你有興趣睇journal paper可參考下:
Lin et. al. (2005) Ferulic Acid Stabilizes a Solution of Vitamins C and E and Doubles its Photoprotection of Skin. J Invest Dermatol. 2005 Oct;125(4):826-32
Cellex及好多其他牌子做唔到stabilized AA。 Pycnogenol (pine bark) stabilize the lifetime of the inactive vitamin C radical 但冇proof 佢可以stabilize AA in aqueous solutions and double up photoprotection ability.