Side-effects from the use of steroids are extremely common and can be quite significant. Most side-effects are reversible once the athlete stops usage although serious long-term side-effects and even death have occurred as a direct result of steroid use.
• Decreased sperm production and sex drive
• Increased aggression, irritability and mood swings
• Liver disorders
• Baldness (alopecia)
• Hypertension (high blood pressure)
• Raised cholesterol
• Gynecomastia (development of over-sized mammary glands in males)
• Menstrual irregularities (in women)
• Hirsuitism (excessive hair growth occurring in females which follows the pattern of male hair growth, . facial)
• Deepening of the voice
• Reduced immunity
• Possible development of tumors (wilm’s tumor, prostate carcinoma and leukemia have been reported, although a connection is not proven)
Transdermal patches (adhesive patches placed on the skin) may also be used to deliver a steady dose through the skin and into the bloodstream. Testosterone-containing creams and gels that are applied daily to the skin are also available, but absorption is inefficient (roughly 10%, varying between individuals) and these treatments tend to be more expensive. Individuals who are especially physically active and/or bathe often may not be good candidates, since the medication can be washed off and may take up to six hours to be fully absorbed. There is also the risk that an intimate partner or child may come in contact with the application site and inadvertently dose himself or herself; children and women are highly sensitive to testosterone and can suffer unintended masculinization and health effects, even from small doses. Injection is the most common method used by individuals administering AAS for non-medical purposes. 
If you are going to start your first cycle soon, 'how to inject' is probably that last thing that you are worried about. You would have started by conducting research on the different injectable anabolic steroids available in the market, whichyou think can help you reach your goal. But when you have the vials and the syringes in front of you, you will surely think about how you will get the steroid out from the bottle and into your body. At this point, some people will become exasperated and even give up. Here is some information on injecting anabolic steroids.