Shelf Life and Usage Period of Serum After Adding Active Ingredients

In the case where you add active ingredients to a pre-preserved base serum, the shelf life and recommended usage period generally depend on the following factors:

1. Recommended Usage Period

• General Rule: If the base serum is well-preserved and the active ingredients are stable, the mixture can typically be used for 3 to 6 months.
• Sensitive Ingredients: If you add ingredients that oxidize easily (such as Vitamin C/L-Ascorbic Acid), the shelf life may be shorter, around 1 month, or until the color/smell changes.

2. Proportion of Ingredients

• If the added active ingredients exceed 10-15% of the total volume, the concentration of the preservative in the base serum will be diluted. In this case, it is recommended to add a small amount of a broad-spectrum preservative to ensure safety.

3. Storage Conditions

• Store the mixture in a cool, dry place away from direct sunlight.
• Using a pump bottle or airless bottle is better than a dropper bottle to minimize exposure to air and contaminants from the skin.

4. Observation

• Always observe changes in color, smell, or texture. If the serum becomes cloudy, changes color significantly, or develops an unusual odor, stop using it immediately.

If you are looking for a high-quality base, you might consider using a professional Serum Base designed to hold various active ingredients effectively.