Important future developments will include selective androgen receptor modulators (SARMs). These drugs will be able to produce isolated effects of testosterone at androgen receptors. They are likely to become useful clinical drugs, but their initial worth may lie in facilitating research into the relative importance of testosterone’s action at the androgen receptor compared to at other sites or after conversion to other hormones. Testosterone will remain the treatment of choice for late onset hypogonadism for some time to come.
^ David KG, Dingemanse E, Freud JL (May 1935). "Über krystallinisches mannliches Hormon aus Hoden (Testosteron) wirksamer als aus harn oder aus Cholesterin bereitetes Androsteron" [On crystalline male hormone from testicles (testosterone) effective as from urine or from cholesterol]. Hoppe-Seyler's Z Physiol Chem (in German). 233 (5–6): 281–83. doi:10.1515/bchm2.1935.233.5-6.281.

The rise in testosterone levels during competition predicted aggression in males but not in females.[86] Subjects who interacted with hand guns and an experimental game showed rise in testosterone and aggression.[87] Natural selection might have evolved males to be more sensitive to competitive and status challenge situations and that the interacting roles of testosterone are the essential ingredient for aggressive behaviour in these situations.[88] Testosterone produces aggression by activating subcortical areas in the brain, which may also be inhibited or suppressed by social norms or familial situations while still manifesting in diverse intensities and ways through thoughts, anger, verbal aggression, competition, dominance and physical violence.[89] Testosterone mediates attraction to cruel and violent cues in men by promoting extended viewing of violent stimuli.[90] Testosterone specific structural brain characteristic can predict aggressive behaviour in individuals.[91]
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]
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]
Several treatments were promoted in the pre-PGE1, pre-prostaglandin era, including yohimbine, trazodone, testosterone, and various herbal remedies. None of these is currently recommended under the updated American Urological Association Guidelines for the Treatment of Erectile Dysfunction.15 Testosterone supplementation is only recommended for men with low testosterone levels.
Testosterone was first used as a clinical drug as early as 1937, but with little understanding of its mechanisms. The hormone is now widely prescribed to men whose bodies naturally produce low levels. But the levels at which testosterone deficiency become medically relevant still aren’t well understood. Normal testosterone production varies widely in men, so it’s difficult to know what levels have medical significance. The hormone’s mechanisms of action are also unclear.
Camacho EM1, Huhtaniemi IT, O'Neill TW, Finn JD, Pye SR, Lee DM, Tajar A, Bartfai G, Boonen S, Casanueva FF, Forti G, Giwercman A, Han TS, Kula K, Keevil B, Lean ME, Pendleton N, Punab M, Vanderschueren D, Wu FC; EMAS Group. “Age-associated changes in hypothalamic-pituitary-testicular function in middle-aged and older men are modified by weight change and lifestyle factors: longitudinal results from the European Male Ageing Study.” Eur J Endocrinol. 2013 Feb 20;168(3):445-55. doi: 10.1530/EJE-12-0890. Print 2013 Mar.

Acupuncture may help treat psychological ED, though studies are limited and inconclusive. You’ll likely need several appointments before you begin to notice any improvements. When choosing an acupuncturist, look for a certified practitioner who uses disposable needles and follows U.S. Food and Drug Administration guidelines for needle disposal and sterilization.
Erectile dysfunction can cause strain on a couple. Many times, men will avoid sexual situations due to the emotional pain associated with ED, causing their partner to feel rejected or inadequate. It is important to communicate openly with your partner. Some couples consider seeking treatment for ED together, while other men prefer to seek treatment without their partner's knowledge. A lack of communication is the primary barrier for seeking treatment and can prolong the suffering. The loss of erectile capacity can have a profound effect on a man. The good news is that ED can usually be treated safely and effectively.
“Although having sex at 70 is not the same as having sex at 20, erectile dysfunction is not a normal part of aging,” according to Michael Feloney, MD, urologic surgeon and expert on sexual dysfunction issues at the Nebraska Medical Center in Omaha. “You should still be able to have a satisfying sex life as you age." If you are experiencing erectile dysfunction, these 10 dos and don'ts may help.
"One of the reasons erectile dysfunction increases with age is that the diseases that lead to it also increase with age," notes Dr. Feloney. Evaluating the causes of erectile dysfunction starts with your doctor taking a good health history and giving you a physical exam. Common medical issues that can lead to erectile dysfunction include diabetes, high blood pressure, hardening of the arteries, low testosterone, and neurological disease. Talk to your doctor about better managing these health conditions.
Psychological Causes of ED – Between 10% and 20% of ED cases have a psychological cause. Because arousal starts in the brain, psychological issues can be a significant contributing factor to erectile dysfunction. Mental health conditions like depression or anxiety can negatively impact your libido, making it more difficult for you to become aroused.

What you need to know about STDs Sexually transmitted diseases (STDs) are infections that are passed on from one person to another through sexual contact. There are many STDs, including chlamydia, genital warts, syphilis, and trich. This article looks at some of the most common STDs, the symptoms, and how to avoid getting or passing an STD one on. Read now
Many clinical studies have looked at the effect of testosterone treatment on body composition in hypogonadal men or men with borderline low testosterone levels. Some of these studies specifically examine these changes in older men (Tenover 1992; Morley et al 1993; Urban et al 1995; Sih et al 1997; Snyder et al 1999; Kenny et al 2001; Ferrando et al 2002; Steidle et al 2003; Page et al 2005). The data from studies, on patients from all age groups, are consistent in showing an increase in fat free mass and decrease in fat mass or visceral adiposity with testosterone treatment. A recent meta-analysis of 16 randomized controlled trials of testosterone treatment effects on body composition confirms this pattern (Isidori et al 2005). There have been less consistent results with regard to the effects of testosterone treatment of muscle strength. Some studies have shown an increase in muscle strength (Ferrando et al 2002; Page et al 2005) with testosterone whilst others have not (Snyder et al 1999). Within the same trial some muscle group strengths may improve whilst others do not (Ly et al 2001). It is likely that the differences are partly due to the methodological variations in assessing strength, but it also possible that testosterone has different effects on the various muscle groups. The meta-analysis found trends toward significant improvements in dominant knee and hand grip strength only (Isidori et al 2005).
Testosterone is a sex hormone that plays important roles in the body. In men, it’s thought to regulate sex drive (libido), bone mass, fat distribution, muscle mass and strength, and the production of red blood cells and sperm. A small amount of circulating testosterone is converted to estradiol, a form of estrogen. As men age, they often make less testosterone, and so they produce less estradiol as well. Thus, changes often attributed to testosterone deficiency might be partly or entirely due to the accompanying decline in estradiol.
In some cases, ED can be a warning sign of more serious disease. One study suggests ED is a strong predictor of heart attack, stroke, and death from cardiovascular disease. The researchers say all men diagnosed with ED should be evaluated for cardiovascular disease. This does not mean every man with ED will develop heart disease, or that every man with heart disease has ED, but patients should be aware of the link.
One of the first steps is to distinguish between physiological and psychological ED. Determining whether involuntary erections are present is important in eliminating the possibility of psychogenic causes for ED.[1] Obtaining full erections occasionally, such as nocturnal penile tumescence when asleep (that is, when the mind and psychological issues, if any, are less present), tends to suggest that the physical structures are functionally working.[19][20] Similarly, performance with manual stimulation, as well as any performance anxiety or acute situational ED, may indicate a psychogenic component to ED.[1]
The FDA recommends that men follow general precautions before taking a medication for ED. Men who are taking medications that contain nitrates, such as nitroglycerin, should NOT use these medications. Taking nitrates with one of these medications can lower blood pressure too much. In addition, men who take tadalafil or vardenfil should use alpha blockers with care and only as instructed by their physician, as they could result in hypotension (abnormally low blood pressure). Experts recommend that men have a complete medical history and physical examination to determine the cause of ED. Men should tell their doctor about all the medications they are taking, including over-the-counter medications.

Hacking your testosterone influences everything from body composition to energy levels to mood. It’s easy to eat more butter; it’s hard to visit a doctor and get tested, but that’s what I recommend: know your levels. If you’re 25, you’ll know what your target is when you’re 35. By the time you’ve noticed symptoms of low testosterone, it’s too late to get your “normal” measurements!
Levels of testosterone naturally decrease with age, but exactly what level constitutes "low T," or hypogonadism, is controversial, Harvard Medical School said. Testosterone levels vary wildly, and can even differ depending on the time of day they're measured (levels tend to be lower in the evenings). The National Institutes of Health includes the following as possible symptoms of low testosterone:

The symptoms of erectile dysfunction include difficulty achieving an erection, trouble maintaining an erection, and a reduced interest in sex. Because male sexual arousal is a fairly complex process, it can sometimes be difficult to identify a specific cause. Arousal starts in the brain but it also involves the nerves, muscles, and blood vessels and can be impacted by hormones and emotions. If a problem develops with any of these things, erectile dysfunction could be the consequence.


The symptoms of erectile dysfunction include difficulty achieving an erection, trouble maintaining an erection, and a reduced interest in sex. Because male sexual arousal is a fairly complex process, it can sometimes be difficult to identify a specific cause. Arousal starts in the brain but it also involves the nerves, muscles, and blood vessels and can be impacted by hormones and emotions. If a problem develops with any of these things, erectile dysfunction could be the consequence.
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.
Although not proven, it is likely that erectile dysfunction can be prevented by good general health, paying particular attention to body weight, exercise, and cigarette smoking. For example, heart disease and diabetes are problems that can cause erectile dysfunction, and both are preventable through lifestyle changes such as sensible eating and regular exercise. Furthermore, early diagnosis and treatment of associated conditions like diabetes, hypertension and high cholesterol may prevent or delay erectile dysfunction, or stop the erectile dysfunction from getting more serious. 

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.
Vitamin D and zinc are both essential to testosterone production. A year-long study looked at the vitamin D and testosterone levels of 2299 men. It found that men with vitamin D levels above 30 nmol/L had more testosterone and lower levels of sex hormone-binding globulin (SHBG). SHBG binds to hormones so your cells can’t use them, and if you have too much of it, your testosterone levels drop [8]. Men with vitamin D deficiency had lower testosterone and higher SHBG levels.
The partial synthesis in the 1930s of abundant, potent testosterone esters permitted the characterization of the hormone's effects, so that Kochakian and Murlin (1936) were able to show that testosterone raised nitrogen retention (a mechanism central to anabolism) in the dog, after which Allan Kenyon's group[183] was able to demonstrate both anabolic and androgenic effects of testosterone propionate in eunuchoidal men, boys, and women. The period of the early 1930s to the 1950s has been called "The Golden Age of Steroid Chemistry",[184] and work during this period progressed quickly. Research in this golden age proved that this newly synthesized compound—testosterone—or rather family of compounds (for many derivatives were developed from 1940 to 1960), was a potent multiplier of muscle, strength, and well-being.[185]
The laboratory results should be discussed with the patient and, if possible, with his sexual partner. This educational process allows a review of the basic aspects of the anatomy and physiology of the sexual response and an explanation of the possible etiology and associated risk factors (eg, smoking and the use of various medications). Treatment options and their benefits and risks should be discussed. This type of dialogue allows the patient and physician to cooperate in developing an optimal management strategy.
Currently available testosterone preparations in common use include intramuscular injections, subcutaneous pellets, buccal tablets, transdermal gels and patches (see Table 2). Oral testosterone is not widely used. Unmodified testosterone taken orally is largely subject to first-pass metabolism by the liver. Oral doses 100 fold greater than physiological testosterone production can be given to achieve adequate serum levels. Methyl testosterone esters have been associated with hepatotoxicity. There has been some use of testosterone undecanoate, which is an esterified derivative of testosterone that is absorbed via the lymphatic system and bypasses the liver. Unfortunately, it produces unpredictable testosterone levels and increases testosterone levels for only a short period after each oral dose (Schurmeyer et al 1983).
^ Jump up to: a b Lazaridis I, Charalampopoulos I, Alexaki VI, Avlonitis N, Pediaditakis I, Efstathopoulos P, Calogeropoulou T, Castanas E, Gravanis A (2011). "Neurosteroid dehydroepiandrosterone interacts with nerve growth factor (NGF) receptors, preventing neuronal apoptosis". PLoS Biol. 9 (4): e1001051. doi:10.1371/journal.pbio.1001051. PMC 3082517. PMID 21541365.

Remember that each person is unique, and each body responds differently to treatment. TT may help erectile function, low sex drive, bone marrow density, anemia, lean body mass, and/or symptoms of depression. However, there is no strong evidence that TT will help memory recall, measures of diabetes, energy, tiredness, lipid profiles, or quality of life.


Side effects include lightheadedness, fainting, priapism, urethral bleeding (intraurethral), dyspareunia in the partner (intraurethral), hematoma (intracavernosal) or penile curvature secondary to scar (intracavernosal). Efficacy of intraurethral alprostadil has been demonstrated to be around 50% ("able to have intercourse") in randomized controlled trials.31,32 For intracorporeal injection, typically alprostadil is tried alone, or compounded with papaverine (nonspecific phosphodiesterase inhibitor that increases intracellular cyclic adenosine monophosphate and cGMP) and/or phentolamine (competitive, non-selective alpha1- and alpha2-adrenoreceptor blocker). Pinsky et al33 reported an extensive review of the benefits and drawbacks of the combinations of these drugs.

Trials of testosterone treatment in men with type 2 diabetes have also taken place. A recent randomized controlled crossover trial assessed the effects of intramuscular testosterone replacement to achieve levels within the physiological range, compared with placebo injections in 24 men with diabetes, hypogonadism and a mean age of 64 years (Kapoor et al 2006). Ten of these men were insulin treated. Testosterone treatment led to a significant reduction in glycated hemoglobin (HbA1C) and fasting glucose compared to placebo. Testosterone also produced a significant reduction in insulin resistance, measured by the homeostatic model assessment (HOMA), in the fourteen non-insulin treated patients. It is not possible to measure insulin resistance in patients treated with insulin but five out of ten of these patients had a reduction of insulin dose during the study. Other significant changes during testosterone treatment in this trial were reduced total cholesterol, waist circumference and waist-hip ratio. Similarly, a placebo-controlled but non-blinded trial in 24 men with visceral obesity, diabetes, hypogonadism and mean age 57 years found that three months of oral testosterone treatment led to significant reductions in HbA1C, fasting glucose, post-prandial glucose, weight, fat mass and waist-hip ratio (Boyanov et al 2003). In contrast, an uncontrolled study of 150 mg intramuscular testosterone given to 10 patients, average age 64 years, with diabetes and hypogonadism found no significant change in diabetes control, fasting glucose or insulin levels (Corrales et al 2004). Another uncontrolled study showed no beneficial effect of testosterone treatment on insulin resistance, measured by HOMA and ‘minimal model’ of area under acute insulin response curves, in 11 patients with type 2 diabetes aged between 33 and 73 years (Lee et al 2005). Body mass index was within the normal range in this population and there was no change in waist-hip ratio or weight during testosterone treatment. Baseline testosterone levels were in the low-normal range and patients received a relatively small dose of 100 mg intramuscular testosterone every three weeks. A good increase in testosterone levels during the trial is described but it is not stated at which time during the three week cycle the testosterone levels were tested, so the lack of response could reflect an insufficient overall testosterone dose in the trial period.

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