Formulating Toner with Ascorbic Acid, BHA/Willow Bark: Effectiveness, pH, and Texture
Question
I am formulating a toner and would like to add active ingredients for acne and skin improvement. I have some questions regarding the combination and properties of Ascorbic Acid (AA), Salicylic Acid (BHA), and Willow Bark Extract (WB) in my toner base which contains Butylene Glycol:
- Which combination would be more effective: AA + WB or AA + BHA? I understand that powdered BHA dissolves in water or alcohol, which is why I thought AA + WB might be more suitable.
- When mixing AA and WB, what is the correct order of addition? After mixing, will the final pH be within the range of 3.5 to 4? I saw in the WB details that its optimal pH range is 4.5 to 6.
- If I use AA at 15% and WB at 13% (to be equivalent to Salicylic Acid 2%), will this make the toner thicker? I want the toner to remain liquid so I can use it with a cotton pad.
Answer
Hello,
Thank you for your question regarding mixing Ascorbic Acid (AA) and BHA (Salicylic Acid or Willow Bark Extract) into your toner base. Based on the information provided by the staff:
It is possible to mix these ingredients into your specific toner base because it contains Butylene Glycol, which helps dissolve Salicylic Acid.
Here are the answers to your specific questions:
AA + WB or AA + BHA? Which is better?
Both combinations are possible with your toner base. Salicylic Acid (BHA) is generally more potent but requires a solvent like Butylene Glycol (which your toner has) or Propylene Glycol to dissolve. Willow Bark Extract (WB) is a milder alternative that is water-soluble. Some formulations even combine both SA and WB.Mixing order for AA + WB and final pH?
The staff did not specify the mixing order, but typically powdered ingredients are dissolved into the liquid base. The ideal pH for the effectiveness of L-Ascorbic Acid, Salicylic Acid, and Willow Bark Extract is around 3.5. Although Willow Bark Extract itself has a pH of 4.5-6, the final mixture should be adjusted to approximately pH 3.5 for optimal activity of all ingredients.Will AA 15% and WB 13% thicken the toner?
L-Ascorbic Acid and Salicylic Acid will not thicken the toner; they dissolve into the liquid. Willow Bark Extract might add a slight stickiness at high concentrations. However, the staff recommended using Willow Bark Extract up to a maximum of 5%. Using 13% is significantly higher than this recommendation and could potentially increase stickiness more noticeably, although the toner should still remain liquid.
Important Considerations:
- L-Ascorbic Acid Stability: L-Ascorbic Acid is highly unstable and oxidizes quickly when mixed into a water-based solution like your toner. Its effectiveness may last only about 5-10 days. To maximize effectiveness, it is strongly recommended to mix only small amounts for immediate use, ideally finishing the batch within 1-2 days. Storing the mixture away from light and in the refrigerator can help slow down oxidation.
- Concentration Limits: The staff recommended maximum concentrations are: L-Ascorbic Acid up to 15%, Salicylic Acid up to 2% (for daily facial use), and Willow Bark Extract up to 5%. Your proposed 13% Willow Bark Extract is higher than the recommended maximum.
Please proceed with caution, especially regarding the stability of Ascorbic Acid and the concentration of Willow Bark Extract. Mixing small batches for fresh use is key for Ascorbic Acid effectiveness.
Thank you!
Staff - MySkinRecipes
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