Solving Vitamin B6 Crystallization in Facial Mist due to pH Conflict with Sebum-Reg™
Question
I am formulating a facial spray mist and encountered a significant solubility issue. When adding Vitamin B6 (Pyridoxine Hydrochloride) to the main water phase, the entire solution became 'crystally and sparkly' and would not dissolve.
My mixing process involved:
- Dissolving Sebum-Reg™ (Capryloyl Glycine) in a portion of water using Sodium Bicarbonate (to achieve a higher pH necessary for Sebum-Reg™ dissolution).
- Adding this high-pH Sebum-Reg™ solution to the main water phase.
- Adding the Vitamin B6 afterward.
The final pH of the resulting mixture was 4.6.
I suspect the initial high pH environment created during the Sebum-Reg™ dissolution step caused the B6 to precipitate, even though the final pH was acidic.
What is the proper procedure or advice for successfully dissolving both Vitamin B6 and Sebum-Reg™ in water for a stable facial mist formulation?
Answer
The "crystally and sparkly" appearance you observed is a classic sign of precipitation or crystallization of the Vitamin B6 (Pyridoxine Hydrochloride) (ID: 643). This issue is caused by the conflicting pH requirements of the two ingredients you are trying to dissolve together.
The Problem: Conflicting pH Requirements
Your mixing process created a temporary high-pH environment that caused the Vitamin B6 to precipitate.
- Vitamin B6 (ID: 643): This ingredient is a salt (Pyridoxine Hydrochloride) and is stable and readily soluble in acidic environments (pH 2-6). If you add it to a solution with a high pH (above 6), it will precipitate out.
- Sebum-Reg™ (Capryloyl Glycine) (ID: 1589): This ingredient is only soluble in water when the pH is higher than 7 (basic). Once dissolved, its working range is pH 4-6, meaning the pH must be adjusted down after dissolution.
When you used Sodium Bicarbonate to dissolve Sebum-Reg™ (raising the pH) and then added the acidic B6 to this high-pH mixture, the B6 immediately reacted and crystallized, even though the final pH (4.6) was in the stable range.
Recommended Mixing Procedure
To successfully dissolve both ingredients and maintain a stable solution, you must dissolve them separately and adjust the pH of the Sebum-Reg™ solution before combining:
Step 1: Dissolve Sebum-Reg™ (ID: 1589)
- Take a small portion of your total water and adjust its pH to above 7 (using Sodium Bicarbonate, Triethanolamine, or another base).
- Add the Sebum-Reg™ and stir until completely dissolved. (You may use heat up to 70°C to speed up this process.)
- CRITICAL: Once dissolved, use a cosmetic-grade acid (like Citric Acid or Lactic Acid) to adjust the pH of this Sebum-Reg™ solution down to your target final pH (e.g., 4.5-5.5).
Step 2: Dissolve Vitamin B6 (ID: 643)
- Take a separate small portion of your total water.
- Add the Vitamin B6 (ID: 643) and stir until completely dissolved. Do not use heat (B6 is unstable above 40°C). Since B6 is naturally acidic, it should dissolve easily in plain water.
Step 3: Combine and Finalize
- Add the dissolved and pH-adjusted Sebum-Reg™ solution (from Step 1) to your main water phase.
- Slowly add the dissolved Vitamin B6 solution (from Step 2) to the main water phase while stirring.
- Check the final pH of your facial mist. It should be in the 4.5-5.5 range, which is ideal for both ingredients and for skin health.
Summary of Key Stability Points
| Ingredient | Solubility Requirement | Stability Range | Mixing Precaution |
|---|---|---|---|
| Vitamin B6 (ID: 643) | Soluble in acidic water (pH 2-6). | Stable pH 2-6. | MUST avoid high pH (>6) and heat (>40°C). |
| Sebum-Reg™ (ID: 1589) | Soluble only in basic water (pH > 7). | Working pH 4-6. | MUST adjust pH down to 4-6 after dissolution and before adding B6. |
Related Products Mentioned
Vitamin B6 (Pyridoxine Hydrochloride)
