How Do You Know if Vitamin C Serum is Oxidised?

How Do You Know if Vitamin C Serum is Oxidised?

The benefits of using a vitamin C serum are endless with so many of us having introduced into our routines. As amazing as vitamin C is for the skin, there is the downside of it becoming oxidised resulting in the ingredient being less potent and effective at treating the skin. There are many things to consider when you are trying to find out if your vitamin C serum has become oxidised. What does it look like? What can you do if you find your product to be affected and what will it do to your skin? These are all the questions we will find out today. 

How do you know if vitamin C serum is oxidised?

Vitamin C is an antioxidant, meaning it has is a powerhouse for keeping your skin healthy, glowing and protected from free radicals and other skin damaging aggressors. Out of all the skincare products available vitamin C has the shortest shelf-life due to the fact that once the product is met with oxygen its potency immediately begins to deplete.

The easiest way to see if your vitamin C serum has become oxidised is by making note of the colour. Serum containing more vitamin C are clear which begins to change to a yellow or brown colour roughly 3 months after opening. Once this begins to happen it is a clear sign that the L-ascorbic acid losing its strength and as it degrades it becomes erythrulose which is in fact the exact ingredient you’ll find in self-tanning products and can last for a long as 7 days. The trouble with erythrulose is that it can also cause some unwanted damage to the skin with increased exposure to free radicals resulting in your skin needing to repair itself.  

What should vitamin C serum look like?

It is always advisable to opt for a vitamin C serum that comes clear in appearance as previously mentioned, which shows how high the levels are of vitamin C is in the formulation and allows you to see if it has become oxidised. As hard as it may be to reconsider your initial thoughts of the vitamin C should look orange and some brands have been known to add colouring to the formulas to replicate this. Ideally it is best to opt for products that have no colour to them that come in opaque, air-tight bottles to ensure you keep the vitamin C staying as fresh as possible and not have it combating too much UV and oxygen exposure that can cause it to go off quicker.

Can you use oxidised vitamin C serum?

The life expectancy of vitamin C is roughly 3 months once the product it open and being used, after this time you should expect to see the formula begin to decrease and look brown. There is nothing stopping you from using the rest of the product, especially if there is over 10% of active vitamin C that is still potent. There is a concern of how the serum will react with your skin and can cause some staining, irritation and some have experienced breakouts such as spots and blemishes.

Is oxidised vitamin C bad for skin?

There are no scientific results to show oxidised vitamin C having an effect on the skin, however there are many cases of the skin irritation and staining due to the fact that oxidised L-ascorbic acid becomes the ingredient, erythrulose, which is formulated into self-tanning products. Oxidised vitamin C is no longer a powerful antioxidant resulting in free radicals, environmental and daily aggressors which leads to the skin vulnerable to damage with premature signs of ageing such as fine lines and wrinkles becoming very prominent and more noticeable.

Due to the fact the L-ascorbic acid levels in the product formulation being so low, or perhaps completely disappeared you may find that vitamin C serums are less effective and will not make any difference to the complexion.

Can you use vitamin C serum every day?

Compared to other Alpha hydroxy acids, also known as AHA, vitamin C is safe to use every day. With its abilities to combat any skin damage and other stresses providing a protective coat on the skin when you are going about your day. With its antioxidant benefits vitamin C serums are very effective to apply in the mornings, however many feel using them in the evenings give the AHA a chance to work undisturbed by any daily damage it encounters during the day.

If you are wanting to learn more about AHAs and what they do for the skin, you can check out our blog all about the skincare benefits of AHAs and BHAs. 

When should you throw out a vitamin C serum?

Once your serum begins to turn yellow, it is a clear sign that too much air has mixed with the formula making the vitamin C less potent, once the formula becomes discoloured in any way it is best to throw out the product completely. Vitamin C is a notoriously tricky ingredient to work with and is unstable in water solutions which makes it harder to establish if the percentage of vitamin C is at an active level and will truly benefit the skin. To ensure it will treat the skin the best way possible it is a good idea to take note of the positioning of L-ascorbic acid in the inky list on the packaging, if it is further down the list than 6th it is not potent enough to deliver the best results to the skin. 

So, there you have some answers to the most frequent questions asked about vitamin C and how you know if it has become oxidised. There is a fully dedicated blog post about the skincare benefits of vitamin C for you to take a look at and gather a better understanding of its full benefits when applying it to the skin and the results you will see.


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