Treatment for low testosterone levels usually involves hormone replacement therapy. The method of delivery can be determined by preference, age and the duration of deficiency. Treatment for adults is aimed at maintaining secondary sex characteristics, improving energy, strength, mood, and feelings of well-being, and preventing bone degeneration. Testosterone replacement should in theory approximate the natural production of the hormone. The average male produces 4-7mg of testosterone per day in a circadian pattern, with maximal plasma levels attained in early morning and minimal levels in the evening.
The modes of delivery include transdermal, injection, and oral.
Transdermal delivery (through the skin) is used to administer therapeutic agents for hormone replacement. Transdermal replacement therapy with a testosterone patch is becoming the most common method of treatment for testosterone deficiency in adults. It establishes and maintains adequate serum levels without causing significant side effects in as many as 92% of men treated. A patch is worn, either on the scrotum or elsewhere on the body, and testosterone is released through the skin at controlled intervals. Patches, like Testoderm (scrotal) or Androderm (nonscrotal), contain natural testosterone and are typically worn for 12 or 24 hours and can be worn during exercise, bathing, and strenuous activity. It delivers about 4-6mg of testosterone daily and is applied to the shaved scrotum. Androderm is a very similar preparation which can be applied anywhere. Patches are applied each morning and result in a surge of hormone within a few hours of application.
The most common side effects associated with transdermal patch therapy include itching, discomfort, and irritation at the site of application. Some men may experience fluid retention, acne, and temporary gynecosmastia.
The results of a study showed that the application of a transdermal cream significantly increased free and total testosterone levels in men. As these testosterone levels persisted for up to 36 months in patients using a cream, the study shows that absorption continued, testosterone did not accumulate and levels remained stable. Creams typically come in 2, 5 and 10% concentrations or 10, 25 or 50mg/ml or gram. The cream dose for men is typically in the range of 25 to 50mg per day. Testosterone cream can also be used by women, but at a much lower dose, usually 1 - 2mg per day. A special caution for women: long term use of a cream has resulted in increased hair and hair darkening at the site of application.
Androgel is a transdermal gel that is applied once daily to the clean dry skin of the upper arms or abdomen. It delivers testosterone for 24 hours when used properly. The gel must be allowed to dry on the skin before dressing and must be applied at least 6 hours before showering or swimming. It cannot be applied to the genitals. Side effects may include adverse reaction at the site of application, acne, headache, and alopecia.
A recent study of hypogonadal men found that patients treated with Testim, a 1% testosterone topical gel marketed by Auxilium Pharmaceuticals, Inc., absorbed 30% more testosterone dose for dose than patients treated with AndroGel. [Biopharmaceutics & Drug Disposition, April 2003 Volume 24, Issue 3; pp. 115-120)]
Intramuscular injection is used less frequently because it is associated with erratic testosterone levels. Levels that get too high and then drop too low before the next dose may cause fluctuating moods, energy levels, and libido.
Children and adolescents with low testosterone and delayed puberty may be treated with low doses of testosterone by this method to induce puberty. Adolescents may receive gradually increasing doses that last longer in the body, because, with age, there is less risk for affecting normal growth patterns.
Oral testosterone (methyltestosterone, Testred - pills) is prescribed sparingly, because it is associated with liver toxicity and liver tumors.
Testosterone and testosterone analogues have long been used in the athletic community for improving lean muscle tissue and strength. Although this action of testosterone was denied over the years, the scientific proof of the link between testosterone and muscle was shown in 1996. Since that time there has been a virtual explosion in the use of testosterone and testosterone analogues.
In individuals with normal levels of testosterone, the use of testosterone will result in a decrease and possible cessation in the body's production of GnRH, LH and testosterone. After an individual stops or halts the use of testosterone, or other androgen, the body does not immediately resume the production of these hormones. A period of androgen induced hypogonadism, begins of an unknown duration and severity. This period is related and proportional to the type, dose and duration of the androgen(s) used during treatment. For the individual beginning testosterone treatment with normal levels the period after androgen cessation deserves important consideration.
While some research suggests that the hormonal axis will spontaneously return to normal shortly after cessation of testosterone administration, birth control studies utilizing testosterone have taken over 6 months for HPGA normalization. Testosterone therapy, once begun, may become a life-long commitment. In the individual who has mild or moderate benign prostatic hyperplasia or latent prostate cancer, androgen treatment may be potentially problematic.