All About The Penis, Men & Male Sexuality

Hypogonadism & abnormal development of the penis and testicles

Index/Home Page

Hypogonadism is defined as inadequate testicular function, with deficiencies in sperm production or hormone (i.e. testosterone) production. Obviously this can have major effects on the development of the penis and male body shape. The notes on this page are taken from the American Association of Clinical Endocrinologists Hypogonadism Guidelines.

The symptoms chiefly depend on the age at which hypogonadism manifests. When it develops before puberty, and if it is not corrected by hormone supplementation, the symptoms include small testes, an underdeveloped penis and prostate, scant body and pubic hair, reduced male muscle mass, and a lack of a deep male voice.

Loss of testicular function after puberty results in slowly evolving changes including gradually reducing muscle mass, loss of libido, impotence, lack of sperm production, hot flushes and lack of ability to concentrate. Symptoms also include osteoporosis in later life, sexual dysfunction, fatigue and mood disturbances. 

Primary testicular failure is usually associated with genetic syndromes like Klinefelter's syndrome, or with damage to the testes as a result of mumps, surgery, testicular trauma, radiation therapy or chemotherapy, or testicular torsion. When the failure of the testes is secondary (i.e., post-puberty), there may be hypothalamic or pituitary disease, and occasionally a brain tumor. However, before any man with a decreased libido in mid-life starts to panic about the state of his brain, he should read two definitive  works on the subject: Maximizing Manhood by Dr Malcolm Carruthers and The Testosterone Syndrome by Eugene Shippen.

In a first consultation, the physician will first conduct a physical examination: the amount of body hair, beard growth, armpit hair, pubic hair (and its shape) can all be indicators of the degree of masculinization of a man's body, and therefore of the amount of testosterone flowing around his body. A measurement of the testicles and their hardness or softness can be helpful in determining the degree of development: an adult man's testicles are generally between 4.5 and 6.5 cm long and 2.8 and 3.3 cm wide. Penis size is less helpful in determining the degree of masculinization, since it is so variable in adult men.

Testosterone levels are another good indicator of hypogonadism, although the measurements need to be taken carefully, because much of the testosterone in the blood stream is not biologically available - it is bound tightly to a protein called sex hormone binding globulin (SHBG). What is important is the free testosterone level in the blood. If a man has a low free testosterone level, then the next step is to measure the level of hormones from his pituitary gland, since these hormones are responsible for prompting testicular activity. If they are abnormally low, then the problem may lie in the pituitary gland or the hypothalamus rather than the testes.

Other tests which may be conducted include semen analysis, to check for the presence of sperm, and bone densitometry - testosterone plays a major role in maintaining bone density in men, just as estrogen does in women. Pituitary imaging studies may be used to reveal any brain dysfunction, and genetic studies will rule out or demonstrate any genetic variations which maybe responsible for a man's low testosterone levels. 

The two most common genetic variations are Klinefelter's syndrome and 47,XYY syndrome, both of which can result in men of greater or lesser masculinity and a range of associated variation in appearance and sexual development. 

Other physiological causes of a lack of sexual development include insensitivity to testosterone in the tissues of a man. The effects of testosterone insensitivity vary, as you would expect, with the degree of insensitivity. The mildest example is seen in some cases of hypospadias, where the penis is slightly abnormal. The most extreme case is a condition known as testicular feminization, where a complete absence of testosterone receptors in a baby's tissues means that the genetically male baby grows up as a female, though lacking a functional vagina (medical treatments can help in forming a vagina by stretching the vaginal opening into a full size vagina). There is much more information on testicular feminization at

Of course, most men with a low testosterone level will not have anything as dramatic as a genetic defect. Often the problem is simply the result of the normal ageing process, though, as I have observed elsewhere on this site, the idea of a male andropause (equivalent to the female menopause) remains somewhat controversial. However, the AACE state: "Growing evidence indicates that some ageing men have reduced production of testosterone associated with decreased libido, impotence, decreased growth of body hair, decreased muscle mass, fatigue, increased risk of myocardial infarction, and decreased bone mass..." They go on to say that recent evidence suggests that many of these symptoms can be age related and will respond well to testosterone replacement therapy. 

The goals of testosterone replacement therapy are to: restore sexual function; reduce mood disturbances; restore erectile capacity in the penis; decrease anger and fatigue; improve mental functioning; maintain virilization; prevent or reverse bone demineralization; and reduce the risk of cardiovascular disease. 

Testosterone replacement may be offered by long or short lasting preparations injected into the muscle of the buttock or thigh, scrotal patches, skin patches, transdermal gel or cream, oral preparations, and pellets of crystalline testosterone implanted under the skin. All have their advantages and disadvantages, which will depend to some extent on the man receiving the treatment, his lifestyle, and his particular physiology. In some cases, treatment with pituitary hormones to stimulate the action of the testes is an alternative option.


Other pages of penis problems

My penis is too large / too small
My foreskin is too tight
Problems with arousal
I can't get an erection
Urethral opening abnormal
Torn frenulum - breve
My penis is twisted
Erectile dysfunction
Penis problems solved!
Andropause & mid-life crisis
Penile problems & injuries
Yeast Infections
Sex addiction & obsession
Sexually transmitted infections
Testosterone declines with age

Other sections on the site

The penis, masculinity and sex
A Cultural History Of The Penis
Penile & Other Problems