I'm using Differin and I can add a few more tips that I've heard and can confirm personally: the purging period can last several weeks and you should see improvement after a few months. It's best to do every other day or every few days initially and then ramp up to daily (for me, this helped avoid a lot of peeling). It's best to apply it after allowing your face to dry so that it's not too intense, and many people also prefer to layer it on top of a buffer like a moisturizer, so you would wash, apply moisturizer, wait 20-30 min, and then apply the product.... (read more)
Yeah, glycolic acid is an exfoliant. The retinoid family also promotes cell turnover, but in a different way. You'd be over-exfoliating by using both of them at the same time.
I'm using Differin and I can add a few more tips that I've heard and can confirm personally: the purging period can last several weeks and you should see improvement after a few months. It's best to do every other day or every few days initially and then ramp up to daily (for me, this helped avoid a lot of peeling). It's best to apply it after allowing your face to dry so that it's not too intense, and many people also prefer to layer it on top of a buffer like a moisturizer, so you would wash, apply moisturizer, wait 20-30 min, and then apply the product.... (read more)