If a man's testosterone looks below the normal range, there is a good chance he could end up on hormone supplements—often indefinitely. "There is a bit of a testosterone trap," Dr. Pallais says. "Men get started on testosterone replacement and they feel better, but then it's hard to come off of it. On treatment, the body stops making testosterone. Men can often feel a big difference when they stop therapy because their body's testosterone production has not yet recovered."
Attention, memory, and spatial ability are key cognitive functions affected by testosterone in humans. Preliminary evidence suggests that low testosterone levels may be a risk factor for cognitive decline and possibly for dementia of the Alzheimer's type,[104][105][106][107] a key argument in life extension medicine for the use of testosterone in anti-aging therapies. Much of the literature, however, suggests a curvilinear or even quadratic relationship between spatial performance and circulating testosterone,[108] where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition.
Testosterone is an anabolic steroid hormone that plays a critical role in metabolism, sex drive, muscle building, mood regulation, memory & cognitive function.  Normal testosterone levels play a huge role in maintaining optimal weight as well as reducing risk of degenerative diseases such as osteoporosis, heart disease, diabetes, & certain cancers (1, 2, 3).
If men’s brain, muscles, and bones are being affected daily due to low testosterone, and it is what makes men, men, why aren’t we doing more about this serious health problem? Could there be a political correctness crept in the scientific community that is hindering newly invigorated research in this area? I thought that scientific inquiry suppose to go where the evidence leads. It appears that some honest experts are opening their eyes to this truth.
I’ve had low testo in the winter for the last 10 years, with the lowest values around april (live in the north). But last year (in september) I started using vitamine D (10 000 IU) and K2 (180 mcg), combined with magnesium (200 mg malate) and zinc (25 mg malate and piccolinate) every night, and since then I no longer have low testo in the winter, and is feeling like I do in the summer and have normal testo levels. This combo may work for other people as well. And the risk for dangerous side effects is probabaly neglectable. But it takes a couple of weeks before it kicks in.
For facts sake I am 51yr old male and I am fat. I do have a large and muscular fat, but I also have a good amount of at on top of that. My body shape is not the typical huge “beer belly” gut that is hard and dangerous, rather, I am fat all over proportionally, but still considered obese. The fat on my body and around my middle is quite soft compared to male friends who have those large and hard bellies. Still, my doctor and reading indicate that fat has an effect on T potentially lowering the overall level that my T would be if I lost a good amount of that fat.
Men's levels of testosterone, a hormone known to affect men's mating behaviour, changes depending on whether they are exposed to an ovulating or nonovulating woman's body odour. Men who are exposed to scents of ovulating women maintained a stable testosterone level that was higher than the testosterone level of men exposed to nonovulation cues. Testosterone levels and sexual arousal in men are heavily aware of hormone cycles in females.[46] This may be linked to the ovulatory shift hypothesis,[47] where males are adapted to respond to the ovulation cycles of females by sensing when they are most fertile and whereby females look for preferred male mates when they are the most fertile; both actions may be driven by hormones.
Sharma, R., Oni, O. A., Gupta, K., Chen, G., Sharma, M., Dawn, B., … & Barua, R. S. (2015, August 6). Normalization of testosterone level is associated with reduced incidence of myocardial infarction. European Heart Journal, 36(40), 2706-2715. Retrieved from https://academic.oup.com/eurheartj/article/36/40/2706/2293361/Normalization-of-testosterone-level-is-associated