These results have been echoed in clinical trials. A meta-analysis of 24 RCTs looked at weight loss caused by diet or bariatric surgery:[22] In the diet studies, the average 9.8% weight loss was linked to a testosterone increase of 2.9 nmol/L (84 ng/dL). In the bariatric-surgery studies, the average 32% weight loss was linked to a testosterone increase of 8.7 nmol/L (251 ng/dL).

A notable study out of Wayne State University in Indiana found that older men who had a mild zinc deficiency significantly increased their testosterone from 8.3 to 16.0 nmol/L—a 93 percent increase—following six months of zinc supplementation. Researchers of the study concluded that zinc may play an important role in modulating serum testosterone levels in normal healthy men.6

Japanese Knotweed (a.k.a Hu Zhang or Polygonum cuspidatum) is highlighted by WebMD as needing more evidence to rate its effectiveness in a number of different areas: like treating constipation and liver or heart disease. They also warn that it can interact poorly with medications that are changed and broken down by the liver, and those that slow blood clotting (anticoagulants and antiplatelets).


Phthalates are found to cause poor testosterone synthesis by disrupting an enzyme required to create the male hormone. Women with high levels of DEHP and DBP (two types of phthalates) in their system during pregnancy were found to have sons that had feminine characteristics Phthalates are found in vinyl flooring, detergents, automotive plastics, soaps and shampoos, deodorants, perfumes, hair sprays, plastic bags and food packaging, among a long list of common products. Aside from phthalates, other chemicals that possess gender-bending traits are:

Nuts are a cool choice that you can make every day that will bring up your testosterone with every handful. Men who eat high amounts of monounsaturated fats show the highest levels of testosterone. And the humble nuts contain a healthy supply of testosterone increasing monounsaturated fats, zinc, protein and omega-3 fatty acids. Also, nutrients like B vitamins and minerals are found in nuts. However, it is crucial to know which nuts to put in your daily diet.
The sexual hormone can encourage fair behavior. For the study, subjects took part in a behavioral experiment where the distribution of a real amount of money was decided. The rules allowed both fair and unfair offers. The negotiating partner could subsequently accept or decline the offer. The fairer the offer, the less probable a refusal by the negotiating partner. If no agreement was reached, neither party earned anything. Test subjects with an artificially enhanced testosterone level generally made better, fairer offers than those who received placebos, thus reducing the risk of a rejection of their offer to a minimum. Two later studies have empirically confirmed these results.[71][72][73] However men with high testosterone were significantly 27% less generous in an ultimatum game.[74] The Annual NY Academy of Sciences has also found anabolic steroid use which increase testosterone to be higher in teenagers, and this was associated with increased violence.[75] Studies have also found administered testosterone to increase verbal aggression and anger in some participants.[76]
Some of the effects of testosterone treatment are well recognised and it seems clear that testosterone treatment for aging hypogonadal men can be expected to increase lean body mass, decrease visceral fat mass, increase bone mineral density and decrease total cholesterol. Beneficial effects have been seen in many trials on other parameters such as glycemic control in diabetes, erectile dysfunction, cardiovascular risk factors, angina, mood and cognition. These potentially important effects require confirmation in larger clinical trials. Indeed, it is apparent that longer duration randomized controlled trials of testosterone treatment in large numbers of men are needed to confirm the effects of testosterone on many aspects of aging male health including cardiovascular health, psychiatric health, prostate cancer and functional capacity. In the absence of such studies, it is necessary to balance risk and benefit on the best available data. At the present time the data supports the treatment of hypogonadal men with testosterone to normalize testosterone levels and improve symptoms. Most men with hypogonadism do not have a contraindication to treatment, but it is important to monitor for adverse consequences including prostate complications and polycythemia.

Testosterone levels generally peak during adolescence and early adulthood. As you get older, your testosterone level gradually declines — typically about 1 percent a year after age 30 or 40. It is important to determine in older men if a low testosterone level is simply due to the decline of normal aging or if it is due to a disease (hypogonadism).
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