Testosterone is a 'male hormone' made in the testicles. It causes male sex characteristics such as a deep voice, facial hair, bone and muscle strength. Some men who have had treatment for testicular cancer or for cancer when they were children may need to have testosterone replacement therapy.

The aim of testosterone replacement therapy is to keep a normal level of testosterone in the blood. This is important for sex drive and for being able to get an erection. Low testosterone levels can also cause tiredness and mood changes.

Testosterone supplements can be given as:

• Injections into the muscle. This is the commonest way of having the treatment. Injections give steady levels of testosterone in the blood for most of that time. Levels may be a bit higher than normal immediately after the injection and a bit lower than normal just before the next injection is due. They are given at regular intervals and the time between injections varies depending on the type of injection you are given. Types of injections include Testosterone Entanate (every 3-6 weeks), Sustanon 100® (every 2 weeks) Sustanon 250® (every 3 weeks), Nebido® (every 10 to 14 weeks).
• Patches applied to the skin daily. The testosterone is slowly absorbed over 24 hours and gives steady blood levels of testosterone. The patches have to be placed on a different area of skin each day for 7 days, before returning to the original area, as they can cause skin reactions. Reactions include soreness, irritation and rashes and happen to about 1 in 3 men who use patches. Patches include, Andropatch®
• Gel put on the skin of the upper arms or shoulder once a day after bathing. It is important not to shower or wash the skin for 6 hours after application of the gel. To prevent transferring testosterone to other people skin to skin contact on the areas where the gel has been applied should be avoided. Gels include Testim® and Testogel®.
• Tablets placed between the gum and lip twice daily. These are called buccal tablets. The testosterone is absorbed through the mouth into the bloodstream to give a steady level of the hormone for 12 hours. Striant® is a type of buccal tablet.
• Tablets or capsules taken 2 -3 times daily after meals. Unfortunately tablets are not as reliable at giving steady blood levels of testosterone as other treatments. This means they are usually only used if other treatments are not suitable. Capsules include Restandol®.
• Implants. Testosterone-based pellets can be implanted under the skin giving a fairly even level of the hormone in the blood for a period of 4 to 6 months. A minor operation is needed to put them in and once they are implanted they cannot be reversed, so implants are not widely used.

So there are a number of ways testosterone can be given. Your doctors will be able to tell you more about them and recommend which preparation may be best for you.