That said, a group of researchers at the National University of Malaysia did a systemic literature review of longjack, looking for clinical research that demonstrated a relationship between the shrub and testosterone levels. Of 150 articles, only 11 met their inclusion criteria — involving humans and scientifically rigorous. However, of those 11 studies, seven “revealed remarkable association” between using longjack and improving male sexual health, while the remaining four “failed to demonstrate sufficient effects.” The team concluded that longjack looks “promising” when it comes to raising low testosterone, and that there is convincing evidence that it works.
55+ million men in america between 40 and 70 years of age is a large enough group to warrant interest in a thorough study of the aged male delivery system and other sex related issues. There is a good chance there are 55 million women out there wishing for some kind of help also. Those are significant numbers, about 1/3 of the total population and the lions share of the income producers. And the best the medical community can do is speculate at the real cause for a significant cancer? Perhaps prostate cancer is the real cause of global warming, there is no real science unless there is a real paycheck?
It doesn’t get more natural than getting a good night’s sleep. Research published in the Journal of the American Medical Association showed that lack of sleep can greatly reduce a healthy young man’s testosterone levels. That effect is clear after only one week of reduced sleep. Testosterone levels were particularly low between 2 and 10 p.m. on sleep-restricted days. Study participants also reported a decreased sense of wellbeing as their blood testosterone levels dropped.
Testosterone may fight depression. If you’ve been battling the black dog of depression, it may be because of low testosterone levels. Researchers have found that men suffering from depression typically have deficient testosterone levels. While scientists haven’t been able to figure out whether it’s low testosterone that causes depression or if depression causes low T levels, preliminary research has shown that some men suffering depression report improvement in mood and other factors of depression after undergoing doctor-directed testosterone treatments.
Clinical trials of the effect of testosterone on glucose metabolism in men have occurred in diabetic and non-diabetic populations. Data specific to aging males is not available. A series of studies investigated the effects of testosterone or dihydrotestosterone given for 6 weeks or 3 months to middle aged, non-diabetic obese men (Marin, Holmang et al 1992; Marin, Krotkiewski et al 1992; Marin et al 1993). It was found that physiological treatment doses led to improved insulin resistance, as measured by the gold standard technique using a euglycemic clamp and/or serum glucose and insulin responses during glucose tolerance test. These improvements were associated with decreased central obesity, measured by computered tomography (CT) or waist-hip ratio, without reduced total fat mass. Insulin resistance improved more with testosterone than dihydrotestosterone treatment and beneficial effects were greater in men with lower baseline testosterone levels. Increasing testosterone levels into the supraphysiological range lead to decreased glucose tolerance.
The maximum hormone concentration in the blood is reported immediately after the workout. And the effect lasts throughout the day. However, it’s important to ensure that your physical activity is moderate. The matter is that too much high-intensity exercise can give an undesirable result. But even if for any reason you can’t attend a gym, it’s not a problem. Just move as much as possible during the day. Even simple walking will be of great benefit.
Vitamin D is arguably the most important vitamin when it comes to testosterone. A study published in the Journal of Clinical Endocrinology examined the relationship between vitamin D supplementation and testosterone levels in men. The authors found that participants with higher levels of vitamin D had significantly higher levels of free testosterone compared to those with insufficient levels of vitamin D.8 Based on these study results, it appears vitamin D has a strong relationship with testosterone levels.
Ginger (also known as Zingiber officinale, family: Zingiberaceae) has been widely consumed as a dietary spice, delicacy, and as a traditional oriental medicine. The rhizome can be used fresh, dried or powdered. Ginger is often applied for treating nausea due to caused by morning sickness during pregnancy, chemotherapy and seasickness. The ginger rhizome also contains several biologically active compounds such as gingerol, shogaols, gingerdiol and gingerdione .
Topical testosterone, specifically gels, creams and liquids, may transfer to others. Women and children are most at risk of harmful effects from contact with them. You should take care to cover the area and wash your hands well after putting on the medication. Be careful not to let the site with the topical TT touch others because that could transfer the drug.
Then in 2017, Melville carried out another study on DAA. This time he recruited 22 men in a randomized, double-blind fashion and had them consume either a placebo or 6g of DAA. After 12 weeks of supplementation, researchers observed that DAA had no significant impact on resting levels of either free or total testosterone. Any improvements in strength or hypertrophy were similar to those in the placebo group.
If you have low testosterone, your functional medicine or anti-aging physician will help you diagnose it. There are several different hormones your physician should measure, but the most important two are your free testosterone and estrogen levels, because converting too much testosterone to estrogen is a problem that’s different from not making enough testosterone in the first place. In my case, I wasn’t making very much testosterone, and what I was making my body converted to estrogen way too effectively.
Tongkat ali (a.k.a. Longjack, a.k.a. Eurycoma Longifolia) is a foundational compound of Ayurveda, commonly used as an aphrodisiac. Similar to DHEA, longjack has been found to be effective in both men and women for improving libido, total and free testosterone concentrations as well as muscle mass and strength in men and women! And, unlike many of the other old world herbs commonly touted as natural testosterone boosters, longjack actually has a fair amount of human research denoting its benefits.
When you’re under stress (be it from lack of sleep, workplace stress, emotional stress, stress from a bad diet, overtraining etc.), your body releases cortisol. Cortisol blunts the effects of testosterone (47), which makes sense from an evolutionary point of view – if we were stressed as cavemen chances are it was a life or death situation – not running late to a meeting - in this state (i.e. running from a lion) the body wouldn’t care if you couldn’t get it up, there was more to worry about!
Ryan is a former college wrestler and lifelong fitness fanatic. He has run half marathons, done mud runs, placed in body transformation contests, coached wrestling and now coaches girls soccer. Not to mention he has also tried literally hundreds of supplements over the years and has a vast and thorough supplement knowledge. He is also the owner of this website. Feel free connect with him on his LinkedIn page below.
The second theory is similar and is known as "evolutionary neuroandrogenic (ENA) theory of male aggression". Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible. The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game. Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.
Drugs.com provides accurate and independent information on more than 24,000 prescription drugs, over-the-counter medicines and natural products. This material is provided for educational purposes only and is not intended for medical advice, diagnosis or treatment. Data sources include IBM Watson Micromedex (updated 1 Mar 2019), Cerner Multum™ (updated 1 Mar 2019), Wolters Kluwer™ (updated 28 Feb 2019) and others. Refer to our editorial policy for content sources and attributions.
Watch out for ingredients that interfere with blood clotting If you are taking any kind of blood medication, take aspirin or ibuprofen, or have any kind of blood-related condition, you’ll want to consult your doctor before taking any of these supplements. Fenugreek, Forskolin, and Acetyl-L-carnitine are just a few of the ingredients that can make these situations worse and increase your chances of bruising and bleeding.
Tarig Elraiyah, Mohamad Bassam Sonbol, Zhen Wang, Tagwa Khairalseed, Noor Asi, Chaitanya Undavalli, Mohammad Nabhan, Osama Altayar, Larry Prokop, Victor M. Montori, Mohammad Hassan Murad; The Benefits and Harms of Systemic Dehydroepiandrosterone (DHEA) in Postmenopausal Women With Normal Adrenal Function: A Systematic Review and Meta-analysis, The Journal of Clinical Endocrinology & Metabolism, Volume 99, Issue 10, 1 October 2014, Pages 3536–3542, https://doi.org/10.1210/jc.2014-2261
There are several supplements on the market claiming to be natural testosterone boosters. I get these sorts of things in the mail all time. The companies that produce these products claim that the herbs (typically stinging nettle and tribulus) in their pills increase free testosterone by reducing SHBG. They also throw in some B vitamins for “increased energy and vitality.”
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.
Glad to be heard. I have been using 10 times the recommended prescription dose of injectable test over the course of 6 years. Yes, 10 times the recommended dose. I use 250 at the lowest and 1000 mgs a week and sometimes 1200 mgs weekly. I am 50 years old. I look better than 90% of the 25 year olds I see in the gym. I have had zero issues. Acne a little , testicle shrinkage maybe 15%. No big deal. My sex drive is on fire. I bench pressed 340 pound today. I weigh 195 pounds and lean and muscles defined and hard as a rock. Doctors in the USA have no clue what they are doing. They read literature and have no experience or facts about test. They prescribe 50 mgs a week. Way short of what we as men need. Everyone is different, but 250mgs weekly is what we need typically. Injectable is the way to go. Gels are a weak joke. My doctor basically told me he was scared to prescribe more than 50 mgs weekly for fear of being sued if something went wrong. I found my own source and have been on top of the world for 6 years. Father died of prostate cancer. Mine prostate is fine. Prostate cancer from test is another example of ignorance in medical field. I am living proof that one can inject 10 times the recommended rate for the better part of a decade with no probs. I do hope the medical field catches up with the times and stops relying on archaic info.
The mineral zinc is important for testosterone production, and supplementing your diet for as little as six weeks has been shown to cause a marked improvement in testosterone among men with low levels.1 Likewise, research has shown that restricting dietary sources of zinc leads to a significant decrease in testosterone, while zinc supplementation increases it2 -- and even protects men from exercised-induced reductions in testosterone levels.3
As a nurse I am very concerned with following my labs as most of these places don’t actually follow my labs. I also happen to have the side effect of polycythemia and donate 2-3 times a year for this reason. At one point I asked my doctor who referred me to a urologist. At the time I was on 150mg IM with half a dose or 0.5mL twice weekly to avoid the “roller coaster”. Anyways, I went there so I could get some concrete answers as to why I was having low T, this doctor all but threw me out of his office stating that “they” are making me dependent on T. As a professional in the medical field I was highly offended, he didn’t even speak with me about anything at all, I had no chance to ask what was going on, if my dosing was correct or if there was anything else I needed to do. He kicked me out and said he wasn’t even charging for the visit. Absolutely applaud. So to those who have found a Dr. that actually listens and works with your individual issues, kuddos. To the rest of us I highly recommend that you research as much as possible before using out of state clinics.
The mechanism of age related decreases in serum testosterone levels has also been the subject of investigation. Metabolic clearance declines with age but this effect is less pronounced than a reduction in testosterone production, so the overall effect is to reduce serum testosterone levels. Gonadotrophin levels rise during aging (Feldman et al 2002) and testicular secretory responses to recombinant human chorionic gonadotrophin (hCG) are reduced (Mulligan et al 1999, 2001). This implies that the reduced production may be caused by primary testicular failure but in fact these changes are not adequate to fully explain the fall in testosterone levels. There are changes in the lutenising hormone (LH) production which consist of decreased LH pulse frequency and amplitude, (Veldhuis et al 1992; Pincus et al 1997) although pituitary production of LH in response to pharmacological stimulation with exogenous GnRH analogues is preserved (Mulligan et al 1999). It therefore seems likely that there are changes in endogenous production of GnRH which underlie the changes in LH secretion and have a role in the age related decline in testosterone. Thus the decreases in testosterone levels with aging seem to reflect changes at all levels of the hypothalamic-pituitary-testicular axis. With advancing age there is also a reduction in androgen receptor concentration in some target tissues and this may contribute to the clinical syndrome of LOH (Ono et al 1988; Gallon et al 1989).
Hello..was prescribe andro gel 1.62 for about 2 years..borderline low..At time 54 year old now 57..a year ago switched doctors..new doctor would not prescribe andro gel..without me stopping use and then being checked after 6 months..it’s been a year..by the way felt great while on it much more energy. .did notice some hair receding. .but felt stronger..my question is..by using andro gel ..did I turn off my body’s natural ability to make testosterone as using andro gel..if so what do I need to do too turn my body on if my doctor does not renew therapy. .by way the past without andro gel…little too no energy..weight gain of 40 lbs..especially around the belly..thank you for your time and reply
If low T is your initial concern, lifestyle changes may help. “Dietary and exercise changes, particularly limiting sugars, especially fructose, eating healthy saturated fats, and engaging in high-intensity exercises may relieve symptoms of low testosterone," Lucille says. "Strength training, reducing stress, and optimizing vitamin D levels can also be very effective at boosting testosterone levels naturally."
Testosterone may decrease your chances of Alzheimer’s Disease. Several studies have linked low testosterone levels to an increased risk of Alzheimer’s disease. In a 2010 study by the University of Hong Kong, researchers studied 153 Chinese men who were recruited from social centers. They were at least 55 years and older, lived in the community, and didn’t have dementia. Of those men, 47 had mild cognitive impairment — or problems with clear thinking and memory loss.
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.
According to studies by Srivastava  and Thomson et al.  ginger can be used as natural antithrombotic agent. Ginger has also been recorded as useful remedy in preventing post-operative nausea and vomiting in humans  as well as preventing morning sickness during pregnancy . At high doses (500 mg/kg) aqueous extract of ginger exhibits cholesterol-lowering effect .
Ginger is also often found in joint support supplements. There is little well-designed research, however, ginger was reported to have some effectiveness for relieving joint pain of osteoarthritis (OA) and rheumatoid arthritis probably due to its anti-inflammatory [17,18,21] and anti-oxidant activity [17,18]. In a meta-analysis of five trials (593 patients) ginger was found to be modestly efficacious and reasonably safe for treatment of OA and was able to reduce pain and disability .
You can find a whole bunch of HIIT workouts online, but the one I used during my 90-day experiment was a simple wind sprint routine. On Tuesdays I went to the football field near my house, marked off 40 yards with some cones, and sprinted as fast as I could. I’d slowly walk back to the starting line, giving my body about a minute to rest, and then I’d sprint again. I typically did 40 sets of 40-yard sprints in a workout. I love sprints.
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.
Before taking any supplements, at either end of the spectrum, you need to check whether it’s low testosterone that is actually causing the problem. Taking something that you don’t need could potentially cause irreversible issues. For that reason, steroid hormones like DHEA should never be prescribed without having blood tests first. Roked also recommends regular blood monitoring to make sure you’re taking the correct dosage.
If you're a man who's experiencing symptoms such as decreased sex drive, erectile dysfunction, depressed mood, and difficulties with concentration and memory, and you think low testosterone may be to blame, you can have your levels tested. Since testosterone levels fluctuate throughout the day, you'll probably need more than a blood test to get a true picture of your levels.
This one is another herb that is known to increase semen volume. It has been found that men who consume this herb in the form of a supplement can expect higher sperm count per milliliter of semen, higher semen volume per ejaculation and also better sperm motility. It is also known to have a positive effect on the sex drive and arousal of both men and women.
Millions of men use testosterone therapy to restore low levels and feel more alert, energetic, mentally sharp, and sexually functional. But it's not that simple. A man's general health also affects his testosterone levels. For instance, being overweight, having diabetes or thyroid problems, and taking certain medications, such as glucocorticoids and other steroids, can affect levels. Therefore, simply having low levels does not always call for taking extra testosterone.
How alpha are you? Well, how many shakes of hot sauce can you handle? A recent study from France found men who have a taste for spicy foods tend to have higher testosterone levels than those who can’t handle the heat. Of the 114 male participants surveyed, researchers saw a clear correlation between frequent hot-sauce usage and higher T-levels. Study authors suggest the findings may be due in part to capsaicin—the fiery compound in chili pepper that previous studies have associated with increased testosterone levels. In animal studies, capsaicin has also shown to increase the size of sex organs, while simultaneously decreasing belly fatbelly fat. Yowza!
Men's levels of testosterone, a hormone known to affect men's mating behaviour, changes depending on whether they are exposed to an ovulating or nonovulating woman's body odour. Men who are exposed to scents of ovulating women maintained a stable testosterone level that was higher than the testosterone level of men exposed to nonovulation cues. Testosterone levels and sexual arousal in men are heavily aware of hormone cycles in females. This may be linked to the ovulatory shift hypothesis, where males are adapted to respond to the ovulation cycles of females by sensing when they are most fertile and whereby females look for preferred male mates when they are the most fertile; both actions may be driven by hormones.
This evidence, together with the beneficial effects of testosterone replacement on central obesity and diabetes, raises the question whether testosterone treatment could be beneficial in preventing or treating atherosclerosis. No trial of sufficient size or duration has investigated the effect of testosterone replacement in primary or secondary prevention cardiovascular disease. The absence of such data leads us to examine the relationship of testosterone to other cardiovascular risk factors, such as adverse lipid parameters, blood pressure, endothelial dysfunction, coagulation factors, inflammatory markers and cytokines. This analysis can supply evidence of the likely effects of testosterone on overall cardiovascular risk. This has limitations, however, including the potential for diverging effects of testosterone on the various factors involved and the resultant impossibility of accurately predicting the relative impact of such changes.
Testosterone is included in the World Health Organization's list of essential medicines, which are the most important medications needed in a basic health system. It is available as a generic medication. The price depends on the form of testosterone used. It can be administered as a cream or transdermal patch that is applied to the skin, by injection into a muscle, as a tablet that is placed in the cheek, or by ingestion.
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.
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.
Why do we need magnesium? Magnesium is an essential nutrient in the body that can help decrease the risk of developing osteoporosis, improve insulin sensitivity, and lower the risk of hypertension. This article looks at other health benefits of magnesium, what happens if a person has a deficiency, supplements, and how to include it in the diet. Read now
Most studies support a link between adult criminality and testosterone, although the relationship is modest if examined separately for each sex. Nearly all studies of juvenile delinquency and testosterone are not significant. Most studies have also found testosterone to be associated with behaviors or personality traits linked with criminality such as antisocial behavior and alcoholism. Many studies have also been done on the relationship between more general aggressive behavior/feelings and testosterone. About half the studies have found a relationship and about half no relationship. However, later it was found out that testosterone activates dominant, aggressive behavior if at the same time a person has high testosterone and low levels of cortisol in the blood. Conversely, a high level of testosterone and high levels of cortisol do not stimulate dominant behavior. Because cortisol inhibits the action of testosterone. This is probably why the results of the experiments were inconsistent.
“I see people who've been doing things in the gym and they've never been told that it can shut off your own production and it can also irreversibly lower your sperm count,” says Roked. “These are all quite serious issues that even though they may be rare if it happened to you it would cause a big impact on your life, so I'd say it's always best to do things with a specialist, but also for anyone it's not a great idea to take things that aren't needed."
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.
With ingredients like Fenugreek, Ashwagandha, Shilajit, and Boron Citrate, you can expect to see some increases in lean muscle mass thanks to the hike in free and total testosterone levels as well as its ability to suppress cortisol, a natural hormone that can reduce the body’s ability to use fat stores as energy. True GRIT Test Booster does not contain proprietary blends, so you can actually see the exact dosage you are getting from each ingredient listed.
"I'm 53 years old and my passion is surfing the oceans worldwide – big waves. Since taking Andro400, I'm now down to my ideal weight – from 185 to 175 now which is probably a net 15 pound loss, taking into account that the increased muscle I have now is heavier than the fat it replaced. My energy level is up. I feel strong and more physically fit in general. Also, from surfing I have been injured many times – for example I've broken my neck and pelvis among other things. Taking Andro400, I have much less pain overall – and I've been able to take less pain medication and anti-inflammatory drugs.”
Test1fy comes in with one of the most unique formulas containing ingredients that not only support testosterone increases and lean mass gains, but also help in increasing hunger making it the perfect addition to anyone’s natural bulking stack. It is overall a well rounded and potent formula making it perfect for anyone, from newbie to the seasoned veteran.
The hormone also plays a role in sex drive, sperm production, fat distribution, red cell production, and maintenance of muscle strength and mass, according to the Mayo Clinic. For these reasons, testosterone is associated with overall health and well-being in men. One 2008 study published in the journal Frontiers of Hormone Research even linked testosterone to the prevention of osteoporosis in men.
The use of these supplements can help to burn fat and build muscles. As a result, the health and strength of your muscles and bones improve that ultimately leads to a strong and healthy body. Another prominent feature of Testosterone Booster is that it can help to elevate mood and energy. These supplements contains a powerful blend of natural herbs. These natural herbs have healthful properties. Thus, you can have the energy and stamina to perform your best in the gym. Furthermore, these supplements will also help you to increase your productivity at work because of your improved energy levels.
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.
A number of research groups have tried to further define the relationship of testosterone and body composition by artificial alteration of testosterone levels in eugonadal populations. Induction of a hypogonadal state in healthy men (Mauras et al 1998) or men with prostate cancer (Smith et al 2001) using a gonadotrophin-releasing-hormone (GnRH) analogue was shown to produce increases in fat mass and decreased fat free mass. Another experimental approach in healthy men featured suppression of endogenous testosterone production with a GnRH analogue, followed by treatment with different doses of weekly intramuscular testosterone esters for 20 weeks. Initially the experiments involved men aged 18–35 years (Bhasin et al 2001) but subsequently the study was repeated with a similar protocol in men aged 60–75 years (Bhasin et al 2005). The different doses given were shown to produce a range of serum concentrations from subphysiological to supraphysiological (Bhasin et al 2001). A given testosterone dose produced higher serum concentrations of testosterone in the older age group (Bhasin et al 2005). Subphysiological dosing of testosterone produced a gain in fat mass and loss of fat free mass during the study. There were sequential decreases in fat mass and increases in fat free mass with each increase of testosterone dose. These changes in body composition were seen in physiological and supraphysiological treatment doses. The trend was similar in younger versus older men but the gain of fat mass at the lowest testosterone dose was less prominent in older patients (Bhasin et al 2001; Bhasin et al 2005). With regard to muscle function, the investigators showed dose dependent increases in leg strength and power with testosterone treatment in young and older men but there was no improvement in fatigability (Storer et al 2003; Bhasin et al 2005).