Vitamin C Forms: Which One Is Best?

L-ascorbic acid, ascorbyl glucoside, sodium ascorbyl phosphate... With so many forms of Vitamin C, how do you know which one is right for your skin? We break it down.

Updated Feb 2026 6 min read Research-backed

Vitamin C Forms Compared

L-Ascorbic Acid (Pure Vitamin C)

Gold Standard • 10-20% concentration

The most researched form of vitamin C. It's the most potent but also the most unstable—it oxidizes quickly when exposed to air and light.

✅ Best For:

  • • Maximum brightening results
  • • Fading dark spots
  • • Collagen production

⚠️ Watch Out:

  • • Can sting on broken skin
  • • Must be fresh (check expiration)
  • • Can oxidize to brown color

Sodium Ascorbyl Phosphate (SAP)

Gentle & Stable • 1-10% concentration

A gentle, stable form that converts to vitamin C on the skin. Particularly good for acne-prone skin due to its additional oil-controlling benefits.

✅ Best For:

  • • Sensitive skin
  • • Acne-prone skin
  • • Beginners to vitamin C

⚠️ Watch Out:

  • • Less potent than L-AA
  • • Takes longer to see results

Ascorbyl Glucoside

Water-Stable • 2-10% concentration

A water-soluble derivative that's very stable and gentle. It slowly converts to pure vitamin C on the skin, providing sustained release.

✅ Best For:

  • • All skin types
  • • Long-term daily use
  • • Layering with other products

⚠️ Watch Out:

  • • Milder effects
  • • Requires conversion on skin

Ascorbyl Tetraisopalmitate (VC-IP)

Oil-Soluble • 1-3% concentration

A unique oil-soluble form that penetrates deeply into the skin. Very stable and often used in high-end Asian skincare products.

✅ Best For:

  • • Deep penetration
  • • Dry/dehydrated skin
  • • Mature skin

⚠️ Watch Out:

  • • More expensive
  • • Less research available

Which Should You Choose?

For maximum results: L-Ascorbic Acid (10-20%)

For sensitive/acne skin: Sodium Ascorbyl Phosphate

For everyday use: Ascorbyl Glucoside

For deep hydration: Ascorbyl Tetraisopalmitate