It is generally recommended to use a Vitamin C serum in the morning. Here's why:

1. Antioxidant protection: Vitamin C is a powerful antioxidant that helps protect the Skin from environmental damage, including pollution and UV radiation. Applying it in the morning helps create a barrier on the skin to shield against these factors throughout the day.

2. Brightening and complexion-evening effects: Vitamin C can help brighten the skin, reduce the appearance of dark spots, and promote a more even skin tone. Applying it in the morning allows these benefits to be maximized during the day when you may want a more radiant complexion.

3. Enhancing sunscreen effectiveness: Vitamin C has been shown to enhance the effectiveness of sunscreen when applied together. By applying a vitamin C serum in the morning before sunscreen, you can potentially boost the sun protection provided by your sunscreen.

That being said, using a vitamin C serum at night is not necessarily harmful. If you prefer to incorporate it into your nighttime routine, it can still provide benefits to your skin. However, using it in the morning allows for optimal protection and brightening effects during the day.

Keep in mind that everyone's skin is unique, and some individuals may experience slight skin sensitivity or irritation when using vitamin C. If you have sensitive skin or are new to using vitamin C serums, it's advisable to start with a lower concentration and gradually increase usage to assess how your skin responds. Additionally, always follow the instructions provided by the specific vitamin C product you are using.

Photo by Sora Shimazaki: https://www.pexels.com/photo/black-woman-applying-cream-on-face-5938600/