According to the IB website, aside from XXX, it looks like One X, Freedberg, and Tight Buns all use the tallow formulation. Here is the ingredients list for those four soaps:
Ingredients: Aqua(Water/Eau), Stearic Acid, Cocos Nucifera(Coconut) Oil, Tallow Acid, Potassium Hydroxide, Sodium Hydroxide, Parfum(Fragrance), Solum Fullonum(Fullers Earth), Benzyl Salicylate, Coumarin, Linonene, Linalool, Hydroxyisohexyl-3-Cyclohexene Carboxaldehyde (HMPCC), A-Isomethylionone. |