Andriol is a revolutionary steroid because, besides methyltestosterone, it is the only effective oral testosterone compound. Testosterone itself, if taken orally, is ineffective since it is reabsorbed through the portal vein and immediately deactivated by the liver.

The substance testosterone undecanoate contained in Andriol, however, is reabsorbed from the intestine through the lymphatic system, thus bypassing the liver and becoming effective. The liver function is not affected by this. Andriol aromatizes only minimally, meaning that only a very small part of the substance can be converted into estrogen, since the dihydrotestosterone does not aromatize.The users of Andriol therefore do not experience feminization symptoms such as gynecomastia or increased body fat.

Andriol's non-aromatizing quality consists of the fact that the body's own hormone production is only affected after a long-term administration of very high dosages. Andriol should be the perfect steroid; however, this is not the case. Another advantage of testosterone undecanoate is that it does not affect the body's own natural testosterone production, perhaps only at disproportionately high doses and prolonged abuse. Significant advances have been reported on the strength and muscle gains that this steroid can cause either alone, but most often in combination with other anabolic-androgenic steroids.

The disadvantage of Andriol is that it only becomes effective if taken in high doses. Even if a dose of 200 mg of Andriol/day is taken, the testosterone level in the blood is still too low for a bodybuilder to gain strength and muscle growth. The capsules, therefore, are effective for only a few hours so that 6-7 capsules, that is 240-280 mg (mini-mum), must be taken daily to achieve good results comparable to those of injectable compounds. This, however, puts the athlete in a dosage range which begins to influence the hormone production and the compound now more readily converts into estrogen. Such a dose can also manifest itself in a higher retention of sodium and water. This is one factor which competing athletes must consider.