It does contain GA - I'm looking at my bottle, and it's the second ingredient listed after water. And according to
UK's Proactiv site, there's 5% GA in the toner.
Ingredients: water (aqua),
glycolic acid, hamamelis virginiana (witch hazel) extract, anthemis nobilis flower extract, rosa canina fruit extract, aloe barbadensis leaf juice, sodium PCA, panthenol, glycerin, propylene glycol, allantoin, polysorbate-20, hydroxyethylcellulose, sodium hydroxide, benzophenone-4, tetrasodium EDTA, methylparaben, propylparaben, imidazolidinyl urea, fragrance (parfum), blue 1, yellow 5.
SOURCE