This is a beginner’s guide on formulating for Vitamin C & its derivatives. I will not be going to detail what each derivative can do or how they compare.

General Guidelines

  • Take note of the pH requirements of the different Vitamin C derivatives for stability in a product.
  • An additional anti-oxidant will be recommended to reduce the rate of oxidation (eg. Vitamin E / Tocopherol).
  • Use a chelator.
  • A pH meter will be required. pH strips may not be accurate enough.
  • A pH adjuster may be required (eg. Citric Acid, TEA, etc).
  • Use of solvents & penetration enhancers.
  • Generally not suitable for heat (long periods), thus recommended to be added in cool down phase, below 40°C.
  • Use an opaque packaging to reduce degradation.
  • Store all raw Vitamin C derivatives away from light and in airtight container/packaging.
  • Vitamin C & its derivatives may be considered quasi-drugs for Korea or Japan. Please check the maximum usage rates, generally 3% or less.

L-Ascorbic Acid (AA)

  • INCI: L-Ascorbic Acid
  • Form: Powder
  • Usage: Up to 20%
  • Solubility: Water (up to 30% in water)
  • pH range: Recommended to be below pH 3.5
  • Stability: Low

Notes:

Magnesium Ascorbyl Phosphate (MAP / APM)

  • INCI: Magnesium Ascorbyl Phosphate
  • Form: Powder
  • Usage: 0.2% – 3%, up to 10%
  • Solubility: Water (up to 15.4% in water)
  • pH range: Recommended to be between pH 6 – 7, optimal pH 6.5
  • Stability: Stable

Note:

  • Due to the interaction between phosphorous group and magnesium ion, MAP sometimes recrystallizes and precipitates in cosmetic formulations, especially in high concentrations.

Sodium Ascorbyl Phosphate (SAP / APS)

  • INCI: Sodium Ascorbyl Phosphate
  • Form: Powder
  • Usage: 1% – 3%, up to 10%
  • Solubility: Water (up to 64% in water)
  • pH range: Recommended to be between pH 6 – 7, optimal pH 6.5
  • Stability: Stable

Ethyl Ascorbic Acid (EAC)

  • INCI: 3-O-Ethyl Ascorbic Acid
  • Form: Powder
  • Usage: 0.5% – 3%, up to 25%
  • Solubility: Water (more than 10% in water. No specific data found)
  • pH range: Recommended to be between pH 3 – 6. Keep at pH 5 or less to reduce degradation
  • Stability: Stable

Ascorbyl Glucoside (AA2G)

  • INCI: Ascorbyl Glucoside
  • Form: Powder
  • Usage: 1% – 2%, up to 5%
  • Solubility: Water (No specific data found)
  • pH range: Recommended to be between pH 5 – 7, optimal pH 6.5 – 6.8 (may vary due to sources)
  • Stability: Stable

Notes:

  • Very acidic (1% of AA2G in water is in the range of pH 2.0 – pH2.5)
  • Need a pH adjuster. Sodium hydroxide not recommended.

Tetrahexyldecyl Ascorbate (BV-OSC) | Ascorbyl Tetraisopalmitate (VC-IP)

  • INCI: Tetrahexyldecyl Ascorbate | Ascorbyl Tetraisopalmitate
  • Form: Liquid
  • Usage: 0.5% – 3%
  • Solubility: Oil / Lipid
  • pH range: Recommended to be below pH 3 – 6
  • Stability: Stable

Notes:

Ascorbyl Tetraisopalmitate (VC-IP)’s recommended guidelines for stability:

  • Below pH 6
  • For formulations containing water, add surfactants with long chain polyoxyethylenes to stabilize the system and strengthen the interfacial membrane. The example used in the sample formula is Peg-20 Glyceryl Triisostearate, a non-ionic surfactant.
  • Soluble in Ethanol, Propyleneglycol Monocaprylate, Caster Oil, Trethylhexanoin, Olive Oil, Cetyl Ethylhexanoin, Mineral Oil.
  • Not soluble in Glycerin, Propylene Glycol, 1,3-Butylene Glycol
  • Recommend to add during the cool down phase.

Ascorbyl Palmitate (AP)

  • INCI: Ascorbyl Palmitate
  • Form: Powder
  • Usage: 1% – 2%
  • Solubility: Oil / Lipid (up to 30%), Ethanol (up to 10%)
  • pH range: No specific data found
  • Stability: Stable

Notes

  • Requires a hot-hot process for phases. Add to the oil phase and heat to ~80°C. Combine both oil & water phase at ~80°C and homogenize. Ascorbyl Palmitate will remain solid till homogenized.

Ascorbyl 2-Phosphate 6-Palmitate (APPS)

  • INCI: Trisodium Ascorbyl Palmitate Phosphate
  • Form: Powder
  • Usage: 1%
  • Solubility: Water
  • pH range: Recommended to be above pH 6
  • Stability: Stable

Notes:

  • Might hydrolyze in formulation with acidic conditions especially in pH below 6
  • To avoid hydrolysis in an aqueous solution, the usage of dihydric alcohol, especially 1,2-hexanediol, is effective. Eg, 1% APPS solution added with 2-3% of 1,2-hexanediol or 5-6% of pentylene glycol is preferable.
  • Sodium palmitates released by APPS hydrolysis makes the solution cloudy. The addition of dihydric alcohol, such as 1,2-hexanediol or pentylene glycol, makes the solution clear.
  • Some natural products have a hydrolyzing activity of APPS. Some of the commercial xanthan gum have negligible hydrolyzing activity, but as the activity differs among the production lots, preliminary tests are highly recommended.

Other Derivatives

  • 2-glyceryl 3-octyl ascorbate (GO-VC)
  • Glyceryl Ascorbate series by Seiwa (Glyceryl Ascorbate, 3-Glyceryl Ascorbate, Bis-Glyceryl Ascorbate, Hexyl 3-Glyceryl Ascorbate, Myristyl 3-Glyceryl Ascorbate, 3-Laurylglyceryl Ascorbate)
  • Ascorbyl Isostearate (AI) by Spec-Chem Industry

References:

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