Like HowStuffWorks on Facebook!

How Performance-enhancing Drugs Work


Human Growth Hormones
Performance-enhancing drugs are the frequent subject of controversy in the sporting world.
Performance-enhancing drugs are the frequent subject of controversy in the sporting world.
Jupiterimages/Photos.com/Thinkstock

Human growth hormones include human chorionic gonadotropin (HCG), luteinizing hormone (LH) and human growth hormone (HGH), insulin and insulin-like growth factor (IGF-1).

Human Chorionic Gonadotropin (HCG)

HCG is a naturally occurring protein hormone produced by the developing fetus and detected in most home pregnancy kits. HCG stimulates the development of natural male and female sex steroids. The increase in testosterone levels in males by the use of HCG would stimulate muscle development as with anabolic steroids. HCG is not banned in female athletes because it would not lead to muscle development and might naturally occur in high levels if the athlete is pregnant. The side effects of HCG in males are the same as those of anabolic steroids.

Luteinizing Hormone (LH)

LH is a peptide hormone secreted by the pituitary gland at the base of the brain. LH is important for maintaining normal levels of testosterone in the male and estrogen in the female. In women, a surge of LH during mid-cycle is the signal for ovulation. In men, excess LH or artificial LH derivatives (tamoxifen) would increase testosterone levels and have the same effects as anabolic steroids. Although no general side effects exist, any possible side effects might be similar to those of anabolic steroids.

Human Growth Hormone (HGH)

HGH is a naturally occurring protein hormone produced by the pituitary gland and is important for normal human growth and development, especially in children and teenagers. Low HGH levels in children and teenagers result in dwarfism. Excessive HGH levels increase muscle mass by stimulating protein synthesis, strengthen bones by stimulating bone growth and reduce body fat by stimulating the breakdown of fat cells. Use of HGH has become increasingly popular because it is difficult to detect. Side effects include:

  • Overgrowth of hands, feet, and face (acromegaly) because of the increased muscle and bone development in these parts
  • Enlarged internal organs, especially heart, kidneys, tongue and liver
  • Heart problems

Insulin-Like Growth Factor (IGF-1)

IGF-1, which is also called somatomedin-C, is a naturally occurring protein that helps in the action of HGH. It also stimulates protein synthesis and reduces fat. Excessive IGF-1 would increase muscle and bone mass as HGH does. Side effects include low blood sugar (hypoglycemia) and other side effects similar to HGH.

Insulin

Insulin is a natural protein hormone produced by the pancreas, which is important for metabolism of sugars, starches, fats, and proteins. It is necessary for the treatment of juvenile (Type 1) diabetes. In athletes, insulin combined with anabolic steroids or HGH could increase muscle mass by stimulating protein synthesis. Side effects are mainly low blood sugar associated with shaking, nausea and weakness, but excessive hypoglycemia can lead to coma and death.