Why vitamin C can harm your skin, if you encounter it, how to avoid it

Vitamin C is one of the few skin care ingredients with a ton of independent research to back up its properties, like its brightening and anti-wrinkle benefits. Those of you who are vitamin C enthusiasts may have noticed that with some vitamin C serums, you end up with the stained orange-brown skin after a few days of use – sort of like fake tan.

Recently I read a document about vitamin C. told me why vitamin C does this: ascorbic acid oxidizes to erythrulose!

As most of you may know, vitamin C in the form of ascorbic acid oxidizes to dehydroascorbic acid, which has an orange-brown color. It does this when it’s stored in water, as well as on your skin. Oxygen and light exposure will speed up the oxidation reaction. This reaction is reversible, so you can get back the ascorbic acid if you have the right antioxidants in the formula.

But, dehydroascorbic acid also decomposes, and it does it . It turns into a number of things, but for our purposes here, we only care about the fact it turns into 2,3-diketogulonic acid, which then turns into erythrulose, according to the reactions I’ve drawn below:

Erythrulose is an ingredient in fake tans and is often included alongside the more found dihydroxyacetone or DHA. These ingredients react with proteins in the dead stratum corneum layer of your skin to produce brown compounds called melanoidins that stay on your skin until the dead cells come off (after around a week). The reaction is a Maillard reaction, like the reactions that happen when meat and baked goods turn brown with heat.

Erythrulose is notable for giving a redder tan than DHA that stains more , less and lasts longer. It’s included in tans from St Tropez, Bondi Sands, Jergens, Dove, and Models Prefer that have DHA as the main ingredient. It’s also the sole ingredient in Deciem’s Hand Chemistry Glow Oil and Hylamide Glow Radiance Booster.

So that’s why vitamin C serums can stain – the ascorbic acid essentially turn into fake tan on your skin! Mystery solved.

HOW TO AVOID VITAMIN C STAINING YOUR SKIN

So now that we know why vitamin C serums can stain, how can we prevent this from happening? There are a few approaches:

PREVENT OXIDATION

Preventing the vitamin C from oxidizing is the obvious way of keeping the erythrulose down in the first place. You can use an antioxidant-rich formulation like vitamin C + vitamin E + ferulic acid. What I’ve found helpful with my low-tech, budget-friendly DIY vitamin C serum is to immediately use oils and creams on top to protect the vitamin C from the air. Using it at night, away from high energy sunlight, will also help.

USE OXIDATION-RESISTANT FORMS OF VITAMIN C

Ascorbic acid is by far the most unstable form of vitamin C and oxidizes very easily. While the other forms of vitamin C aren’t as researched and require your skin to take a few extra steps before working, they also won’t oxidize anywhere near as badly on your skin. Some of these oxidation-resistant vitamin C ingredients include:

magnesium ascorbyl phosphate

sodium ascorbyl phosphate

ascorbyl tetraisopalmitate

tetrahexyldecyl ascorbate

WASH YOUR HANDS AFTER APPLYING VITAMIN C SERUMS

Fake tan ingredients stain dead skin cells, and your hands tend to have a thicker stratum corneum. This means that sometimes your hands will turn brown even if your face doesn’t stain! To avoid stained hands, just wash them with soap immediately after applying the vitamin C serum.

APPLY VITAMIN C SERUM EVENLY OVER FACE

Some of you might not mind the color – it can actually give you a nice rosy glow! If that’s you, then apply the serum as as possible and exfoliate your face so the tan fades . If you notice streaking, increase the waiting time between applying vitamin C serum and your next product.