The biologically available part of total testosterone is called free testosterone, and it’s readily available to the cells. Almost every lab has a blood test to measure free testosterone. Even though it’s only a small fraction of the total, the free testosterone level is a pretty good indicator of low testosterone. It’s not perfect, but the correlation is greater than with total testosterone.
I had been on testosterone cyperonate 250-300 mg every 2 weeeksfor one year when diagnosed as having hypercythemic. I was cut of treatments immediately. Scanned from head to toe side to side. All clear. My urologist refuses to resume any HRT as my total testosterone is 701 immunoassay. However, he never mentions my Free % T value of 1.3. The labs range is 1.6-2.9. SHGB =70.6. Albumin 4.1. Is not the Free T we should be concerned with? Do I not need to go “Uologist Hunting”????
The regulation of testosterone production is tightly controlled to maintain normal levels in blood, although levels are usually highest in the morning and fall after that. The hypothalamus and the pituitary gland are important in controlling the amount of testosterone produced by the testes. In response to gonadotrophin-releasing hormone from the hypothalamus, the pituitary gland produces luteinising hormone which travels in the bloodstream to the gonads and stimulates the production and release of testosterone.
Early infancy androgen effects are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4–7 months of age.[15][16] The function of this rise in humans is unknown. It has been theorized that brain masculinization is occurring since no significant changes have been identified in other parts of the body.[17] The male brain is masculinized by the aromatization of testosterone into estrogen, which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein, which binds the estrogen so that female brains are not affected.[18]

When looking for a solid natural testosterone booster, you’ll want one that has the ability to increase natural testosterone levels, increase muscular strength, improve performance and stamina, and help pack on lean muscle mass.  With a mix of key ingredients like D-AA, Tribulus, Fenugreek, and DIM, Evlution’s booster aims to take your training to the next level.  It can also help improve your sleep which is vital in allowing the body to recover from intense sessions in the gym.
In a placebo-controlled study, 27 Division II football players received either a placebo or a ZMA supplement for a total of seven weeks during their scheduled spring practice. At the end of the seven weeks, the players taking the ZMA supplement had a 30 percent increase in testosterone, while the placebo group had a 10 percent decrease. The ZMA group also saw an 11.6 percent increase in strength, compared to only 4.6 percent in the placebo group.[7]
Sitting for long stretches of time increases the odds of illness and untimely death. Here are some simple tricks to get yourself out of your chair: While you're on the phone, stand up and walk around. When watching TV, stand and pace during commercials. Instead of sitting at your makeup table, stand up. In general, try to get on your feet every 30 minutes.
The other problem researchers run into when studying the benefits of testosterone is distinguishing between “cause” and “effect.” Is it T that’s providing all these great health benefits or does simply being healthy give you optimal levels of testosterone? It’s tricky because in some instances the answer is “both.” Testosterone (like all hormones) often plays a part in a “virtuous cycle” that regulates a whole host of  processes in our bodies — as you increase T, you get healthier; as you get healthier, your T levels rise. It can also play a part in a “vicious cycle” — as your T levels go down, your health suffers; as your health suffers, your T levels decrease even more.
“Life for the winner is more glorious. It enters the next round of competition with already elevated testosterone levels, and this androgenic priming gives it an edge that increases its chances of winning yet again. Through this process an animal can be drawn into a positive-feedback loop, in which victory leads to raised testosterone levels which in turn leads to further victory.”

Why bother with such common micronutrients? Because it's not uncommon for athletes to suffer from zinc and magnesium deficiencies, partly due to inadequate replenishing of levels after intense bouts of exercise. Deficiencies in these key minerals can lead to a poor anabolic hormone profile, impaired immune function, and increased cortisol, ultimately leading to decreases in strength and performance.[6]

In addition to conjugation and the 17-ketosteroid pathway, testosterone can also be hydroxylated and oxidized in the liver by cytochrome P450 enzymes, including CYP3A4, CYP3A5, CYP2C9, CYP2C19, and CYP2D6.[159] 6β-Hydroxylation and to a lesser extent 16β-hydroxylation are the major transformations.[159] The 6β-hydroxylation of testosterone is catalyzed mainly by CYP3A4 and to a lesser extent CYP3A5 and is responsible for 75 to 80% of cytochrome P450-mediated testosterone metabolism.[159] In addition to 6β- and 16β-hydroxytestosterone, 1β-, 2α/β-, 11β-, and 15β-hydroxytestosterone are also formed as minor metabolites.[159][160] Certain cytochrome P450 enzymes such as CYP2C9 and CYP2C19 can also oxidize testosterone at the C17 position to form androstenedione.[159]
On review of the patient’s history, he was found to have undergone laboratory tests before starting to use the aforementioned testosterone booster product. All blood parameters (testosterone hormone and full chemical profile) before product intake were in the normal range. A physical examination that included blood pressure and pulse assessments showed nothing out of the ordinary, and the man appeared to be in good condition before product consumption. After that medical checkup, the athlete began to consume the product for 42 continuous days divided into 2 cycles (each cycle comprised 24 days). The daily dose was a single pack of Universal Nutrition Animal Stak (ingredients are listed in Table 1), following the exact direction of the manufacturing company hoping to get the best results.
Your diet is the best source of zinc; along with protein-rich foods like meats and fish, other good dietary sources of zinc include raw milk, raw cheese, beans, and yogurt or kefir made from raw milk. It can be difficult to obtain enough dietary zinc if you're a vegetarian, and also for meat-eaters as well, largely because of conventional farming methods that rely heavily on chemical fertilizers and pesticides. These chemicals deplete the soil of nutrients ... nutrients like zinc that must be absorbed by plants in order to be passed on to you.
Your first step should be to see your doctor. If you think you have low testosterone, we cannot stress enough that you should proceed with caution and talk to a medical professional — taking a booster can definitely do more harm than good. Low testosterone can be a symptom of more serious problems, like a pituitary disorder or a side-effect of medication, and a booster can mask the root cause. A doctor will be able to evaluate your testosterone levels with a simple blood test, and if you both decide a booster is the way to go, give the ingredients of any supplement a once-over to make sure that they’re not at risk of making your personal health situation worse.
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.
Cardiovascular disease, and its underlying pathological process atherosclerosis, is an important cause of morbidity and mortality in the developed and developing world. Coronary heart disease in particular is the commonest cause of death worldwide (AHA 2002; MacKay and Mensah 2004). As well as increasing with age, this disease is more common in the male versus female population internationally, which has led to interest in the potential role of sex hormones in modulating risk of development of atherosclerosis. Concerns about the potential adverse effects of testosterone treatment on cardiovascular disease have previously contributed to caution in prescribing testosterone to those who have, or who are at risk of, cardiovascular disease. Contrary to fears of the potential adverse effects of testosterone on cardiovascular disease, there are over forty epidemiological studies which have examined the relationship of testosterone levels to the presence or development of coronary heart disease, and none have shown a positive correlation. Many of these studies have found the presence of coronary heart disease to be associated with low testosterone levels (Reviews: Jones, Jones et al 2003; Jones et al 2005).
Testosterone is an androgen hormone produced by the adrenal cortex, the testes (in men), and the ovaries (in women). It is often considered the primary male sex hormone. Testosterone stimulates the development of male secondary sex characteristics (like body hair and muscle growth) and is essential in the production of sperm. In women, testosterone plays a role in egg development and ovulation.

The science is clear: Men’s body fat drains testosterone. We’re not talking pinchable back fat or squishable love handles. We’re talking classic belly fat. In medical parlance, it’s called visceral fat. Unlike fat that lies just beneath the surface of the skin, visceral fat nestles deep in the abdomen around the organs. It’s tenacious, dangerous, and hormonally active. The more visceral fat a man has, the higher his risk of type 2 diabetes, heart disease, high cholesterol, hypertension, insulin resistance, and colon cancer.
The potential downside of this positive feedback loop, Coates argues, is that testosterone levels can eventually surge past optimal levels and have the opposite effect – leading to overconfidence and poor decision-making. When this happens to animals, Coates, observed, they “go out in the open, pick too many fights [and] patrol areas that are too large…Risk taking becomes risky behaviour.”
Another recent development is the production of adhesive tablets which are applied twice daily to the buccal mucosa on the gum above the incisor teeth. The tablets gradually release testosterone into the systemic venous circulation and steady state physiological concentrations are achieved in most patients within two days (Ross et al 2004). Some patients do not like the feeling of the tablet in the mouth or find that there is an abnormal taste in the mouth, but local adverse effects are usually mild and transient (Wang, Swerdloff et al 2004).
I am 50 yrs old. I tried to go the route my urologist provide of 50mgs of injectable test weekly. No man can live on that dose. For the past five years I have self administered injectable cyponate at the rate of 250 mgs to 750 mgs weekly. Non stop , no breaks. I have polycythemia from these injections. I give blood every 8 weeks to combat this. I have administered 10 X the recommended dose with no bad side effects. I get full blood work done yearly. Doctors are so scared they will get sued if something happens that they wont give you enough. Its a shame.

The most popular way is to combine with a good tasting protein powder. Advanced BCAA’s taste very bitter due to the high amount of peptides. Peptides taste very bitter. You want to use 1 tsp of Advanced BCAA’s with every serving of protein powder. This will really upgrade the quality of the protein powder by adding BCAA, AND in peptides form. If you are using a whey protein you’ll increase the overall BCAA content by over 20%
This information is not designed to replace a physician's independent judgment about the appropriateness or risks of a procedure for a given patient. Always consult your doctor about your medical conditions. Vertical Health & EndocrineWeb do not provide medical advice, diagnosis or treatment. Use of this website is conditional upon your acceptance of our user agreement.
14. Volek JS, Volk BM, Gómez AL, Kunces LJ, Kupchak BR, Freidenreich DJ, Aristizabal JC, Saenz C, Dunn-Lewis C, Ballard KD, Quann EE, Kawiecki DL, Flanagan SD, Comstock BA, Fragala MS, Earp JE, Fernandez ML, Bruno RS, Ptolemy AS, Kellogg MD, Maresh CM, Kraemer WJ. Whey protein supplementation during resistance training augments lean body mass. J Am Coll Nutr. 2013;32(2):122-35. PMID: 24015719

Since 2004, Andro400 has been the leader among natural testosterone boosters with a proven track record of successfully helping tens of thousands of customers increase their testosterone safely without side effects. Andro400 contains only the most highly researched and time-tested ingredients proven to naturally increase T levels. Enjoyed by men (and women) of all ages and results are backed by the industry's leading Satisfaction Guarantee.


The unsexy truth is that increasing T naturally simply comes down to making some long-term changes in your diet and lifestyle. As you’ll see, what I did to increase T largely boils down to eating better, exercising smarter, and getting more sleep. That’s pretty much it. But as with most things in life, the devil is in the details, so I’ll share with you exactly what I did and provide research that explains why the things I did helped boost my testosterone.
Research shows that bone density increases with testosterone treatment as long as the dose is high enough. on the effect of testosterone on bone density found increases in spinal and hip bone density. Another of females transitioning into males found that testosterone increased bone mineral density. But it’s unknown if testosterone can help with reducing fracture risk.
Testosterone causes prostate cancer. Since the 1940s, it was commonly believed in the medical field that high testosterone levels were the cause of prostate cancer in men. Doctors reached this conclusion because two scientists in 1941 noticed that prostate cancer regressed in a patient after they castrated him and his T levels subsequently declined. This conclusion was based on the results from a single patient!
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. 
“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.
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.
In my late 40’s I was on Androgel. I lost weight and gained muscle; became healthier over all, brighter outlook, more active, and a harder erection that had a mind of it’s own. Then I went on injectable testosterone. My numbers are normal but my weight is up even after eating less. As well everything else is shelter smelter. I intend to get back to Androgel. (this, of course, is my own personal study)
Stored food in glassware and never, ever, ever heated food in plastic containers. Most modern plastics contain phthalates. Phthalates are what give plastic their flexibility, durability, and longevity. But they also screw with hormones by imitating estrogen. Because I didn’t want any of those T-draining molecules in my food, I kept all my food in glassware. I also made sure to never heat food in plastic containers, as heat increases the transfer of phthalates into food.

“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. 
Why is there no information on the increase of estrogen when on Testosterone replacement therapy? I have been on t replacement for about 2 years and over that time my balls have gotten to the size of a large grape. I have fatty tissue on my chest and my estrogen level is over 400. There needs to be a study created to test all of these side effects and posable treatments like estrogen lowering drugs and HCG for maintaining Testicle size.
I was depressed, getting fat, and zero libido. My doc did a full blood work up. My Total Testosterone level was 289 ng/dl. He offered TRT but I declined because I knew, at 53, that if I went on TRT my own testosterone production would shut down and at my age I would have a pretty difficult time kick starting it up again. I researched and researched for about a month. I started on Vitamin D 10,000 iu per day ( I knew this was a safe amount because I tested at 26ng/dl and optimum level is anywhere between 40-80ng/dl. I also took 1,200 mg of magnesium, 9mg of Boron and Vitamin K Complex. Tested again 3 months later and blood work showed I was at 720.

Likewise, there are also natural ways to pep up your testosterone through diet, exercise and other lifestyle changes. So if you’re the wrong side of 30 and not feeling as strong in the gym anymore, or if you’re gaining weight where there wasn’t weight before, or if you can't find the energy to finish the day, let alone pleasure your partner, then keep reading — our expert advice may restore you to the peak of masculinity.


Let’s first start off by saying, there is no comparison of natural testosterone boosters to synthetic.  When referring to synthetic, we’re talking anabolic steroids.  At that point, you’re comparing apples and oranges.  Which is best—natural or synthetic?  Synthetic.  It is much easier to put on quality muscle mass while using anabolics than it is using a natural testosterone booster.  One is basically giving you synthetic testosterone while the other is giving you a minor boost in natural testosterone production.  However, not only are there side effects to the use of anabolics, but they are also illegal in the United States unless used under a doctor’s supervision with a prescription.
In this podcast, I will review the key biomarkers for achieving peak male health, along with the most potent and effective practices for optimizing biological variables for men's fertility and longevity. I will also unveil a host of little-known biohacks proven to enhance or restore peak testosterone and drive, along with how to practically implement a blend of ancestral wisdom and modern science to amplify sexual performance.
NHT works to reach a targeted level of hormones in your body, restoring your body’s natural ability to keep healthy and fit. Hormones are beneficial at any age, but most commonly we administer the therapy to people in their 40’s, when your body naturally begins to slow production of certain hormones. Supplementing these declining hormones can keep your body fit and active for much longer. Bio-identical hormones are made from plants and are identical to the hormones naturally produced by your own body. We never use synthetic hormones, which have been shown to increase your risk of heart disease and diabetes.
I am 35 and had the non sexual symptoms for awhile now( weight gain/muscle loss, extreme fatigue, lack of clarity/concentration) I got my testosterone levels checked last week and it was 35.4 ng. Not a typo, 35.4. I was told by my dr. That I needed to start TRT right away as low t can effect a lot different things in your body. I did my first injection last night (200mg/ml every 2 weeks) about 8 pm and td now 3:30 am and I’m wide awake and feel extremely motivated to go to the gym and work out. I know each person is different but should I feel like this already, or is it a placebo effect at this point?
Herbalists have used _Trifolium pratense_, red clover, to treat menopausal symptoms like hot flashes. The mechanisms underlying these effects remain unknown. Testosterone decreases hot flashes in some postmenopausal women, so red clover may work in this way. A 2015 paper in the Avicenna Journal of Phytomedicine reviewed the literature testing this idea.
Infertility in men and women Infertility or a couple being unable to conceive a child can cause significant stress and unhappiness. There are numerous reasons for both male and female infertility but many ways in which medical assistance can overcome problems that people may face. Everything concerning infertility is discussed and explained here. Read now

When I told people that I was doing an experiment to increase my testosterone, the question that people would invariably ask in hushed tones was, “So, did it, you know, improve your sex life?” Honestly, I didn’t see too much change. I had a robust and healthy sex life before the experiment and continued to do so afterwards. I guess I was a bit more randier than usual, but not much. I’d imagine if you had been suffering from low T for a long time and took steps to increase it, you’d likely see improvement in the bedroom department.

Our bodies make testosterone while we sleep. In one study, men who got five hours of sleep a night had testosterone levels 10 to 15 percent lower than when they got a solid eight hours. The study, conducted by the University of Chicago, found that skimping on sleep reduced the men’s T levels by an amount equivalent to aging 10 or more years. While it can be challenging to change your sleep habits, says Natasha Turner, ND, you can “start going to bed 15 minutes earlier each week until you reach your target time.”


Such sort of injuries varies in severity and extent of damage markedly from one person to the other and withdrawal of the drug/supplement coupled with proper medical attention suffice in terms of alleviating the symptoms.[8,12] This was observed in the present case. However, the liver injury observed here may not be confidently linked to product consumption as the subject later reported that the following recovery he consumed two more courses of the booster with no side effects. Tests performed following hospital discharge, and repeated use of the product showed AST and ALT to be slightly high, whereas the rest of the blood parameters tested appeared to be normal. The AST/ALT ratio is considered to be a very important parameter for the evaluation of liver diseases, such as non-alcoholic fatty liver disease,[13] though it is rarely considered alone. Overall, the evidence was inconclusive in the present work in terms of linking the use of a testosterone booster with liver injury. However, even though a single case report cannot establish causality with statistical power.[13] Further research on the usage of a commercial testosterone booster within large populations for a long period is necessary to investigate whether the symptoms shown in the present case were significantly present in other athletes consuming the same commercial product or not. To guarantee an optimal outcome with no severe side effects, further research is warranted to confirm the present findings and determine whether the effects observed in this case report would be statistically significant in larger samples.
Since 2004, Andro400 has been the leader among natural testosterone boosters with a proven track record of successfully helping tens of thousands of customers increase their testosterone safely without side effects. Andro400 contains only the most highly researched and time-tested ingredients proven to naturally increase T levels. Enjoyed by men (and women) of all ages and results are backed by the industry's leading Satisfaction Guarantee.
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.
2009 had heart attack, placed coronary stent, everything okay. Put on statins to keep lipid levels down to prevent further artery blockage. One year later developed Peyronie’s disease, low sex drive, fatigue, testicles withdrawn and hurting. Testosterone level was 85. Diagnosed with hypogonadism. Started Androgel, felt normal after a couple of weeks. I believe statins is the cause of my low T, you need lipids for hormone transport. Androgel could only bring my T level in the 250 range. Switched to Axiron (better, less messy), and my T level stays around 500 range. I get samples of Testim every now and then, it has a manly woody fragrance that women like. At present, I’m feeling a little fatigue, and mild dehydration. My lab work is always normal, except my red blood cells is always on the high side, almost abnormal. Next week I am going to donate some blood, to bring my RBC count down, and see if that will help.
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.
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:
It’s worth emphasizing that these supplements are totally legit. They’re NOT steroids. Meaning, only the natural and harmless ingredients have been used to make these products, which can help the guys dealing with the low testosterone problems, such as low energy, fatigue, muscle loss, irritability, and similar. Usually, the guys tend to start experience these problems in their late 20s and in some cases in their early 30s.

Ten healthy men aged around 24 years old spent 1 week sleeping for 8 hours per night at home, they then spent the next 11 nights in a lab. They slept for 10 hours per night for 3 nights, followed by 8 nights of restricted sleep, when they slept for only 5 hours. Doctors checked their blood every 15 to 30 minutes during the last night that they slept 10 hours, as well as on the sleep-restricted session.


A: Testosterone products can improve a male's muscle strength and create a more lean body mass. Typically, these effects are not noticed within the first two weeks of therapy, but it is possible that he is more sensitive and responds well to the therapy. Some of the other more common side effects of testosterone patches are headache, depression, rash, changes in libido, acne, male pattern baldness, and increased cholesterol levels. This is not a complete list of the side effects associated with testosterone patches. Megan Uehara, PharmD

Hi.i have a simple question…I AM 60 YEARS OLD and my free testosterone is 7… and my regular testosterone is 700+…I really need TRT …and in case yes i need it the doctor said if i start i need to do it for the rest of my life !!! he said is not coming back!!! ..i don’t know is true or not??? With my testosterone levels i need or not to do TRT???..i am going in gym daily and i feel good in general …all my blood results are perfect …///Again if i take the TRT will help me in general ??or is better to not use the “TRT”..Thank you for your time to answer HONEST for my question ..I ask this because i don’t know what to do ..i don’t want to do something wrong???…!!!..ps .if is possible to answer me on my email ..Thank you v v much and GOD BLESS YOU …Chris…R…
Beast Sports Nutrition - Super Test has all four of our dream ingredients: magnesium, fenugreek, longjack, and zinc. These ingredients have all been demonstrated to help increase natural testosterone levels, with plenty of scientific research to support them (done on humans too, and not just rats). By combining all four ingredients, Super Test has the best chance of helping to increase your testosterone levels, and thereby helping you gain muscle or have a more active sex life.
Japanese Knotweed (a.k.a Hu Zhang or Polygonum cuspidatum) is highlighted by WebMD as needing more evidence to rate its effectiveness in a number of different areas: like treating constipation and liver or heart disease. They also warn that it can interact poorly with medications that are changed and broken down by the liver, and those that slow blood clotting (anticoagulants and antiplatelets).
If you are serious about losing weight, you have got to strictly limit the amount of processed sugar in your diet, as evidence is mounting that excess sugar, and fructose in particular, is the primary driving factor in the obesity epidemic. So cutting soda from your diet is essential, as is limiting fructose found in processed foods, fruit juice, excessive fruit and so-called "healthy" sweeteners like agave.
Epidemiological evidence supports a link between testosterone and glucose metabolism. Studies in non-diabetic men have found an inverse correlation of total or free testosterone with glucose and insulin levels (Simon et al 1992; Haffner et al 1994) and studies show lower testosterone levels in patients with the metabolic syndrome (Laaksonen et al 2003; Muller et al 2005; Kupelian et al 2006) or diabetes (Barrett-Connor 1992; Andersson et al 1994; Rhoden et al 2005). A study of patients with type 2 diabetes using measurement of serum free testosterone by the gold standard method of equilibrium dialysis, found a 33% prevalence of biochemical hypogonadism (Dhindsa et al 2004). The Barnsley study demonstrated a high prevalence of clinical and biochemical hypogonadism with 19% having total testosterone levels below 8 nmol/l and a further 25% between 8–12 nmol/l (Kapoor, Aldred et al 2007). There are also a number longitudinal studies linking low serum testosterone levels to the future development of the metabolic syndrome (Laaksonen et al 2004) or type 2 diabetes (Haffner et al 1996; Tibblin et al 1996; Stellato et al 2000; Oh et al 2002; Laaksonen et al 2004), indicating a possible role of hypogonadism in the pathogenesis of type 2 diabetes in men. Alternatively, it has been postulated that obesity may be the common link between low testosterone levels and insulin resistance, diabetes and cardiovascular disease (Phillips et al 2003; Kapoor et al 2005). With regard to this hypothesis, study findings vary as to whether the association of testosterone with diabetes occurs independently of obesity (Haffner et al 1996; Laaksonen et al 2003; Rhoden et al 2005).
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