As I talked about vitamin C in my latest post, we know it is a great antioxidant with so much power. But what we don’t love about vitamin C or pure ascorbic acid (AA) is that it is very unstable; it can be oxidized already in the solution with water. For this reason, cosmetic industry is creating many vitamin C derivatives having similar actions with ascorbic acid but more chemical stability.
When comparing these derivatives, we’ll take a look at their stability, skin penetration, and rate of conversion to AA. Since the derivatives not only have to be absorbed well into the skin but also converted to AA once applied to actually do the work.
Now let’s get started!
Sodium Ascorbyl Phosphate (SAP)
SAP is water soluble. It has greater stability than pure AA and is not dependent on low pH (up to 7).
Research shows that SAP does have photo-protective properties as an antioxidant and help promote the collagen production as well as skin brightening. Several studies also prove that SAP have antimicrobial activity so it can be used to target acne. So it is also a must-try ingredient for acne-prone skin 😊
Unfortunately, SAP have a poor absorption compared to pure AA, and there is not much data on the conversion rate to AA. However, SAP is usually paired with other ingredients (penetration enhancers, humectants, antioxidants…) to increase its efficacy.
Magnesium Ascorbyl Phosphate (MAP)
MAP is also water soluble. It has greater stability than AA, pH up to 7.
Studies show that MAG have properties of pure vitamin C as a collagen booster and a skin brightening agent but weaker. There is not enough data on its photoprotective capabilities.
MAG does convert to AA when applied to skin but it doesn’t have a good skin absorption.
Ascorbyl Glucoside (AG)
An another water-soluble vitamin C derivative is Ascorbyl glucoside (actually also my favorite ingredient 😊). It is more stable than pure AA and also does have similar properties as vitamin C but the extent of benefits are not the same.
Research shows that AG can penetrate to skin without causing irritation and convert to ascorbic acid once applied (however the conversion rate is still unclear).
So AG is a promising ingredient that does the vitamin C’s work and is suitable for all skin types.
Ethyl Ascorbic Acid (EAA)
Or also known as 3-O-L-ascorbic acid, so far this is a very stable form of vitamin C derivatives.
What can it bring: EAA has both antioxidant and anti-inflammation properties. It does promote collagen production according to studies. It has a strong skin brightening effect (time to say goodbye to skin dullness and dark spot).
Another good news is EAA penetration rate is higher than other forms of vitamin C. Thus there are some report of skin irritation, but it also depends on your skin types. The conversion rate to AA is also higher, 86 % compared to the average 50-60%.
Aminopropyl Ascorbyl Phosphate (AAP)
A water-soluble, stable form of vitamin C.
AAP is proved to have antioxidant properties, anti-wrinkle and brightening effects.
Although there is not much information on this newish ingredient, it is a promising vitamin C derivatives that you can give a try.
Ascorbyl Palmitate (AP)
AP is fat-soluble, and it’s not as stable as other forms of vitamin C. AP can penetrate skin easily than others because it is oil-soluble. However it doesn’t convert well to AA, which mean a small amount of AP is not doing anything to your skin.
Studies show that AP has antioxidant properties but exposure to UVB rays can cause damage to skin cell membrane. There is not much data on collagen boosting and skin brightening benefits of AP, so it is probably my least favorite vitamin C ingredient on this list.
Tetrahexyldecyl Ascorbate (THD)
It is also known as Ascorbyl Tetraisopalmitate, and it is fat-soluble. THD can penetrate skin easily and convert to AA. Good news is THD can bring the antioxidant, skin brightening, and collagen boosting benefits. In addition, studies show that it can promote the production of natural moisturizing factors in our skin and increase skin hydration.
That’s a lot of information already. I hope this is helpful for you when choosing your vitamin C products. Remember to wear SPF when using vitamin C to protect your skin better.
Reference
Klock, Jochen, et al. “Sodium ascorbyl phosphate shows in vitro and in vivo efficacy in the prevention and treatment of acne vulgaris.” International journal of cosmetic science 27.3 (2005): 171-176.
Journal of Cosmetic Dermatology, Volume 11 (4) – Dec 1, 2012, Stability, transdermal penetration, and cutaneous effects of ascorbic acid and its derivatives
Journal of Investigative Dermatology, 2002 Nov, Volume 119, Issue 5, Vitamin C Derivative Ascorbyl Palmitate Promotes Ultraviolet-B-Induced Lipid Peroxidation and Cytotoxicity in Keratinocytes
Gillbro, J. M., and M. J. Olsson. “The melanogenesis and mechanisms of skin‐lightening agents–existing and new approaches.” International journal of cosmetic science 33.3 (2011): 210-221.
