According to the Mayo Clinic, testosterone therapy can help treat hypogonadism. This condition occurs when the body can’t produce enough testosterone on its own. However, it’s unclear whether supplements can help. A study published in Nature Reviews Endocrinology found no scientific reason to prescribe testosterone to men over 65 years of age with normal or low to normal testosterone levels.

The effect excess testosterone has on the body depends on both age and sex. It is unlikely that adult men will develop a disorder in which they produce too much testosterone and it is often difficult to spot that an adult male has too much testosterone. More obviously, young children with too much testosterone may enter a false growth spurt and show signs of early puberty and young girls may experience abnormal changes to their genitalia. In both males and females, too much testosterone can lead to precocious puberty and result in infertility. 
Rumor has it that the Kim sisters' testosterone pill received a reaction that no other product has ever gotten on Shark Tank. Apparently, after watching a presentation from the pair and hearing about how well their product has performed so far, all five judges got into a heated argument over who would make a deal with the two young entrepreneurs. It's been said that the fight lasted nearly an hour before the judges decided to do something that's never been done before. All five Sharks teamed up to invest an unbelievable $2.5 million into the Kim sisters' product!
As crazy as it seems, it has lately been proven that there is a no relation between cholesterol intake and heart attack as doctors once thought (and many still do). This is slowly becoming common knowledge, regardless of pharmaceutical companies wishes. (Trust me, this billion dollar industry does not want you to know this. You don;t have to be a conspiracy theorist to see this.)
It is now well-established that elderly men with type 2 diabetes mellitus have reduced levels of testosterone (Barrett-Connor 1992; Betancourt-Albrecht and Cunningham 2003). It is known, however, that obese men and diabetic men have reduced levels of SHBG (Barrett-Connor 1990) which could account for the lower total testosterone levels found in diabetic men. Dhindsa et al (2004) studied 103 male patients who had type 2 diabetes mellitus using free testosterone (done by equilibrium dialysis) or calculated free testosterone which takes SHBG levels into account. Of the 103 patients, 57 had free testosterone by equilibrium dialysis and of these, 14 (25%) had a free T below 0.174 nmol/L and were considered hypogonadal. Using a total testosterone of 10.4 nmol/L (300ng/dl) as the lower limit of normal 45 patients (43%) were in the hypogonadal range. They also found that LH and FSH concentrations were significantly lower in the hypogonadal group. The authors thus concluded that hypogonadotropic hypogonadism was a common finding in type 2 diabetes irrespective of glycemic control, duration of disease or the presence of complications of diabetes or obesity.
ZMA (unnecessary). So when I researched how to increase testosterone, a supplement called ZMA kept popping up. It’s a blend of zinc, magnesium, and vitamin B6. The purported benefits of ZMA include better and deeper sleep which indirectly is supposed to increase testosterone. Zinc and magnesium are necessary minerals in testosterone production, so a mega-dose should be useful, right? Well, no. I bought some and took it during the duration of experiment. I should have done some more research before I made the purchase. While one study in 1998 showed increased strength among athletes taking ZMA, two recent studies (study 1, study 2) have shown that it has absolutely no effect on total or free testosterone levels. Crap. My advice, unless you have a zinc and magnesium deficiency, no need to waste your money on this.
Osteoporosis refers to pathological loss of bone density and strength. It is an important condition due to its prevalence and association with bone fractures; most commonly of the hip, vertebra and forearm. Men are relatively protected from the development of osteoporosis by a higher peak bone mass compared with women (Campion and Maricic 2003). Furthermore, women lose bone at an accelerated rate immediately following the menopause. Nevertheless, men start to lose bone mass during early adult life and experience an increase in the rate of bone loss with age (Scopacasa et al 2002). Women of a given age have a higher prevalence of osteoporosis in comparison to men but the prevalence increases with age in both sexes. As a result, men have a lower incidence of osteoporotic fractures than women of a given age but the gap between the sexes narrows with advancing age (Chang et al 2004) and there is evidence that hip fractures in men are associated with greater mortality than in women (Campion and Maricic 2003).
In accordance with sperm competition theory, testosterone levels are shown to increase as a response to previously neutral stimuli when conditioned to become sexual in male rats.[40] This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction.
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