Color Change in Ferulic Acid and Vitamin C E Ferulic Solution

Regarding the color change you observed:

• Ferulic Acid Powder: It is normal for Ferulic Acid powder to range in color from white to light yellow. The product description confirms that this is the typical appearance of Pure-Ferulic Acid™. So, the change in the powder's color to light yellow over time is expected and does not necessarily mean it has gone bad.

• Vitamin C E Ferulic Solution: Solutions containing L-Ascorbic Acid (Vitamin C), even when stabilized with ingredients like Vitamin E and Ferulic Acid, are prone to oxidation over time. A change in color from clear to yellow is a common indicator that the Vitamin C is oxidizing and losing its potency. While refrigeration helps slow down this process and might temporarily affect the appearance, the yellow color indicates that some degradation has occurred.

Is it still usable?

While the Ferulic Acid powder's color change is normal, the yellowing of the mixed Vitamin C E Ferulic solution suggests that the Vitamin C has likely lost some of its effectiveness due to oxidation. A slightly yellow solution might still offer some benefits, but a distinctly yellow or orange color indicates significant degradation. It is generally recommended to discard Vitamin C serums once they turn a noticeable yellow or orange, as their antioxidant power is significantly reduced.

Proper storage, such as keeping the mixed solution in the refrigerator as you have been doing, is crucial for extending the life of Vitamin C serums by slowing down oxidation.