Total testosterone goes down by about 1-2% per year , starting sometime in your 30s, and bioavailable testosterone decreases by about 2-3% a year. Those numbers can be pretty misleading though. Men approaching middle age tend to exercise a lot less, and eat a lot worse. So nobody really knows what a “natural” decline in testosterone looks like, on a population-wide basis. It’s kind of like saying muscle mass decreases 1-2% a year once you hit middle age … that decrease can have a lot to do with more time spent on work and family, and less time spent trying to get ripped to attract a partner (among other reasons, of course).
Organic is generally a better way to for your health and also for your testosterone levels. It’s not because of anything special they put in the food or anything like that, it is because of what doesn’t go into the plants, things like pesticides and herbicides. Little do most people know that pesticides and herbicides are also contributors to lower testosterone. Studies have shown that the pesticide Chlorpyrifos has a negative effect on testosterone and this study showed that Chlorpyrifos has been found in more than 90% of Americans. Other pesticides such as Vinclozolin , Atrazine , and PCBs , have been linked to lower testosterone levels as well.