Some of the approved drugs are synthetic versions of the natural hormones, such as trenbolone acetate and zeranol. Just like the natural hormone implants, before FDA approved these drugs, FDA required information and/or toxicological testing in laboratory animals to determine safe levels in the animal products that we eat (edible tissues). Furthermore, FDA required that the manufacturers demonstrate that the amount of hormone left in each edible tissue after treatment is below the appropriate safe level. As described above, a safe level is a level which would be expected to have no harmful effect in humans.
Not shortly after Roger Maris record was broken, another baseball player, Jason Giambi and various other athletes were either suspected of, or proven to have, taken anabolic steroids. Again, Congress convened a hearing, and just as they did the first time in 1990, they did not determine that steroids were a danger, but rather that the danger was more in protecting professional sports organizations. The updated statute has been updated to proscribe pro-hormones also The definition of an anabolic steroid as defined currently in the United States under (41)(A) is that "anabolic steroid" means any drug or hormonal substance, chemically and pharmacologically related to testosterone (other than estrogens , progestins, corticosteroids, and dehydroepiandrosterone (7).
Because steroids are lipophilic, they diffuse easily through the cell membranes, and therefore have a very large distribution volume. In their target tissues, steroids are concentrated by an uptake mechanism which relies on their binding to intracellular proteins (or " receptors ", see below). High concentration of steroids are also found in adipose tissue, although this is not a target for hormone action. In the human male, adipose tissue contains aromatase activity, and seems to be the main source of androgen-derived estrogens found in the circulation. But most of the peripheral metabolism occurs in the liver and to some extent in the kidneys, which are the major sites of hormone inactivation and elimination, or catabolism (see below).