While “Vitamin C Serum for Sensitive Skin Type 90 ml” is not a single specific product, it most likely refers to the Cos-IQ 8% Vitamin C Face Serum, which is one of the few brands that offers a larger 90 ml value pack specifically formulated for sensitive skin. 

Featured Product: Cos-IQ 8% Vitamin C Serum
 (90 ml) 
This serum is designed for those with sensitive skin who find higher concentrations of Vitamin C (like 15% or 20%) too irritating. 
Key Ingredients: It uses 3-O-Ethyl Ascorbic Acid, a highly stable and gentle derivative of Vitamin C that brightens skin without the “burn” often associated with pure L-Ascorbic acid.
Formula Highlights:Gentle & Non-Irritating: Specifically “Formulated & Tested For Sensitive Skin”.
Texture: Lightweight, non-sticky, and non-greasy formula.
“Free From” List: Free from silicones, mineral oils, parabens, phthalates, and sulphates.
Benefits: Targets dullness and provides a “glowing skin” effect while remaining beginner-friendly.
Why Choose a 90 ml Vitamin C Serum?
Most Vitamin C serums come in 10 ml to 30 ml bottles because Vitamin C can oxidize (turn brown and lose effectiveness) quickly when exposed to air and light. 
Value: A 90 ml pack is often marketed as a “90-Day Pack,” offering a better price-per-ml for long-term users.
Stability: Large-format serums like this one use stabilized derivatives (like Ethyl Ascorbic Acid) that don’t degrade as fast as traditional pure Vitamin C.