In discussions about diagnosis and health consequences of hypogonadism, aka testosterone deficiency, the prime focus is given to testosterone levels and signs/symptoms.[1-3] However, emerging research has identified a less clinically evident gonadal dysfunction called “subclinical” hypogonadism (or “compensated” hypogonadism).[4, 5]
Subclinical hypogonadism is characterized by normal testosterone levels in the presence of elevated LH level. As testosterone levels are not markedly reduced in subclinical hypogonadism, intuitively one may think it does not confer negative health consequences.
However, a recent study by Corona et al., which specifically was conducted to investigate the potential health ramifications of subclinical hypogonadism, shows that it should not be neglected. Surprisingly, subclinical hypogonadism is associated with an almost 10-fold increased risk of cardiovascular mortality, which is comparable to that for overt hypogonadism! 
One of the most debated issues related to testosterone therapy is its effects on cardiovascular risk and clinical events, like for example heart attack.
January 27th, 2015 a comprehensive medical review paper was published, addressing the controversial topic of testosterone therapy and cardiovascular risk. It was written by the Androgen Study Group academicians and published in Mayo Clinic Proceedings.
Here I summarizes key conclusions from this milestone medical review.
In an effort to slash heart disease, the Dietary Guidelines for Americans  have since 1977 been urging people to:
1. Reduce total fat consumption to 30% of total caloric intake.
2. Reduce saturated fat consumption to 10% of total energy intake.
Government issued dietary guidelines are highly authoritative and regarded by a majority as being backed by solid research. However, as it turns out, this is not the case…
Dietary recommendations regarding intake of total and saturated fat are highly controversial, and the debate is heating up. A recent systematic review and meta-analysis of six studies that were available 1977, when the first version of the Dietary Guidelines for Americans was published, shows: 
Population studies show that men with low or low-normal testosterone levels are at an increased risk of mortality compared to those with higher levels, and that cardiovascular disease accounts for the greater proportion of deaths in men with low testosterone.
Here I summarize a medical review paper which addressed the following two questions: 
1. Is testosterone deficiency directly involved in the pathogenesis of these conditions or is it merely a biomarker of ill health and the severity of underlying disease processes?
2. Does testosterone replacement therapy retard disease progression and ultimately enhance the clinical prognosis and survival?
A key hallmark of aging is a progressive loss of muscle mass, which occurs independently of health status. Exercise and nutrition are the two main anabolic stimuli for muscle growth and its maintenance throughout the life course.[2-11]
It is clear that maintaining high physical activity and exercise levels throughout ones lifespan reduces aging related loss of muscle mass and function, compared with living a sedentary life.[12-19]
However, even active older adults and master elite athletes still experience some loss of muscle and physical performance with advancing age.[8, 13, 20]
When it comes to nutrition, high protein intake [2, 3, 10, 21] and creatine supplementation [4-8, 22] are two of the best documented interventions, which together with resistance exercise training, result in greater increases muscle mass and strength in both young [21-23] and older people [2-8, 10], and prevent its loss with aging. Here I will present the relatively unknown effevts of fish oil (most well-known for its cardiovascular health promoting effects) on muscle growth (anabolism) and its possible contribution to prevention of aging related loss of muscle mass and function...
The cardiovascular effects of testosterone and testosterone therapy are subject to intense investigation in medical research and have recently generated heated discussions among healthcare professionals.
While the main focus has been on testosterone per se, it is important to remember that testosterone is both a hormone in its own right, and a pro-hormone that gets converted to both estradiol and DHT (dihydrotestosterone). Estradiol and DHT exert effects themselves that are different from the effects of testosterone.
Therefore, when analyzing the effects of testosterone, especially supplemental testosterone administered as testosterone replacement therapy, it is critical to take into consideration how it affects downstream testosterone metabolites like estradiol and DHT.
Here I will present results from a recent systematic review and meta-analysis that specifically investigated how different routes of testosterone therapy administration (i.e different testosterone preparations) affect blood levels of testosterone and espcially DHT , and how this in turn relates to cardiovascular adverse events.
It is well documented that obesity may cause hypogonadism, and that hypogonadism may cause obesity [1-4] This has generated debate about what condition comes first; obesity or hypogonadism? And what should be the first point of intervention?
In this article I will summarize data from several reviews on the associations of hypogonadism and obesity [1-4], and make the case that these conditions create a self-perpetuating vicious circle. Once a vicious circle has been established, it doesn’t matter where one intervenes; one can either treat the obese condition or treat hypogonadism first. The critical issue is to break the vicious circle as soon as possible before irreversible health damage arises.
Nevertheless, as I will explain here, treating hypogonadism first with testosterone replacement therapy may prove to be a more effective strategy because it to a large extent “automatically” takes care of the excess body fat and metabolic derangements. In addition, treating hypogonadism first also confers psychological benefits that will help obese men become and stay more physically active.
In a previous article "Combined Testosterone and GH therapy for best results on body composition and safety profiles" I covered a study showing that testosterone replacement therapy alone produced significant gains in total lean body mass, leg/arm muscle mass, strength and aerobic endurance, together with significant reductions in whole-body and trunk fat. 
In the same study, addition of GH (growth hormone) further enhanced these beneficial results.
In a follow-up to that that study, the researchers looked deeper into the data with the following analyses: 
- Pathway analysis to test the hypothesis that testosterone and GH affected muscle mass directly and that a threshold change in lean tissue (muscle) mass was needed to generate significant improvements in muscle performance and physical function.
- Bootstrap analysis to determine threshold hormone levels associated with threshold changes in whole-body and appendicular lean mass that would be necessary for improving muscle performance and functional outcomes.
Here I report on the results of this insighful analysis...
Testosterone deficiency is especially common in men who are obese and/or have the metabolic syndrome or diabetes, with a prevalence ranging from 35% to almost 80%.[1-5] However, there is a subgroup of non-obese men who have low testosterone levels and suffer from typical symptoms of low-T, but who do not (yet) have any co-morbidities.
Many studies show that suboptimal testosterone levels may contribute to the development of obesity (including abdominal obesity) [6, 7], metabolic syndrome [8-13] and/or diabetes.[9, 14-20] Therefore, testosterone therapy in non-obese men with testosterone deficiency may be an effective intervention to correct not only symptoms associated with hypogonadism, but also prevent the development of obesity, metabolic syndrome and/or diabetes.
A notable study was set out to specifically investigate this…
A rapidly growing body of medical research is showing that testosterone deficiency (aka hypogonadism and low-T) is strongly associated with a wide range of detrimental health outcomes [1, 2], and that testosterone replacement therapy improves those health parameters that are negatively affected by testosterone deficiency.[2, 3]
Therefore, leading testosterone scientists now view testosterone deficiency as a cardiovascular risk factor that contributes to the development of cardiovascular disease.[4-7]
As general practitioners and cardiologists primarily care for these patients with cardiovascular disease, a survey study was conducted to assess their knowledge, beliefs and clinical practice with respect to testosterone deficiency and cardiovascular health.