Ingredient Encyclopedia

The purest, most researched form of Vitamin C and the only form with the strongest clinical backing for collagen synthesis and pigmentation reduction. It is water-soluble and highly unstable — it oxidises quickly on exposure to light, air and heat, turning the serum yellow/brown.

A stable, water-soluble derivative of Vitamin C that converts to L-Ascorbic Acid once absorbed into skin. Formulated at a near-neutral pH, making it far gentler than pure L-Ascorbic Acid — a common pick for sensitive and acne-prone skin.

Another stable, water-soluble derivative that converts to active Vitamin C in the skin. Slightly more hydrating than SAP and considered one of the mildest forms available, making it common in drugstore and sensitive-skin formulas.

An oil-soluble, highly stable Vitamin C ester that penetrates the skin's lipid barrier efficiently. THD does not require a low pH to work, so formulas are typically much gentler than L-Ascorbic Acid while still showing solid brightening results in studies.

A glucose-bound Vitamin C derivative that is broken down by skin enzymes into active Vitamin C over time. It is water-soluble, stable at near-neutral pH, and popular in Indian and Korean formulas for its gentleness in hot, humid climates.

A vitamin C derivative in which an ethyl group is attached to the third carbon of ascorbic acid. The change makes it more resistant to oxidation than pure L-ascorbic acid in water-based serums. It is widely used in lightweight brightening serums, including many from Indian brands, as a gentler alternative to L-ascorbic acid. Independent clinical evidence is much more limited than for L-ascorbic acid.