The best replacement for hydroxy is hydroxyl.

The best alternatives to hydroxy are rated as following:
★★★★★  hydroxyl
★★★★★  retinol
★★★★  glycolic acid
★★★  beta hydroxy
★  alpha hydroxy
★  salicylic acid
★  vitamin d 1 25 dihydroxy
★  retin a
★  retinol a
★  dihydroxy
  hyaluronic acid
  vitamin d 1,25 dihydroxy
  lactic acid
  glycolic

Your alternative for hydroxy is not listed? Suggest!
Speaking about hydroxy, one probably shouldn't forget about retinol.

Other search terms related to hydroxy and their ratings are:
★★★★★ retinol
You have in mind a companion for hydroxy and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of hydroxy in all years. Click on graph for more.
hydroxy
hydroxyl
retinol