Very good article I found on another site.
Testosterone dose-response relationships in healthy young men
The following text outlines the benefits and risks of Testosterone administration based on a clinical human trial of 61 healthy men in 2001. The purpose of the trial was to determine the dose dependency of testosterone’s effects on fat-free mass and muscle performance. In this trial 61 men, 18-35years old were randomized into 5 groups receiving weekly injections of 25, 50, 125, 300, 600 mg of Testosterone enanthate for 20 weeks. They had previous weight-lifting experience and normal T levels. Their nutritional intake was standardized and they did not undertake any strength training during the trial. The only two groups that reported significant muscle building benefits were the 300 and 600 mg groups so any dose lower than 300mg will not be considered in this essay. 12 men participated in the 300 mg group and 13 men in the 600 mg group.
600mg of Testosterone a week for 20 weeks resulted in the following benefits. Increased fat free mass, muscle strength, muscle power, muscle volume, hemoglobin and igf-1.
The same 600 mg administration resulted in 2 side effects. HDL cholesterol was negatively correlated and 2 men developed acne.
The normal range for total T in men is 241-827 ng/dl according to Labcorp and 260-1000 ng/dl according to Quest Laboratories. The normal range for igf-1 is 81-225 according to Labcorp. Total T and igf-1 levels were taken after 16 weeks and resulted in the following;
300 mg group-1,345 ng/dl a 691 ng increase from baseline
600 mg group-2,370 ng/dl a 1,737 ng increase from baseline
300 mg group-388 ng/dl a 74 ng increase from baseline
600 mg group-304 ng/dl a 77 ng increase from baseline
Body composition was measured after 20 weeks.
Fat Free Mass by underwater weighing
300 mg group-5.2kg (11.4lbs) increase
600 mg group-7.9kg (17.38lbs) increase
Fat Mass by underwater weighing
300 mg group-.5kg (1.1lbs) decrease
600 mg group-1.1kg (2.42lbs) decrease
Thigh Muscle Volume
300 mg group-84 cubic centimeter increase
600 mg group-126 cubic centimeter increase
Quadriceps Muscle Volume
300 mg group-43 cubic centimeter increase
600 mg group-68 cubic centimeter increase
Leg Press Strength
300 mg group-72.2kg (158.8lbs) increase
600 mg group-76.5kg (168.3lbs) increase
300 mg group-38.6 watt increase
600 mg group-48.1 watt increase
300 mg group-6.1 gram per liter increase
600 mg group-14.2 gram per liter increase
Plasma HDL Cholesterol
300 mg group-5.7 mg/dl decrease
600 mg group-8.4 mg/dl decrease
300 mg group-7 of the 12 men developed acne
600 mg group-2 of the 13 men developed acne
There were no significant changes in PSA or liver enzymes at any dose up to 600mg. However, long-term effects of androgen administration on the prostate, cardiovascular risk, and behavior are unknown. The study demonstrated that there is a dose dependant relationship with testosterone administration. In other words the more testosterone administered the greater the muscle building effects and potential for side effects.
Given the results of the study and based on years of personal experience I believe the first time user can safely use between 300-600 mg of testosterone enanthate or cypionate per week for 8-12 weeks. Because it is desirable to have even blood androgen levels I advise at least 2 equal injections per week. Testosterone cypionate peaks within 1-2 days after injection and falls off to almost baseline by day 10. Therefore waiting 7 days between injections of cypionate would cause wide fluctuations in blood androgen levels.
If a first time user wanted to use 600 mg of cypionate or enanthate per week he would inject 300 mg on Tuesday and another 300 mg on Saturday each week for 10 weeks. When injecting long heavy esters like cypionate with this frequency I tend to have less acne then 1 injection per week.
There are a number of esters which provide varying release times. Acetate or propionate esters extend the release time of testosterone a couple of days. In contrast, a deconate ester prolongs the release of testosterone about 3 weeks. Testosterone enanthate and cypionate are almost identical esters. The use of an ester allows for a less frequent injection schedule than using a water based testosterone like suspension which has no ester at all and is rapidly in and out of your system after injection. The published release times are not exact and are many times based on a single injection not many multiple injections which can delay the release of the hormone. Other factors affect release times of esters such as scar tissue and the muscle group injected. Only a blood test can confirm when the active hormone has cleared your system.
Esters not only effect release times but also the potency of the Testosterone as esters make up part of the steroid weight. This must be taken into account when calculating dosages. The longer the release time the less free hormone. For example propionate is about 15% more potent mg. for mg. then enanthate so 500mg of propionate would equal about 575 mg. of enanthate.