In addition to these effects, DHEA supplementation also increases FREE testosterone levels. As you may or may not know, testosterone is found in the body in both free and bound forms. Free testosterone is the biologically active kind that we want more of in order to improve energy, strength, recovery, and sexual function. Bound testosterone is biologically inactive, due to serum hormone-binding globulin (SHBG).
I have been on Testosterone and semorilin for 3 years now and just wanted to talk on what for me is the BIGGEST side effect NO ONE talks about. In those 3 years I have seen my body transformed in every way. I have such DRIVE and AMBITION I can’t believe it I look and act 30 years younger. I have a GF 25 years younger than me and she can’t keep up! I am very sexually active especially for my age.

Consuming high amounts of sugary foods raises your blood glucose levels, which causes your body to release insulin as a response to the raised blood glucose levels. If not managed correctly, the body begins to develop a tolerance to insulin and cannot absorb the sugars in the blood stream as it used to, causing you to become insulin resistant. Being insulin resistant releases cortisol, and as you know, cortisol has extremely negative effects, lowering testosterone by quite a bit.

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.
Fenugreek, in the form of a capsule, testofen, or Fenugreek tea could do the trick. The fact that fenugreek increases libido is not mythology; it is backed by a clinical study which showed the libido of men aged 25-52 increased by 25%[1] on average when taking fenugreek extract for six weeks.  According to Lee Myer, of www.peaktestosterone.com fame, fenugreek will help you achieve orgasm as well, so if this is an issue for you, fenugreek may be the answer.  It’s a frustrating problem to have.
Felt I was more sluggish than I should be,Went on TRT ’cause my bloodwork said I fell in the parameters for hormone therapy. When i started felt I was 17, (I was 50))I did everything possible and passed for type A, and physiologically, things seem to heal faster. But I missed memories, now that I was speeded-up I no longer could easily connect and be a part of them.
Statins are some of the most prescribed drugs in the world for reducing cholesterol levels and preventing heart disease. Various studies in the 1990s, including a study published in the ‘European Journal of Clinical Nutrition,’ supported the claim that Fenugreek could help reduce cholesterol levels[2]. One possible explanation is the high fiber content in fenugreek.  A fiber-rich diet has been shown to help reduce the levels of LDL (‘bad’ cholesterol) in your blood. (Note: The validity of the various studies from the 1990s have been questioned though because of small sample sizes[3])
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.

The testosterone booster pills are effective from 4 to 8 hours. To maintain testosterone levels high during the whole day, you need a multiple daily dosing regimen. 2-times daily dosing still not always can improve hormone production to the greatest extent. 3-4-times daily dosing is the best solution to make your body normalize testosterone synthesis and prevent it from decreasing before you take another pill. Don’t forget that the regularity of daily supplement intake is crucial if you really aspire to give a boost to hormone production.
Despite all the wonderful benefits of testosterone boosters, it will only work as well as you are able to make it work. This means that if you’re living a sloppy lifestyle, then your testosterone booster will produce poor results. Testosterone boosters work best when you make small, healthy changes to your lifestyle and diet that will allow your T-booster to give you its full benefits.

Low testosterone levels may contribute to decreased sex drive, erectile dysfunction, fragile bones, and other health issues. Having low testosterone levels may also indicate an underlying medical condition. See your doctor if you suspect you have low testosterone. A simple blood test is all it takes to check if your testosterone falls within the normal range.
There are three ways to increase testosterone activity naturally with simple lifestyle choices. The first is to increase total testosterone production. Second is to increase the amount of free and active testosterone that can stimulate testosterone receptors. The third is to unblock testosterone receptors, opening them up for testosterone stimulation.
^ Mehta PH, Jones AC, Josephs RA (Jun 2008). "The social endocrinology of dominance: basal testosterone predicts cortisol changes and behavior following victory and defeat" (PDF). Journal of Personality and Social Psychology. 94 (6): 1078–93. CiteSeerX 10.1.1.336.2502. doi:10.1037/0022-3514.94.6.1078. PMID 18505319. Archived from the original (PDF) on April 19, 2009.

Men who watch a sexually explicit movie have an average increase of 35% in testosterone, peaking at 60–90 minutes after the end of the film, but no increase is seen in men who watch sexually neutral films.[43] Men who watch sexually explicit films also report increased motivation, competitiveness, and decreased exhaustion.[44] A link has also been found between relaxation following sexual arousal and testosterone levels.[45]
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.
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Zaima, N., Kinoshita, S., Hieda, N., Kugo, H., Narisawa, K., Yamamoto, A., ... Moriyama, T. (2016, September). Effect of dietary fish oil on mouse testosterone level and the distribution of eicosapentaenoic acid-containing phosphatidylcholine in testicular interstitium. Biochemistry and Biophysics Reports, 7, 259–265. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613343/
For this reason I recommend doing your own research on this supplement before taking it. 5g of ground up dried powder is what was used in the studies. I recommend taking 1-2 capsules of the concentrated form from Paradise Herbs. Alternatively, the Aggressive Strength Test Booster also has MP in its formula so you may prefer to use that blend instead. 
Testosterone [Figure 1] is the main male sex hormone. It is responsible for male sexuality and is the main hormone-producing the features associated with masculinity such as substantial muscle mass, facial hair, libido, and sperm production.[1] Besides, the hormone has other vital functions as the basic chemical composition of testosterone is steroidal; and steroids are known to have significant physiological, as well as psychological, effects in male individuals, especially adults.[1] Testosterone production is reduced gradually in men starting from the age of 30.[2] Hence, testosterone blood concentrations slowly diminish as age progresses. As a result, men may experience a number of physiological and psychological events, such as a lack of sex-drive, erectile dysfunction, acute depression, fatigue, low energy levels, and insomnia.[3]
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.
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
“Life for the winner is more glorious. It enters the next round of competition with already elevated testosterone levels, and this androgenic priming gives it an edge that increases its chances of winning yet again. Through this process an animal can be drawn into a positive-feedback loop, in which victory leads to raised testosterone levels which in turn leads to further victory.”
^ 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.
The information presented on this website is intended to be used for educational purposes only. The statements made have not been evaluated by the Food and Drug Administration (U.S.). Products are not intended to diagnose, treat, cure or prevent any condition or disease. Please consult with your own physician or health care practitioner regarding any suggestions and recommendations made.
Also, due to the intake of these synthetic substances, men start behaving in a very excited way, as well as demonstrate high levels of aggression and even violence. So, the men’s behavior may be antisocial. In addition, the men will experience breast enlargement and testicular shrinkage. The other adverse effects include hypertension, tumor growth, heart attacks and strokes, as well as development of liver disorders. It’s obvious that the numerous dangers of steroid use far outweigh a few benefits which they bring.
Lean beef, chicken, fish, and eggs are some of your options. Tofu, nuts, and seeds have protein, too. Try to get about 5 to 6 ounces per day, although the ideal amount for you depends on your age, sex, and how active you are. When you don't eat enough of these foods, your body makes more of a substance that binds with testosterone, leaving you with less T available to do its job.
It goes without saying that what you eat significantly influences your hormone balance and body composition. This is nothing new. There are countless athletes and bodybuilders who are paying a close attention to what they eat for a reason. For example, if you consume a lot of so-called junk food, then you inevitably end up with a poor nutritional profile. In plain English, you can forget about a six-pack and the high testosterone.

What makes TestoFuel different from other testosterone boosters on the market is that the company is constantly researching and updating the ingredients. So, you know you are getting a product that has been formulated using the latest clinical studies. Unlike most other companies that formulate a product and update it every 3 – 5 years or never at all.

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.
The oldest form is an injection, which we still use because it’s inexpensive and because we reliably get good testosterone levels in nearly everybody. The disadvantage is that a man needs to come in every few weeks to get a shot. A roller-coaster effect can also occur as blood testosterone levels peak and then return to baseline. [See “Exogenous vs. endogenous testosterone,” above.]

Thanks for reaching out buddy. Sorry to hear about your situation. First off, what I’d suggest is to forget about creams, they are a waste of money unless you are trying to moisturize your body – which I guess you’re not. As for estrogen blockers, the same goes here – but testosterone boosters on the other hand, they work with your body instead of against it to give you everything your body is missing – it sounds like it’s the missing piece to your puzzle. Bear in mind Graham, you’ll need to pay close attention to your diet – aim to cut down on refined carbohydrates and simple sugars – these are terrible for testosterone production and weight gain. If you drink more water, eat a balanced diet, and exercise occasionally while supplementing with testofuel.com you’ll soon be back on track. All the best!
Avoid stressful situations – It is actually that simple. If you can avoid stressful situations, then you can significantly improve your overall testosterone production. Why is that? Well, you should know that stress makes our bodies to produce cortisol that is a notorious and well-known testosterone killer. So, what can you do about it? Well, you should definitely try deep breathing, meditating, exercising, and other lifestyle changes that can help you deal with the stressful situations the right way.
Hi I just turned 50 , and for the past 6 years I have been going through depression , low energy , insomnia , but my sex drive was not bad, I really did not know what it was , so last month my family doctor asked that I test my testosterone and the result was 7.2 noml/l (208 ngdl. So I was prescribed 2.5g 1% androgel, after two weeks I did not feel a difference , on the box it says that the recommended dose is 5g 1% , so my doctor prescribed the 5g 1 % , its now a week since I started the 5 g ( all together three weeks since I started androgel ) & now I feel great, my mood and energy level is way better, I never had an issue with my libdo , so no difference there. I asked my family doctor to refer me to an endocrinologist, just to get a second opinion but that appointment will happen only after 5 months, huge wait time. I am not worried about all that is said about side effects like prostate cancer , heart issues etc because otherwise I am very healthy and have family history of cancers and heart issues , but what worries me is , will my testes & p.glands stop producing Testosterone because of this external replacement? Something I would not want to happen at 50, because probably with exercise & diet I could try boosting by my T.Level naturally. More over will I become sterile , I have a young wife and we may have more kids. Also the gel application is very uncomfortable since I have young kids in the house I have o take extreme caution. Last was it worth starting TRT without finding out the level of my free testosterone. appreciate your advise. Thanks.
The final two studies looked directly at soy vs testosterone levels. The first looked at introducing consumption of soya flour on testosterone levels. They found that those who ate the Soy flour lowered their T levels during the study (43). And the second study looked at the consumption of soy protein isolates (powder) in healthy men. They found that testosterone levels decreased upon consumption of soy powder (45).
46 year old whose suffered with low libido and all the related symptoms for over a decade. Finally had the courage to have a frank talk with dr. and urologist. Testosterone level 165, free testos level 3.6. Re-doing blood work again just to be sure in the next week or so, and will post updates then as things progress. Normal ranges are 300-1200 and 6 to 12.
Falling in love decreases men's testosterone levels while increasing women's testosterone levels. There has been speculation that these changes in testosterone result in the temporary reduction of differences in behavior between the sexes.[53] However, it is suggested that after the "honeymoon phase" ends—about four years into a relationship—this change in testosterone levels is no longer apparent.[53] Men who produce less testosterone are more likely to be in a relationship[54] or married,[55] and men who produce more testosterone are more likely to divorce;[55] however, causality cannot be determined in this correlation. Marriage or commitment could cause a decrease in testosterone levels.[56] Single men who have not had relationship experience have lower testosterone levels than single men with experience. It is suggested that these single men with prior experience are in a more competitive state than their non-experienced counterparts.[57] Married men who engage in bond-maintenance activities such as spending the day with their spouse/and or child have no different testosterone levels compared to times when they do not engage in such activities. Collectively, these results suggest that the presence of competitive activities rather than bond-maintenance activities are more relevant to changes in testosterone levels.[58]
I know the experiment didn’t simply bring me back to my pre-August levels because of the fact that when I learned that the original test I took can sometimes overestimate your T levels, I took a more accurate test around four months after the start of the experiment (I’ve continued the lifestyle changes made during the experiment) and my total T had gone up again to 826.9 ng/dL.
Pine Pollen is an androgen, meaning in theory it can raise testosterone levels – effectively making it a naturally derived source of testosterone. Read more about this on the links below. But like I said I started taking it for a few weeks and did notice a bit more ‘up and go’ so to speak, but it did only last a few weeks. I have tried cycling it but haven’t noticed the same effects as I had when I initially started with it. I’m still experimenting and will keep this page updated. Therefore I recommend doing your own research.
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.
6)  Take Cold Showers:  Cold showers have been known to stimulate and boost testosterone production and improve metabolism, detoxification and brain function.  Start your shower with warm/hot water and turn it to cold for the last 30-60 seconds while pumping your muscles and creating a big shiver as your muscles contract.  That will help to boost internal heat and boost testosterone production.  This article will help you.
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.
Research shows that bone density increases with testosterone treatment as long as the dose is high enough. on the effect of testosterone on bone density found increases in spinal and hip bone density. Another of females transitioning into males found that testosterone increased bone mineral density. But it’s unknown if testosterone can help with reducing fracture risk.
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.
Testosterone fluctuates according to age and life circumstance, often plummeting at the onset of parenthood, and spiking (for some) during moments of triumph. Romantic relationships, too, can impact a person’s testosterone production; though the reasons are still not fully understood, entering a relationship tends to increase women’s testosterone levels, while decreasing men’s. Since males produce significantly more testosterone than females—about 20 times more each day—females can be more sensitive to these fluctuations. High levels of testosterone, particularly in men, have been correlated with a greater likelihood of getting divorced or engaging in extramarital affairs, though a causal link has not been established.

Women also feel the effects of testosterone imbalance. Common knowledge holds that testosterone is just for men, but that’s not true. Low testosterone in women results in a wide variety of hard to diagnose symptoms: fatigue, anxiety, sleeplessness, depression, and weight gain are some common symptoms. These effects are commonly seen after menopause, but hormone imbalances can happen at any age. Properly balancing the body’s natural testosterone and estrogen levels prevents these symptoms.


When I was on 4 pumps per day, I had a reduction of ejaculate, and sometimes found it hard to ejaculate. Getting erections is no problem, and I even take BP meds. I vary it now. When I’m not going to the gym, or traveling, I cut down to 2 pumps, or take a break for a few days. When I’m intense in the gym, I stick with 4 pumps (about 5mg). I do still have the belly flab unfortunately. I need to increase cardio, and change up the diet some, but honestly, I am not too bad with my diet, so I’m a little frustrated.
“I can't tell you how good the product is! I'm in the best shape of my life. I used to take blood pressure medication and I don't even take that anymore. It's changed every aspect of my life. I was a 40 waist and I'm down to a 36. I'm 54 years old, and people tell me I look better than I ever have, and I look like I'm in my early 40s! And I'm telling you it's the Andro. This product is so much better than even the advertisements! From taking Andro400 I immediately notice a burst of energy . . . and my skin color, my sexual advancements, my energy, plus the weight loss, the toning of the body, and the increase strength and endurance . . . it's like night and day where I was then and where I am now, and Andro400 has made the difference. And my wife also takes it, 1 pill every other day, and she has experienced an amazing transformation in her body alone, with her hair, her complexion, and as well as in the gym. It's an outstanding product. My customers, my friends, my family, everybody is noticing the difference!”
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.
A number of epidemiological studies have found that bone mineral density in the aging male population is positively associated with endogenous androgen levels (Murphy et al 1993; Ongphiphadhanakul et al 1995; Rucker et al 2004). Testosterone levels in young men have been shown to correlate with bone size, indicating a role in determination of peak bone mass and protection from future osteoporosis (Lorentzon et al 2005). Male hypogonadism has been shown to be a risk factor for hip fracture (Jackson et al 1992) and a recent study showed a high prevalence of hypogonadism in a group of male patients with average age 75 years presenting with minimal trauma fractures compared to stroke victims who acted as controls (Leifke et al 2005). Estrogen is a well known determinant of bone density in women and some investigators have found serum estrogen to be a strong determinant of male bone density (Khosla et al 1998; Khosla et al 2001). Serum estrogen was also found to correlate better than testosterone with peak bone mass (Khosla et al 2001) but this is in contradiction of a more recent study showing a negative correlation of estrogen with peak bone size (Lorentzon et al 2005). Men with aromatase deficiency (Carani et al 1997) or defunctioning estrogen receptor mutations (Smith et al 1994) have been found to have abnormally low bone density despite normal or high testosterone levels which further emphasizes the important influence of estrogen on male bone density.
In 2002, the federally sponsored Women’s Health Initiative (WHI) stopped its hormone replacement therapy (HRT) trial (estrogen plus progestin), which included more than 16,000 women, three years early because those taking the pills had an increased risk of developing breast cancer and blood clots, and an increased risk of suffering a stroke or heart attack than those taking a placebo. The findings ran counter to the long-held belief that HRT could preserve health — and trim heart-disease risk in women.

In summary it’s important to know that this topic is still hotly debated, and there are a lot of inconsistencies in the data. We do know that soy contains phytoestrogens and does seem to have a lot of affects on the body, including some studies that show decreased Testosterone levels. For that reason (and the fact that it tastes like ass) I avoid it, and I recommend you also avoid it (in particular soy isolates!) if you’re seeking higher testosterone.
Hi Dean, thanks for reaching out bro! While testosterone boosters will help increase your T levels, strength, and libido, you need to make sure you’re eating the right foods and exercising in the right way. What is your current diet and workout plan? Maybe we can help? If you’re serious about getting in shape, a quality testosterone booster can certainly help. If you have a look at our top testosterone booster page, you’ll see TestoFuel is our best choice. If you have any more questions, don’t hesitate to write back! All the best bro, don’t give up, you can do it!
Hello everyone. First off, thank you Dr. Abraham Morgentaler, for the excellent and refreshing article. I do not intend to spill my guts about symptoms or values on here as it has already been done so many times over. I will say that I am an RN BSN and have been on HRT for going on 6 yrs. I live in Oklahoma and when I first started noticing symptoms I knew something was wrong and began to do research myself. With an initial level of 241 no doctor here at that time, would even consider HRT as I was only 35ish at the time.
It is hard to know how many men among us have TD, although data suggest that overall about 2.1% (about 2 men in every 100) may have TD. As few as 1% of younger men may have TD, while as many as 50% of men over 80 years old may have TD. People who study the condition often use different cut-off points for the numbers, so you may hear different numbers being stated.
Dr. Resnick and colleagues assessed 788 participants in the cognitive function arm of the TTrials but focused on the 493 participants who were classified as having age-associated memory impairment with a confirmation of both subjective and objective indicators of cognitive decline. The authors detected no significant effect after 1 year of testosterone treatment on either the primary outcome of verbal memory, as measured by delayed paragraph recall or on any of the secondary outcomes of visual memory, executive function, and spatial ability.1
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).
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