Testosterone Enanthate is probably the most commonly used form of testosterone by both athletes and bodybuilders alike. It´s very effective for building muscle and strength, losing fat, and is cheap & readily available.

To understand exactly how Testosterone Enanthate (a.k.a. "test enth" or just "enth") builds muscle and burns fat, first we´ll take a look at androgens and what they do in the body. You see, hormones are substances secreted by one cell, that has an effect on the functions of another cell. Testosterone is manufactured in the Leydig´s cells of the testes (in men). The adult male produces between 2.5 and 11mgs of Test per day.

Testosterone induces changes in shape, size and also can change the appearance and the number of muscle fibres(7). Androgens like testosterone can protect your hard earned muscle from the catabolic (muscle wasting) glucocorticoid hormones(8), thus inhibiting their ability to send a message to muscle cells to release stored protein. Remember, Testosterone sends a message to muscle cells to store more contractile protein (called actin and myosin); glucocorticoid hormones send the opposite message. In addition, Testosterone has the ability to increase erythropoiesis (red blood cell production) in your kidneys(9), and a higher Red Blood Cell (RBC) count may improve endurance via better oxygenated blood. More RBCs can also improve recovery from strenuous physical activity. Agression levels often rise dramatically with the use of exogenous testosterone (15).

All of these great benefits are to be had with the use of test enth alone, but realistically, it will be part of a cycle containing one or more other drugs. People who are bulking will probably choose Deca or Eq (possibly with Dbol as well) and those who are cutting will probably steer towards Eq and perhaps Trenbolone. Very often users will shoot this drug once or twice a week, but blood levels are still above baseline with this drug at around day eight (16).Common wisdom holds that the testosterone portion of any such cycle should be equal to or greater than any other injectable drug(s) portion (on a mg basis)... I believe that you can get away with less, but in general, this is a good guideline.

As you may have suspected, Testosterones´ anabolic/androgenic effects are dose dependant, the higher the dose the higher the muscle building effect.

Change in fat-free mass, fat mass, leg press strength, thigh muscle volume, quadriceps muscle volume, sexual function, insulin-like growth factor I, and prostate-specific antigen. Data are means ± SE. *Significant differences from all other groups (P < 0.05); significant difference from 25-, 50-, and 125-mg doses (P < 0.05); +significant difference from 25- and 50-mg doses (P < 0.05); and significant difference from 25-mg dose (P < 0.05). (14)

Most fat was lost by the group in this study who used the highest dose (600mgs/week), and the most Fat Free mass, Strength and Muscle Volume was gained, when compared to any of the lower doses studied. Basically, the more testosterone you use (and this holds true for almost all steroids), the more gains you´ll get!

Did the men in this study experience side effects at the 600mg dose? HDL cholesterol was lowered (but not total cholesterol or triglyceride levels), and two guys got Acne.

A large percentage of those side effects occur from the body´s ability to turn testosterone into estrogen via a metabolic pathway mediated by the aromatase enzyme. This process, known as aromatization causes a portion of testosterone to be converted to estrogen. Aromatase Inhibitors (Arimidex and Letroaole, for example) can combat this very effectively, and are usually necessary with doses over ½ a gram per week.

17b-hydroxy-4-androsten-3-one
     Testosterone base + Enanthate ester
     Molecular Weight: 412.6112
     Molecular Weight (base): 288.429
     Molecular Weight (ester): 130.1864
     Formula (base): C19 H28 O2
     Formula (ester):C7 H12 O
     Melting Point (base): 155
     Manufacturer: Various
     Effective Dose (Men): 300-2000mg+ week
     Effective Dose (Women): Not recommended
     Active life: 15 days
     Detection Time: 3 months
     Anabolic/Androgenic ratio:100/100.

Source: steroid.com