Adding Preservatives to Active Ingredients Before Mixing into Serum
Question
I would like to ask for further information regarding the formulation process:
- If I want to add other active ingredients (similar to
Syn-Ake) into a main serum, can I add a preservative—provided it is compatible with both the active and the main serum—into the active ingredient first, before incorporating it into the final serum base?
Answer
Yes, you can add a preservative to other active ingredients before incorporating them into your main serum, similar to the approach for Syn-Ake (Dipeptide Diaminobutyroyl Benzylamide Diacetate). However, there are several important factors to consider:
1. Compatibility
The preservative must be compatible with both the active ingredient and the main serum base.
- pH Level: Ensure the preservative works effectively within the pH range required by the active ingredient.
- Charge: If your active is cationic (positively charged), avoid anionic (negatively charged) preservatives to prevent clumping or instability.
2. Redundancy and Concentration
- Pre-preserved Actives: Many liquid active ingredients already contain preservatives from the manufacturer. Adding more might be unnecessary.
- Final Concentration: When you add the "pre-mixed" active to your main serum, the total concentration of the preservative in the final formula must not exceed the recommended safety limits (usually 0.5% - 1.0% depending on the type).
3. When is it necessary?
- Storage: Adding a preservative to an active is primarily necessary if you are diluting the active in water or another solvent to create a "stock solution" that will be stored for a period before use.
- Immediate Mixing: If you are adding the active directly into a main serum that is already well-preserved, you generally do not need to add extra preservative to the active itself.
4. Recommended Preservatives
If you need to preserve a water-based active solution, you should use a broad-spectrum preservative that is stable and gentle. Common choices include:
- Phenoxyethanol SA (Optimized Phenoxyethanol)
- Mild Preservative (Eco) (for natural-focused formulations)
Summary: While possible, it is usually only recommended if you are creating a separate solution of the active ingredient to be stored. If mixing directly into a preserved base, it is often redundant. Always ensure the total preservative level in your final serum remains within safe, effective limits.
