1)What are retinoids? Retinoids are relatives of vitamin A, which is a factor important for building healthy skin. 

2) Are retinoids the same as retinol? No, they are related but retinol is much weaker. 

3)Do  they help acne?  Yes, by regulating cell turnover and decreasing inflammation. 

4)How do I apply them?  Unlike spot treatments a small amount is applied lightly to the entire face. 

5) Can I use them in summer?  Since you only apply at night, the answer is yes. 

6)Do they have other uses?  Yes, by promoting collagen production, they reduce fine line wrinkling as you age. 

These are prescription medicines, so ask your dermatologist if retinoids are right for you.