Formulation tool

Free Acid & Intensity Calculator

At a given pH, only a fraction of glycolic acid is present in its active, un-ionised form. Slide the inputs to estimate the bioavailable free-acid % and resulting exfoliation intensity.

Inputs

Glycolic concentration7.0%

1%10%20%

Formulation pH3.60

2.03.83 pKa5.5

free_acid_% = conc × 1 / (1 + 10^(pH − 3.83))

Estimated output

4.41% free acid

62.9% of the glycolic in the formula is in its bioavailable, un-ionised form at pH 3.60.

Exfoliation intensity

Strong

Weekly resurfacing — experienced users only.

Conc.

7.0%

3.60

pKa

3.83

Educational use only. Formulation insights are for cosmetic design study and consumer literacy. Actual product efficacy and tolerability depend on buffering system, partition coefficient, vehicle, and overall formulation context. Always validate with stability and patch testing.