For targeted benefits of glutathione for skin, direct application of topical skincare products containing glutathione is your best bet
It is also used to diminish the visibility of age spots, sun spots, and other forms of skin discoloration
It simply provides support for what your body is already trying to accomplish

A 2021 review published in Biomedicine & Pharmacotherapy explains that silymarin, the main active compound in milk thistle, can:25 Regulate the cell cycle, helping to ensure proper division and replication Induce apoptosis, or programmed cell death, by which the body can eliminate mutated cells (e.g., cancer cells) Regulate the body's immune response, increasing its ability to recognize and attack cancer cells Keep tumor cells from growing and spreading Inhibit angiogenesis, the process by which tumors create new blood vessels that increase their blood supply and help them grow The review specifically discusses silymarin's therapeutic potential for gastrointestinal cancer, but as another set of researchers note, silymarin has a pleiotropic effect, meaning it can act on multiple targets.26 Again, more research may be needed, but the current science suggests that milk thistle may have fairly broad complementary utility in cancer therapy