How We Found the Best Testosterone Booster. We started with a list of 214 testosterone boosters, found in their natural habitats on websites like Bodybuilders.com, BroScience, and The Art of Manliness. These supplements are marketed almost exclusively to men looking for that extra edge in the weight room, the bedroom, and the mirror.
1 These are common and often don't cause symptoms, but may lead to a small amount of blood in your stool.  sexually transmitted infections (STIs) â any sexual activity involving the anal area can spread STIs, which may sometimes lead to rectal bleeding.
To figure out how much blood is present in a black stool a physician may order a fecal occult blood test. Melena can be caused by 200 milliliters (or more) of blood being passed in the stool, which is also equivalent to a quarter of a cup, or 4 tablespoons.