Can I Still Use Oxidised Vitamin C?

Vitamin C as a skincare ingredient has a deep-rooted reputation for being highly effective, yet unstable powerhouse. Pushing all those outdated reports aside, vitamin C is certainly a favourite amongst skincare experts and fans alike.

You’ll find that the most common formula everyone tends to reach for are serums, this is because many find applying a serum enriched in vitamin C is the most effective way of benefiting from the skin reviving ingredient. If you are wanting to know more about vitamin C and how it can benefit the skin, check out our dedicated blog post about it over on the Beauty Insiders.

Now, let’s move on to exploring what happens and whether we can still use oxidised vitamin C. If you are sat there wondering how vitamin C can oxidise, here is a brief recap on the tell-tale signs your serum has oxidised.

• Vitamin C, also known as L-Ascorbic Acid, is often formulated into serums that are light in consistency and colour, typically clear, or sometimes champagne in colour.
• Once it oxidises, the serum will appear dark yellow, orange, and sometimes brown in colour.
• You’ll find that once a serum is oxidised its potency is reduced up to 25%
• If you find your serum or product to have an unusual odour it is clear sign you must stop using it completely as it will not benefit the skin in any way and could potentially cause irritation.

You can find out more about how to tell if your vitamin C has become oxidised in our blog post.

Can we use oxidised vitamin C serum?

Yes, you can, but only if it has turned slightly yellow. This is usually a sign of the oxidisation has started, but the formula is still potent enough to deliver its benefits to the skin. If however, it has a dark orange or brown colour to it, it’s best to avoid using it all together as it not only useless on the skin, it will also create a barrier on the surface of the skin that can interfere with other active ingredients and formulas absorbing effectively into the skin. 

You will sometimes find there are different types of vitamin C found in various skincare products that vary in stability, the stable forms taking longer to oxidised and generally more potent. By this I mean some vitamin C types, such as L-ascorbic acid and sodium ascorbyl phosphate, both of which are water-soluble and are often formulated into products suited for those with an oily skin type that are prone to blemishes and acne flare-ups. If you have a dry skin type you may find other types of vitamin C that are richer in consistency and moisturising, such as ascorbly palmitate and tetrahexyldecyl ascorbate are better suited due to the fact they are lipid-soluble vitamin C types.

Is oxidised vitamin C harmful?

In a word, yes, oxidised vitamin C can become harmful to the skin. You’ll find that in some cases people suffer from unwanted skin irritation, but this isn’t the only problem. The effectiveness of your vitamin C serum is completely depleted. This means the skin no longer benefits from the benefits of the active. Benefits such as the antioxidants found in the formula that can ward off any exposure to free radicals, like pollution, central heating, harsh climates, and other environmental aggressors. With the vitamin C no longer containing the right potency it is unable to keep the lipid barrier of the skin strong and protected from further skin damage. This damage can result as fine lines, wrinkles, loss of elasticity, dark spots, and hyperpigmentation.

Finally, in some rare cases, applying oxidised vitamin C to the skin can lead to discolouration and yellowing of the skin which can take some time to subside.

Is vitamin C still good after oxidation?

Yes and no, as I have just explained, using an oxidised vitamin C product can often lead to some side effects if the formula has turned dark orange or brown. With it lacking in potency and the risk of it staining your skin it is said to avoid using vitamin C products once they have severely oxidised.

How do I know if my vitamin C has oxidised?

As I have already mentioned, the colour of your formula is a vital factor to keep an eye on. It is generally considered that if your serum begins to look yellow, orange, or brown, it’s time to chuck it out.

When using vitamin C serums, it is important to remember to store your product the correct way and use it in the most effective way too. This is something we will cover in the next section to share some tips with you about how to keep your vitamin C product fresher for longer.

How can you stop vitamin C from oxidising?

There are a few ways of preventing your vitamin C serum from oxidising too quickly and staying fresher for longer. So, here are our top tips of extending the shelf life of these potent powerhouse formulations.

• Keep your vitamin C away from sunlight

Exposure to the sun can rapidly decrease the effectiveness and potency of the active ingredient. To keep it delivering the best results keep it in a cupboard or drawer. You must also not that all products containing vitamin C must come in an opaque or light blocking packaging.

• Always secure your lid

This may sound silly to some, but it is very important you keep oxygen out of your serums. Any exposure to oxygen will make the vitamin C effectiveness deteriorate making it unable to perform. Misplacing a lid is something that is easily done, so better to be safe than sorry and double check before storing your vitamin C serum away.

• Keep your products out of the bathroom

I understand how storing your skincare products in your bathroom cabinet makes sense. But it is possibly the worse place for your skincare products. The fluctuation in heat and being exposed to frequent humidity will alter the formulations and can interfere with how they work on the skin.

• Remember about the products life cycle

If a vitamin C product is left unopened and stored in a drawer away from direct sunlight, it will last up to three years. Once it’s opened however, you’re looking at about 3 months until the potency begins to wear off. It is important to use your vitamin C serum as frequently as possible to reap the rewards and use up the formula whilst it is at its most potent state.

There you have a little insight into using oxidised vitamin C and how it will affect the skin. Don’t forget, if you have any further questions, you can come and find us in Instagram.