For example, in February 2017, scientists reported on trials involving men over age 65 who had low testosterone due to aging. Each trial included a different number of men depending on the subject of the research. Roughly half of the participants received testosterone therapy for a year; the rest underwent a placebo treatment. The researchers discovered the following:
Bushey, Brandon; Taylor, Lem W.; Wilborn, Colin W.; Poole, Chris; Foster, Cliffa A.; Campbell, Bill; Kreider, Richard B. and Willoughby, Darryn S. (2009). “Fenugreek Extract Supplementation Has No effect on the Hormonal Profile of Resitance-Trained Males” International Journal of Exercise Science: Conference Abstract Submissions: Vol. 2: Iss. 1, Article 13.

A couple years ago I was having a problem with my thighs burning when walking up stairs. I noticed the muscles in my legs looking smaller. So I had my doc to check my T levels , and it was under 100. So she started me on testosterone injections weekly 200mg . After several injections I felt great , muscles in legs came back , lots of energy everything good . Leveled out at 3 injections a week 100mg , had a T level of 550 . So I go in for my scheduled injection and they tell me there out of testosterone . I might mention, this is a health care facilility that gives financial assistant if needed. And they have 3 or doctors and a nurse practitioner, which was who I was seeing . So I went on to check back often and got the same reply , were out of supply . So finally after months of the same , I gave up . I started loosing wait and my nerves got bad . Was having panic attacks etc. but I was coming off Prozac at the same time so I blamed it all on that. I was so bad with my nerves I ended up in the ER while on vacation . Doc there put me on a med for stress which I’m still using . After close to a year I checked back with the place I was getting TRT and they were resupplyed with testosterone. So I started back up because of low sex drive and ED. My first injection of 200mg was just short of a Marical , nerves felt great ED gone , had a sex drive , lot of energy . Then after 7 days or so all gone bad nerves started back up . He had me scheduled for anouther injection in 4 weeks 100mg . I went in for injection and after a couple days started feeling a little better . Then same thing as before about 7 days later nerves and everything else as before got worse . 3 weeks later I finally got a appt. with this different doc then I use to have . Told him the problems I was having , which included a horrible down mood , no energy . He decided to start injections every 2 weeks and upped the dose slitley. It’s been 5 days and already noticing ED problem reaccuring . He’s worried about the threat of prostate cancer. And doesn’t want to add any more injection to the schedule. I guess I’m going to have to start seeing the nurse practitioner who seemed to be more liberal and informed about TRT. I feel once a week injection is what it will take to get feeling good again. I’m 57 now with good health . Just need to get my T level on track with a doctor that will listen to how his patient is feeling . My last T level was at 365 . I failed to mention before I started the injections I was on androgel Dailey , 5 pumps a day . Then he gave me the injection of 200mg test . That’s when I felt fantastic for about a week or so . Then down hill . And I wanted to switch because the injection just seem so much better and they are . I noticed a big difference.
^ Jump up to: a b Sapienza P, Zingales L, Maestripieri D (September 2009). "Gender differences in financial risk aversion and career choices are affected by testosterone". Proceedings of the National Academy of Sciences of the United States of America. 106 (36): 15268–73. Bibcode:2009PNAS..10615268S. doi:10.1073/pnas.0907352106. PMC 2741240. PMID 19706398.
Vitamin D, a steroid hormone, is essential for the healthy development of the nucleus of the sperm cell, and helps maintain semen quality and sperm count. Vitamin D also increases levels of testosterone, which may boost libido. In one study, overweight men who were given vitamin D supplements had a significant increase in testosterone levels after one year.5
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A large number of side-effects have been attributed to testosterone. In our clinical experience, the incidence of significant adverse effects with treatment producing physiological testosterone levels is low, and many side effects attributed to testosterone are mainly relevant to supraphysiological replacement. Some adverse effects are specific to a given mode of delivery and have already been described. Potential adverse effects concerning the prostate have also been discussed and require appropriate monitoring of symptoms, PSA and digital rectal examination. Other tumors which may be androgen responsive include cancer of the breast and primary liver tumors, and these are both contraindications to testosterone treatment
With the help of the three main ingredients, you have the ability to naturally raise your free testosterone levels giving you an increase in strength, muscle mass, stamina, and libido.  NutriSuppz Ultra Test aims to help you sleep better, burn fat easier, and feel energized, and have improved mental alertness.  Another perk of NutriSuppz Ultra Test is that it is a fully transparent profile with no proprietary blends—allowing you to know exactly what you are getting in each dose.

The first period occurs between 4 and 6 weeks of the gestation. Examples include genital virilisation such as midline fusion, phallic urethra, scrotal thinning and rugation, and phallic enlargement; although the role of testosterone is far smaller than that of dihydrotestosterone. There is also development of the prostate gland and seminal vesicles.
Longjack, also known as Tongkat ali and pasak bumi, is a shrub hailing from Southeast Asia purporting to improve libido. It’s gaining traction in the scientific community for potentially increasing testosterone levels, and researchers at South Africa’s University of the Western Cape found that longjack improved testosterone levels and muscular strength in physically active seniors (a population with typically low testosterone).
^ Butenandt A, Hanisch G (1935). "Uber die Umwandlung des Dehydroandrosterons in Androstenol-(17)-one-(3) (Testosterone); um Weg zur Darstellung des Testosterons auf Cholesterin (Vorlauf Mitteilung). [The conversion of dehydroandrosterone into androstenol-(17)-one-3 (testosterone); a method for the production of testosterone from cholesterol (preliminary communication)]". Chemische Berichte (in German). 68 (9): 1859–62. doi:10.1002/cber.19350680937.
Zinc deficiency also negatively affects testosterone levels, according a 2014 article in the Journal of Plant Biochemistry and Physiology. The authors of this review note that zinc supplementation can increase circulating testosterone in some populations. In fact, daily supplementation with typical doses may double testosterone within a few months.
“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!”

Intramuscular testosterone injections were first used around fifty years ago. Commercially available preparations contain testosterone esters in an oily vehicle. Esterification is designed to retard the release of testosterone from the depot site into the blood because the half life of unmodified testosterone would be very short. For many years intramuscular preparations were the most commonly used testosterone therapy and this is still the case in some centers. Pain can occur at injection sites, but the injections are generally well tolerated and free of major side effects. Until recently, the available intramuscular injections were designed for use at a frequency of between weekly and once every four weeks. These preparations are the cheapest mode of testosterone treatment available, but often cause supraphysiological testosterone levels in the days immediately following injection and/or low trough levels prior to the next injection during which time the symptoms of hypogonadism may return (Nieschlag et al 1976). More recently, a commercial preparation of testosterone undecanoate for intramuscular injection has become available. This has a much longer half life and produces testosterone levels in the physiological range throughout each treatment cycle (Schubert et al 2004). The usual dose frequency is once every three months. This is much more convenient for patients but does not allow prompt cessation of treatment if a contraindication to testosterone develops. The most common example of this would be prostate cancer and it has therefore been suggested that shorter acting testosterone preparations should preferably used for treating older patients (Nieschlag et al 2005). Similar considerations apply to the use of subcutaneous implants which take the form of cylindrical pellets injected under the skin of the abdominal wall and steadily release testosterone to provide physiological testosterone levels for up to six months. Problems also include pellet extrusion and infection (Handelsman et al 1997).
This post can absolutely change your life, and probably help you avoid some pitfalls. Like shrunken balls. (I am not an expert in the synthetic anabolic testosterone drugs used by bodybuilders — they carry lots of risks but pack a big punch if you want to get swole. Bulletproof is all about having massive clean energy, looking good, and living a very long time…so anabolic steroids aren’t on my roadmap.)
Pellets. Your doctor will place the testosterone pellets under the skin of your upper hip or buttocks. Your doctor will give a shot of local anesthesia to numb your skin, then make a small cut and place the pellets inside the fatty tissues underneath your skin. This medication dissolves slowly and is released over about 3-6 months, depending on the number of pellets. 
Amazing this thread is going after 3 years. Very good indeed. I have low cortisol and my doctor decided to check testosterone. It came back at 5! Not 500, but 5! My doctor did not believe this to be correct. She indicated I would not be able to grow facial hair and that my arm hair would have fell out. She retested. It came back at 23. WTH. So she wanted to start me on Clomid. Well of course my insurance would not cover this. Most pharmacies wanted $300-400 for a 30 day supply. Can’t afford that! The 2 pharmacies that were reasonable cannot get it from their suppliers at this time. So my doctor wants to start weekly injections. I do not know what to think but am trying to find all the information I can on the subject as I am quite nervous. So if anyone else is still reading or comes across this please let me know what you think or your story. it would very much be appreciated. i will be 38 next month and am a little “lost” about all of this. Many thanks! 🙂
For men with low blood testosterone levels, the benefits of hormone replacement therapy usually outweigh potential risks. However, for most other men it's a shared decision with your doctor. It offers men who feel lousy a chance to feel better, but that quick fix could distract attention from unknown long-term hazards. "I can't tell you for certain that this raises your personal risk of heart problems and prostate cancer, or that it doesn't," Dr. Pallais says.
Caffeine: While caffeine can’t ramp up testosterone directly, it can help you put in the quality work in the gym that will spike your T. One International Journal of Sports Nutrition and Exercise Metabolism study, for instance, found that athletes who consumed caffeine before training lifted more—and experienced a greater subsequent lift in testosterone—than those who took a placebo.
The doctor regularly measured my levels to be sure they were within the normal range for a male my age. In other words, I wasn’t taking ‘roids to get big; I was getting control of hormones that were not functioning well. This is how you should look at testosterone therapy – it is a gentle nudge to help you be in normal ranges, not a big push to get you huuu-yge. If you’re like me, you want “normal ranges” of a 27-year-old, not of a 60-year-old. It’s my plan to keep my testosterone where it is now (around 700) no matter what it takes. Right now, the Bulletproof Diet and the other biohacks I’ve written about do that! I’m 43.
"I am only 10 weeks into taking your product and I have lost 12 pounds and three inches from my waist. Normally I scoff at radio or TV ads promising results like this. But in this case, my results have far exceeded my expectations. My energy level has increased and my appetite has decreased! All this without any extra exercise program. Thanks from a very satisfied customer!"

Bushey, Brandon; Taylor, Lem W.; Wilborn, Colin W.; Poole, Chris; Foster, Cliffa A.; Campbell, Bill; Kreider, Richard B. and Willoughby, Darryn S. (2009). “Fenugreek Extract Supplementation Has No effect on the Hormonal Profile of Resitance-Trained Males” International Journal of Exercise Science: Conference Abstract Submissions: Vol. 2: Iss. 1, Article 13.
A: According to the NIH, normal values for testosterone levels in men can range from 300 to 1,200ng/dL. There can be many different causes of low testosterone including age, diseases, accidents, and medications. Symptoms of low testosterone may include: loss of sex drive, erectile dysfunction, depressed mood, and difficulty concentrating. Low testosterone levels may also bring around body changes including: hair loss, decrease in blood cells possibly leading to anemia, fragile bones, and a decrease in muscle mass. There are different testosterone replacement therapies including patches, such as Androderm; gels, such as Androgel and Testim; and injections, such as testosterone cypionate. Only your health care provider can decide if and what kind of testosterone replacement therapy is appropriate for you. Testosterone replacement therapy is not right for everyone. Patient with certain prostate issues or breast cancer should not take testosterone. For more specific information, consult with your doctor for guidance based on your health status and current medications, particularly before taking any action. Kristen Dore, PharmD
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,[104][105][106][107] 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,[108] where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition.
Testosterone levels naturally rise in response to sexual arousal and activity. Men with higher levels of testosterone usually have greater sexual activity. Older men need more testosterone for libido and erectile function. But it’s important to note that erectile dysfunction is often due to other conditions or medications rather than low testosterone levels.

Dr. Darryn Willoughby, a professor of health, human performance and recreation and the director of the Exercise and Biochemical Nutrition Laboratory at Baylor University, told us that even in studies where there was an increase in testosterone, it was only around 15–20 percent. “In men with clinically normal testosterone levels, this modest increase will most likely not be anabolic enough to improve exercise performance,” he says. So if you have normal testosterone levels, and are simply trying to get an extra edge in gaining muscle, losing weight, or some extra time in the bedroom — you might see some results from taking a testosterone booster. But really, these will be most useful for men with low testosterone trying to get back to a healthy testosterone range.

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.
It has also been found that college graduates with higher levels of T (men and women alike) are more likely to go into riskier careers. Another study discovered that among financial traders, a trader’s morning level of testosterone accurately predicted his day’s profitability – higher levels of T mean he’s more likely to take risks that day and score big.
So, this past summer I talked with my doctor about starting T injections to see if that would work. I started injection 1 small bottle every 2 weeks. I started some time in later July, 2016. After around the 3 injection I had a blood test and my T level was OVER 800, something like 832. Apparently, my body reacted and took to it very quickly and easily, but the T level was now TOO high. So, I extended the injection interval to 18 days instead of 15 days. I just had another blood test last week and my T level was in the mid 600’s. It’s better now, but my doctor and I want to get that down to around 500, so I’m going to 20-21 days and see what happens.
Epidemiological studies have also assessed links between serum testosterone and non-coronary atherosclerosis. A study of over 1000 people aged 55 years and over found an inverse correlation between serum total and bioavailable testosterone and the amount of aortic atherosclerosis in men, as assessed by radiological methods (Hak et al 2002). Increased intima-media thickness (IMT) is an early sign of atherosclerosis and has also been shown to predict cardiovascular mortality (Murakami et al 2005). Cross-sectional studies have found that testosterone levels are negatively correlated with carotid IMT in independently living men aged 74–93 years (van den Beld et al 2003), diabetic men (Fukui et al 2003) and young obese men (De Pergola et al 2003). A 4-year follow up study of the latter population showed that free testosterone was also inversely correlated with the rate of increase of IMT (Muller et al 2004).

The bogus products that have been draining your wallet and fattening the bank accounts of supplement companies are the so-called “natural testosterone boosters.” Billed as the saving grace to your low testosterone levels, poor body composition, and pitiful strength levels, natty test boosters were viewed by consumers as the answer to everything that was wrong.
I’m a 70 year old male. Here’s my brief story, I was exhausted all the time after an encounter with H-Py-Lori. After may tests it was found out that my T-count was at about 250. I was put on a testosterone cream replacement therapy. Before I knew it, at about month I was at 1500 count. This was at 4 cream applications a day. The doctor took me down to twice/two applications a day, now I was at 600. I felt great at both levels.
“We need carbs, fats, and proteins to have optimal T levels,” says Howse. A healthy amount of carbs, for example, keeps cortisol levels low (more on why this is important to come). Meanwhile, dietary fats produce cholesterol, which our body can later convert into testosterone. And, finally, protein supports body composition by enhancing muscle repair and growth and increasing satiety.

Pine Pollen is an androgen, meaning in theory it can raise testosterone levels – effectively making it a naturally derived source of testosterone. Read more about this on the links below. But like I said I started taking it for a few weeks and did notice a bit more ‘up and go’ so to speak, but it did only last a few weeks. I have tried cycling it but haven’t noticed the same effects as I had when I initially started with it. I’m still experimenting and will keep this page updated. Therefore I recommend doing your own research.
In males, testosterone is synthesized primarily in Leydig cells. The number of Leydig cells in turn is regulated by luteinizing hormone (LH) and follicle-stimulating hormone (FSH). In addition, the amount of testosterone produced by existing Leydig cells is under the control of LH, which regulates the expression of 17β-hydroxysteroid dehydrogenase.[132]
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.
Recently my testosterone level came back at 380. and I am on max dose of 1% 8 pumps per day. The Dr. put me on 1.62% 8 pumps once a day and I will test in a few weeks to see how my level has changed. The issue is I am afraid of is putting 4 pumps a day in each shoulder and upper arm. Has anyone used this much to get there levels up? I am very fit and workout 4 times a week . The other issue is cost because 1.62% is not available 1n generic and cost has skyrocketed.
Testosterone is the primary male sex hormone and an anabolic steroid. In male humans, testosterone plays a key role in the development of male reproductive tissues such as testes and prostate, as well as promoting secondary sexual characteristics such as increased muscle and bone mass, and the growth of body hair.[2] In addition, testosterone is involved in health and well-being,[3] and the prevention of osteoporosis.[4] Insufficient levels of testosterone in men may lead to abnormalities including frailty and bone loss.
I started doing prostate biopsies before putting men on testosterone therapy because the fear had always been that a hidden cancer might grow due to increased testosterone. It was also believed that low testosterone was protective. Well, we found prostate cancer in one of the first men with low testosterone we biopsied, even though his PSA level and digital rectal exam (DRE) were normal. As we did more of these, we found more and more cases, about one out of seven, despite normal DRE and normal PSA. When we had data for 77 men and the cancer rate was about the same, 14%, the Journal of the American Medical Association published our findings. At the time, that rate of prostate cancer in men with normal PSA was several times higher than anything published previously, and it approximated the risk of men who had an elevated PSA or an abnormal DRE. That was in 1996.
Dr. Darryn Willoughby, a professor of health, human performance and recreation and the director of the Exercise and Biochemical Nutrition Laboratory at Baylor University, told us that even in studies where there was an increase in testosterone, it was only around 15–20 percent. “In men with clinically normal testosterone levels, this modest increase will most likely not be anabolic enough to improve exercise performance,” he says. So if you have normal testosterone levels, and are simply trying to get an extra edge in gaining muscle, losing weight, or some extra time in the bedroom — you might see some results from taking a testosterone booster. But really, these will be most useful for men with low testosterone trying to get back to a healthy testosterone range.
Alterations in mood and depression are a symptom of, but not confined to, hypogonadism.1,6 Outcomes in clinical trials of the effect of testosterone treatment on mood have varied. However, there is evidence that testosterone treatment results in improvements in mood, particularly in older men with hypogonadism.7,8Similarly, although there is an established association between measures of cognitive ability and serum levels of testosterone, the benefits of testosterone treatment on cognition are less clearly established, with some studies reporting improvements in some measures of cognitive function and others failing to detect benefits.6,9-11 Although a potential role for testosterone in protecting cognitive function and preventing Alzheimer’s disease has been proposed by some researchers, confirmation from appropriately-designed clinical trials is awaited.

Unlike injection or ingestion of anabolic steroids, the use of testosterone boosters is relatively safe for daily consumption. In order to ward off any negative side effects, it is best to take a rest after finishing a bottle of your preferred testosterone booster. This will allow the body to relax after months of taking supplements that increase testosterone levels. This practice effectively cleans the body as well.
When I was on 4 pumps per day, I had a reduction of ejaculate, and sometimes found it hard to ejaculate. Getting erections is no problem, and I even take BP meds. I vary it now. When I’m not going to the gym, or traveling, I cut down to 2 pumps, or take a break for a few days. When I’m intense in the gym, I stick with 4 pumps (about 5mg). I do still have the belly flab unfortunately. I need to increase cardio, and change up the diet some, but honestly, I am not too bad with my diet, so I’m a little frustrated.
My favorite overall tool to manage stress is EFT (Emotional Freedom Technique), which is like acupuncture without the needles. It's a handy, free tool for unloading emotional baggage quickly and painlessly, and so easy that even children can learn it. Other common stress-reduction tools with a high success rate include prayer, meditation, laughter and yoga, for example. Learning relaxation skills, such as deep breathing and positive visualization, which is the "language" of the subconscious.
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).
“However, the parallels don’t necessarily follow logically, creating a real need to bring more evidence to this area so that physicians and patients would be able to make more  informed decisions based on the best possible evidence,” said Dr. Gill, a professor of medicine and the lead investigator at the Yale study site, the largest site participating in the TTrials, and coauthor of all 4 TTrials. 

The content here is for information purposes only. By delivering the information contained herein is does not mean preventing, diagnosing, mitigating, treating or curing any type of medical condition or disease. When beginning any natural supplementation regiment or integrative treatment, the advice of professionally licensed healthcare providers is advisable to seek.
When we face stress, our adrenal glands secrete cortisol to prepare our bodies and minds to handle the stressful situation — the primal fight-or-flight response. In small dosages, cortisol is fine and even useful, but elevated cortisol levels for prolonged periods can do some serious damage to our bodies and minds. One area that seems to take a hit when cortisol is high is our testosterone levels. Several studies have shown a link between cortisol and testosterone. When cortisol levels are high, testosterone levels are low; and when testosterone levels are high, cortisol levels are low.

The content here is for information purposes only. By delivering the information contained herein is does not mean preventing, diagnosing, mitigating, treating or curing any type of medical condition or disease. When beginning any natural supplementation regiment or integrative treatment, the advice of professionally licensed healthcare providers is advisable to seek.

The testosterone booster pills are effective from 4 to 8 hours. To maintain testosterone levels high during the whole day, you need a multiple daily dosing regimen. 2-times daily dosing still not always can improve hormone production to the greatest extent. 3-4-times daily dosing is the best solution to make your body normalize testosterone synthesis and prevent it from decreasing before you take another pill. Don’t forget that the regularity of daily supplement intake is crucial if you really aspire to give a boost to hormone production.
Testosterone is a steroid from the androstane class containing a keto and hydroxyl groups at the three and seventeen positions respectively. It is biosynthesized in several steps from cholesterol and is converted in the liver to inactive metabolites.[5] It exerts its action through binding to and activation of the androgen receptor.[5] In humans and most other vertebrates, testosterone is secreted primarily by the testicles of males and, to a lesser extent, the ovaries of females. On average, in adult males, levels of testosterone are about 7 to 8 times as great as in adult females.[6] As the metabolism of testosterone in males is greater, the daily production is about 20 times greater in men.[7][8] Females are also more sensitive to the hormone.[9]
“I'm 55 years old and hitting the ball further than I've ever hit, and I'm not getting tired going 18 holes! And when I play softball I'm hitting the ball further. I work for the DWP in LA and it's a very physically demanding job. Andro400 really helps because we work 16 hour days a lot. I was turning down a lot of overtime, but when I started taking Andro400, it got me through the day. I really notice a difference – even my wife did. It really works!”
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).[119] 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.[120]
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.
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