Ingredient Science Hub
Not All Vitamin C is the Same
From the gold-standard L-Ascorbic Acid to the ultra-stable AA2G — each derivative has a different stability, pH requirement, bioavailability, and skin type suitability. Learn the science before you buy.
Stability Comparison (higher = more stable on shelf)
Pure Vitamin C
3-O-Ethyl Ascorbic Acid
Stay-C® 50
VC-PMG
Vitamin C Glucoside
L-Ascorbic Acid (LAA)
Pure Vitamin C
3
Stability /10
Irritation
High
Bioavail.
10/10
pH Needed
<3.5
Best For
The gold standard of Vitamin C. L-Ascorbic Acid is the most researched and bioavailable form, but also the most unstable. It requires a low pH (below 3.5) to penetrate the skin and work effectively. Best stored in dark, cool conditions and used within 3 months of opening.
5 serums in our DB use this
Deep DiveEthyl Ascorbic Acid (EAA)
3-O-Ethyl Ascorbic Acid
9
Stability /10
Irritation
Low
Bioavail.
8/10
pH Needed
4.5–6.5
Best For
The best all-rounder Vitamin C derivative for Indian skin. EAA offers exceptional stability even in warm conditions, making it ideal for a country like India where temperatures and humidity are high. It converts to pure Vitamin C upon absorption.
6 serums in our DB use this
Deep DiveSodium Ascorbyl Phosphate (SAP)
Stay-C® 50
9
Stability /10
Irritation
Very Low
Bioavail.
6/10
pH Needed
5.5–7.0
Best For
The dermatologist's choice for acne-prone skin. SAP has an added antibacterial property that makes it unique among Vitamin C derivatives — it actually helps fight Cutibacterium acnes (the acne-causing bacteria) while brightening skin simultaneously.
2 serums in our DB use this
Deep DiveMagnesium Ascorbyl Phosphate (MAP)
VC-PMG
8
Stability /10
Irritation
Very Low
Bioavail.
5/10
pH Needed
6.0–7.0
Best For
The hydration hero of Vitamin C derivatives. MAP is a water-binding form of Vitamin C that uniquely moisturizes the skin while brightening. It's the gentlest option available and works beautifully for dry and mature skin types.
1 serums in our DB use this
Deep DiveAscorbyl Glucoside (AA2G™)
Vitamin C Glucoside
10
Stability /10
Irritation
None
Bioavail.
4/10
pH Needed
4.0–7.0
Best For
The most stable Vitamin C derivative available. AA2G is formed by bonding Ascorbic Acid with glucose, creating an incredibly stable molecule that resists oxidation under virtually all conditions. The tradeoff is lower bioavailability, requiring enzymatic cleavage by skin glucosidases.
1 serums in our DB use this
Deep Dive