorite for treating hyperpigmentation and for use on sensitive skin. This more stable form is oil-soluble, has optimal skin penetration, is highly effective AND less irritating. Because THD vitamin C is newer, it is not yet widely available in beauty products. 

Which Vitamin C Product Is Best for Acne Prone Skin? 

“My patients were struggling with skin irritation and acne breakouts often caused by pore-clogging skin care products including many vitamin C serums!” says Dr. Murphy-Rose. “Vitamin C serums tend to be problematic for acne-prone skin because they are almost universally formulated with vitamin E (tocopherol), which is highly comedogenic, and due to the increased inflammation vitamin C can induce. We developed Skincare Junkie® Megadose Super Antioxidant Face Moisturizer to solve this problem for my patients.”

“We tested many reduced concentrations of ascorbic acid while developing the Megadose Super Antioxidant Moisturizer and formulated it with a combination of skin-soothing and highly effective antioxidants Coquinone 10, resveratrol and green tea to reap the all of the free radical-neutralizing benefits while minimizing potential side effects. Our proprietary formulation has surpassed extensive sensitive skin testing and was awarded the National Eczema Association Seal of Approval. This non-comedogenic lightweight, oil-free moisturizer also contains centella asiatica to calm skin and reduce redness. This is the best Vitamin C product for acne-prone skin.”

How to Use Vitamin C Safely  

Vitamin C is generally considered safe, but can cause skin irritation for those with sensitive skin or underlying skin conditions. Dr. Murphy-Rose advises using a vitamin C serum or other bioavailable topical antioxidant(s) every morning. Vitamin C is safe to use during pregnancy and helps prevent melasma, or “the mask of pregnancy,” when used in conjunction with mineral sunscreen. It should be the first step in your daily morning routine after cleansing.

To reduce likelihood of irritation, it is important to store skincare products containing vitamin C correctly: 

• Packaging. Vitamin C is unstable and reacts to air, light, and heat. It should be packaged in opaque or dark glass packaging and stored away from direct sunlight. For example, Skincare Junkie® Megadose Super Antioxidant Face Moisturizer comes in an airless, opaque bottle that keeps vitamin C and antioxidants in its formula intact. 
• Expiration date. Check the use-before date. If the vitamin C product is yellow or brown in color, it may have expired. It should ideally be a light straw color. 
• Other ingredients. To stabilize vitamin C, skincare manufacturers often add other ingredients like acids or oils that can be comedogenic. Make sure you read the label and check for other ingredients such as fragrance, vitamin E (tocopherol), etc. 

Vitamin C is a potent acid and not advised for use on children’s skin. It increases sun sensitivity, so applying SPF 30 or higher as the final step of your skincare routine is essential. Finally, to avoid skin irritation, dermatologists advise against mixing vitamin C products with other potent active ingredients such as AHAs, BHAs, and retinoids.