Vitamin C : Frequently Asked Questions

There are so many benefits to adding Vitamin C to your skincare routine but there are also many questions about how you going to achieve maximum antioxidant benefits to your skin. Dr Webster has also written his Ultimate Guide to Vitamin C which covers the various types of Vitamin C commonly used in skincare.

Read on below for frequently asked questions and answers about everyone’s favourite antioxidant.

Can I use other serums with Vitamin C?

It is always suggested to start active serums slowly and to also introduce one serum at a time. When introducing another serum in conjunction with Vitamin C we suggest using each of your actives on either alternative days to one another or use one in the morning, for example, your Vitamin C and then your exfoliating serum that could be an AHAs/BHAs or retinol in the evening. This will prevent any possible interaction with ingredients that could cause sensitivity.

Why does my Vitamin C serum tingle?

Particularly L-Ascorbic Acid or Vitamin C serums that are formulated at a very low pH can cause sensitivity on the skin. They are formulated at a low pH and high concentration to ensure it is able to penetrate and be absorbed by the skin and this can cause a little irritation. You could consider introducing a lower concentration with a slightly higher pH if you start out with Vitamin C.

What is Ferulic Acid and is it important for my vitamin C?

Ferulic acid is another antioxidant that helps boost the potency of Vitamin C and stabilises both vitamins C and E. The combination of Vitamin C, E, and Ferulic acid yields 8 times more defence against environmental damage.

Why do I need a Vitamin C serum if I am protecting my skin with an SPF?

Vitamin C moisturisers and serums are not a replacement for SPF protection! While sunscreen is the first line of defence and is essential for protecting the skin’s surface from the damaging effects of UVA & UVB rays… sunscreen filters only protect up to 55% of damaging free radicals*.

Topical antioxidants, such as Vitamin C work within the skin to neutralise free radicals generated from all sources of oxidation and protect against UV damage.

Incorporating topical antioxidants and sunscreen into a daily skincare regimen provides complete protection.

How do I apply my Vitamin C products?

The general rule of thumb for skincare order of operations is to work from thin to thick. Apply formulas with a thinner consistency first so they have a chance to absorb into the skin before applying thicker products. Generally, serums come in the form of a glass dropper or ampoule, where you can simply drop 4-5 drops directly onto the skin and spread using your fingertips.

Should I apply Vitamin C once or twice a day?

Vitamin C is most effectively used on the skin in the morning. It builds better protection responses against UV rays and free radicals that are the main culprit in photoaging and we are exposed to these mostly during the day. Vitamin C can be useful in the evening to repair and quicken healing, but since ascorbic acid has a reservoir effect (for up to 72 hours) it is not usually necessary. It’s all about allocating your resources effectively. There are however some antioxidants like Resveratrol that have been shown to work better at night.

What is the correct way to store a Vitamin C serum?

To keep your vitamin C serum from degrading or losing efficacy, take care of the serum so it will take care of you!

KEEP IT IN THE DARK
L-Ascorbic acid is vulnerable to oxidation from light exposure and is the reason many Vitamin C products come in darker colour glass bottles (brown, blue or green). Always try to keep your Vitamin C  somewhere dark (like a cupboard) and away from any direct sunlight.

KEEP A LID ON IT
Oxygen can also break down Vitamin C. Always put the cap back on and make sure it is screwed on tight to keep air from seeping in.

KEEP IT COOL
High temperatures can degrade Vitamin C. It is therefore recommended to avoid extreme heat exposure. It is especially something to consider if you travel a lot and can’t always regulate a product’s immediate climate. That said, good manufacturers test their formulations under real-world conditions and so many can withstand formula integrity up to 30 degrees + for short periods. But it comes down to the manufacturer, so always check your product instructions to be on the safe side.

What colour should my Vitamin C serum be?

Your serum should be clear, white, or a light champagne colour. If it’s very cloudy or dark in colour, it may have already oxidised but each manufacturer formulates differently and batches can differ, so reach out to them if you aren’t sure about the colour of your Vitamin C.

Are there any side effects when using Vitamin C products?

Vitamin C is generally well-tolerated, especially the milder, derivative forms. However, if you have very sensitive or allergy-prone skin, it is best to seek professional or medical guidance before using a Vitamin C product for the first time.

ref: Haywood, R., et al, J Invest Dermatol 2006;121:862-868