Studies of the effects on cognition of testosterone treatment in non-cognitively impaired eugonadal and hypogonadal ageing males have shown varying results, with some showing beneficial effects on spatial cognition (Janowsky et al 1994; Cherrier et al 2001), verbal memory (Cherrier et al 2001) and working memory (Janowsky et al 2000), and others showing no effects (Sih et al 1997; Kenny et al 2002). Other trials have examined the effects of testosterone treatment in older men with Alzheimer’s disease or cognitive decline. Results have been promising, with two studies showing beneficial effects of testosterone treatment on spatial and verbal memory (Cherrier et al 2005b) and cognitive assessments including visual-spatial memory (Tan and Pu 2003), and a recent randomized controlled trial comparing placebo versus testosterone versus testosterone and an aromatase inhibitor suggesting that testosterone treatment improves spatial memory directly and verbal memory after conversion to estrogen (Cherrier et al 2005a). Not all studies have shown positive results (Kenny et al 2004; Lu et al 2005), and variations could be due to the different measures of cognitive abilities that were used and the cognitive state of men at baseline. The data from clinical trials offers evidence that testosterone may be beneficial for certain elements of cognitive function in the aging male with or without cognitive decline. Larger studies are needed to confirm and clarify these effects.

A recent study compared total and bioavailable testosterone levels with inflammatory cytokines in men aged 65 and over. There was an inverse correlation with the pro-inflammatory soluble interleukin-6 receptor, but no association with interleukin-6 (IL-6), highly sensitive CRP (hsCRP), tumor necrosis factor-α (TNF-α) or interleukin-1β (IL-1β (Maggio et al 2006). Another trial found that young men with idiopathic hypogonadotrophic hypogonadism had higher levels of proinflammatory factors interleukin-2 (IL-2), interleukin-4 (IL-4), complement C3c and total immunoglobulin in comparison to controls (Yesilova et al 2000). Testosterone treatment in a group of hypogonadal men, mostly with known coronary artery disease, induced anti-inflammatory changes in the cytokine profile of reduced IL-1β and TNF-α and increased IL-10 (Malkin, Pugh, Jones et al 2004).
Using steroids eventually trains your body to realize that it doesn’t have to produce as much testosterone to reach its equilibrium, so to reach the same highs you’ll need to take more steroids, and when you stop taking them, your body will need to readjust — you’ll be living with low testosterone for a while (and you’ll need to see a doctor if your body doesn’t readjust on its own). Forcing your body to stay above your natural testosterone, even if you’re naturally low, can create this kind of dependency which ultimately decreases the amount of testosterone your body will produce on its own.
Before a boy is even born, testosterone is working to form male genitals. During puberty, testosterone is responsible for the development of male attributes like a deeper voice, beard, and body hair. It also promotes muscle mass and sex drive. Testosterone production surges during adolescence and peaks in the late teens or early 20s. After age 30, it’s natural for testosterone levels to drop by about one percent each year.
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.
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.
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"I am so thankful to your company. I have lost 50 lbs. and went from a size 38 waist to an unbelievable 30! I am 56 years old, and now with Andro 400, I feel like I am 25 again. I was taking ramipril for high blood pressure and celebrex for my arthritis. Gone!!! My doctor has not seen a transformation like mine ever! Exercise used to be a chore -- now I have the energy to jog, exercise and be intimate with my partner when we share our love for each other. My mood has changed. I don't get stressed out anymore. I'm so happy now. I'm just a completely different man! Thank you, thank you, thank you!"
Trials of testosterone treatment in men with type 2 diabetes have also taken place. A recent randomized controlled crossover trial assessed the effects of intramuscular testosterone replacement to achieve levels within the physiological range, compared with placebo injections in 24 men with diabetes, hypogonadism and a mean age of 64 years (Kapoor et al 2006). Ten of these men were insulin treated. Testosterone treatment led to a significant reduction in glycated hemoglobin (HbA1C) and fasting glucose compared to placebo. Testosterone also produced a significant reduction in insulin resistance, measured by the homeostatic model assessment (HOMA), in the fourteen non-insulin treated patients. It is not possible to measure insulin resistance in patients treated with insulin but five out of ten of these patients had a reduction of insulin dose during the study. Other significant changes during testosterone treatment in this trial were reduced total cholesterol, waist circumference and waist-hip ratio. Similarly, a placebo-controlled but non-blinded trial in 24 men with visceral obesity, diabetes, hypogonadism and mean age 57 years found that three months of oral testosterone treatment led to significant reductions in HbA1C, fasting glucose, post-prandial glucose, weight, fat mass and waist-hip ratio (Boyanov et al 2003). In contrast, an uncontrolled study of 150 mg intramuscular testosterone given to 10 patients, average age 64 years, with diabetes and hypogonadism found no significant change in diabetes control, fasting glucose or insulin levels (Corrales et al 2004). Another uncontrolled study showed no beneficial effect of testosterone treatment on insulin resistance, measured by HOMA and ‘minimal model’ of area under acute insulin response curves, in 11 patients with type 2 diabetes aged between 33 and 73 years (Lee et al 2005). Body mass index was within the normal range in this population and there was no change in waist-hip ratio or weight during testosterone treatment. Baseline testosterone levels were in the low-normal range and patients received a relatively small dose of 100 mg intramuscular testosterone every three weeks. A good increase in testosterone levels during the trial is described but it is not stated at which time during the three week cycle the testosterone levels were tested, so the lack of response could reflect an insufficient overall testosterone dose in the trial period.
Zinc: Another potent ingredient to add to any testosterone booster is zinc. This study shows how zinc is able to prevent a decline in testosterone levels during intense and hard workouts performed by wrestlers. Researchers found that the group who was administered with a placebo had a reduction in testosterone, as opposed to the group who were supplemented with zinc. The placebo group had a notable drop in their testosterone count during this process. Zinc has also been shown to increase the number of free testosterone and lower SHBG.
Ashwagandha is sometimes included in testosterone supplements because of the hypothesis that it improves fertility. However, we couldn’t find sufficient evidence to support this claim (at best, one study found that ashwagandha might improve cardiorespiratory endurance). WebMD advocates caution when taking this herb, as it may interact with immunosuppressants, sedative medications, and thyroid hormone medications.
Using steroids eventually trains your body to realize that it doesn’t have to produce as much testosterone to reach its equilibrium, so to reach the same highs you’ll need to take more steroids, and when you stop taking them, your body will need to readjust — you’ll be living with low testosterone for a while (and you’ll need to see a doctor if your body doesn’t readjust on its own). Forcing your body to stay above your natural testosterone, even if you’re naturally low, can create this kind of dependency which ultimately decreases the amount of testosterone your body will produce on its own.
More can be learned from a large, randomized, placebo-controlled trial of finasteride treatment in 18,800 men aged 55 or more. Finasteride is a 5α-reductase inhibitor which acts to prevent the metabolism of testosterone to dihydrotestosterone (DHT) – the most active androgen in the prostate. The trial showed a greater overall incidence of prostate cancer in the control group, but men treated with finasteride were more likely to have high grade tumors (Thompson et al 2003), suggesting that reduced androgen exposure of the prostate may delay the presentation of prostate cancer and/or promote advanced disease in some other way.
Hello I’m 22 years old and for years I’ve been struggling with hypothyroidism and depression. Recently I went to check my blood for low T and was shocked but not surprised at the level (125). That’s terrible for a 22 year old given that’s the time my testosterone is supposed to be the highest. Anyways I’ve been prescribed depo testosterone 200ml bottle. I give myself a shot each week and haven’t really noticed much change. I know I have to give it time, but is there anything else I can do or should be prescribed to help speed up the process?

Testosterone increases dominance and the desire for power. The link between testosterone and dominance has been demonstrated in numerous studies. T motivates men to gain and maintain social status. The desire for dominance can be a bad thing if it leads to criminal behavior, but it’s also what fuels the climb for success, motivates men to resist oppression and buck authority, and may even help you with the ladies…


In the early days of testosterone boosters, the ingredients used were not placed or based on clinical trials that proved the effectiveness of each of them. Most testosterone boosters were compiled with ingredients that were coming from the mouth of a bro scientist, so to speak. These ingredients had no real evidence to back their effects on testosterone production.
Sergeant Steel ran into trouble here because it contains Shilajit — a type of plant-based resin. Shilajit is banned in Canada because the Canadian government found heavy metal levels when investigating the ingredient. Shilajit is hard to find, and sensitive to water and variations in temperature, so most manufacturers mix it with additives to make it more stable. Research at Boston University School of Medicine found that “nearly 21 percent of 193 ayurvedic herbal supplements [...] contained lead, mercury or arsenic,” and included shilajit on the list of contaminated ingredients. Even though Sergeant Steel lists its shilajit is “purified,” it doesn’t offer any third-party testing to confirm whether or not their shilajit contains heavy metals, and so we cut it.
Epidemiological data has associated low testosterone levels with atherogenic lipid parameters, including lower HDL cholesterol (Lichtenstein et al 1987; Haffner et al 1993; Van Pottelbergh et al 2003) and higher total cholesterol (Haffner et al 1993; Van Pottelbergh et al 2003), LDL cholesterol (Haffner et al 1993) and triglyceride levels (Lichtenstein et al 1987; Haffner et al 1993). Furthermore, these relationships are independent of other factors such as age, obesity and glucose levels (Haffner et al 1993; Van Pottelbergh et al 2003). Interventional trails of testosterone replacement have shown that treatment causes a decrease in total cholesterol. A recent meta-analysis of 17 randomized controlled trials confirmed this and found that the magnitude of changes was larger in trials of patients with lower baseline testosterone levels (Isidori et al 2005). The same meta-analysis found no significant overall change in LDL or HDL cholesterol levels but in trials with baseline testosterone levels greater than 10 nmol/l, there was a small reduction in HDL cholesterol with testosterone treatment.
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.
Cognitive abilities differ between males and females and these differences are present from childhood. In broad terms, girls have stronger verbal skills than boys who tend to have stronger skills related to spatial ability (Linn and Petersen 1985). It is thought that the actions of sex hormones have a role in these differences. Reviewing different cognitive strengths of male versus female humans is not within the scope of this article but the idea that cognition could be altered by testosterone deserves attention.
First is quality, Advanced BCAA’s are made from whey protein isolate. Typical free form amino acids are made from human hair and other not so favorable sources. In addition many free form amino acids are made in China. Secondly is the “form” the amino acids are in. Advanced BCAA’s are in peptide form. Meaning they are in di and trip peptide form. The body ABSORBS amino acids in di and trip peptide form, through the intestinal wall and into the blood stream. It is still not known whether free form amino acids are absorbed by the body. Keep in mind that free form amino acids supplements have been around since the 80’s. They have never been proved to help muscle recovery and grow. Di and tri peptides have been proven to be beneficial for muscle recovery.

Testosterone boosters are supplementary substances that can be used for the purpose of increasing testosterone levels in the blood. This study aimed to evaluate the side effects and health risks of testosterone boosters among athletes. A sportsman came to the King Saud Hospital, Unaizah, Qassim, Saudi Arabia, suffering from abdominal pain. The attending doctor requested general laboratory tests. He admitted to having consumed two courses of a testosterone booster over a period of 42 days following the instructions of the manufacturer. In total, the athlete in question consumed several courses, twice before the abdominal pain started and twice after it subsided. The blood tests and reports suggested that the commercial product consumed might negatively affect several hepatic functions and resulted in slightly increased testosterone concentrations after the fourth course. In conclusion, administration of testosterone booster products, although obtained from trusted sources, may still present some health risks. Further studies with large sample size and for a long period need to be done to confirm the current findings.


“I have seen them work for people,” says GP and hormonal therapy expert at Omniya London, Dr Sohere Roked. “I think sometimes people feel that it’s not a good thing to do or they’re just wasting their time taking it, but I have seen people who combine that with a good diet and exercise and have noticed a change in their physique, their energy, their mood, and the sort of things that testosterone would naturally help.”

There’s a significant failure rate of the PDE5 inhibitors for erectile dysfunction, something on the order of 25% to 50%, depending on the underlying condition. It turns out that a third of those men will have adequate erections with testosterone-replacement therapy alone and another third will have adequate erections with the pills and testosterone combined. There’s still a third who don’t respond, but normalizing their testosterone level has definitely rescued many men who had failed on PDE5 inhibitors.
A man with shrinking levels of testosterone actually may lose some body hair. Testosterone replacement therapy comes with a few potential side effects, including acne and breast enlargement. Testosterone patches may cause minor skin irritation. Topical gels may be easier to use, but great care must be taken to avoid transferring testosterone to someone else though skin-to-skin contact.

Oral/buccal (by mouth). The buccal dose comes in a patch that you place above your incisor (canine or "eyetooth"). The medication looks like a tablet but you should not chew or swallow it. The drug is released over 12 hours. This method has fewer harmful side effects on the liver than if the drug is swallowed, but it may cause headaches or cause irritation where you place it.
This is the best BCAA supplement ever created.  You see this is not your typical BCAA supplement that all the other supplement companies sell.  Those products are simply free-form amino acids made by some Chinese manufacturer and packaged in the United States.  Free form amino acid supplements have been around since the 1980’s and they have never been proven to be helpful in building muscle mass.  In fact after whey protein came out in the 90’s it really made BCAA amino acids obsolete because whey protein contains over 30% BCAA.  If you want more BCAA’s simply use another scoop of whey protein instead of BCAA powder.  Its cheaper, tastes better, and contains plenty of BCAA plus all the other amino acids.  Ok so now that I have convinced you that free form BCAA’s supplements are pretty much worthless let me tell you about our new Advanced BCAA’s.
Testosterone therapy improves body composition (increase in lean body mass, decrease in fat mass) in men with hypogonadism.1 There is a supplementary improvement in muscle strength and physical function. The benefits of testosterone treatment on body composition have consistently been demonstrated in clinical studies of testosterone therapy in hypogonadal men or men with borderline low testosterone levels,1,6,8,12,13 and confirmed by systematic reviews or meta-analyses of randomized controlled trials.4,5,6,13
I definitely enjoyed an increase in muscle mass during my experiment. Despite dropping six percentage points in body fat in three months, my weight stayed about the same; I began the experiment weighing 185 pounds and I ended it weighing the same. The body fat I lost was replaced with muscle. It was fun to see and hear Kate’s reaction when I’d take off my shirt to get into the shower. “Whoa! Your muscles have gotten huge!”
Our clients love the results and energy they’ve get once their hormonal levels are fully balanced. Because hormones are so important, we’re proud to lend our medical expertise to ensure all our hormonal treatments are tailored to your specific needs. If you’re curious about NHT, you can take a short quiz to see if NHT would be a good fit for your body.
I’ve been reading all these comments and replies here. This was a great article and if it does anything, it should stimulate you to talk to your physician. Your Dr. can take blood and have it annylized, then prescribe the proper direction to take. A lot of people here have been giving free advice, but who knows your system best? Am I going to take advice from someone who doesn’t know anything other than the symptoms I present? I’m not, but what if I’m allergic?

In high-fat high-furctose fed rats, ginger neutralized diet induced impairment in glucose regulation, dyslipidemia, and oxidative stress [28]. This observed anti-diabetic activity of ginger powder is credited to two active components: 6-paradol and 6-shogaol [29]. They both exhibit potent activity in stimulating glucose utilization by 3T3-L1 adipocytes and C2C12 myotubes. In the high-fat diet mouse model, 6-paradol decreased blood glucose, cholesterol and body weight.
More can be learned from a large, randomized, placebo-controlled trial of finasteride treatment in 18,800 men aged 55 or more. Finasteride is a 5α-reductase inhibitor which acts to prevent the metabolism of testosterone to dihydrotestosterone (DHT) – the most active androgen in the prostate. The trial showed a greater overall incidence of prostate cancer in the control group, but men treated with finasteride were more likely to have high grade tumors (Thompson et al 2003), suggesting that reduced androgen exposure of the prostate may delay the presentation of prostate cancer and/or promote advanced disease in some other way.

Exercise boosts testosterone in two important ways. First, specific types of exercise actually cause our body to produce more testosterone. We’ll talk more about those in a bit. Second, exercise helps to increase muscle mass and decrease body fat. As we’ve discussed previously, adipose tissue converts testosterone into estrogen. The less fat we get, the more T we have.
Maybe someone could help me out here. I am a 21 year old former college football player and have been experiencing low test for a while now, about a year ago i went in to see my doctor, and after becoming an expert over the subject thanks to the internet, i told him that i thought it had to be my testosterone level. So he had me come back the next day and got a level of 107ng/dL. He was shocked to say the least. He referred me to an IDIOT endocrinologist, and he which tested me again and got a level of 187. He said to do nothing for the next 3 MONTHS and levels should be 700-900… Yeah well about 4 months later, which was last week, i had to go in, there is some serious shit wrong with me, physically, mentally, you name it. The level came back at 57ng/dL… They said we need to run further tests… WTF is going on, i am dying here. What do i do people???
^ 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.
When many people think of someone with a high level of testosterone, they may picture a man loaded with strength, sexual prowess, and machismo. But while high-T has been correlated with all those things, it’s also been correlated with aggression, sexual misconduct, and violence. One of testosterone’s most common uses—as a performance-enhancing steroid—illustrates both sides of the hormone. Injecting steroids can be a quick way for athletes to dramatically improve performance, but the side effects can also be extreme, and can include excessive body hair growth, sexual dysfunction, and the hard-to-corral anger known as “roid rage.”
D-AA:  D-Aspartic Acid has been known to increase libido and sex drive as well as fertility in infertile men. D-AA was the craze a few years back but the issue found was that after a month of use, the results started to diminish.  Also, if you currently have normal levels of testosterone, D-AA won’t do much good for you in terms of an increase in T-levels. 
I need an answer regarding getting testoroene after having your Prostate removed. I had my Prostate removed 3 months ago and my PSA levels are zero. I want to go back on testoroene because I felt great when I was on it before having my prostate taken out. I am 44 years old and I workout 4-5 days a week hard. I am in excellent shape and I didn’t have any symptoms of prostate cancer other then my PSA levels went up.
Stress less – I know this is easier said than done but if you can reduce your stress levels it will help your testosterone production. This is because stress makes your body produce cortisol which has many negative effects on the body including being a testosterone killer. Try meditating, exercising, deep breathing and other lifestyle changes to keep stress down and cortisol in check.
Another study in 2015 by Melville and friends gave subjects either three or six grams of DAA per day for a 14 days (2 weeks). Researchers noted that the 3g dose of D-aspartic acid did not result in any meaningful changes in testosterone levels (or any other anabolic hormones for that matter).[3] However, the group of men receiving 6g per day experienced a significant reduction in both total testosterone and free testosterone levels, with no concurrent change in other hormones tested.[3]
Also, for those with abnormal fatigue. It’s being found too often that hypogonadism is pared with another abnormality of the endocrine system called Hypothyroidism which causes intense fatigue and even alzheimer like cognitive disruption. Both the Testis and Thyroid need to receive signaling hormones from the Pituitary to function correctly and the Pituitary relies heavily on the Hypothalamus. Simple blood tests can check all of those. It is important you find out the reason you have low Testosterone!
To get your levels into the healthy range, sun exposure is the BEST way to optimize your vitamin D levels; exposing a large amount of your skin until it turns the lightest shade of pink, as near to solar noon as possible, is typically necessary to achieve adequate vitamin D production. If sun exposure is not an option, a safe tanning bed (with electronic ballasts rather than magnetic ballasts, to avoid unnecessary exposure to EMF fields) can be used.
Cross-sectional studies conducted at the time of diagnosis of BPH have failed to show consistent differences in testosterone levels between patients and controls. A prospective study also failed to demonstrate a correlation between testosterone and the development of BPH (Gann et al 1995). Clinical trials have shown that testosterone treatment of hypogonadal men does cause growth of the prostate, but only to the size seen in normal men, and also causes a small increase in prostate specific antigen (PSA) within the normal range (Rhoden and Morgentaler 2005). Despite growth of the prostate a number of studies have failed to detect any adverse effects on symptoms of urinary obstruction or physiological measurements such as flow rates and residual volumes (Snyder et al 1999; Kenny et al 2000, 2001). Despite the lack of evidence linking symptoms of BPH to testosterone treatment, it remains important to monitor for any new or deteriorating problems when commencing patients on testosterone treatment, as the small growth of prostate tissue may adversely affect a certain subset of individuals.
You may be interested in boosting your testosterone levels if your doctor says you have low levels, or hypogonadism, or need testosterone replacement therapy for other conditions. If you have normal testosterone levels, increasing your testosterone levels may not give any additional benefits. The increased benefits mentioned below have only been researched in people with low testosterone levels.

Thanks for reaching out, looks like you’re in a difficult situation here, but don’t worry, you can turn it around. For starters I would focus on getting your stress under control, this has a direct impact on your T-levels. Then look at your diet. Try to eat healthy fats, along with good carbs, and proteins. I’d recommend cutting down on anything containing sugar – again it’s testosterone worst nightmare. If you really want to kick it up a gear, and it sounds as if you do, we recommend using testofuel.com – its’ by far the best natural testosterone booster on the market – you won’t be disappointed! Good luck my friend.
Hi my names Graham. I’ve suffered with Gyno for most of my adult life. Even when I’ve lost a ton of weight , those two unhelpful bags of fat are still there. To save me 4 to 6 grand on liposuction or surgery, will an estrogen blocker and testosterone booster help. I’ve also heard of a cream called andractim that can help , but they are expensive. Any advice would be great . Thanks.
Low testosterone levels have a dramatic effect on emotional state. The American Academy of Family Physicians lists depression, impaired cognition and increased fatigue as symptoms of low testosterone production, or hypogonadism. Testosterone replacement therapy for hypogonadal men has successfully reduced negative moods relating to fatigue and depression while increasing feelings of self-esteem. Increasing testosterone in eugonadal men has also shown positive emotional benefits such as increased feelings of self-esteem and reduction of fatigue. The intensity of these benefits is dependent on dosage; a wide body of literature on testosterone increase has shown that at higher dosage aggression, and aggressive response, can become pronounced.
Mínguez-Alarcón, L., Chavarro, J. E., Mendiola, J., Roca, M., Tanrikut, C., Vioque, J., ... Torres-Cantero, A. M. (2017, March–April). Fatty acid intake in relation to reproductive hormones and testicular volume among young healthy men [Abstract]. Asian Journal of Andrology, 19(2), 184–190. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/27834316

Studies of the effects on cognition of testosterone treatment in non-cognitively impaired eugonadal and hypogonadal ageing males have shown varying results, with some showing beneficial effects on spatial cognition (Janowsky et al 1994; Cherrier et al 2001), verbal memory (Cherrier et al 2001) and working memory (Janowsky et al 2000), and others showing no effects (Sih et al 1997; Kenny et al 2002). Other trials have examined the effects of testosterone treatment in older men with Alzheimer’s disease or cognitive decline. Results have been promising, with two studies showing beneficial effects of testosterone treatment on spatial and verbal memory (Cherrier et al 2005b) and cognitive assessments including visual-spatial memory (Tan and Pu 2003), and a recent randomized controlled trial comparing placebo versus testosterone versus testosterone and an aromatase inhibitor suggesting that testosterone treatment improves spatial memory directly and verbal memory after conversion to estrogen (Cherrier et al 2005a). Not all studies have shown positive results (Kenny et al 2004; Lu et al 2005), and variations could be due to the different measures of cognitive abilities that were used and the cognitive state of men at baseline. The data from clinical trials offers evidence that testosterone may be beneficial for certain elements of cognitive function in the aging male with or without cognitive decline. Larger studies are needed to confirm and clarify these effects.
Before a boy is even born, testosterone is working to form male genitals. During puberty, testosterone is responsible for the development of male attributes like a deeper voice, beard, and body hair. It also promotes muscle mass and sex drive. Testosterone production surges during adolescence and peaks in the late teens or early 20s. After age 30, it’s natural for testosterone levels to drop by about one percent each year.
In order to discuss the biochemical diagnosis of hypogonadism it is necessary to outline the usual carriage of testosterone in the blood. Total serum testosterone consists of free testosterone (2%–3%), testosterone bound to sex hormone binding globulin (SHBG) (45%) and testosterone bound to other proteins (mainly albumin −50%) (Dunn et al 1981). Testosterone binds only loosely to albumin and so this testosterone as well as free testosterone is available to tissues and is termed bioavailable testosterone. Testosterone bound to SHBG is tightly bound and is biologically inactive. Bioavailable and free testosterone are known to correlate better than total testosterone with clinical sequelae of androgenization such as bone mineral density and muscle strength (Khosla et al 1998; Roy et al 2002). There is diurnal variation in serum testosterone levels with peak levels seen in the morning following sleep, which can be maintained into the seventh decade (Diver et al 2003). Samples should always be taken in the morning before 11 am to allow for standardization.
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