How ph effects potency of beta hydroxy acids ( salicylic acid)
OK so I think im going to start with how you heard of the chemical which is from some METHOD mentioned on the interweb right ? They tell you to use among a a laundry list of crap pink clean and clear and i think neutragena TSAL. Both are listed as %3 .
( allow me to ask ... why use two thing with same ingredient ? whats the logic in that? anyway ...)
Neutragena TSAL and Clean and Clear are far less effective than home method touters think
You see salicylic acid is a beta hydroxy acid and like similar acids the PH determines the FAV or Free available value. Salicylic acid has a ph of 2.8 and begins to loose it potency at ph of 3 and is useless by ph 4 .
Now, if you multiply the percentage of free acid by the concentration of Salicylic acid present in the bottle, you can work out how much is ready to pass through your hair.
Neutragena TSAL %3 at ph 3.5
( %22.8 available of the % 3 solution) = % 0.68
Hair Razors Step 2 at ph 2.5 ( %90 available of the % 4 solution) = % 3.6 Salycilic acid
Products and Wait Times
pH affects the acid you use and how it works. Another consideration is not to disturb an acid while it is on your hair, which can alter pH and affect its action.
Generally speaking an acid is effective for approximately 20 minutes. After that point the hair pH has risen enough to lessen the action, and the acid is effectively neutralized. During this time frame, the acid is working at effective levels.