Review (5/5): One of the best products out there
Holy grail item I've been using for 6 years now. I wear this at night instead of a night cream and it gently exfoliates and makes your skin radiate. Just rub a little on clean skin. To my knowledge it is not more powerful if you apply more-- just about a pea-size is enough. Once the "acid" works on that top layer... I suppose you could wash and reapply however here is my recommendation: Once your skin can handle this awesome stuff, you can try adding a few drops of 20% glycolic acid (purchased from Amazon) to the mixture. Now I can handle just the 20% stuff -- makes my skin burn but it has, over time, greatly helped with my freckles and melasma. (Ok, so I also use an exfoliating brush like the Clarsonic.)
Most importantly, find yourself an excellent sunscreen to pair with this- especially if you're using this product to fight sun damage. You can check them in at EWG.org for safety or please prefer one with only the safe zinc oxide in it. Sunology is an ok one...Badger is a suitable one... Juice Beauty is supposed to be good but haven't tried....EltaMD physical Broad spectrum is a great one but contains titanium dioxide...just ordered ThinkBaby but haven't tried yet.
Anyway, I hope this helps.
BTW I did recommend this to someone who stopped using because her skin started to peel. This is actually good! People spend a lot of money to have someone else slather their face in higher concentrated glycolic acid and yes, it peels. If you don't like it, you could always try a lower concentration of the alpha hydrox product