Vitamin C

What does it do?
It’s an antioxidant, and helps protect against UV damage
Increases collagen production
Blocks pigment production

Why should I use it?
Protect against UV damage
Skin ageing

How do I use it?
In the morning, followed by sunscreen

What should I look for in a product?
L-ascorbic acid, 15-20%
The addition of ferulic acid +/- vitamin E
Opaque, airless packaging

What’s the evidence?

There’s a lot of talk about Vitamin C. You’ve probably heard of it, but you may not be quite sure what it really does, or if it’s worth adding into your skin routine. 

What is Vitamin C and how does it work?

Vitamin C is an antioxidant, which protects against UVB and UVA. It increases collagen production and prevents melanogenesis (pigment production). There’s lots of good evidence including a number of scientific studies that show Vitamin C works to help improve signs of skin aging and combat hyperpigmentation.

Why should I use it?

Vitamin C is really useful in protecting your skin against UV damage. It can also help to improve the signs of aging and even out hyperpigmentation (darker patches of skin). Vitamin C can also be useful if you have melasma.

What do I look for in a product?

Vitamin C can easily break down and become ineffective. To help stop this from happening, it’s best to look for products in packaging that protects from exposure to air and light (opaque, air-restricted packaging). The most active and effective form of vitamin C available is L-ascorbic acid. Look for concentrations of 15 – 20%. Ferulic acid is an antioxidant that makes L-ascorbic acid more stable. Products that contain both, +/- vitamin E, are a great combination for your skin. 

How do I use it?

Because it helps to protect against UV, it’s best to apply Vitamin C products in the morning, followed by sunscreen. Vitamin C can safely be used every morning, although if it’s irritating, reduce use to every second day. 

What are the issues to consider?

Vitamin C can cause skin irritation. To prevent this, use it every second day to begin with. Take care if you also use alpha or beta hydroxy acids or retinoids, as these can all cause irritation too. 

L-ascorbic acid is the most irritating form of Vitamin C. As an alternative, you could consider products that contain less irritating forms of Vitamin C, such as magnesium or sodium ascorbyl phosphate, ascorbyl glycoside, ascorbyl palmitate, or tetrahexyldecyl ascorbate

Avoid applying Vitamin C at the same time as benzoyl peroxide, as benzoyl peroxide can oxidise and inactivate vitamin C. 

What are the different forms of Vitamin C?

There are many forms of vitamin C, with varying levels of evidence, stability, and efficacy. 

  • L-ascorbic acid is the most active form of vitamin C, but the most unstable. It’s prone to breaking down and becoming inactive, which can occur if it is formulated or packaged incorrectly, for example at the wrong pH, at the wrong temperature, or if it’s exposed to too much light or air. 
  • The vitamin C derivatives sodium and magnesium ascorbyl 2-phosphate are more stable than L-ascorbic acid, but are less well absorbed and less potent. They need to be converted in the skin to L-ascorbic acid to be effective.
  • Other vitamin C derivatives such as ascorbyl-6-palmitate, ascorbyl 2-glycoside and tetrahexyldecyl ascorbate are also more stable than L-ascorbic acid, but may be less effective.  


Al-Niaimi F, Chiang NYZ. Topical Vitamin C and the Skin: Mechanisms of Action and Clinical Applications. J Clin Aesthet Dermatol. 2017;10(7):14-17.

Telang PS. Vitamin C in dermatology. Indian Dermatol Online J. 2013;4(2):143-146. 


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Spotlight on Skin was created by award-winning Melbourne-based dermatologist, Dr Julia Rhodes.

Julia knows first-hand how overwhelming the skincare world can be, and that’s with over 10 years of experience practicing dermatology. Given that even she gets overwhelmed, she appreciates how hard it can be for those of you without a scientific background to make sense of all the information available, and choose products that are right for your skin…