VITAMIN C (and its derivatives)

Pure vitamin C (INCI: ascorbic acid) is the second superstar ingredient in cosmetics with efficacy also proven by various clinical studies for percentages between 5 and 20%, it has:
  • Antioxidant properties
Several studies have shown that vitamin C has antioxidant activity which helps protect the skin from external aggressions (sun, smoke, pollution) and reduces the presence of erythema on the skin during sun exposure. This is why vitamin C is strongly recommended for application in the morning, especially since several studies show that the combination of vitamin C + sunscreen provides better protection compared to the use of a sunscreen alone. Being an antioxidant, vitamin C could also be useful in fighting against damage caused by visible light and infrared rays, which UV filters will not do.
  • Anti-aging properties
It increases collagen production for firmer skin and less visible wrinkles.
Clinical studies carried out on % between 5 and 10%.
  • Anti-stain properties
Vitamin C fades dark spots by inhibiting tyrosinase, the enzyme responsible for melanin production.
Vitamin C problems:
  • Its stability: vitamin C can oxidize very quickly, which can reduce its effectiveness
  • Its penetration: since vitamin C is water-soluble, it has difficulty penetrating into the skin.
  • Its irritant nature: to overcome the two problems above, one of the solutions is to lower the pH to a pH of around 3.5, which can be irritating for certain skin types.
This is why vitamin C derivatives are often used because they are stable and less irritating. The best derivatives that have been studied in vivo are:
  • ascorbyl tetraisopalmitate
  • ascorbyl glucoside: stable and easy to formulate, in vitro studies show that it can penetrate the skin and is then converted into pure vitamin C. It also exhibits the three anti-aging benefits of pure vitamin C: antioxidant protection, collagen strengthening and reduction of hyperpigmentation which has been tested in vivo. Ascorbyl glucoside is typically used in 2-5% concentrations when the goal is to brighten dull skin and fade the appearance of hyperpigmentation.
  • ethyl ascorbic acid: stable and penetrates the skin. According to the supplier, EAC is metabolized in the skin to pure ascorbic acid and they also claim that EAC seems to have both an antioxidant and anti-inflammatory effect, and may be able to stimulate the production of collagen skin. The strong point of the EAC however is the lightening of the skin. In addition to the manufacturer's claims, there is also in vivo clinical data (tested on real people) showing that 2% EAC can improve skin tone.


  • Stability, transdermal penetration, and cutaneous effects of ascorbic acid and its derivatives, Journal of Cosmetic Dermatology, 2012
  • Assessment of penetration of Ascorbyl Tetraisopalmitate into biological membranes by molecular dynamics, Computers in Biology and Medicine, Volume 75, 2016