vitamin c serum has truned brown

What’s that yellow tinge in my serum? I swear it wasn’t there yesterday. What’s going on?!

Yep, your vitamin C serum is a magician. It can change colour and go from clear to yellow all the way to brown. Ain’t that cool?

Not really. That’s Vitamin C’s way of warning you it’s stopped working. Oops!

What Is Vitamin C And Why Should You Use It?

In case you’re wondering why you should bother using something that stops working after a while, here’s the lowdown on vitamin C:

  • It’s a powerful antioxidants that fight the free radicals that cause premature wrinkles
  • It stimulates the production of collagen, the protein that keeps skin elastic
  • It has photoprotective properties that help prevent and treat sun damage (especially when used with vitamin E and ferulic acid)
  • It brightens the complexion and fades dark spots

You want this stuff in your skincare routine, trust me!

Related: 5 Anti-Aging Superstars You Should Include In Your Skincare Routine


Struggling to put together an anti-aging skincare routine that really reduces the look of wrinkles and gives your skin a youthful glow? Download your FREE “Best Anti-Aging Skincare Routine” to get started (it features product recommendations + right application order):


Why Does Vitamin C Turn Brown?

L-Ascorbic Acid, the pure form of vitamin C, is super unstable. As soon as it comes in contact with air, heat or light, it throws a tantrum and loses a bit of its effectiveness.

Actually, it gets weaker and weaker by the day even if you don’t put it in touch with its enemies (just like food). But if you do, you’ll accelerate the oxidation process.

You know when this is happening because your vitamin C turns darker until it takes on a brown hue. In other words, the darker the colour, the less effective the vitamin c.

medik8 ce tetra vitamin c antioxidant serum

How To Prevent Your Vitamin C Serum From Turning Brown

You can’t stop vitamin C from going bad. But you can slow down the process so your vitamin C serum doesn’t go bad before you’ve had the chance to use up the entire bottle. Here’s how:

1. Choose A Stable Form Of Vitamin C

L-Ascorbic Acid is the most effective form of vitamin C out there. But it ain’t the only one. Scientists are coming out with new types all the time. These derivates are less powerful but more stable so they don’t go bad as quickly. Some of my faves are ascorbyl glucoside, magnesium ascorbyl phosphate and tetrahexyldecyl ascorbate.

Best Picks:

Related: Types Of Vitamin C In Skincare (And Where To Find Them)

2. Avoid Jars

You’re exposing your precious vitamin C to light and air every time you open the jar. You know what happens when you do that, right? Instead, go for airtight, opaque tubes and bottles that keep it well protected.

Related: Why Jar Packaging Is A Waste Of Money

Sunday Riley CEO Rapid Flash Brightening Serum 02

3. Opt For Sample Sizes

If you’re not sure you can finish a whole bottle, why not ask for samples? Some brands even make their serums in different sizes so you can choose the one that’s more convenient for you. You can even hunt down for gift sets with mini sizes of your fave vitamin C serums. If you find one you love and know would use daily, you can upgrade to the full size.

The Bottom Line

Vitamin C is a potent antioxidant that works wonders for the skin. But it’s so unstable, it goes bad quickly. Opt for derivatives packaged in tubes and bottles to get the most bang for your buck.