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How to best store your Vitamin C Serum


Time to read 2 min

Vitamin C is an active ingredient that has been making a comeback for some time now as a potent antioxidant as well as one of the key players in antiaging skincare routine. 


As mentioned in our previous post, one of the most potent Vitamin C forms out there is L-ascorbic acid. 

1. What is ascorbic acid (Vitamin C)?

Ascorbic acid is Vitamin C in its pure, natural state. Ascorbic acid has many benefits for mature and young skin alike:


  • Helps our skin against free radical damage

  • Boosts sun protection of sunscreens like Protection Cream

  • Helps fade dark spots

  • Promotes the production of collagen for firmer-looking skin.

Ascorbic acid in aqueous solution is most effective when it is “unstable” and ready to bond with free radicals that are looking to attack our skin, which means protecting our skin cells. (Ascorbic acid in aqueous solution basically means ascorbic acid dissolved in water formula. So any ascorbic acid serum would fall into this category.) The trouble with this “unstable” ascorbic acid is that it oxidizes fast, meaning the colour changes fast.

2. How we tested for the best way to store Vitamin C serum

To find out the best way to store ascorbic acid (Vitamin C Serum), we put test samples of ascorbic acid in aqueous solution in different temperature settings for 3 months. And at the end of 3 months, we took out the samples and checked them against our hypothesis.


As a result, we found that the rate at which ascorbic acid in aqueous solution oxidized and changed colour was the fastest at a high temperature, such as 40C˚. We also discovered that at a low temperature, such as 4C˚ which is similar to your refrigerator, the speed at which it oxidized and changed colour was extremely slow, indicating almost no change in effectiveness of ascorbic acid within 3 months.

3. The best way to store Vitamin C Serum

So we concluded that the best way to store opened ascorbic acid is at 4C˚.


But don’t freak out if you haven’t kept it in the refrigerator. Because for the most part, it is still okay to keep your ascorbic acid serum at room temperature as long as it is not exposed to direct sunlight or heat. (But of course, if you have it opened for more than 6 months, it will have oxidized.)


And colour change does NOT mean that it is no longer effective. It does mean that there has been some oxidization, but that does NOT render the product ineffective as most Vitamin C products have other antioxidants to protect ascorbic acid for oxidization.


For example, our Vitamin C Serum has EmblicaTM, which is another potent, CASCADING antioxidant, meaning that it has layers of antioxidants that fight off free radicals. (Click to read more about this amazing ingredient, EmblicaTM.)


And if a Vitamin C product has not been opened yet, it will not be subject to oxidization as long as direct sunlight and heat are avoided.


But once it has been opened, we recommend keeping it in your refrigerator to keep it at its best for a longer period of time.

Our Vitamin C Serum, which uses 20% ascorbic acid, has been protected against oxidization by our patented Self-Preservation System. And because we use 200,000ppm of ascorbic acid, there are MANY antioxidants to fight off free radicals. So if even some were oxidized, there would still be MORE THAN ENOUGH to protect your skin against free radical damage.


But to make it even more effective and less prone to oxidization, our Lab has been researching various ways, from changing formulation to storing it in a refrigerator, to store Vitamin C Serum once it’s been opened so that it can maintain its effectiveness for longer.


4. Vitamin C Serum works best with