Each 100 grams of gel contain 4 grams of hydroquinone.
Excipients/Inactive Ingredients: ethanol 96%, glycolic acid 70%, propylene glycol, polyquaternium-10, ammonium hydroxide, citric acid anhydrous (E-330), sodium metabisulfite (E-223), sodium sulfite anhydrous (E-221), disodium edetate, butylhydroxytoluene (E-321) and purified water.