When females have a higher baseline level of testosterone, they have higher increases in sexual arousal levels but smaller increases in testosterone, indicating a ceiling effect on testosterone levels in females. Sexual thoughts also change the level of testosterone but not level of cortisol in the female body, and hormonal contraceptives may affect the variation in testosterone response to sexual thoughts.[51]
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Men's levels of testosterone, a hormone known to affect men's mating behaviour, changes depending on whether they are exposed to an ovulating or nonovulating woman's body odour. Men who are exposed to scents of ovulating women maintained a stable testosterone level that was higher than the testosterone level of men exposed to nonovulation cues. Testosterone levels and sexual arousal in men are heavily aware of hormone cycles in females.[46] This may be linked to the ovulatory shift hypothesis,[47] where males are adapted to respond to the ovulation cycles of females by sensing when they are most fertile and whereby females look for preferred male mates when they are the most fertile; both actions may be driven by hormones.
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. 
Dr. Ronald Swerdloff, chief of the endocrinology division at the Harbor-UCLA Medical Center and a professor of medicine at UCLA's David Geffen School of Medicine, served on the panel of experts who developed the Endocrine Society's guidelines. He is also the principal investigator for one of the 12 sites of The Testosterone Trial in Older Men, a nationwide study funded mainly by the National Institute on Aging. The study of 800 men over age 65 with low testosterone is looking at whether men using AndroGel for one year, compared to placebo, will show improvements in walking speed, sexual activity, vitality, memory, and anemia. The study will be completed in June 2015.

In a prospective, multicenter, single-armed study of ED patients who exhibited a suboptimal response to PDE5 inhibitors, the investigators found that percutaneous implantation of zotarolimus-eluting stents in focal atherosclerotic lesions was both safe and feasible and was associated with clinically meaningful improvement on subjective and objective measures of erectile function. [3]
A number of research groups have tried to further define the relationship of testosterone and body composition by artificial alteration of testosterone levels in eugonadal populations. Induction of a hypogonadal state in healthy men (Mauras et al 1998) or men with prostate cancer (Smith et al 2001) using a gonadotrophin-releasing-hormone (GnRH) analogue was shown to produce increases in fat mass and decreased fat free mass. Another experimental approach in healthy men featured suppression of endogenous testosterone production with a GnRH analogue, followed by treatment with different doses of weekly intramuscular testosterone esters for 20 weeks. Initially the experiments involved men aged 18–35 years (Bhasin et al 2001) but subsequently the study was repeated with a similar protocol in men aged 60–75 years (Bhasin et al 2005). The different doses given were shown to produce a range of serum concentrations from subphysiological to supraphysiological (Bhasin et al 2001). A given testosterone dose produced higher serum concentrations of testosterone in the older age group (Bhasin et al 2005). Subphysiological dosing of testosterone produced a gain in fat mass and loss of fat free mass during the study. There were sequential decreases in fat mass and increases in fat free mass with each increase of testosterone dose. These changes in body composition were seen in physiological and supraphysiological treatment doses. The trend was similar in younger versus older men but the gain of fat mass at the lowest testosterone dose was less prominent in older patients (Bhasin et al 2001; Bhasin et al 2005). With regard to muscle function, the investigators showed dose dependent increases in leg strength and power with testosterone treatment in young and older men but there was no improvement in fatigability (Storer et al 2003; Bhasin et al 2005).
The hypogonadal-obesity-adipocytokine cycle hypothesis. Adipose tissue contains the enzyme aromatase which metabolises testosterone to oestrogen. This results in reduced testosterone levels, which increase the action of lipoprotein lipase and increase fat mass, thus increasing aromatisation of testosterone and completing the cycle. Visceral fat also promotes lower testosterone levels by reducing pituitary LH pulse amplitude via leptin and/or other factors. In vitro studies have shown that leptin also inhibits testosterone production directly at the testes. Visceral adiposity could also provide the link between testosterone and insulin resistance (Jones 2007).
Do erectile dysfunction exercises help? Many people have erectile dysfunction (ED), but it is often possible to reverse this with exercises to strengthen muscles in the area. These include pelvic floor exercises. ED can often be due to lifestyle factors including obesity and low physical activity levels. Learn more about exercises for ED here. Read now
It is hard to know how many men among us have TD, although data suggest that overall about 2.1% (about 2 men in every 100) may have TD. As few as 1% of younger men may have TD, while as many as 50% of men over 80 years old may have TD. People who study the condition often use different cut-off points for the numbers, so you may hear different numbers being stated.
Low testosterone levels can cause mood disturbances, increased body fat, loss of muscle tone, inadequate erections and poor sexual performance, osteoporosis, difficulty with concentration, memory loss and sleep difficulties. Current research suggests that this effect occurs in only a minority (about 2%) of ageing men. However, there is a lot of research currently in progress to find out more about the effects of testosterone in older men and also whether the use of testosterone replacement therapy would have any benefits.
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The availability of phosphodiesterase-5 (PDE5) inhibitors—sildenafil, vardenafil, tadalafil, and avanafil—has fundamentally altered the medical management of ED. In addition, direct-to-consumer marketing of these agents over the last 15 years has increased the general public’s awareness of ED as a medical condition with underlying causes and effective treatments.
Erectile dysfunction (ED) is the inability to get an erection or to keep one that's firm enough or that lasts long enough for a man to have a satisfying sexual experience. Occasional bouts of ED aren't unusual. In fact, as many as one in five men deal with erectile dysfunction to some degree. Symptoms, of course, are rather obvious. And while age can be a risk factor, so can medication use, health conditions, lifestyle factors (like smoking), and other concerns. Treatment is available and may involve prescriptions, habit changes, or other options.
A vacuum erection device is a plastic tube that slips over the penis, making a seal with the skin of the body. A pump at the other end of the tube makes a low-pressure vacuum around the erectile tissue, which results in an erection. An elastic ring is then slipped onto the base of the penis. This holds the blood in the penis (and keeps it hard) for up to 30 minutes. With proper training, 75 out of 100 men can get a working erection using a vacuum erection device.
The hypogonadal-obesity-adipocytokine cycle hypothesis. Adipose tissue contains the enzyme aromatase which metabolises testosterone to oestrogen. This results in reduced testosterone levels, which increase the action of lipoprotein lipase and increase fat mass, thus increasing aromatisation of testosterone and completing the cycle. Visceral fat also promotes lower testosterone levels by reducing pituitary LH pulse amplitude via leptin and/or other factors. In vitro studies have shown that leptin also inhibits testosterone production directly at the testes. Visceral adiposity could also provide the link between testosterone and insulin resistance (Jones 2007).

ED usually has something physical behind it, particularly in older men. But psychological factors can be a factor in many cases of ED. Experts say stress, depression, poor self-esteem, and performance anxiety can short-circuit the process that leads to an erection. These factors can also make the problem worse in men whose ED stems from something physical.
The most common treatment for erectile dysfunction is drugs known as phosphodiesterase-5 (PDE-5) inhibitors. These include tadalafil (Cialis), vardenafil (Levitra), and sildenafil citrate (Viagra). These are effective for about 75% of men with erectile dysfunction. They are tablets that are taken around an hour before sex, and last between 4 and 36 hours. Sexual stimulation is required before an erection will occur. The PDE-5 inhibitors cause dilation of blood vessels in the penis to allow erection to occur, and help it to stay rigid. Men using nitrate medication (e.g. GTN spray or sublingual tablets for angina) should not use PDE-5 inhibitors.
When you become aroused, your brain sends chemical messages to the blood vessels in the penis, causing them to dilate or open, allowing blood to flow into the penis. As the pressure builds, the blood becomes trapped in the corpora cavernosa, keeping the penis erect. If blood flow to the penis is insufficient or if it fails to stay inside the penis, it can lead to erectile dysfunction.
Testosterone is only one of many factors that influence aggression and the effects of previous experience and environmental stimuli have been found to correlate more strongly. A few studies indicate that the testosterone derivative estradiol (one form of estrogen) might play an important role in male aggression.[66][67][68][69] Studies have also found that testosterone facilitates aggression by modulating vasopressin receptors in the hypothalamus.[70]
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:

Erectile dysfunction (ED) is commonly called impotence. It’s a condition in which a man can’t achieve or maintain an erection during sexual performance. Symptoms may also include reduced sexual desire or libido. Your doctor is likely to diagnose you with ED if the condition lasts for more than a few weeks or months. ED affects as many as 30 million men in the United States.

Alprostadil is injected into the side of penis with a very fine needle. It's of great value to have the first shot in the doctor's office before doing this on your own. Self-injection lessons should be given in your doctor's office by an experienced professional. The success rate for getting an erection firm enough to have sex is as high as 85% with this treatment. Many men who do not respond to oral PDE5 inhibitors can be ‘rescued' with ICI.

Male hypogonadism is a clinical syndrome caused by a lack of androgens or their action. Causes of hypogonadism may reflect abnormalities of the hypothalamus, pituitary, testes or target tissues. Increases in the amount of testosterone converted to estrogen under the action of the enzyme aromatase may also contribute to hypogonadism. Most aspects of the clinical syndrome are unrelated to the location of the cause. A greater factor in the production of a clinical syndrome is the age of onset. The development of hypogonadism with aging is known as late-onset hypogonadism and is characterised by loss of vitality, fatigue, loss of libido, erectile dysfunction, somnolence, depression and poor concentration. Hypogonadal ageing men also gain fat mass and lose bone mass, muscle mass and strength.

The physical side effects of chemotherapy are usually temporary and resolve within one to two weeks after stopping the chemotherapy. However, chemotherapy agents, such as Ciplatin or Vincristine, may interfere with the nerves that control erection leading to possible impotence. Make sure you discuss potential side effects of cancer chemotherapy with your doctor or healthcare provider. 

Erectile dysfunction in older men. Because erections primarily involve the blood vessels, it is not surprising that the most common causes in older men are conditions that block blood flow to the penis, such as atherosclerosis or diabetes. Another vascular cause may be a faulty vein, which lets blood drain too quickly from the penis. Other physical disorders, as well as hormonal imbalances and certain operations, may also result in erectile dysfunction.
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).
Some anti-aging physicians also use sublingual ( taken under the tongue) forms of non-bioidentical testosterone like oxandrolone. I took oxandrolone with a physician’s guidance for about two weeks, and I got pimples and hair loss. I quit and was bummed that it didn’t generate enough impact to write a blog post about it. I have continued to recommend bioidentical testosterone since.
There are relatively few contraindications to the use of vacuum devices. Some conditions can predispose to priapism or perhaps bleeding with constriction, such as sickle cell disease, polycythemia, and other blood dyscrasias. Patients taking anticoagulants can safely use vacuum constriction devices but need to accept a higher risk of bleeding (ecchymosis). Good manual dexterity is also needed to use the device; if manual dexterity is impaired, a willing sexual partner can learn to apply the device.

In accordance with sperm competition theory, testosterone levels are shown to increase as a response to previously neutral stimuli when conditioned to become sexual in male rats.[40] This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction.

Studies of the effects on cognition of testosterone treatment in non-cognitively impaired eugonadal and hypogonadal ageing males have shown varying results, with some showing beneficial effects on spatial cognition (Janowsky et al 1994; Cherrier et al 2001), verbal memory (Cherrier et al 2001) and working memory (Janowsky et al 2000), and others showing no effects (Sih et al 1997; Kenny et al 2002). Other trials have examined the effects of testosterone treatment in older men with Alzheimer’s disease or cognitive decline. Results have been promising, with two studies showing beneficial effects of testosterone treatment on spatial and verbal memory (Cherrier et al 2005b) and cognitive assessments including visual-spatial memory (Tan and Pu 2003), and a recent randomized controlled trial comparing placebo versus testosterone versus testosterone and an aromatase inhibitor suggesting that testosterone treatment improves spatial memory directly and verbal memory after conversion to estrogen (Cherrier et al 2005a). Not all studies have shown positive results (Kenny et al 2004; Lu et al 2005), and variations could be due to the different measures of cognitive abilities that were used and the cognitive state of men at baseline. The data from clinical trials offers evidence that testosterone may be beneficial for certain elements of cognitive function in the aging male with or without cognitive decline. Larger studies are needed to confirm and clarify these effects.
Erectile dysfunction is known to be associated with general health status, thus, lifestyle modification improves erectile function and decreases the rate of decline of function with aging. One year after discontinuation of smoking, patients were found to have a 25% improvement in erectile quality.16 In addition, multivariate analysis found obesity is associated with erectile dysfunction with an approximately 50% increase in ED in obese men as compared with normal weight men.17
Dr. Adriane Fugh-Berman, associate professor of pharmacology and director of the industry watchdog group PharmedOut.org at Georgetown University School of Medicine, calls this kind of direct-to-consumer pharmaceutical advertising "evil." She likened the efforts to sell TRT to earlier campaigns to push hormone replacement therapy for post-menopausal women. "They stole the playbook," she said. "This hormone is being thrown around like sugar water."
In rare cases, the drug Viagra ® can cause blue-green shading to vision that lasts for a short time. In rare cases, the drug Cialis® can cause or increase back pain or aching muscles in the back. In most cases, the side effects are linked to PDE5 inhibitor effects on other tissues in the body, meaning they are working to increase blood flow to your penis and at the same time impacting other vascular tissues in your body. These are not ‘allergic reactions'.
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.
The association between low testosterone and ED is not entirely clear. Although these 2 processes certainly overlap in some instances, they are distinct entities. Some 2-21% of men have both hypogonadism and ED; however, it is unclear to what degree treating the former will improve erectile function. [17] About 35-40% of men with low testosterone see an improvement in their erections with testosterone replacement; however, almost 65% of these men see no improvement. [15]
Overall, few patients have a compelling contraindication to testosterone treatment. The majority of men with late onset hypogonadism can be safely treated with testosterone but all will require monitoring of prostate parameters HDL cholesterol, hematocrit and psychological state. It is also wise to monitor symptoms of sleep apnea. Other specific concerns may be raised by the mode of delivery such as local side effects from transdermal testosterone.

Studies have demonstrated reduced testosterone levels in men with heart failure as well as other endocrine changes (Tappler and Katz 1979; Kontoleon et al 2003). Treatment of cardiac failure with chronic mechanical circulatory support normalizes many of these changes, including testosterone levels (Noirhomme et al 1999). More recently, two double-blind randomized controlled trials of testosterone treatment for men with low or low-normal serum testosterone levels and heart failure have shown improvements in exercise capacity and symptoms (Pugh et al 2004; Malkin et al 2006). The mechanism of these benefits is currently unclear, although a study of the acute effects of buccal testosterone given to men with chronic cardiac failure under invasive monitoring showed that testosterone increased cardiac index and reduced systemic vascular resistance (Pugh et al 2003). Testosterone may prove useful in the management of cardiac failure but further research is needed.
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Cross-sectional studies have found a positive association between serum testosterone and some measures of cognitive ability in men (Barrett-Connor, Goodman-Gruen et al 1999; Yaffe et al 2002). Longitudinal studies have found that free testosterone levels correlate positively with future cognitive abilities and reduced rate of cognitive decline (Moffat et al 2002) and that, compared with controls, testosterone levels are reduced in men with Alzheimer’s disease at least 10 years prior to diagnosis (Moffat et al 2004). Studies of the effects of induced androgen deficiency in patients with prostate cancer have shown that profoundly lowering testosterone leads to worsening cognitive functions (Almeida et al 2004; Salminen et al 2004) and increased levels of serum amyloid (Gandy et al 2001; Almeida et al 2004), which is central to the pathogenesis of Alzheimer’s disease (Parihar and Hemnani 2004). Furthermore, testosterone reduces amyloid-induced hippocampal neurotoxity in vitro (Pike 2001) as well as exhibiting other neuroprotective effects (Pouliot et al 1996). The epidemiological and experimental data propose a potential role of testosterone in protecting cognitive function and preventing Alzheimer’s disease.
ICI therapy often produces a reliable erection, which comes down after 20-30 minutes or with climax. Since the ICI erection is not regulated by your penile nerves, you should not be surprised if the erection lasts after orgasm. The most common side effect of ICI therapy is a prolonged erection. Prolonged erections (>1 hour) can be reversed by a second injection (antidote) in the office.
Obesity and metabolic syndrome can cause changes in blood pressure, body composition, and cholesterol which may lead to ED. Other conditions that may contribute to erectile dysfunction include Parkinson’s, multiple sclerosis, Peyronie’s disease, sleep disorders, alcoholism, and drug abuse. Taking certain medications can also increase your risk for ED.
When you become aroused, your brain sends chemical messages to the blood vessels in the penis, causing them to dilate or open, allowing blood to flow into the penis. As the pressure builds, the blood becomes trapped in the corpora cavernosa, keeping the penis erect. If blood flow to the penis is insufficient or if it fails to stay inside the penis, it can lead to erectile dysfunction.
The Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) study, designed to determine whether an individual man’s sexual outcomes after most common treatments for early-stage prostate cancer could be accurately predicted on the basis of baseline characteristics and treatment plans, found that 2 years after treatment, 177 (35%) of 511 men who underwent prostatectomy reported the ability to attain functional erections suitable for intercourse. [45]
"By expanding the boundaries of this disease to common symptoms in aging males, such as fatigue and reduced libido, drug companies seek to increase their markets and boost their sales," wrote Barbara Mintzes, an assistant professor at the University of British Columbia School of Public Health, and Agnes Vitry, a senior research fellow at the University of South Australia, in a 2012 article in the Medical Journal of Australia .
The other interesting thing about the study: men’s testosterone levels were lowest in March (at the end of winter) and highest in August (at the end of summer). Sunlight affects your vitamin D production, so you have seasonal dips and peaks. Get a blood test to check your levels, and if you’re low, take a high-quality vitamin D3 supplement. If you’re going to take D3, take vitamin K2 and vitamin A with it. The three work in sync, so you want them all to be balanced. Here are my dosage recommendations.
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