Steroids, Athletic Performance, and Red Blood Cells. Part 1/2.

Many performance-enhancing drugs and training techniques increase the oxygen-carrying capacity of the blood. This leads to an improvement in both performance and endurance.

Some methods for increasing red blood cell count (sometimes called “blood boosting”) include:
– Administration of erythropoietin
– Training at altitude
– Using a hypobaric chamber
– Blood transfusions
– Steroids

The increase in endurance gained from so-called “blood boosting” products and techniques has made them highly popular among endurance athletes, most notably in cycling. The widespread use of autologous blood transfusions and erythropoietin (at the time undetectable) in cycling in the 1990s and beyond led to many records being broken – and the eventual downfall and vilification of its most iconic figure, Lance Armstrong.

“I viewed it as very simple. You had things that were oxygen-boosting drugs that were incredibly beneficial for performance, or endurance sports – whether it’s cycling or running or whatever. And that’s all you needed. My cocktail was only EPO, but not a lot, transfusions, and testosterone.” – Lance Armstrong [1]

Erythropoietin is the hormone that stimulates the production of erythrocytes (red blood cells) in the bone marrow, a process that takes about seven days. Mature red blood cells contain hemoglobin, which carries oxygen from the lungs to the tissues, where it is used by the cells to facilitate the conversion of nutrients to energy in a process called respiration. The red blood cell is then carried back to the lungs to repeat the process.

EPO administration has been found in a double-blind, placebo-controlled experiment to produce a significant increase in VO2max (maximal aerobic capacity, an indicator of physical fitness) in male athletes after four weeks administration, [2] which is unsurprising given the clear relationship between VO2max and hemoglobin. [3]

vo2max and hemoglobin

Total body hemoglobin and whole body maximal oxygen uptake (VO2max) for 94 subjects age 7–30 years.
Br J Sports Med. 2003 Jun;37(3):190–1. [3]

The widespread use of EPO in professional athletics is believed to be responsible for a sharp drop in running times in long distance events, as illustrated by the graph below.

mens 5000m times influenced by EPO

Mean finishing times of the top 20 athletes in the men’s 5000 m from 1985 to 2010
Drug Test Anal. 2012 Aug 29 [4]

One positive aspect of EPO (for the doping athlete) is that the mature red blood cell has a functional lifetime of around 120 days, yet the detection window of EPO is much shorter, so EPO-doping athletes can still be reaping the rewards of ‘blood boosting’ long after the risk of testing positive has passed.

Drawbacks of EPO include frequent injections, and that testing for EPO has been routine in many sports since the year 2000.


It has been known for over 50 years that the sex steroids affect red blood cell production (erythropoiesis); androgens increase red blood cell count, and estrogens have the opposite effect. [5]
For this reason men have more red blood cells than women, and are able to regenerate blood losses after donations faster than female donors. [6]

“The stimulation of erythropoiesis by anabolic steroids is primarily mediated by ESF [erythropoietic stimulating factor; erythropoietin]. Androgens enhance the renal production of ESF in normal and hypoxic animals and in humans” [7]

A number of steroids have been clinically prescribed for treatment of anaemia (a medical condition consisting of a lack of red blood cells or hemoglobin), including fluoxymesterone, methandrostenolone, methyltestosterone, stanozolol, and oxymetholone.

Adverse effects from anabolic steroids include virilization (masculinization of women and children), hepatotoxicity, and an adverse shift in lipoprotein subfraction (they are bad for cholesterol levels). The risk of side-effects is increased for the treatment of anaemia (relative to other uses), as to achieve a clinically relevant erythropoietic effect they must be administered at high doses. [7][8]

“[To treat anaemia] The dosage of the anabolic steroid has to be considerably higher than necessary for the achievement of a good nitrogen-retaining [i.e. anabolic] effect alone. The dosage has to be around 1-2 mg of 17a-methyl-testosterone per kilogram of bodyweight per day, or its equivalent. Side-effects, consequently, tend to appear fairly frequently.” – H. L. Krüskemper [8]

There is a school of thought that suggests some androgens are better than others for the purpose of increasing red blood cell count – oxymetholone and boldenone are commonly believed to be superior – and another opposing view holds that all steroids appear to be roughly equally effective at increasing RBC. It’s true that most studies have failed to show any significant benefit of one synthetic anabolic agent over another, and in the case of oxymetholone it’s probably true that it is not significantly better than the others, even though it is the anabolic steroid that has been investigated most extensively for that purpose. [7] Boldenone, however, may be different, and in part two of this article you will see why.

[1] Oprah and Lance Armstrong: The Worldwide Exclusive Part 1
[2] Birkeland KI, Stray-Gundersen J, Hemmersbach P, Hallen J, Haug E, Bahr R. Effect of rhEPO administration on serum levels of sTfR and cycling performance. Med Sci Sports Exerc. 2000 Jul;32(7):1238–43.
[3] Joyner M. VO2MAX, blood doping, and erythropoietin. Br J Sports Med. 2003 Jun;37(3):190–1.
[4] Ernst S, Simon P. A quantitative approach for assessing significant improvements in elite sprint performance: Has IGF-1 entered the arena? Drug Test Anal. 2012 Aug 29;
[5] Mirand EA, Gordon AS. Mechanism of Estrogen Action in Erythropoiesis. Endocrinology. 1966 Feb 1;78(2):325–32.
[6] Kappas A, Palmer RH. Selected aspects of steroid pharmacology. Pharmacol. Rev. 1963 Mar;15:123–67.
[7] Evens RP, Amerson AB. Androgens and erythropoiesis. J Clin Pharmacol. 1974 Mar;14(2):94–101.
[8] Krüskemper, Hans Ludwig. 1968. Anabolic Steroids. Academic Press. p158.

Any quotes are for illustrative purposes only and are not to be taken as an endorsement or approval of any course of action or product.

© Total Flex Blog 2013