The partition coefficient of the ester in question is important because is effects how long the drug itself stays in the system. If the testosterone transfers too quickly from the oil to the blood, the result is a sudden spike in testosterone which then rapidly drops once the dose has been used up. In the example of free testosterone injected into the muscle from a water suspension (as in Aquiviron, mentioned above), the testosterone is essentially immediately available to the bloodstream due to its low partition coefficient, and thus there is an immediate spike of testosterone which is used up quickly in the body.
Testosterone itself possesses a moderate level of Estrogenic activity, whereby it holds a moderate affinity to bind to the aromatase enzyme (the enzyme responsible for the conversion of Testosterone into Estrogen). Therefore, a moderate level of aromatization is to be expected with Testosterone use unless an aromatase inhibitor is utilized (such as Arimidex, Aromasin, and Letrozole) to inhibit the aromatase enzyme and therefore render it unable to aromatize any Testosterone into Estrogen. Therefore, Testosterone serves as a preferable compound for bulking but can also be utilized for cutting and fat loss phases as well. At the end of the day, however, Testosterone of any type is required in any cycle of any anabolic steroid if at least for the maintenance of proper physiological function of Testosterone in the body during a period in which the endogenous production of Testosterone has been suppressed or shut down from the use of anabolic steroids. Testosterone itself is also a very strong anabolic compound, suitable even on its own for any purpose, and is in fact suggested as the very first and only anabolic steroid that should be utilized in all first-time and beginner cycles.
Test-P injections are made as a rule every day or every other day. Steroid cycle lasts 6-8 weeks. Testosterone enanthate and cypionate cycles shall be run not less than for 10 weeks. On shorter cycles long esters will not be able to expose their full potential. For enanthate and cypionate is one injection every 5-7 days is enough. However, some athletes prefer more frequent injections in order to provide more even hormone level in blood and to avoid dramatic fluctuations. And don`t forget, that steroid aromatizes very easily to estradiol. Independent on the compound you use, keep your estradiol under control by taking aromatase inhibitors (anastrozole preferably). Antiestrogens (SERMs) are in this context not recommended, because they will reduce the cycle efficiency.