Some of the most popular supplements today are the so called pre-workout nitric oxide (NO) boosters [1, 2]. These contain a panoply of ingredients, but one the main ones is arginine. The rationale goes that L-arginine is a nitric oxide (NO) precursor and NO is a potent vasodilator [3, 4]. Theoretically this would increase blood flow and nutrient/oxygen delivery to exercising muscles and thereby boost performance, as well as recovery. 

 

While it is true that L-arginine supplementation may be beneficial for various clinical populations (see below), studies in healthy adults have not unequivocally supported the marketing hype surrounding arginine supplementation and nitric oxide boosters [1, 5, 6]. Why? Let's take a look under the hood...

 

 

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! [6]