Understanding the Dose vs Response Relationship with AAS

Understanding the Dose vs Response Relationship with AAS

Today’s Master Class opens up the question

How much Testosterone does what ?  

To begin that discussion we look at a study from the American Journal of Physiology Endocrinology and Metabolism.

Testosterone dose-response relationships in healthy young men

 

 

Shalender Bhasin, Linda Woodhouse, Richard Casaburi, Atam B. Singh, Dimple Bhasin, Nancy Berman, Xianghong Chen, Kevin E. Yarasheski, Lynne Magliano, Connie Dzekov, Jeanne Dzekov, Rachelle Bross, Jeffrey Phillips, Indrani Sinha-Hikim, Ruoquing Shen, Thomas W. Storer

American Journal of Physiology – Endocrinology and Metabolism Published 1 December 2001 Vol. 281 no. 6, E1172-E1181 DOI:

Testosterone increases muscle mass and strength and regulates other physiological processes, but we do not know whether testosterone effects are dose dependent and whether dose requirements for maintaining various androgen-dependent processes are similar. To determine the effects of graded doses of testosterone on body composition, muscle size, strength, power, sexual and cognitive functions, prostate-specific antigen (PSA), plasma lipids, hemoglobin, and insulin-like growth factor I (IGF-I) levels, 61 eugonadal men, 18–35 yr, were randomized to one of five groups to receive monthly injections of a long-acting gonadotropin-releasing hormone (GnRH) agonist, to suppress endogenous testosterone secretion, and weekly injections of 25, 50, 125, 300, or 600 mg of testosterone enanthate for 20 wk. Energy and protein intakes were standardized. The administration of the GnRH agonist plus graded doses of testosterone resulted in mean nadir testosterone concentrations of 253, 306, 542, 1,345, and 2,370 ng/dl at the 25-, 50-, 125-, 300-, and 600-mg doses, respectively. Fat-free mass increased dose dependently in men receiving 125, 300, or 600 mg of testosterone weekly (change +3.4, 5.2, and 7.9 kg, respectively). The changes in fat-free mass were highly dependent on testosterone dose

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;

Total Testosterone
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

igf-1
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

Hemoglobin
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

Acne
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.

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.