Because of inconclusive or conflicting results of testosterone treatment studies reported in the literature, Rabkin and colleagues (2004) undertook a comparison study among testosterone, the anti-depressant, fluoxetine, and placebo in eugonadal HIV positive men. They found that neither fluoxetine nor testosterone were different from placebo in reducing depression, but that testosterone did have a statistically significant effect in reducing fatigue. It is note-worthy that fatigue was reduced with testosterone treatment even though virtually all the men in the study had testosterone levels within the reference range.
Everyone knows that carbohydrates are extremely important for testosterone production, but instead of reaching for grains during your next meal, stack your plate high with potatoes. Research reveals that grains have inflammatory properties, but the testosterone-friendly starches in potatoes will have the bodybuilder in your life smiling at dinnertime!
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]
At the National Population and Family Development Board in Malaysia, men between the ages of 31 and 52 were given two capsules of the herb (E. longifolia) in Andro400 every day for three weeks. They reported erections were stronger and, in some cases, lasted longer. Overall, they felt more virile. Their levels of testosterone doubled within three weeks.5
Ensure that you get adequate restful sleep each night. Sleeping less than the recommended 6 to 8 hours per night increases stress hormones, which lowers testosterone production. Additionally, learn to manage stress levels in healthy ways to naturally increase testosterone. Hormone replacement therapy may be required for some men with low testosterone levels. Consult your physician about treatment options.

The reason I started the experiment at that point is because I know a lot of guys who live my last-August lifestyle all the time, and I wanted to see what would happen to an “average” guy who turned things around. At the same time, there was no “normal” time in my life which would have been better for me to start the experiment. My stress level and diet fluctuates throughout the year anyway, so at any point, factors in my current lifestyle would have influenced the results. I wanted to begin at “ground zero.”
Lets touch on these individually. Gluten has been shown to increase prolactin levels in male mice (48 & 49). Increased prolactin levels in males leads to all sorts of horrible things: Man Boobs (50), High inflammation (51), and most importantly, higher prolactin levels have been shown to be testosterone lowering and lead to shrinking of the testicle (52).
Now that we know chronic insulin spikes lead to lower Testosterone production, I hope I haven’t sent you running into the low carb camp! There are a few studies out there showing that long term low carb or ketogenic dieting leads to higher cortisol levels (especially with subjects who are training), and decreased testosterone levels (28 & 29). I have used low carb diets in the past with successful results (winning a national bodybuilding title), however the key is to use cyclical carb re-feeds. If you’re going to go on a low carb diet for whatever reason, be sure to work in a large carb reefed once a week.
I highly recommend using a great essential amino acid mix post-exercise in order to boost testosterone.  These essential amino acids and especially the concentrated branched chain amino acids leucine, isoleucine and valine stimulate muscle protein synthesis.  Getting these amino acids in the post-workout window dramatically boosts testosterone production (14).  I like using our Amino Strong and will often recommend a scoop pre-workout and post-workout for the best muscle building, testosterone boosting benefits.

^ Mehta PH, Jones AC, Josephs RA (Jun 2008). "The social endocrinology of dominance: basal testosterone predicts cortisol changes and behavior following victory and defeat" (PDF). Journal of Personality and Social Psychology. 94 (6): 1078–93. CiteSeerX 10.1.1.336.2502. doi:10.1037/0022-3514.94.6.1078. PMID 18505319. Archived from the original (PDF) on April 19, 2009.


It may be unlikely to completely eliminate products with EDCs, but there are a number of practical strategies that you can try to limit your exposure to these gender-bending substances. The first step would be to stop using Teflon cookware, as EDCs can leach out from contaminated cookware. Replace them with ceramic ones. Stop eating out of cans, as the sealant used for the can liner is almost always made from powerful endocrine-disrupting petrochemicals known as bisphenols, e.g. Bisphenol A, 

Most studies support a link between adult criminality and testosterone, although the relationship is modest if examined separately for each sex. Nearly all studies of juvenile delinquency and testosterone are not significant. Most studies have also found testosterone to be associated with behaviors or personality traits linked with criminality such as antisocial behavior and alcoholism. Many studies have also been done on the relationship between more general aggressive behavior/feelings and testosterone. About half the studies have found a relationship and about half no relationship.[66]
This causes your body to burn fat for the next 36 hours to replace your body’s vital energy stores. It addition to increasing your T-levels, it can help burn between 3–9 times more fat, lower your resting heart rate, lower blood pressure, keep your brain young by increasing circulation, and aids in detoxification by stimulating the lymphatic system.
It's not enough just to increase the testosterone your body produces, because as we age, the testosterone we naturally produce is often bound by SHBG (sex hormone binding globulin) thus becoming unavailable for use in the body. It’s imperative that your testosterone remains unbound or “free” if you want to enjoy all the wonderful benefits testosterone provides.

You can search every supplement on the market, and you can try reading “how to be good at sex” books (there’s about a million of them); You can even try those strange penis exercises (please do not waste your time). Or you can take a daily supplement that is designed and developed to do one thing: transform your penis and sex life so the next time a girl is talking about some guy who “could not stop making me orgasm,” that guy is you!
6., 7. JK, Udani, George AA, Musthapa M, Pakdaman MN, and Abas A. "Effects of a Proprietary Freeze-Dried Water Extract of Eurycoma Longifolia (Physta) and Polygonum minus on Sexual Performance and Well-Being in Men: A Randomized, Double-Blind, Placebo-Controlled Study." National Center for Biotechnology Information. U.S. National Library of Medicine, 12 Jan. 2014.
The testosterone supplements are primarily used to enhance the body muscle mass. Various studies have shown that testosterone therapy is also crucial in development of the memory as well as concentration, increase the level of energy, and increase libido or sexual desire. However, use of high levels of testosterone booster can also contribute to the development of certain medical conditions and health problems. Two types are available on the market, legal boosters, and illegal boosters. There are also certain excellent natural testosterone boosters that are efficient and so not have side effects.
A number of epidemiological studies have found that bone mineral density in the aging male population is positively associated with endogenous androgen levels (Murphy et al 1993; Ongphiphadhanakul et al 1995; Rucker et al 2004). Testosterone levels in young men have been shown to correlate with bone size, indicating a role in determination of peak bone mass and protection from future osteoporosis (Lorentzon et al 2005). Male hypogonadism has been shown to be a risk factor for hip fracture (Jackson et al 1992) and a recent study showed a high prevalence of hypogonadism in a group of male patients with average age 75 years presenting with minimal trauma fractures compared to stroke victims who acted as controls (Leifke et al 2005). Estrogen is a well known determinant of bone density in women and some investigators have found serum estrogen to be a strong determinant of male bone density (Khosla et al 1998; Khosla et al 2001). Serum estrogen was also found to correlate better than testosterone with peak bone mass (Khosla et al 2001) but this is in contradiction of a more recent study showing a negative correlation of estrogen with peak bone size (Lorentzon et al 2005). Men with aromatase deficiency (Carani et al 1997) or defunctioning estrogen receptor mutations (Smith et al 1994) have been found to have abnormally low bone density despite normal or high testosterone levels which further emphasizes the important influence of estrogen on male bone density.
Use natural grooming products. Most grooming products these days contain parabens, another type of xenoestrogen. And by most, I mean more than 75% of all products. To reduce my exposure as much as possible, I became a hippy during my experiment and started using all natural, paraben-free grooming products. You can find most of these items at most health food stores:
Studies also show a consistent negative correlation of testosterone with blood pressure (Barrett-Connor and Khaw 1988; Khaw and Barrett-Connor 1988; Svartberg, von Muhlen, Schirmer et al 2004). Data specific to the ageing male population suggests that this relationship is particularly powerful for systolic hypertension (Fogari et al 2005). Interventional trials have not found a significant effect of testosterone replacement on blood pressure (Kapoor et al 2006).
A previous meta-analysis has confirmed that treatment of hypogonadal patients with testosterone improves erections compared to placebo (Jain et al 2000). A number of studies have investigated the effect of testosterone levels on erectile dysfunction in normal young men by inducing a hypogonadal state, for example by using a GnRH analogue, and then replacing testosterone at varying doses to produce levels ranging from low-normal to high (Buena et al 1993; Hirshkowitz et al 1997). These studies have shown no significant effects of testosterone on erectile function. These findings contrast with a similar study conducted in healthy men aged 60–75, showing that free testosterone levels achieved with treatment during the study correlate with overall sexual function, including morning erections, spontaneous erections and libido (Gray et al 2005). This suggests that the men in this older age group are particularly likely to suffer sexual symptoms if their testosterone is low. Furthermore, the severity of erectile dysfunction positively correlates with lower testosterone levels in men with type 2 diabetes (Kapoor, Clarke et al 2007).
We start with plastic. A lot of plastic contains bisphenol A (BPA); BPA is a weak synthetic estrogen. Like many other chemicals used in making plastics, BPA is a hormone disruptor and can block or mimic hormones and how they act in the body (34). If you think you’re safe with BPA plastic, think again. Research shows that BPA free plastic has similar estrogen-like effects on the body.
Reduce stress levels. Stress is ubiquitous in the modern world, particularly for teenagers who face a variety of pressures and expectations. High levels of stress triggers the release of the stress hormone cortisol, which tends to counteract the negative physiological effects of stress. That's certainly beneficial, but cortisol also blocks the effects and impact of testosterone within the body, which can cause significant problems for teenage boys.[7] As such, try to provide a low-stress, stable environment for your teenager and give him opportunities to vent his frustrations and other emotions. Exercising, playing sports and developing enjoyable hobbies are all great at reducing stress.
When testosterone and endorphins in ejaculated semen meet the cervical wall after sexual intercourse, females receive a spike in testosterone, endorphin, and oxytocin levels, and males after orgasm during copulation experience an increase in endorphins and a marked increase in oxytocin levels. This adds to the hospitable physiological environment in the female internal reproductive tract for conceiving, and later for nurturing the conceptus in the pre-embryonic stages, and stimulates feelings of love, desire, and paternal care in the male (this is the only time male oxytocin levels rival a female's).[citation needed]
Hooper, D. R., Kraemer, W. J., Saenz, C., Schill, K. E., Focht, B. C., Volek, J. S. … Maresh, C. M. (2017, July). The presence of symptoms of testosterone deficiency in the exercise-hypogonadal male condition and the role of nutrition [Abstract]. European Journal of Applied Physiology, 117(7), 1349–1357. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/28470410
Most people associate testosterone with facial hair, gigantic muscles & illegal steroids.  Naturally produced testosterone plays a very important role in male/female metabolic function.  Lowered testosterone is a chronic epidemic that is threatening lives all around the world.  This article will go over 12 ways to boost testosterone levels naturally through healthy lifestyle measures.

And remember, saturated fats work best (along with monounsaturated fats – olive oil, almonds, avocados etc.). In fact higher intakes of polyunsaturated fats (canola oil, sunflower oil, soybean oil, safflower oil, margarine etc.) are linked to LOWER testosterone levels (14 & 15). I explore the dangers of PUFA's in a lot more detail in this article - PUFA's: The Worst Thing For Your Health That You Eat Everyday.
In addition to weight training, combining this with interval training like burst training is the best overall combo to increase HGH. In fact, Burst training has been proven to not only boost T-levels, it helps keeps your testosterone elevated and can prevent its decline. Burst training involves exercising at 90–100 percent of your maximum effort for a short interval in order to burn your body’s stored sugar (glycogen), followed by a period of low impact for recovery.
The finding of hypogonadism in diabetic men is not just a scientific curiosity, it may have practical management implications. Kapoor and colleagues (2006) undertook a placebo-controlled double blind study to determine the effect of testosterone therapy on insulin resistance and glycemic control in hypogonadal men with type 2 diabetes. They found that men treated with testosterone had reductions in glycated hemoglobin insulin resistance, fasting blood sugar, waist circumference, waist/hip ratio and total cholesterol.

Stick to protocols that stress large degrees of muscle mass and are moderate- to high-intensity. Additionally, more seasoned gym-goers may want to incorporate forced repetitions periodically into their programs, as testosterone increases have been observed with this type of training.14 Incorporating other post-failure training techniques such as dropsets or partials may similarly be associated with higher T production.
There are three categories of healthy fat. Number one is healthy saturated fat. The truth about saturated fat is it’s actually good for you if it’s the proper kind. Healthy saturated fat is found in coconut oil and raw, fermented dairy products like goat milk kefir, yogurt, or raw goat or sheep milk cheese. However, avoid conventional dairy because it will actually damper your testosterone.

The reasons for considering such therapy become evident from the many associations, indicated above, that reduced testosterone has with a variety of both physiological functions (bone metabolism, muscle mass, cognitive function, libido, erectile function) and pathophysiological states (metabolic syndrome, diabetes mellitus, obesity, insulin resistance, autoimmune disease). Although a definitive long-term, large scale placebo-controlled double-blind study of testosterone therapy in the aging male has not yet been carried out, multiple shorter-term trials have suggested improvement by testosterone with a resultant enhancement of muscle mass, bone density, libido, erectile function, mood, motivation and general sense of well-being.


If you want to naturally boost testosterone and HGH then combining weight training with HIIT workouts (high intensity interval training). Go to the gym at least three days a week, ideally at least three days a week, and lift heavy weights. Lifting heavy weights 6–12 reps with larger muscle groups like your quadriceps, hamstrings, back, shoulders and chest will help your body pack on the maximum amount of muscle. Specifically, lifting at least 30 minutes up to as long as an hour or so can be very, very beneficial boost low testosterone levels.
The only other concern regarding Testosterone Max is that it is a Crazy Bulk product, and their products are generally more directed towards the bodybuilding crowd. With that said, it does contain the necessary ingredients in order to raise testosterone levels, and that’s what produces the benefits. Therefore, as long as it can achieve boosted testosterone levels, which it can, it can be deemed an effective supplement.

Dr. Anthony’s Notes: DHEA is a powerful supplement for testosterone, energy, and overall well-being in our older Fit Fathers. A small dose of 25-50mg/day is enough to exert noticeable benefits. This supplement is over-the-counter. Verdict: this is one of the testosterone supplements that work. How To Take DHEA: Take 25-50mg once per day with food. Special Medical Note: DHEA is a MILD CYP3A4 inhibitor (a liver enzyme that processes MANY very common medications). This is the same isoenzyme that Grapefruit inhibits – albeit DHEA inhibits to a much weaker degree. If you’ve ever heard “don’t eat grapefruit with your Lipitor (cholesterol medication)”… this is the reason why. When we inhibit the CYP3A4 enzyme, more of the medications you're taking circulates (it’s not metabolized as fast). Check with your doctor for medication interactions before using DHEA.


The brain is also affected by this sexual differentiation;[13] the enzyme aromatase converts testosterone into estradiol that is responsible for masculinization of the brain in male mice. In humans, masculinization of the fetal brain appears, by observation of gender preference in patients with congenital diseases of androgen formation or androgen receptor function, to be associated with functional androgen receptors.[95]


Testosterone is used as a medication for the treatment of males with too little or no natural testosterone production, certain forms of breast cancer,[10] and gender dysphoria in transgender men. This is known as hormone replacement therapy (HRT) or testosterone replacement therapy (TRT), which maintains serum testosterone levels in the normal range. Decline of testosterone production with age has led to interest in androgen replacement therapy.[105] It is unclear if the use of testosterone for low levels due to aging is beneficial or harmful.[106]
Men who produce more testosterone are more likely to engage in extramarital sex.[55] Testosterone levels do not rely on physical presence of a partner; testosterone levels of men engaging in same-city and long-distance relationships are similar.[54] Physical presence may be required for women who are in relationships for the testosterone–partner interaction, where same-city partnered women have lower testosterone levels than long-distance partnered women.[59]
One of the most important nutrients that can help boost testosterone levels is vitamin D3. In 2011, the results of a study published in the journal Hormone and Metabolic Research announced that vitamin D supplementation boosts testosterone naturally in overweight men by up to 30 percent. (12) This is pretty exciting because research has shown that vitamin D3 is also linked to helping to prevent and treat cancer! (13)
During the month before my experiment, I was definitely sleep deprived. Some nights I was only getting 4 to 5 hours. Testosterone killer! During my experiment I tried to get 8 to 9 hours of sleep at night as consistently as possible. I had to go to bed earlier, but I was only cutting into time that I would have been using to mindlessly surf the net anyway.
It also has vitamin B6. One study called out folate and vitamins B6 and B12 as important nutrients for athletes to achieve optimal health and performance. Vitamin B6 is commonly found in food, like fortified cereals, and as with magnesium, it’s possible to have too much vitamin B6. The NIH recommends an upper daily limit for adults of 100mg per day. Beast Sports comes well under this limit at 10mg per day, but still well above the minimum recommended dose of 1.7mg needed to see benefits.
Testosterone is the primary sex hormone in men, and it is responsible for the development of many of the physical characteristics that are considered typically male. Women also produce the hormone in much smaller amounts. Testosterone, part of a hormone class known as androgens, is produced by the testicles after stimulation by the pituitary gland, which is located near the base of the brain, and it sends signals to a male's testicles (or to a woman's ovaries) that spark feelings of sexual desire. (1)
Afrisham, R., Sadejh-Nejadi, S., SoliemaniFar, O., Kooti, W., Ashtary-Larky, D., Alamiri, F., … Khaneh-Keshi, A. (2016, November 24). Salivary testosterone levels under psychological stress and its relationship with rumination and five personality traits in medical students. Psychiatry Investigations, 13(6), 637–643. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5128352/
That said, magnesium is one of a few ingredients demonstrated to impact testosterone levels. Researchers at Italy’s University of Palermo found that magnesium improved participants’ anabolic hormone status — including their testosterone levels. In a follow-up study, they confirm that even adjusting for age differences in their participant group, “magnesium was positively associated with total testosterone.” They propose that magnesium supplementation might help improve muscle performance in aging men — a group particularly vulnerable to declining/low testosterone levels. Outside of Italy, researchers at Turkey’s Selçuk University found that magnesium supplementation increased testosterone levels for both athletes and more sedentary men alike.
The bones and the brain are two important tissues in humans where the primary effect of testosterone is by way of aromatization to estradiol. In the bones, estradiol accelerates ossification of cartilage into bone, leading to closure of the epiphyses and conclusion of growth. In the central nervous system, testosterone is aromatized to estradiol. Estradiol rather than testosterone serves as the most important feedback signal to the hypothalamus (especially affecting LH secretion).[115] In many mammals, prenatal or perinatal "masculinization" of the sexually dimorphic areas of the brain by estradiol derived from testosterone programs later male sexual behavior.[116]
We scoured the database of the National Center for Biotechnology Information (part of the U.S. National Library of Science) for articles. Of the many ingredients marketed as boosting testosterone levels, we only found four backed by multiple articles based on human testing. For the best chance of boosting testosterone levels, a supplement needs to contain magnesium, fenugreek, and longjack — and some zinc wouldn’t go astray, either.
When testosterone and endorphins in ejaculated semen meet the cervical wall after sexual intercourse, females receive a spike in testosterone, endorphin, and oxytocin levels, and males after orgasm during copulation experience an increase in endorphins and a marked increase in oxytocin levels. This adds to the hospitable physiological environment in the female internal reproductive tract for conceiving, and later for nurturing the conceptus in the pre-embryonic stages, and stimulates feelings of love, desire, and paternal care in the male (this is the only time male oxytocin levels rival a female's).[citation needed]
Once your elevate testosterone levels, you will also sharpen your focus, enhance sports performance, and enjoy enormous competitive spirit. You will also soon notice that the lack of motivation is no longer your problem. Being highly motivated and aggressive due to the action of testosterone boosters, you will experience better muscle gain. Whether you are a novice or a professional sportsman, you will quickly reach your sports goals.
The diagnosis of late-onset hypogonadism requires the combination of low serum testosterone levels with symptoms of hypogonadism. Questionnaires are available which check for the symptoms of hypogonadism. These have been validated for the assessment of aging patients with hypogonadism (Morley et al 2000; Moore et al 2004) but have a low specificity. In view of the overlap in symptoms between hypogonadism, aging and other medical conditions it is wise to use a formal method of symptom assessment which can be used to monitor the effects of testosterone replacement.

The basis for my thinking that T levels could be boosted by cold baths came from a post I wrote a few years ago on the benefits of cold showers. One benefit I found in my research was that they could increase testosterone levels. I mentioned a 1993 study done by the Thrombosis Research Institute in England that found increased T levels after taking a cold shower. Here’s the thing. I can’t find a link to the original source and I can’t find any other studies that support this claim! So without supporting research, I’m unsure of the effects of cold showers on testosterone.

Transdermal preparations of testosterone utilize the fact that the skin readily absorbs steroid hormones. Initial transdermal preparations took the form of scrotal patches with testosterone loaded on to a membranous patch. Absorption from the scrotal skin was particularly good and physiological levels of testosterone with diurnal variation were reliably attained. The scrotal patches are now rarely used because they require regular shaving or clipping of scrotal hair and because they produce rather high levels of dihydrotestosterone compared to testosterone (Behre et al 1999). Subsequently, non-scrotal patches were developed but the absorptive capacity of non-scrotal skin is much lower, so these patches contain additional chemicals which enhance absorption. The non-scrotal skin patches produce physiological testosterone levels without supraphysiological dihydrotestosterone levels. Unfortunately, the patches produce a high rate of local skin reactions often leading to discontinuation (Parker and Armitage 1999). In the last few years, transdermal testosterone gel preparations have become available. These require daily application by patients and produce steady state physiological testosterone levels within a few days in most patients (Swerdloff et al 2000; Steidle et al 2003). The advantages compared with testosterone patches include invisibility, reduced skin irritation and the ability to adjust dosage, but concerns about transfer to women and children on close skin contact necessitate showering after application or coverage with clothes.
The yolks of eggs exclusively are a fine source of Zinc. Egg yolks have all of the vitamins that are present in the whole egg as well. So, by consuming the yolk itself, you would get more than required fat, but you also get vitamins A, E, D and K, as well as additional amounts of minerals. Zinc and vitamin D - the pro-testosterone duo are in the captain seat in egg yolks.

“About 2 weeks after starting Andro400, I noticed my belly fat disappearing. Now, after only one month, I've lost about ten pounds all in my mid section. What a miracle! I have more energy and don't have to hold my gut in any longer. I'm more relaxed and my libido has increased 5 fold! I'm 58 years old and beginning to feel like a teenager again! Your product has delivered exactly as advertised. I'm elated!”
Bisphenol-A also known under the name of BPA is a chemical compound which is very widespread for manufacturing a wide spectrum of plastic items and aluminum cans. Many studies have already proven the fact that even the smallest amount of BPA is very harmful to the human health. This compound causes hormonal imbalance and even may lead to prostate cancer.
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.
Opioid substances are in common use both licit and illicit. Opiates are potent analgesics but they are also highly addictive. They are frequently prescribed for both acute and chronic pain and when used chronically, often induce opiate dependence in the user. Pain clinics regularly use narcotic agents in many of their patients. Methadone, in particular, is regularly prescribed to opiate addicts who have entered a program aimed at reducing narcotic dosage and ultimately weaning the patient off it altogether. Most men who are on chronic high doses of an opiate become hypogonadal. This was first recognized in the 1970’s when heroin addicts were found to have suppressed levels of testosterone (Brambilla et al 1977). Also suppressed were LH and FSH pointing to a probable inhibition of GnRH release.
Present in much greater levels in men than women, testosterone initiates the development of the male internal and external reproductive organs during foetal development and is essential for the production of sperm in adult life. This hormone also signals the body to make new blood cells, ensures that muscles and bones stay strong during and after puberty and enhances libido both in men and women. Testosterone is linked to many of the changes seen in boys during puberty (including an increase in height, body and pubic hair growth, enlargement of the penis, testes and prostate gland, and changes in sexual and aggressive behaviour). It also regulates the secretion of luteinising hormone and follicle stimulating hormone. To effect these changes, testosterone is often converted into another androgen called dihydrotestosterone. 
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