The use of anabolic steroids (manufactured androgenic hormones) shuts down the release of luteinising hormone and follicle stimulating hormone secretion from the pituitary gland, which in turn decreases the amount of testosterone and sperm produced within the testes. In men, prolonged exposure to anabolic steroids results in infertility, a decreased sex drive, shrinking of the testes and breast development. Liver damage may result from its prolonged attempts to detoxify the anabolic steroids. Behavioural changes (such as increased irritability) may also be observed. Undesirable reactions also occur in women who take anabolic steroids regularly, as a high concentration of testosterone, either natural or manufactured, can cause masculinisation (virilisation) of women.
I’m currently 64 y.o. After close to 10 years of twice-weekly injections of 20 units of testosterone cypionate my PSA gradually increased from 4.4 to more than 16. My urologist has performed 4 biopsies and one prostate MRI over that time, all of them negative. The last was 15 months ago. Early last year, after my fluctuating PSA reached 16, I discontinued the injections for about 6 months. My PSA dropped back to 6.1, and by the end of that time, my testosterone levels were about 240 but my libido seemed almost non-existent. I resumed the injections at a reduced level, 15 units, and 3 months later, the testosterone level was in the 700 range but the PSA was back to 16. My doctor told me to discontinue the injections pending another biopsy when I’m 65 in June.(I can’t afford another one immediately because of a high insurance deductible and previous family medical bills.) I am now gradually reducing the injections to 10 units once weekly, in hopes of limiting the withdrawal. Am I playing with fire or doing the right thing and have you had other patients with similar histories?
Studies have demonstrated reduced testosterone levels in men with heart failure as well as other endocrine changes (Tappler and Katz 1979; Kontoleon et al 2003). Treatment of cardiac failure with chronic mechanical circulatory support normalizes many of these changes, including testosterone levels (Noirhomme et al 1999). More recently, two double-blind randomized controlled trials of testosterone treatment for men with low or low-normal serum testosterone levels and heart failure have shown improvements in exercise capacity and symptoms (Pugh et al 2004; Malkin et al 2006). The mechanism of these benefits is currently unclear, although a study of the acute effects of buccal testosterone given to men with chronic cardiac failure under invasive monitoring showed that testosterone increased cardiac index and reduced systemic vascular resistance (Pugh et al 2003). Testosterone may prove useful in the management of cardiac failure but further research is needed.
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.
The TTrials were funded by the National Institutes of Health, and consist of 7 integrated, placebo-controlled, randomized clinical trials evaluating the short-term efficacy of testosterone treatment in older men with low circulating levels of the hormone. The benefits of testosterone were evaluated in 7 clinically relevant medical concerns and at least preliminary evidence of efficacy in sexual function, physical function, vitality, cognition, anemia, bone health, and cardiovascular health.
Ashwagandha: One of the hottest herbs out there right now, this adaptogen packs a one-two punch. First, it helps the body fight off stress: According to one Indian Journal of Psychological Medicine study, ashwagandha has a cortisol-lowering effect—a major benefit to anyone who wants their body to be more T-friendly. And, second, it can also support your T-boosting training efforts. One Journal of the International Society of Sports Nutrition study, for example, found that men who supplemented with ashwagandha saw significantly greater strength and T gains after eight weeks of resistance training than those who took a placebo.
This common kitchen spice can actually play a role in testosterone production. It has been said that through supplementing with ginger, that users have the ability to not only increase testosterone production naturally, but also improve sexual function and drive, improve sperm health, as well as increasing sperm count. This is great for infertile men as well as those looking for another avenue when it comes to boosting natural testosterone levels.
One study looking at alcohol consumption found that increasing alcohol consumption led to a higher level of free & total testosterone compared to a non-drinking control group (20). Drinking did however lower SHBG testosterone levels, though this type of testosterone is bound to a protein meaning our bodies cannot use it to build muscle or increase our mood.
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.
Based on my research, I guess fenugreek is kind of a crapshoot, a toss-up, a gamble, a coin toss, a roulette spin of sorts, you get the idea. There are a lot of conflicting reports on whether it increases or decreases testosterone levels, but it seems like the libido-improvement is consistent. The vast majority of men report positive effects from fenugreek so go ahead and give it a shot.
Let’s do a quick review of what I shared in the introduction to this series. August of last year was a tough month for me, primarily because of a huge and grueling project we were in the midst of here on the site. I was stressed out and my sleeping, healthy eating habits, and workout regimen all suffered. At the end of the month I got my testosterone levels tested and found that my total T was 383 ng/dL and my free T was 7.2 pg/mL – close to the average for an 85-100-year-old man.
AML Test includes each of the best natural testosterone boosters discussed above as well as red wine polyphenols which function as powerful, all-natural aromatase inhibitors that lower estrogen and increase testosterone levels. These polyphenols also boost nitric oxide production which enhances vasodilation and blood flow to all regions of the body.
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!
Like most supplements, Beast Sports contains several ingredients with little research about their long-term effects. WebMD describes Suma powder, Rhodiola Rosea, Cissus quadrangularis, Tribulus extract, and ashwagandha extract as possibly safe when taken for a short period of time (usually around 6-10 weeks). However, their long-term safety remains unknown. It also has a few ingredients, like cyanotis vaga root, safed musli, and polygonum cispidatum root extract for which there is a lack of data on even short term safety.
In the last few years, a lot of men and women have switched over to a pellet that goes under your skin. This is probably the best way to take testosterone now. The pellet is life-changing for both men and women (the dose for women is much lower than it is for men). Women, you won’t get bulky and grow a beard when you take testosterone to achieve normal levels, but you will probably lean out a little without losing your curves, and your energy and sex drive will be amazing. Female bodybuilders who experience weird scary side effects are taking anabolic steroids.
^ Butenandt A, Hanisch G (1935). "Uber die Umwandlung des Dehydroandrosterons in Androstenol-(17)-one-(3) (Testosterone); um Weg zur Darstellung des Testosterons auf Cholesterin (Vorlauf Mitteilung). [The conversion of dehydroandrosterone into androstenol-(17)-one-3 (testosterone); a method for the production of testosterone from cholesterol (preliminary communication)]". Chemische Berichte (in German). 68 (9): 1859–62. doi:10.1002/cber.19350680937.
Known as the "male hormone," testosterone is produced primarily by the testicles. "Beginning around age 30, testosterone levels begin to decline naturally and continue to do so as a man ages," says Holly Lucille, ND, RN, a naturopathic doctor, educator, and author, "sometimes leading to low testosterone symptoms such as depressed moods, decreased sex drive, erectile dysfunction, and difficulties with concentration and memory.”
When the body cannot produce enough testosterone on its own, the term is called hypogonadism. Testosterone boosters do not give the user actual testosterone (like with steroids), rather, they kickstart the production of this very important hormone. For that reason, it’s important to find a potent formulation that has one or multiple key ingredients in it.
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
Binge drinking on the other hand does impact Testosterone levels – especially on a short term basis. Two studies (22 & 23) show that large acute quantities of alcohol consumption in a short period led to decreases in Testosterone levels by a whooping 20-23% after 24hours! Note however this is drinking to extreme excess! Likewise, chronic alcohol abuse is known to reduce testosterone more notably (as seen in alcoholics).
Cruciferous vegetables like broccoli are rich in indoles, anti-cancer compounds that indirectly boost testosterone production by breaking down and flushing the system of excess estrogen, which inhibits the production of male sex hormones. As men age, their estrogen levels gradually rise, while testosterone levels fall. Indoles can help strike the balance. In one study, supplementing with indole-3-carbinol from cruciferous vegetables for just 7 days cut the estrogen hormone estradiol in half for men. Another study found indole supplementation significant increased urinary excretion of estrogens among men.
However, studies have found that social success among men is actually linked with high testosterone levels. For example, teenage boys who were perceived as socially adept and dominant had higher levels of testosterone than boys that were low on the totem pole. What’s even more interesting is that this same study found that teenage boys who had a history of being anti-social and displaying high physical aggression were found to have lower testosterone levels at age 13 compared with boys with no history of high physical aggression.
These researchers took saliva samples from recreational women athletes before and after playing 10 minutes of flag football. The data showed that this short, intense burst of competitive sport triggered the immediate release of testosterone. Interestingly, the subjects' mental state also contributed to the data. Self-rated performance scores were directly related to testosterone levels.
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.
during therapy. It is very hard to find a local endo who is thinking with his head vs complying with old trt programs. I tool clomid in the past to see what it would do and it elevated my t level to 520 in 2 weeks from low 220. Aromason will do same but clomid is more potent. Not sure what the long effect would be since you tend to get bit moody on clomid after 2 months. LH is also being affected in negative way since the lh receptors can burn out to a degree. I will contact the trt clinic in order to start my trt as they have much more experience with these things.
With the exception of increasing my fat and cholesterol intake, my diet wasn’t that unconventional. I didn’t follow a strictly low-carb or Paleo diet because recent research has suggested that a diet high in protein and low in carbs actually causes T levels to decrease. With that said, I was judicious with the carbs. I tried to get most of my carbs from veggies and fruit, but I didn’t freak out if my wife made us spaghetti for dinner.
Any supplement can have side effects, and testosterone pills or powder are no exception. Talk to your doctor before beginning any new regimen to be sure it is right for you. Side effects can include sleep apnea, ankle swelling, prostate growth, increased urination, acne, and an increased risk of developing a blood clot, which can be serious or even deadly.
You may find this hard to believe, but some common breakfast foods like Kellogg’s corn flakes and Graham crackers were invented 100 years ago to lower male libido. Kellogg and Graham believed that male sexual desire was the root of society’s problems, so they set out to make bland foods that would take away libido (this is absolutely true; look it up). That low fat, grain-based thing absolutely works wonders for lowering testosterone.
I just started TRT gel. On the first day I noticed an improvement in my awareness/energy level. This is now day three and I feel much better. Before I was tired and lacked the mental clarity I now feel. I have not yet noticed and increase in my libido but I think it is improving. Probably need the stimulation from my fiancé and more time to get my T levels up. Before I started the gel, total T levels were 450, and then 500+. I went to an Integrative MD who suggested Free T. That level was low and my SBGH was 100 (high). I then went to an NP who ordered the Free T. She referred me to an Endocrinologist. She along with her Attending interviewed me and decided to prescribe. They asked if I wanted the gel or the injections. I opted for the gel. I will wait and see how the gel works. So far so good.
Vitamin D: Recent research suggests a strong link between vitamin D and hormone function—but as much as 40 percent of Americans are estimated to be deficient. That’s where supplements come in: According to a study published in the journal Hormone and Metabolic Research, vitamin D-deficient men who also had low T experienced a roughly 25 percent increase in T levels after supplementing with 3,000 IU of vitamin D3 for one year.
Much like female hormone replacement, you should never, never ever use conjugated equine estrogen and synthetic progestins. Those two coupled together are evil twins. It is not hormone replacement that is the issue in men or women. The issue is the type of hormone used and doctors not knowing what they are doing. I always use bio-identical hormones. Synthetics are not the proper administration of any hormone program.
Testosterone, historically believed to be important only for male sexual function, has over the past decades transformed from niche hormone to multi-system player.22 There is increasing recognition of the harmful consequences of hypogonadism (also known as testosterone deficiency) wide spectrum of beneficial health effects of testosterone therapy and.23, 24
It also has vitamin B6. One study called out folate and vitamins B6 and B12 as important nutrients for athletes to achieve optimal health and performance. Vitamin B6 is commonly found in food, like fortified cereals, and as with magnesium, it’s possible to have too much vitamin B6. The NIH recommends an upper daily limit for adults of 100mg per day. Beast Sports comes well under this limit at 10mg per day, but still well above the minimum recommended dose of 1.7mg needed to see benefits.
We start with plastic. A lot of plastic contains bisphenol A (BPA); BPA is a weak synthetic estrogen. Like many other chemicals used in making plastics, BPA is a hormone disruptor and can block or mimic hormones and how they act in the body (34). If you think you’re safe with BPA plastic, think again. Research shows that BPA free plastic has similar estrogen-like effects on the body.
As with a number of treatments or medicines that have been around for a long, long time, it hasn’t been scrutinized like a new drug would be. And although they’ve been discussed, there aren’t any large-scale, randomized controlled clinical trials of testosterone-replacement therapy under way. [See “A male equivalent to the Women’s Health Initiative?” below.]
Cross-sectional studies have not shown raised testosterone levels at the time of diagnosis of prostate cancer, and in fact, low testosterone at the time of diagnosis has been linked with more locally aggressive and malignant tumors (Massengill et al 2003; Imamoto et al 2005; Isom-Batz et al 2005). This may reflect loss of hormone related control of the tumor or the effect of a more aggressive tumor in decreasing testosterone levels. One study found that 14% of hypogonadal men, with normal digital rectal examination and PSA levels, had histological prostate cancer on biopsy. It is possible that low androgen levels masked the usual evidence of prostate cancer in this population (Morgentaler et al 1996). Most longitudinal studies have not shown a correlation between testosterone levels and the future development of prostate cancer (Carter et al 1995; Heikkila et al 1999; Stattin et al 2004) but a recent study did find a positive association (Parsons et al 2005). Interpretation of such data requires care, as the presentation of prostate cancer could be altered or delayed in patients with lower testosterone levels.
Androgens may modulate the physiology of vaginal tissue and contribute to female genital sexual arousal. Women's level of testosterone is higher when measured pre-intercourse vs pre-cuddling, as well as post-intercourse vs post-cuddling. There is a time lag effect when testosterone is administered, on genital arousal in women. In addition, a continuous increase in vaginal sexual arousal may result in higher genital sensations and sexual appetitive behaviors.
The overweight men participated in one German study. The first group of the participants used a placebo for one year. The second group of the participants consumed vitamin D3. All the participants aspired to shed excessive weight. Those men who took this vitamin lost up to 6 kg of unwanted weight. Also, they got the additional bonus; that is, the increase in testosterone production by about 25%.4
Ok. So this product is meant to be taken continuously and without side-effects. But my question is, will there be replenishment from this product in aiding the body's natural ability to produce testosterone? In other words, will there ever be a time when I can say well I don't have to take this any more as my body is producing testosterone again on it's own and my muscle mass has been enhanced?
A couple years ago I was having a problem with my thighs burning when walking up stairs. I noticed the muscles in my legs looking smaller. So I had my doc to check my T levels , and it was under 100. So she started me on testosterone injections weekly 200mg . After several injections I felt great , muscles in legs came back , lots of energy everything good . Leveled out at 3 injections a week 100mg , had a T level of 550 . So I go in for my scheduled injection and they tell me there out of testosterone . I might mention, this is a health care facilility that gives financial assistant if needed. And they have 3 or doctors and a nurse practitioner, which was who I was seeing . So I went on to check back often and got the same reply , were out of supply . So finally after months of the same , I gave up . I started loosing wait and my nerves got bad . Was having panic attacks etc. but I was coming off Prozac at the same time so I blamed it all on that. I was so bad with my nerves I ended up in the ER while on vacation . Doc there put me on a med for stress which I’m still using . After close to a year I checked back with the place I was getting TRT and they were resupplyed with testosterone. So I started back up because of low sex drive and ED. My first injection of 200mg was just short of a Marical , nerves felt great ED gone , had a sex drive , lot of energy . Then after 7 days or so all gone bad nerves started back up . He had me scheduled for anouther injection in 4 weeks 100mg . I went in for injection and after a couple days started feeling a little better . Then same thing as before about 7 days later nerves and everything else as before got worse . 3 weeks later I finally got a appt. with this different doc then I use to have . Told him the problems I was having , which included a horrible down mood , no energy . He decided to start injections every 2 weeks and upped the dose slitley. It’s been 5 days and already noticing ED problem reaccuring . He’s worried about the threat of prostate cancer. And doesn’t want to add any more injection to the schedule. I guess I’m going to have to start seeing the nurse practitioner who seemed to be more liberal and informed about TRT. I feel once a week injection is what it will take to get feeling good again. I’m 57 now with good health . Just need to get my T level on track with a doctor that will listen to how his patient is feeling . My last T level was at 365 . I failed to mention before I started the injections I was on androgel Dailey , 5 pumps a day . Then he gave me the injection of 200mg test . That’s when I felt fantastic for about a week or so . Then down hill . And I wanted to switch because the injection just seem so much better and they are . I noticed a big difference.
So if you’re intent on maximizing your testosterone levels, and/or you have applied all of the above and you’re still not satisfied with your results (which would be surprising) then you could try the below. I will point out that some of these tips may not have the scientific evidence to back them up like the previous points, but I can assure you that either I have or do use them (and have positive results), or a client has used them with pleasing results, or finally it is such a new conception that there isn’t enough evidence to prove it one way or another.
I have tried pellets, I went from 5 grams/day gel, to 10 grams, had little change due to work schedule and no energy made it difficult to manage daily. Levels got down to 78 at one point. Testo pellets worked great but it took 10 to make a difference and it brought me up to the 300-400 range. My body rejected 3 pellets and expelled them. Tried axiron, didn’t work, natesto, which the doc never heard off next, a Nasal spray which helped but the bottle ran out 5 days early either by my mistake or dosage problems. Back to 10 grams Testim AG ($360 after deductible) which helps if i could stay consistent but I’m 28. With a job, and health insurance, deductible issues I can not afford 800 dollars a month, 360 after deductible. Recent levels of FSH/LH are .7 and 1.2 (low). Total testosterone 114, free 18.9, and bioavalability at 39.6 (low). I had a MRI of my pituitary gland today, and get results next week. Hoping to start depo T next week as I return to work. If I can recommend anything to anyone, is make sure it’s affordable, you have the time or energy to apply/administer, and understand most people will not understand what you are going through. 2 killers of testosterone are chronic stress and lack of sleep. In 3 years of treatment I wish I came to this man’s article and others and read up prior because I’m on the brink of losing everything I’ve worked for due to hypogonadism. Wish you all results and good health, and thank you for a great article!
There are two ways that we determine whether somebody has low testosterone. One is a blood test and the other is by characteristic symptoms and signs, and the correlation between those two methods is far from perfect. Generally men with the lowest testosterone have the most symptoms and men with highest testosterone have the least. But there are some men who have low levels of testosterone in their blood and have no symptoms.
BCAA peptides are the building blocks of muscle. Your body cannot make BCAA’s. You have to eat them. One easy way of course is food and things like whey protein powder. That is why whey protein works so well because it contains BCAA’s at high levels. Advanced BCAA is 50% BCAA in peptide form!! Peptides are digested faster and more efficiently than whole foods and normal protein powders. This means more muscle building and recovery support!!
ZMA (unnecessary). So when I researched how to increase testosterone, a supplement called ZMA kept popping up. It’s a blend of zinc, magnesium, and vitamin B6. The purported benefits of ZMA include better and deeper sleep which indirectly is supposed to increase testosterone. Zinc and magnesium are necessary minerals in testosterone production, so a mega-dose should be useful, right? Well, no. I bought some and took it during the duration of experiment. I should have done some more research before I made the purchase. While one study in 1998 showed increased strength among athletes taking ZMA, two recent studies (study 1, study 2) have shown that it has absolutely no effect on total or free testosterone levels. Crap. My advice, unless you have a zinc and magnesium deficiency, no need to waste your money on this.
Always worry of side effects i.e. prostate cancer! Also feels like I am doping like a pro-cyclist (hate cheaters) Without it my muscles and joints stiffens so painfully, fuzzy and somewhat depressed, when pushing very hard while exercising the sensations become bizarre and again so incredibly painful — it feels so good after the injection if I had waited too long!
I think we’ll also find out in five years that there very well may be general health benefits of having normal testosterone compared to low testosterone. There are growing data for all-cause mortality that men who have low testosterone die earlier than those who have normal testosterone. A study by the Veterans Administration reported about a year ago showed low testosterone levels were associated with a dramatically increased mortality rate. It’s hard to know why that is, but I think we’ll be focused on that in the coming years.
Many clinical studies have looked at the effect of testosterone treatment on body composition in hypogonadal men or men with borderline low testosterone levels. Some of these studies specifically examine these changes in older men (Tenover 1992; Morley et al 1993; Urban et al 1995; Sih et al 1997; Snyder et al 1999; Kenny et al 2001; Ferrando et al 2002; Steidle et al 2003; Page et al 2005). The data from studies, on patients from all age groups, are consistent in showing an increase in fat free mass and decrease in fat mass or visceral adiposity with testosterone treatment. A recent meta-analysis of 16 randomized controlled trials of testosterone treatment effects on body composition confirms this pattern (Isidori et al 2005). There have been less consistent results with regard to the effects of testosterone treatment of muscle strength. Some studies have shown an increase in muscle strength (Ferrando et al 2002; Page et al 2005) with testosterone whilst others have not (Snyder et al 1999). Within the same trial some muscle group strengths may improve whilst others do not (Ly et al 2001). It is likely that the differences are partly due to the methodological variations in assessing strength, but it also possible that testosterone has different effects on the various muscle groups. The meta-analysis found trends toward significant improvements in dominant knee and hand grip strength only (Isidori et al 2005).
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.
Testosterone improves not just your sex drive, but it also enhances exercise drive, energy for work, mental sharpness, muscle repair, and revs your metabolism to help with weight control. Although improving testosterone levels has not yet been shown to increase lifespan, having a healthy testosterone level improves quality of life for both men and women.
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).