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Anabolic-androgenic steroids, more commonly known as anabolic steroids, are chemically synthesized drugs that act analogous to androgen; the male sexual hormone.These drugs provide anabolic activity by increasing protein synthesis which causes muscle build up. These drugs also provide androgenic activity by enhancing the male secondary sexual characteristics. [1, 2]
Anabolic-androgenic steroids were first identified and synthesized in 1935. It was first used for medical purposes.  These drugs were used primarily in the treatment of hypogonadism, a condition in which the testes is unable to produce sufficient testosterone for normal growth, development and sexual functioning.These drugs have been used therapeutically to stimulate growth in treating chronic diseases associated by cachexia, the excessive loss of muscle tissue. These have been used in treating cancer and acquired immune deficiency syndrome (AIDS). 
However, in 1954, bodybuilders and athletes began using these drugs for ergogenic purposes. Anabolic steroids tend to increase muscle size and strength, thus, improving athletic performance. These drugs also aid in fast injury recovery. Non-athletes also use these drugs for physical appearance enhancement. Due to these instances, others tend to abuse these drugs to attain their desired effects in a short period of time. [2, 4]
Furthermore, using anabolic steroids does not improve muscular strength immediately. Muscular strength is much attainable by taking these drugs accompanied by intense strength training. The efficacy of anabolic steroids depends upon the unbound receptor sites in the muscle cells. Intense strength training increases the number of unbound receptor sites.This increases the effectiveness of anabolic steroids. 
In spite of the beneficial effects of anabolic steroids in athletic performance, doctors discourage the use of these drugs.  Inappropriate use of these drugs threatens the health. Abusive use of anabolic steroids may cause cardiovascular, skin, hormonal, reproductive, musculoskeletal, personality and behavioral disorders. In addition, steroids, parentally administered, may increase risks of having dangerous infections such as AIDS, and hepatitis B/C through the use of shared and non-sterile equipment. [7, 8]
In 1975, these drugs were placed on the lists of banned substances by the International Olympic Committee (IOC). The use of steroids by athletes has been prohibited because of their potential dangerous side effects. The use of these drugs also gives unfair advantage to the users. The International Olympic Committee (IOC), National Collegiate Athletic Association (NCAA) and many professional sports leagues conduct doping control procedures within the training period of the participants and during competitions. The presence of steroids in athletes is identified through urine tests. Athletes’ steroid presence would cause disqualification of athletes from the competition. [1, 9]
Anabolic steroids are considered as over-the-counter supplements. This means that these drugs are not regulated by the authority and, thus, the quantity, quality and safety of the ingredients is unknown. Suppliers of these drugs have no protocol standards to monitor the claims of their products. Aside from the proven side effects of anabolic steroids in the body, these drugs are highly dangerous since they are not fully monitored by the authorities. [2, 4]
I. How anabolic steroids are made?
Anabolic steroids are synthetic derivatives of androgen. The primary and most potent naturally occurring androgen is testosterone. Anabolic steroids are made through chemical modifications of testosterone.These modifications in the structure of testosterone led to substances with different action modes. 
The first step to creating the anabolic steroids is by isolation of androgens. During the early exploration of this technology, isolation of androgens would require a large number of urine from where the hormone is extracted. The isolated androgens are then further synthesized to function as they are expected in the body of the host.
The previous method, however, was found to be flawed for the reason that the potency of the steroid is affected by the environment to where the urine is placed. Laboratories would have to find ways to simulate conditions inside the body to address this problem.
Later developments to the method would include a mechanism on how to synthetically make anabolic steroids. After several years of laboratory work and exploration of the naturally occurring androgens, scientists were able to study more about the properties of androgens. From their study, they were able to find out that androgens can actually be made through chemical synthesis. The first work on the chemical synthesis of testosterone was the successful attempt of making it from cholesterol.
II. How these modifications alter the natural testosterone?
The modifications in the structure of testosterone change its ability to react within the human body. The alkylation of 17-α position with methyl or ethyl group makes the testosterone orally active. The 17-αalkylatedanabolic steroids have slower degradation in the liver during the first-pass metabolism. Thus, it reaches the systemic circulation without greatly reducing its activity. [9, 10]
The esterification of testosterone at the 17-β-position reduces the diffusion of the steroid from the muscular site into the circulation.This type of anabolic steroids is usually dissolved in oil for intramuscular injections. This modification results in a longer duration of anabolic steroid effectiveness. The chemical alterations in the ring structure of testosterone particularly at the 2, 9, 11, and 19 carbon positions have also been known to increase the anabolic activity of steroids. [9, 10]
III. How the anabolic steroids work and affect once entered into one's body?
Anabolic steroids work on the body through direct action. Since these substances are lipid-soluble, they are permeable to the cell membrane. As they enter the cell, they bind to specific androgen receptors present in the cytoplasm. The hormone-receptor complex penetrates the nucleus and binds to specificregions of chromatin.This enhances the stimulation of messenger ribonucleic acid (mRNA) for protein synthesis.An increase in protein synthesis results to cell tissue build-up. Its androgenic activity is caused by the alteration of genes which causes the enhancement of certain male traits and the detraction of some traits. [5, 11]
The body’s normal hormone production is affected by the abnormal amount of testosterone in the body. In men, it causes the reduced sperm production and shrinking of the testicles (testicular atrophy) and the development of breasts (gynecomastia). In women, it causes masculinization of facial features, deepening of voice, and the excessive body hair growth (hirtuism). [2, 4]Hormonal changes also cause skin disorders such as acne, cysts and oily scalps. Hormonal changes also affect behavior, causing irritability, aggression, and depression. 
The use of anabolic steroids also weakens the cardiovascular system due to the increase of low density lipoprotein (LDL, bad cholesterol) and the decrease of high density lipoprotein (HDL, good cholesterol) in the blood. The sudden change in the concentrations of lipoproteins in the blood results to irregular heartbeat and high blood pressure.Thus, anabolic steroids may heighten the risks of heart attack. These drugs also cause the overusing of the liver. The liver considers anabolic steroid as toxic substances that must be degraded in the body. Abusive intake of these drugs damages the liver causing liver tumors. 
Anabolic steroids also influence the protein catabolism. These drugs have anti-catabolic effects. They inhibit the hormone cortisol, specifically glucocorticoids. These hormones promote muscle catabolism by using protein as a fuel source. The prevention of these hormones lessens the protein degradation, thus, enhances recovery. This is beneficial to the user, yet it negatively rebounds when the user stops taking the drug. The catabolic effects of cortisol are enhanced when the user stops taking it.  This result in mood swings, loss of appetite, and fatigue due to rapid loss of muscle size and strength.The degree of anabolic steroids side effects on the behavior of human beings is still unknown. 
Anabolic steroids are drugs chemically synthesized for people to take advantage of the known positive properties of androgens. Though naturally occurring in humans, androgen supply was found to be lacking when compared to the surmounting need for the hormone which characterized some communities in the past.
The need for synthetic androgen was first felt during the period where the source of good nutrition was scarce. It was said to have been used to help children who were once victims of slavery to quickly recuperate. These children were administered with anabolic steroids to aid in their growth, increase their appetite, and treat some serious medical conditions.
Later, however, the use has been extended to include ergogenic uses. And it is during this time that anabolic steroid was placed in a bad light. The drug has become related to substance abuse. As a consequence, the medical industry and the government was made vigilant in regulating the use of the drug.