Kefir is symbiotic culture of yeast and bacteria used to ferment milk into a thick, delicious drink. You can make your own or go to a local grocery store to see if they carry any Lifeway or The Greek Gods brands. Unfortunately, most branded Kefir drinks are fermented with low fat milk. So if you want whole milk fermented, you have to do it yourself, like Adam Raw does in the video above. Forget about supplements, just drink this everyday like I do. I haven't taken a supplement in months and this is cheaper in some cases and is awesome for making gains and doing good for the body. :-)