Vitamin C is an antioxidant, enables collagen synthesis, and reduces inflammatory pathways. It also inhibits melanogenesis – i.e. prevents age spots and hyperpigmentation.
All of this can have a big impact on reducing the signs of skin ageing.
Reducing hyperpigmentation and age spots:
Vitamin C does not absorb UV light but exerts an UV protective effect by neutralizing free radicals – this is its antioxidant effect.
It works as a depigmenting agent by interacting with copper ions at the tyrosinase-active site which inhibits action of the enzyme tyrosinase, thereby decreasing melanin formation.
Collagen production:
Vitamin C is also essential for collagen biosynthesis. Clinical studies have shown that the topical use increases collagen production in young as well as aged human skin.
Vitamin C also inhibits certain pro-inflammatory cytokines, and therefore has potential anti-inflammatory properties.
Therefore, vitamin C is found in many skincare products – but how can you tell if a product has significant amounts of active vitamin C, or if it is just some orange extract and a marketing claim?
To answer this, we need to consider 4 things:
1: What form of Vitamin C is in the product? L’Ascorbic acidis more bioavailable that BV-OSC.
2: What percentage of this vitamin C is in the product? At least 10-15%is required before it will be enough for collagen production.
3: Is the formulation still active? Vitamin C oxidises and becomes inactive, turning brown, when exposed to sunlight.
4: What else is in the product? When combined with vitamin E or Ferulic acid as well, vitamin C can be more effective.
Question 1: What form of Vitamin C is in the product?
L’Ascorbic acid:
- Bioavailable
- Water soluble
- Antioxidant
- Stimulates collagen
Tetrahexyldecyl ascorbate (BV-OSC), Ascorbyl glucoside, Acsorbyl-6-palmitate, Magnesiun ascorbyl phosphate, and Aminopropyl ascorbyl phosphate:
- Have to convert to L’ascorbic acid
- Oil soluble
- Antioxidant
Tetrahexyldecyl ascorbate (BV-OSC), Ascorbyl glucoside, Acsorbyl-6-palmitate, Magnesiun ascorbyl phosphate, and Aminopropyl ascorbyl phosphate are oil soluble, so offers hydration and antioxidant protection in the upper layers of skin.
They have to be converted into L’Ascorbic acid before the body can use it to stimulate collagen.
If a product claims to have 15% Vitamin C but this is BV-OSC, that will offer antioxidant protection. However, to stimulate collagen production, the BV-OSC needs to be converted to L’Ascorbic acid first. This will occur on the skin to some degree.
The amount of the 15% BV-OSC that is then converted to L’Ascorbic acid depends on the health, age and skin condition of the person.
The amount converted may not be enough for collagen synthesis.
Therefore, even a product that is “15% vitamin C” may not be optimum for anti-ageing.
Question 2: What percentage of Vitamin C is in the product?
10-15% of L’Ascorbic acid is needed for a product to have anti-ageing properties
The efficacy of the Vit. C serum is proportional to the concentration, but only up to 20%.
Beyond 20%, there is not a greater anti-ageing effect, and concentrations above this have a higher risk of causing skin irritation.
Question 3: Is the product still active?
L’Ascorbic acid is water soluble and very unstable.
On exposure to light, L’Ascorbic acid gets oxidized to the yellow Dehydro Ascorbic Acid.
As a water soluble and charged molecule. L’Ascorbic acid is repelled by the skin.
For cosmetic products, the stability of the product can be increased by lowering the pH (making it more acidic). A pH of less than 3.5 is ideal.
The skins normal pH is 5.4, so many skin products aim to be closer to this pH, which is problematic for vitamin C.
At this pH, the ionic charge on the molecule is removed and it is transported well across the stratum corneum of the skin.
L’Ascorbic acid oxidises and becomes inactive, turning brown, when exposed to sunlight. Using an oxidised product is not going to be beneficial for the skin.
A pH below 4, an airless tube and packaging that is not transparent is necessary. If this is not the case, there is no value in applying L’Ascorbic acid to the skin.
One way to stabilise L’Ascorbic acid is by adding a phosphate group. BV OSC is a stabilised form of L’Ascobic acid.
Examples include:
- Ascorbyl glucoside
- Acsorbyl-6-palmitate
- Magnesiun ascorbyl phosphate.
- Aminopropyl ascorbyl phosphate
- Tetrahexyldecyl ascorbate (BV-OSC)
These are fat soluble and stable at a neutral pH. The conversion rate of these back to L’Ascorbic acid is unknown.
Therefore, while a product containing “15% vitamin C” may be L’ascorbic acid, but oxidised and so not effective, or a stabilised product such as BV OSC, which will be partly converted to L’Ascorbic acid in the skin.
Question 4: What else is in the product?
Some formulations incorporate other antioxidants, for examplevitamin E (Tocopherol).
Forms of vitamin E to look out for in products include:
- Alpha-tocopherol
- Tocopherol acetate
Ferulic acidis another antioxidant, and is sometimes combined with vitamin C in products as it increases the L’Ascorbic acids stability by lowering the pH of the product.
And finally:
Always apply Vitamin C products in the morning; they are intended for daytime use due to their ability to neutralise free radicals caused by UV rays and pollution throughout the day.
Don’t forget to follow up with a broad-spectrum sunblock.
Taking a vitamin C supplement and/or getting plenty in the diet can also increase the levels in the skin.
beautiPHI Aesthetics by Dr Louisa Godwin 