Milk thistle assists the glutathione-S-transferase (GST), a Phase II enzyme that adds a glutathione group to Phase I products, activity by increasing glutathione production up to 35%, but it does not directly stimulate the enzyme. Silymarin also causes liver regeneration, but milk thistle is dangerous for one with impaired sulfation (PST) for it also enhances cytochrome p450 (Phase I) activity. The glutathione it supplies is best supplied by other herbs and foods.