Testosterone and Weight
A growing body of literature is finding a link between body weight and testosterone.
What is testosterone?
Testosterone is the primary male hormone produced in the testicles responsible for the development of the male sexual characteristics (e.g. growth of facial and pubic hair, deepening of the voice, increase in muscle mass and strength, and a growth in height). This hormone also helps to maintain sex drive, sperm production, muscle mass and bone mass. Small amounts of testosterone are also produced in women by the ovaries and adrenal glands.
Low testosterone levels linked to excess weight.
While many factors can cause low testosterone levels, it appears that excess weight may play a role. In a 2006 study on more than 2,100 men aged 45 and older, obese men were 2.4 times more likely to have low testosterone compared to those at a healthy weight..1 Studies have also shown that as Body Mass Index (BMI) increases, there is proportionate reduction in testosterone levels.2, 3
Why is this important?
Clinically low testosterone levels, also known as hypogonadism, has been linked to several health problems, including erectile dysfunction, low sperm count, fatigue, mood changes and weaker bones. Research suggests that low testosterone may be linked to the metabolic syndrome, which is characterized by an increase in body fat, particularly abdominal fat, and chronic medical conditions such as type 2 diabetes, high cholesterol levels, high blood pressure, and heart disease.5 However, more studies are needed to confirm this relationship.
What can be done?
Testosterone replacement therapy is an option for men with low testosterone levels. However, it is up to the individual and his doctor to evaluate whether this treatment option should be considered. A meta-analysis published in 2010 concluded that testosterone replacement therapy was associated with lower blood glucose and triglyceride levels and a reduction in fat mass.6 There is some controversy about the risks associated with the long-term safety of testosterone replacement therapy and no definitive conclusions have been drawn about this treatment's effect on body weight or body composition, although it is likely minimal at best.
Losing weight may help.
Weight loss may also help. For example, in a study published in Obesity Research, researchers measured testosterone levels in two groups of middle-aged obese men. One group underwent a 16-week weight loss programme while a second group did nothing.6 The weight loss group lost an average of 45lb and had significant increases in testosterone levels. Larger studies are needed, however, before any firm conclusions can be drawn.
1 Mulligan T, Frick MF, Zuraw QC, Stemhagen A, McWhirter C. Prevalence of hypogonadism in males aged at least 45 years: the HIM study. Int J Clin Pract. 2006 Jul;60(7):762-9.
2 Kaplan SA, Meehan AG, Shah A. The age related decrease in testosterone is significantly exacerbated in obese men with the metabolic syndrome. What are the implications for the relatively high incidence of erectile dysfunction observed in these men ? J Urol. 2006 Oct;176(4 pt 1):1524-7.
3 Osuna JA, Gomez-Perez R, Arata-Bellabarba G, Villaroel V. Relationships between BMI, total testosterone, sex hormone-binding globulin, leptin, insulin and insulin resistance in obese men. Arch Androl. 2006 Sep-Oct;52(5):355-61.
4 MacDonald AA, Herbison GP, Showell M, Farquhar CM. The impact of body mass index on semen parameters and reproductive hormones in human males: a systematic review with meta-analysis. Hum Reprod Update. 2010 May-Jun;16(3):293-311.
5 Guay AT, Traish A. Testosterone deficiency and risk factors in the metabolic syndrome: implications for erectile dysfunction. Urol Clin North Am. 2011 May;38(2):175-83. Epub 2011 Apr 3.. J Clin Endocrinol Metab. 2004 Nov;89(11):5462-8
6 Corona G, Monami M, Rastrelli G, et al. Type 2 diabetes mellitus and testosterone: a meta-analysis study. Int J Androl. 2010 Oct 24. doi: 10.1111/j.1365-2605.2010.01117.x. [Epub ahead of print]
7 Kaukua J, Pekkarinen T, Sane T, Mustajoki P. Sex hormone and sexual function in obese men losing weight. Obes Re. 2003 Jun;11(6):689-94.