NT: Don't use multiple products with glycolic acid at the same time since it might overwhelm the skin. I'm a believer in not overwhelming the skin with too many things, and I think the most important thing for your skin is to just have enough moisture.
Benzoyl peroxide, along with salicylic acid, is an active that’s used in acne treatments that doesn’t necessarily mesh with glycolic acid. It's not necessarily bad, but they can neutralize each other. When in doubt, contact an esthetician or dermatologist.
Over-exfoliating is also a concern, not just with chemical exfoliants, but physical as well. You never want to exfoliate your skin too much because your skin is a protective layer of your body, preventing infections and protecting you against the elements.
Also don't use glycolic acid products the same time you're using vitamin C products. If you are using vitamin c in your skincare routine, I would use it in the morning and the glycolic acid product at night.
If you are using a retinol, do not use glycolic acid at all since it could cause significant irritation and skin peeling if used together.
So, to recap, when using glycolic acid it’s best to avoid:
- Benzoyl peroxide
- Over exfoliating with physical exfoliants
- Vitamin C