A few more details about milk thistle. If you go to the NIH (National Institutes of Health) website and do a search for "silymarin/silybin & liver disease" many articles appear. One such abstract (which I couldn't cut & paste for some reason) is "Silymarin/Silybin and Chronic Liver Disease: A Marriage of Many Years." By Federico, Dallio, Loguero; Jan. 24, 2017.
From my reading, it seems that it's milk thistle seed (not the leaf) that contains the portent ingredients. Silymarin is a component within the seed and Silybin is thought to be the active component that is so potent within Silymarin. Silymarin and Silybin are easily & quickly absorbed by the liver. Here is an article explaining what I've just summarized: Google "Difference Between Milk Thistle, Slymarin & Silybin." Click on the Mega BIO-LIFE entry (7/2019).
Long ago I used Nature's Bounty but then discovered Ultra Thistle which is pure silybin at high amounts. It's more expensive that Nature's Bounty, which often goes on sale at 2-for 1. -- Rose