Lactic acid is the most effective form on skin chemical peel. Lactic acid can be done at a beauty spa or by a medical professional or dermatologist. Lactic acid can also be done at home but should be done with caution because lactic acid is a a very strong chemical solution and it can permanently damage the skin. Lactic acid can be prepared and made at home but should be properly measure for accurate percentages and concentration. Improper measurement and concentration can result into serious skin burns and PIH.
This is from one of the forum member post i found.
To get other % other than the half(You would need the formula)
C1= Concentration of the acid
V1=Volume of the acid
C2=Concentration to get
V2= volume you get
Multiply the original concentration of the acid and the amount you want to use = C1 x V1 (100% x 40ml)
Divide it by the concentration you are trying to get= C1 x V1/30%=(100% x 40ml) divided by 30%
That would be equal to 133.33ml approximatlet 133ml of water
So you would need to add 133ml to the 40ml bottle to get your 30% acid solution
This is from one of the forum member post i found.
To get other % other than the half(You would need the formula)
C1= Concentration of the acid
V1=Volume of the acid
C2=Concentration to get
V2= volume you get
Multiply the original concentration of the acid and the amount you want to use = C1 x V1 (100% x 40ml)
Divide it by the concentration you are trying to get= C1 x V1/30%=(100% x 40ml) divided by 30%
That would be equal to 133.33ml approximatlet 133ml of water
So you would need to add 133ml to the 40ml bottle to get your 30% acid solution