• Marsha


Updated: Apr 20

Vitamin C is a great antioxidant, often formulated in a lot of cosmetic products as a brightening agent. However, stability and penetration of this ingredient remain the biggest challenge and for this reason, some experts do not believe in the topical use of vitamin C.

The active form of Vitamin C is Ascorbic Acid (or L-Ascorbic Acid). When applied topically, vitamin C can neutralize reactive oxygen species (ROS) triggered by exposure to UV radiation, smoke, and other pollutants. Studies further suggest that vitamin C is effective in treating hyperpigmentation, by acting on tyrosinase (the enzyme that produces melanin). However, formulating vitamin C is the biggest challenge given that it is easily degraded in water-based medium, as well as in the presence of oxygen and metal ions. If you check the ingredients list on your serum bottle, you'll find water to be in the first 3 ingredients on the list. That is because water-based serum gives it its light texture.

Several strategies have been developed to tackle these concerns:

  • controlling the presence of oxygen during formulation and storage

  • reducing water content, through the use of anhydrous formulation (e.g. The Ordinary Vitamin C 23% suspension) - higher viscosity increases stability (Vitamin C formulation can stay 10% longer)

  • adding antioxidants and other preservatives to prevent degradation - adding ferulic acid has been shown to have good results. Just as little as 0.5% ferulic acid can boost stability of vitamin C by 90% and double the photoprotective effect of vitamin C.

  • Adding glycerin and palmitic acid (humectants) increase vitamin C stability.

Further, some modifications have been done to Vitamin C to make it more stable. On the ingredients list, if you see anything other than Ascorbic Acid or L-Ascorbic Acid, such as Ascrorbyl 2-phosphate, ascorbic acid 2-glucoside, ascorbyl 6-palmitate, or tetra-isopalmitoyl ascorbic acid, these are the more stable derivatives of Vitamin C. Bear in mind that they need to be converted to ascorbic acid to have antioxidant benefits! Yes, studies have shown that these derivatives are far more stable than ascorbic acid, but the crucial data, i.e. clinical data on the efficacy of these stable derivatives, are lacking.

Collectively, there could be reasons explaining why your vitamin C serum is not really giving you any results, some of which could be:

  • Not formulated/manufactured well

  • Vitamin C degraded due to prolonged exposure to light, oxygen, or drastic changes in temperature

  • Using Vitamin C derivatives - limited evidence that this will be converted to ascorbic acid in the skin and transform your skin

  • Vitamin C below 8% in concentration (needs to be at least 8% to have biological significance)

My recommendations for Vitamin C serums:

1. SkinCeuticals C E Ferulic serum (Vitamin C, E, Ferulic Acid)

2. Paula's Choice C15 Booster (Vitamin C, E, Ferulic Acid)

3. The Ordinary Vitamin C suspension 23% + HA spheres 2% - anhydrous Vitamin C (not formulated in water)

4. Timeless 20% Vitamin C + E Ferulic Acid serum (affordable alternative to SkinCeuticals)

Remember that results may take time, so be patient and diligent with your skincare and you'll witness great benefits!

Till next time,

The Skin Press

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