Anabolic and androgenic steroids are available as prescription medications to be used in cases in which the body does not make enough hormone and supplementation may be required. Some hormone supplements in this pathway include growth hormone and testosterone itself. These medications are legally prescribed by health-care providers, but this group of drugs is often used illegally and abused to help increase athletic performance and improve body appearance. When used in a well-nourished body, anabolic steroids will cause weight gain primarily due to an increase in muscle mass.
Erythropoietin (EPO): A 165 amino acid glycoprotein hormone (glycoproteins consist of several sugar molecules linked with a protein molecule). EPO stimulates erythrocyte (red blood cell) production in the bone marrow, boosting the blood's ability to carry oxygen. Studies have shown that significant amounts of EPO resist digestion and survive to reach receptors in the intestinal tract. One raw milk-drinking athlete was wrongly accused of blood-doping, so there's at least anecdotal evidence of EPO's activity in our systems!