I have sensitive, oily, acne-prone skin & use both microdermabrasion & glycolic acid peels. With the microdermabrasion, it seems like it mostly gets rid of any dry, flaky skin & smooths the skin surface - I really didn't see any changes, but my skin felt smoother. With the glycolic acid peel, it took a few weeks to see a difference, but I have actually seen a decrease in fine lines & imperfections. I feel the glycolic acid goes deeper & causes more changes. However, I do follow the glycolic acid peel with copper peptide serum, which promotes cellular renewal. This is probably why I don't get any major flaking with the peel. So I'm sure it's all of these things working together. I also use salicylic acid (2%) on my face in the morning, followed by DMAE, & a facial oil I make myself. In the evening, I use the copper peptide serum, eiher Differin or Renova (I alternate nights), & the homemade facial oil. One day a week, I just use the oil to give my skin a break.