Stability of Vitamin C in Skincare Products

Exposure to UV rays, pollution, poor diet and smoking cause the formation of free radicals in our bodies. Free radicals are extremely harmful. They are aggressive and can destroy human cells. They also lead to rapid ageing of the skin. Antioxidants are substances that neutralise the harmful effects of free radicals.

Vitamin C is a powerful antioxidant. Vitamin C is also known as ascorbic acid.

Vitamin C skincare products are however highly unstable. They oxidise when exposed to air, light, heat, iron and copper. Once oxidised, it becomes less effective on our skin. A good vitamin C skincare product should stay unoxidised for a while for it to continue being effective. Otherwise, it will end up having a short shelf life.

Some ways skincare manufacturers increase the shelf life of Vitamin C products:

• Some manufacturers add additional ingredients to a Vitamin C product. Example: Vitamin E and ferulic acid. Specific ingredients like ferulic acid and Vitamin E, prevent the quick oxidisation of Vitamin C.
• Some manufacturers don't use ascorbic acid at all and instead use derivatives of ascorbic acid. These derivatives are more stable than ascorbic acid. They are less effective than ascorbic acid. That is the compromise: longer shelf life vs effectiveness Example: Magnesium ascorbyl phosphate.
• Packaging plays an important role. Packaging should be opaque (not see-through) and airtight. Exposure to sun/light makes the Vitamin C product go rancid.

Quick tips for the Vitamin C product in your cabin: Always close the lid tightly after use. Don't expose it to light. You will know your product is going rancid when it starts turning yellow around the lid.