The Latin term impotentia coeundi describes simple inability to insert the penis into the vagina; it is now mostly replaced by more precise terms, such as erectile dysfunction (ED). The study of ED within medicine is covered by andrology, a sub-field within urology. Research indicates that ED is common, and it is suggested that approximately 40% of males experience symptoms compatible with ED, at least occasionally.[38] The condition is also on occasion called phallic impotence.[39] Its antonym, or opposite condition, is priapism.[40][41]

Hypogonadism (as well as age-related low testosterone) is diagnosed with blood tests that measure the level of testosterone in the body. The Endocrine Society recommends testing for suspected low T with a total testosterone test. It may be performed in the morning when testosterone levels tend to be highest in young men, although this isn't necessarily the case in older men. The test may be repeated on another day if the results show a low T level. (5)
During the second trimester, androgen level is associated with sex formation.[13] This period affects the femininization or masculinization of the fetus and can be a better predictor of feminine or masculine behaviours such as sex typed behaviour than an adult's own levels. A mother's testosterone level during pregnancy is correlated with her daughter's sex-typical behavior as an adult, and the correlation is even stronger than with the daughter's own adult testosterone level.[14]
Attention, memory, and spatial ability are key cognitive functions affected by testosterone in humans. Preliminary evidence suggests that low testosterone levels may be a risk factor for cognitive decline and possibly for dementia of the Alzheimer's type,[100][101][102][103] a key argument in life extension medicine for the use of testosterone in anti-aging therapies. Much of the literature, however, suggests a curvilinear or even quadratic relationship between spatial performance and circulating testosterone,[104] where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition.
Topical testosterone, specifically gels, creams and liquids, may transfer to others. Women and children are most at risk of harmful effects from contact with them. You should take care to cover the area and wash your hands well after putting on the medication. Be careful not to let the site with the topical TT touch others because that could transfer the drug.

Epidemiological evidence supports a link between testosterone and glucose metabolism. Studies in non-diabetic men have found an inverse correlation of total or free testosterone with glucose and insulin levels (Simon et al 1992; Haffner et al 1994) and studies show lower testosterone levels in patients with the metabolic syndrome (Laaksonen et al 2003; Muller et al 2005; Kupelian et al 2006) or diabetes (Barrett-Connor 1992; Andersson et al 1994; Rhoden et al 2005). A study of patients with type 2 diabetes using measurement of serum free testosterone by the gold standard method of equilibrium dialysis, found a 33% prevalence of biochemical hypogonadism (Dhindsa et al 2004). The Barnsley study demonstrated a high prevalence of clinical and biochemical hypogonadism with 19% having total testosterone levels below 8 nmol/l and a further 25% between 8–12 nmol/l (Kapoor, Aldred et al 2007). There are also a number longitudinal studies linking low serum testosterone levels to the future development of the metabolic syndrome (Laaksonen et al 2004) or type 2 diabetes (Haffner et al 1996; Tibblin et al 1996; Stellato et al 2000; Oh et al 2002; Laaksonen et al 2004), indicating a possible role of hypogonadism in the pathogenesis of type 2 diabetes in men. Alternatively, it has been postulated that obesity may be the common link between low testosterone levels and insulin resistance, diabetes and cardiovascular disease (Phillips et al 2003; Kapoor et al 2005). With regard to this hypothesis, study findings vary as to whether the association of testosterone with diabetes occurs independently of obesity (Haffner et al 1996; Laaksonen et al 2003; Rhoden et al 2005).


Capogrosso, P., Colicchia, M., Ventimiglia, E., Castagna, G., Clementi, M. C., Suardi, N., ... Salonia, A. (2013, July). One patient out of four with newly diagnosed erectile dysfunction is a young man — worrisome picture from the everyday clinical practice. The journal of sexual medicine. 10(7), 1833–1841. Retrieved from https://onlinelibrary.wiley.com/doi/full/10.1111/jsm.12179
It may also become a treatment for anemia, bone density and strength problems. In a 2017 study published in the journal of the American Medical Association (JAMA), testosterone treatments corrected anemia in older men with low testosterone levels better than a placebo. Another 2017 study published in JAMA found that older men with low testosterone had increased bone strength and density after treatment when compared with a placebo. 
The aim of treatment for hypogonadism is to normalize serum testosterone levels and abolish symptoms or pathological states that are due to low testosterone levels. The exact target testosterone level is a matter of debate, but current recommendations advocate levels in the mid-lower normal adult range (Nieschlag et al 2005). Truly physiological testosterone replacement would require replication of the diurnal rhythm of serum testosterone levels, but there is no current evidence that this is beneficial (Nieschlag et al 2005).
Capogrosso, P., Colicchia, M., Ventimiglia, E., Castagna, G., Clementi, M. C., Suardi, N., ... Salonia, A. (2013, July). One patient out of four with newly diagnosed erectile dysfunction is a young man — worrisome picture from the everyday clinical practice. The journal of sexual medicine. 10(7), 1833–1841. Retrieved from https://onlinelibrary.wiley.com/doi/full/10.1111/jsm.12179

The nerves and endothelium of sinusoids and vessels in the penis produce and release transmitters and modulators that control the contractile state of corporal smooth muscles. Although the membrane receptors play an important role, downstream signaling pathways are also important. The RhoA–Rho kinase pathway is involved in the regulation of cavernosal smooth muscle contraction. [12]
Vascular damage may result from radiation therapy to the pelvis and prostate in the treatment of prostate cancer. [36] Both the blood vessels and the nerves to the penis may be affected. Radiation damage to the crura of the penis, which are highly susceptible to radiation damage, can induce ED. Data indicate that 50% of men undergoing radiation therapy lose erectile function within 5 years after completing therapy; fortunately, some respond to one of the PDE5 inhibitors.
Stanley A Brosman, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Pediatrics, American Association for the Advancement of Science, American Association for Cancer Research, American College of Surgeons, American Medical Association, American Urological Association, Society for Basic Urologic Research, Society of Surgical Oncology, Society of Urologic Oncology, Western Section of the American Urological Association, Association of Clinical Research Professionals, American Society of Clinical Oncology, International Society of Urology, International Society of Urological Pathology

In the short term, alcohol relaxes muscles in the penis, letting blood to flow in (which is a good thing). However, alcohol also prevents other blood vessels from closing and trapping all the extra blood. Erections depend on trapping increased blood flow in the erectile tissue of the penis. If you don’t trap that extra blood, you don’t get an erection. In the long run, excessive alcohol consumption can cause liver scarring, high blood pressure, and can damage your blood vessels resulting in erectile dysfunction.


However, testosterone is only one of many factors that aid in adequate erections. Research is inconclusive regarding the role of testosterone replacement in the treatment of erectile dysfunction. In a review of studies that looked at the benefit of testosterone in men with erection difficulties, nearly half showed no improvement with testosterone treatment. Many times, other health problems play a role in erectile difficulties. These can include:
A team led by Dr. Joel Finkelstein at Massachusetts General Hospital investigated testosterone and estradiol levels in 400 healthy men, 20 to 50 years of age. To control hormone levels, the researchers first gave the participants injections of a drug that suppressed their normal testosterone and estradiol production. The men were randomly assigned to 5 groups that received different amounts (from 0 to 10 grams) of a topical 1% testosterone gel daily for 16 weeks. Half of the participants were also given a drug to block testosterone from being converted to estradiol.
Rest and recovery is just as important as exercise, if not more so. Every time you do an intense workout, give yourself a minimum of 2 days to recuperate afterward, if not more. And don’t mix exercise with sleep hacking. If you’re exercising, get at least 8 hours of sleep every night. Your body uses it to rebuild, and you can throw your hormones out of whack if you don’t rest up properly. Here’s a more in-depth guide to Bulletproof weight training, complete with sample workouts.
Most men may not openly talk about their erection problems, but erectile dysfunction — when a man cannot achieve or maintain an erection well enough or long enough to have satisfying sex — is very common. According to the National Institutes of Health, 5 percent of 40-year-olds and 15 to 25 percent of 65-years old have ED. But while ED is more likely to occur as a man gets older, it doesn’t come automatically with age.
Miscellaneous: Sleep: (REM sleep) increases nocturnal testosterone levels.[138] Behavior: Dominance challenges can, in some cases, stimulate increased testosterone release in men.[139] Drugs: Natural or man-made antiandrogens including spearmint tea reduce testosterone levels.[140][141][142] Licorice can decrease the production of testosterone and this effect is greater in females.[143]
The dorsal artery provides for engorgement of the glans during erection, whereas the bulbourethral artery supplies the bulb and the corpus spongiosum. The cavernous artery effects tumescence of the corpus cavernosum and thus is principally responsible for erection. The cavernous artery gives off many helicine arteries, which supply the trabecular erectile tissue and the sinusoids. These helicine arteries are contracted and tortuous in the flaccid state and become dilated and straight during erection. [9]
Many experts believe that atrophy, a partial or complete wasting away of tissue, and fibrosis, the growth of excess tissue, of the smooth muscle tissue in the body of the penis (cavernous smooth muscle) triggers problems with being able to maintain a firm erection. Poor ability to maintain an erection is often an early symptom of erectile dysfunction. Although the condition is called venous leak, the real problem is not with the veins but malfunction of the smooth muscle that surrounds the veins. The end result is difficulty with maintain a firm erection (losing an erection too quickly) that is now believe to be an early manifestation of atherosclerosis and vascular disease.

The Massachusetts Male Aging Study (MMAS) documented an inverse correlation between ED risk and high-density lipoprotein (HDL) cholesterol levels but did not identify any effect from elevated total cholesterol levels. [15] Another study involving male subjects aged 45-54 years found a correlation with abnormal HDL cholesterol levels but also found a correlation with elevated total cholesterol levels. The MMAS included a preponderance of older men.
The mechanism of age related decreases in serum testosterone levels has also been the subject of investigation. Metabolic clearance declines with age but this effect is less pronounced than a reduction in testosterone production, so the overall effect is to reduce serum testosterone levels. Gonadotrophin levels rise during aging (Feldman et al 2002) and testicular secretory responses to recombinant human chorionic gonadotrophin (hCG) are reduced (Mulligan et al 1999, 2001). This implies that the reduced production may be caused by primary testicular failure but in fact these changes are not adequate to fully explain the fall in testosterone levels. There are changes in the lutenising hormone (LH) production which consist of decreased LH pulse frequency and amplitude, (Veldhuis et al 1992; Pincus et al 1997) although pituitary production of LH in response to pharmacological stimulation with exogenous GnRH analogues is preserved (Mulligan et al 1999). It therefore seems likely that there are changes in endogenous production of GnRH which underlie the changes in LH secretion and have a role in the age related decline in testosterone. Thus the decreases in testosterone levels with aging seem to reflect changes at all levels of the hypothalamic-pituitary-testicular axis. With advancing age there is also a reduction in androgen receptor concentration in some target tissues and this may contribute to the clinical syndrome of LOH (Ono et al 1988; Gallon et al 1989).

When Solvay Pharmaceuticals, maker of market-dominating Androgel, launched its "Low T" campaign, in 2008, it claimed that 13 million American men over age 45 suffered from low testosterone, 90 percent of them undiagnosed. Its website, IsItLowT.com, showed dumpy, depressed men and their unhappy spouses remembering how it "used to be." Why settle for dumpiness and depression, the website and related TV ads suggested, when a little dab'll do you?
In order to discuss the biochemical diagnosis of hypogonadism it is necessary to outline the usual carriage of testosterone in the blood. Total serum testosterone consists of free testosterone (2%–3%), testosterone bound to sex hormone binding globulin (SHBG) (45%) and testosterone bound to other proteins (mainly albumin −50%) (Dunn et al 1981). Testosterone binds only loosely to albumin and so this testosterone as well as free testosterone is available to tissues and is termed bioavailable testosterone. Testosterone bound to SHBG is tightly bound and is biologically inactive. Bioavailable and free testosterone are known to correlate better than total testosterone with clinical sequelae of androgenization such as bone mineral density and muscle strength (Khosla et al 1998; Roy et al 2002). There is diurnal variation in serum testosterone levels with peak levels seen in the morning following sleep, which can be maintained into the seventh decade (Diver et al 2003). Samples should always be taken in the morning before 11 am to allow for standardization.
Between 10 and 88% of patients diagnosed with cancer experience sexual problems following diagnosis and treatment. The prevalence varies according to the location and type of cancer, and the treatment modalities used. Sexuality may be affected by chemotherapy, alterations in body image due to weight change, hair loss or surgical disfigurement, hormonal changes, and cancer treatments that directly affect the pelvic region.
Low testosterone levels may contribute to decreased sex drive, erectile dysfunction, fragile bones, and other health issues. Having low testosterone levels may also indicate an underlying medical condition. See your doctor if you suspect you have low testosterone. A simple blood test is all it takes to check if your testosterone falls within the normal range.
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