Using a Plastic Pump with L-Ascorbic Acid Serum

Thank you for your question regarding the use of a plastic pump dispenser with your 12% L-ascorbic acid serum. It's thoughtful to consider how packaging affects product stability.

You are absolutely right that L-ascorbic acid is sensitive to oxygen and degrades when exposed to air. Using a pump dispenser is an excellent way to minimize this exposure compared to a dropper or screw cap, thus helping to maintain the stability and effectiveness of your Vitamin C serum.

Regarding your concern about the plastic reacting with the acidic serum: L-ascorbic acid solutions used in cosmetics typically have a low pH (acidic), usually between 2.0 and 4.0. Standard cosmetic-grade plastics commonly used in packaging, such as those found in pump dispensers, are generally designed to be resistant to weak acids at typical cosmetic concentrations and temperatures.

While glass is often considered the most inert material, plastic packaging is widely used in the cosmetic industry due to its practicality and safety when appropriate materials are selected. Significant degradation of the plastic or leaching of harmful substances into the serum from a cosmetic-grade plastic pump tube is unlikely under normal usage conditions.

Therefore, you can generally feel confident using the plastic pump dispenser. The benefit of reduced air exposure for the stability of your L-ascorbic acid serum outweighs the minimal risk of reaction with the plastic components of a standard cosmetic pump.

For optimal storage of L-ascorbic acid products, remember to keep the container tightly sealed, away from direct sunlight and heat, and ideally in a cool place like a refrigerator, as mentioned in the product information for Vitamin C (L-ascorbic acid) Fine and Ultra-Fine grades.