Long-Term Use of Vitamin C Serums

Using Vitamin C serums like Stabilized Vitamin C (Natural-C Glycol™) Serum or Vitamin C E Ferulic continuously and long-term generally does not have significant negative effects when used correctly. Here's a breakdown of your concerns:

1. Acidity and Skin Thinning: The mild acidity of Vitamin C is actually beneficial for the skin, helping with cell turnover. It does not cause the skin to thin. Skin thinning is typically associated with strong acids or alkaline substances, not the mild acidity found in properly formulated Vitamin C products.
2. Skin Getting Used to It: Your skin doesn't become "used to" Vitamin C in a way that makes it ineffective. The ingredient continues to perform its functions (like antioxidant protection, collagen support, or reducing pigmentation). However, the visible results might plateau over time once your skin reaches its optimal state. For example, if using for whitening, your skin will reach a certain level of brightness and may not get significantly lighter with continued use, but the Vitamin C is still working to prevent further pigmentation.
3. Effects of Stopping Use: Stopping the use of Vitamin C will not make your skin worse than its original condition before you started using it. Any benefits gained, such as increased collagen production or reduced pigmentation, will gradually revert to your skin's natural baseline over time.
4. Other Recommendations: Vitamin C can be used both during the day and at night. If applying around the eye area, it is generally recommended to use a lower concentration (around half the concentration used on the rest of the face) as the skin around the eyes is more delicate.