Vitamin C, as an active ingredient in cosmetic products, combats skin aging.
- It protects the skin from the formation of free radicals.
- It increases collagen synthesis.
- It has a whitening effect.
- When combined with ferulic acid, it further enhances the whitening effect on the skin.
There are different forms of Vitamin C, with varying tolerances from the skin depending on whether the form is water-soluble or fat-soluble. Thus, the product form will either be more oily or absorbed faster by the skin without leaving any greasiness.
Forms of Vitamin C in Cosmetics
- Ascorbic Acid
Action: Strong antioxidant, protects from free radicals, stimulates collagen synthesis, reduces dark spots.
Properties: It is the most potent and effective form of Vitamin C, but also the most unstable (easily oxidized when exposed to light, air, and water). For this reason, it should be stored separately in packaging, with the ascorbic acid powder mixed with the other ingredients before use or mixed in small quantities in bottles that last for a few days before preparing the next batch.
Typically requires a pH of 3.5 or lower to be bioavailable.
Use: Recommended for morning use, but only if combined with sunscreen due to potential photosensitivity.
- Ethylated Vitamin C (Ethyl Ascorbic Acid – EAC)
Action: Stable form, water-soluble Vitamin C with similar effects to ascorbic acid, but less irritating.
Properties: Has better stability compared to ascorbic acid.
Use: Safe for both morning and evening use.
- Vitamin C Ester (Ascorbyl Palmitate)
Action: Fat-soluble form of Vitamin C, more stable and less irritating. Often combined with other antioxidants like Vitamin E. It penetrates more easily into the skin’s lipids, but its action is milder.
Properties: Suitable for sensitive skin.
Use: Safe for both morning and evening use.
- Lipophilic Vitamin C (Tetrahexyldecyl Ascorbate)
Action: Strongly antioxidant, penetrates deeper layers of the skin due to its fat-soluble nature. It increases collagen synthesis and reduces discolorations.
Properties: One of the most stable forms of Vitamin C and suitable for sensitive skin.
Use: Safe for both morning and evening use.
- Magnesium Ascorbyl Phosphate – MAP
Action: Water-soluble Vitamin C, but has lipophilic nature. This allows it to be stable and penetrate deeper into the skin’s layers. It is one of the most hydrating forms among other Vitamin C derivatives. Less irritating, and commonly used in products for sensitive skin.
Use: Suitable for both morning and evening use.
Bioavailability & Lower Irritation Ways of absorption by the skin:
- Vitamin C needs to have an appropriate form (e.g., stable and fat-soluble) to penetrate deeper layers of the skin.
- Using microencapsulation or liposomes enhances its stability and penetration.
Reducing Irritation:
- Fat-soluble forms (e.g., Ascorbyl Palmitate and Tetrahexyldecyl Ascorbate) are less irritating.
- Products with lower Vitamin C concentrations (5%-10%) are suitable for beginners or sensitive skin.
- Choose products with a pH close to the skin’s natural pH (~5.5).
Maria Kyriaki
Beautician- Cosmetologist
Graduate of the Technological Educational Institute of Athens
