Necessity of Preservatives in Skin Barrier Cream Base Dilution
คำถาม
Question about Preservative Necessity
If I am preparing a Skin Barrier Lotion for personal use (100g batch) using the Skin Barrier Cream Base (Emulsifier Free) (ID 9673) based on the website's recommendation, do I need to add an additional preservative?
The formulation is as follows:
Skin Barrier Cream Base (Emulsifier Free): 50%- Water: 49.7%
Xanthan Gum: 0.3%
Since the base already contains a preservative system, is it still necessary to add more when it is diluted with water in this ratio?
คำตอบ
Yes, it is necessary to add a preservative to your final formula.
Although the Skin Barrier Cream Base (Emulsifier Free) (ID 9673) contains a preservative system to maintain its stability as a raw material, when you dilute it 1:1 with water (49.7% water), the concentration of all ingredients, including the preservatives, is halved.
Any cosmetic formula containing a significant amount of water is highly susceptible to microbial contamination (bacteria, yeast, and mold), which can cause product spoilage and potential skin irritation or infection. This is true even for small, personal-use batches. It is a best practice to ensure the final product is adequately preserved.
Recommendation
You should add a broad-spectrum preservative to your final lotion formula (Skin Barrier Cream Base 50% + Water 49.7% + Xanthan Gum 0.3%).
Suitable options include:
- Mild Preserved™ COS (ID 33939): A broad-spectrum preservative suitable for a wide pH range (2-8) and is odorless.
- K940 Preservative (ID 125908): Another effective broad-spectrum preservative.
Please follow the recommended usage rate for the chosen preservative (typically 0.5-1.0% of the total formula) and reduce the amount of water accordingly to keep the total formula at 100%.
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Skin Barrier Cream Base (Emulsifier Free)
