Freemale replied: "First, you should have a baseline measurement of what your current level of testosterone is. This should include free testosterone or bioavailable testosterone (free testosterone + albumin-bound testosterone), in addition to total testosterone & estradiol. Free testosterone is the testosterone that is "unbound" in circulation (hence free to bind to androgen receptors), so it is important to know how much you have- range is usually 50-210 pg/mL). A "normal" level of total testosterone (300-1000 ng/dL or so, depending on lab reference range) with low free testosterone could mean that much of your testosterone is not able to do its work. Additionally, high estradiol (above 30 pg/mL according to more recent studies) can sap the effectiveness of normal total testosterone, as well as diminish free testosterone. SHBG lowers the amount of "free testosterone", so this is worth measuring, too. Finally, DHT is worthwhile to check, since many features such as body hair, facial hair, erectile function, etc. depend on DHT. With that in mind, you can determine what direction to proceed. If you have low testosterone (generally below 300 ng/dL) or low free testosterone, your doctor may prescribe it in one of its various modes of administration (implant, injection, gel, cream, patch, etc.). He should aim to keep you within the upper 1/3 of the reference range (760 - 1000 ng/dL). DHT may be used if your DHT level is below reference range (normal 25-75 ng/dL, depending on the lab reference range). Arimidex may be used to decrease excessive estradiol (though it is generally prescribed for women with breast cancer, it is used by knowledgeable doctors for management of excess estrogen in men as well). Of course, I am assuming you would only obtain & use these under doctor supervision & prescription. Assuming your levels are "normal" (within reference range), certain natural means can increase testosterone. Regular, heavy resistance exercise (especially squatting & bench pressing) can elevate testosterone by as much as 40%. Foods such as oats can slightly elevate testosterone, as can the supplement Tribulus Terrestris. One guy in the testosterone group I belong to reported between 50-75 ng/dL increase in testosterone since using Tribulus- not a lot, but still an increase. Zinc can elevate testosterone & favorably alter testosterone to estrogen ratio, but too much can result in too much estrogen conversion from testosterone. I can't mention prohormones since they are now illegal & probably didn't give significant increase anyway. DHEA is likewise a wild card (though currently legal, but that could change due to McCain's legislative suggestion), as it can elevate testosterone or estrogen. Interestingly, it seems to elevate estrogen in men & testosterone in women. Other factors to keep in mind are stress, sleep, drugs, & other factors. Controlling/avoiding/minimizing/reversing these factors can help you maintain higher testosterone or bring it up. Adequate sleep helps ensure sufficient testosterone production; inversely, less sleep can lower testosterone. Stress can lower testosterone, especially if it is prolonged stress that is neglected. Certain drugs such as ketoconazole (an antifungal) can lower testosterone, as can cortisol, prednisone, spironolactone, accutane (lowers DHT) various antidepressants & anti anxiety meds, etc. Fact is, lots of meds can lower testosterone. Some block receptors without necessarily lowering testosterone, therefore decreasing its effects without lowering the level that can be measured in the bloodstream. Treatment for prostate cancer often involves meds the block the effects of DHT, block production of DHT, or lower testosterone production altogether (which lowers the rate & amount of DHT conversion from testosterone). Natural products like flaxseed may lower DHT production, while soy (via a product of daidzein called Equol) blocks DHT receptors. Saw palmetto does both, but it's hard to say if it does this specifically at the prostate or systemically throughout the body. Chronic conditions like HIV/AIDs, hyperthyroidism, hypothyroidism, prolactin excess, aromatase excess (& consequent estrogen excess), unexplained weight/lean body mass loss, & diabetes, as well as temporary issues like surgery, can lower testosterone significantly. By the way, the name of the group I belong to is We deal with men who have low testosterone. Hope that helps."