The Truth About Your Vitamin C Serum.

You pay good money for your skincare products, so it's only natural that you'd want to make the most out of them. 

But if you see them change in color, consistency, or odor over time, the truth is that it may be nearing the end of its shelf life -- especially if the product in question contains more unstable ingredients like vitamin C or retinol.

Luckily, the changes your skincare is going through can provide clues on whether you can keep using them or if it's better to toss them out. Let's take a closer look at what's going on, focusing on our Vitamin C E + F serum.

Vitamin C E + F


What's Going On with Your Vitamin C E + F?

In addition to being the most abundant antioxidant found in your skin, vitamin C has powerful benefits that make it useful in skincare for anti-aging, dark spot correction, and more.

When you receive a fresh bottle of our C E + F, the serum inside is either clear or the color of champagne with a thin and watery consistency. But because vitamin C in particular is known for being very finicky, it quickly oxidizes when it's exposed to oxygen, heat, or sunlight -- over time, this can change the color to a dark yellow, orange, or even brown. 

Just think about the last time you ate or cut open an apple. Apples contain a large amount of vitamin C, which explains why they turn brown pretty quickly once the insides are exposed to the oxygen in the air. The same thing happens to the vitamin C in your serum. 

Our chemists use a specific ratio of vitamin C, E, and ferulic acid to keep our vitamin C serum effective for up to 6 months after you open it. However, if it's used as recommended, it should only last for about 3 months or so -- giving you enough time to use it before it starts to lose its effectiveness. 

All good things don't last forever, and that's definitely the case with C E + F too. You don't have to worry about the serum if it's still slightly yellow, but if it begins to get into orange or brown territory, unfortunately it may be time to toss it out and replace it with a new bottle.

Why Does Your Skin Change Color After Applying Vitamin C?

This oxidation process also explains why sometimes vitamin C serums stain your skin yellow or orange after it's applied.

As you just learned, skincare formulas that contain l-ascorbic acid (like ours does) can turn brown after being exposed to sunlight or oxygen. That's why it's important to use just the right amount -- about 3-5 drops' worth. Why? Using too much product means that it'll take longer for the serum to absorb into your skin. As it sits on the surface of your skin, the excess vitamin C oxidizes and changes color, eventually changing the color of your skin along with it.

You can reduce the chances of this happening by making a few tweaks to your skincare regimen whenever you use a serum with l-ascorbic acid in it:

  • Apply 3-5 drops of the serum directly after cleansing and toning so it absorbs into your skin faster, giving it less time to oxidize
  • Add a layer of your favorite face oil over the serum to act as a barrier between the vitamin C and the oxygen in the air
Vitamin C E + F

3 Tips to Make Your Vitamin C Serum Last Longer

  • Close the lid tightly after use: The oxygen in the air is one of the biggest factors that degrade the efficiency of vitamin C and the other ingredients in the serum. Leaving even the tiniest opening can cause some air to get into the bottle and break down the formula.

  • Store it in the right place: Vitamin C doesn't just react to oxygen and sunlight -- it's highly sensitive to changes in temperature too, so any exposure to heat can affect the product too. And we're going to be honest with you, your bathroom is probably one of the worst places in your home to store your serum. The constant temperature changes from taking showers and baths can seriously mess with the stability of the product.

  • Minimize its exposure to sunlight: The dark amber color of the bottle helps prevent exposure to UV rays, but if you want to take extra precautions you can always wrap your bottle in aluminum foil and keep it in a cool, dark place (your fridge would work great!).

Of course, these are all great tips to help stop all your products with actives in them from breaking down and oxidizing -- not just those with vitamin C. 

Skincare and Life Lessons from DRMTLGY

Essentially, what all of this means is that moderation is key. Using too much or too little of a good thing (in this case, the C E + F serum) means that more of the product will go to waste, even with your best intentions.Don't be shy to finish it up. Because of its relatively shorter shelf life, you definitely don't want to save your vitamin C serum for a rainy day. Skincare is meant to be used -- and it looks and works best on your skin, not in the bottle.

Get in touch with our skincare experts for any other questions you might have about your favorite DRMTLGY products, and you might even see your next question addressed in a future blog post!


Clinics in Dermatology, September-October 2009, Volume 27, Issue 5, pages 469-474

Dermatologic Surgery, July 2005, Volume 31, Issue s1, pages 814-818

Indian Dermatology Online Journal, April 2013, Volume 4, Issue 2, pages 143-146

All information is created for informational purposes only and is not intended to be a substitute for professional medical advice, diagnosis, or treatment.