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:
- Normally recommended to purchase in small batches & produced in small batches.
- Patent for SkinCeuticals’ C E Ferulic formulation (15% L-Ascorbic Acid + 1% Alpha Tocopherol + 0.5% Ferulic Acid)
- May irritate the skin at high percentages.
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
- 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:
- On the combination of 10% L-ascorbic acid & 7% Ascorbyl Tetraisopalmitate in a waterless silicone base.
- Some brands or sellers may mix up the two, so do take note.
- Realize Beauty – Don’t get your oil soluble Vitamin C mixed up! (A brief article on the difference between Tetrahexyldecyl Ascorbate (BV-OSC) & Ascorbyl Tetraisopalmitate (VC-IP))
- Tetrahexyldecyl Ascorbate (BV-OSC) is manufactured by Barnet (USA), Hangzhou Rebtech Novel Material (China), etc
- Ascorbyl Tetraisopalmitate (VC-IP) is manufactured by Nikko Chemicals (Japan).
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:
- The Beauty Brains – Which kind of Vitamin C is best for skin?
- Realize Beauty – Don’t get your oil soluble Vitamin C mixed up!
- lotioncrafter.com | bulkactives.com
- Supplier & manufacturer product information from Ulprospector
- Vitamin C (GO-VC) The New Kid On The Block
For any updates, changes, or corrections, please leave a comment below with information.