Steroids do, indeed, increase muscle mass and strength, and the bigger the dose, the better the results. And even though there are no studies directly showing that steroids increase speed, performance in power sports such as sprinting is highly related to basic measures of strength.
Strength, size, and speed may be just part of what steroids do for an athlete. Testosterone seems to enhance response time and decision making. Studies have found that men with higher testosterone levels could solve spatial-relationship problems faster and more accurately than their more hormonally challenged counterparts. Testosterone enters a cell and acts like a nerve transmitter in the part of the brain that has to do with the fear response.

Sports are all about fear, or at least stress. They are also about confidence. A steroid-using athlete could be faster, better prepared, and more confident, which all play into how well someone does in anything. With steroid-induced increases in muscle size come more of all the things that make the muscles work. Sportsmen are well-known to be ardent consumers of amphetamines, caffeine, and other stimulants that improve reaction times. And, of course, HGH is part of it.

From diabetes to high blood pressure to arthritis, studies in older people have identified some unwanted side effects from HGH, including excess bone growth from fluid retention, enlargement of the heart and other organs, joint pain, carpal tunnel syndrome, increases in blood sugar levels, and soft-tissue swelling. Some plastic surgeons give HGH to patients just for the
effect of fluid retention on wrinkles.

There are a series of experiments by researchers are happening worldwide which showed that HGH made people’s muscles bigger, but not necessarily stronger. One possible explanation for these and other similar results is that HGH causes fluid retention and adds connective tissue, but doesn’t bulk up the contractile tissue that adds strength. But is to be kept in mind that these controlled experiments bear little resemblance to how HGH is used by elite athletes or even people at the local gym who want to look better. Endurance athletes may combine it with erythropoietin, the hormone that stimulates production of red blood cells. Some athletes say they've used HGH not to add muscle but only to speed recovery from an injury.

HGH was not readily available as there were limited sources but the scenario changed in the 1980s with the development of recombinant genetic techniques that made it possible to splice the genes that churn out the hormone into microorganisms. Though there are studies and researches going around the subject but lack of long-term studies also makes it difficult to be certain about whether HGH might hike cancer risk. Despite all the scary side effects, the product is still very popular and comes in form of HGH pills, sprays and creams. Safe or not, HGH molecules are too large for the skin or the intestine to absorb them. It is surely profitable for the people selling it. All in the name for better looks and power.