Article: Relationship between Cortisol and Testosterone

  1. Article: Relationship between Cortisol and Testosterone

    Article of interest:
    JSSM- 2005, Vol.4, Issue 1, 76 - 83


    Kaye K. Brownlee1, Alex W. Moore1 and Anthony C. Hackney1,2

    1Endocrine Section - Applied Physiology Laboratory, Department of Exercise & Sport Science,
    2Department of Nutrition - School of Public Health, University of North Carolina, Chapel Hill, NC, USA

    Human research has shown the administration of cortisol into the circulation at rest will result in reduced blood testosterone levels. Many researchers have used these results to imply that physical exercise induced cortisol increases would perhaps result in subsequent reductions in circulating testosterone levels. Our purpose was to examine this concept and determine what, if any, relationship exists between circulating cortisol (C) and testosterone (T) in men (n = 45, 26.3 3.8 yr) at rest and after exercise. Blood samples were collect at rest (10 hour post-prandial; denoted as 'Resting'; n = 45) and again on the same day at 1.0 hr into recovery from intensive exercise (denoted as 'Exercise Recovery'; n = 45). Approximately 48-96 hr after this initial (Trial # 1) blood collection protocol the subjects replicated the exact procedures again and provided a second Resting and Exercise Recovery set of blood samples (Trial # 2). Blood samples from Trial # 1and Trial # 2 were pooled (Resting, n = 90; Exercise Recovery, n = 90). The blood samples were analyzed by radioimmunoassay for C, total T (TT), and free T (fT). Pearson correlation coefficients for the Resting samples ([TT vs. C] r < +0.01; [fT vs. C] r = +0.06) were not significant (p > 0.05). For the Exercise Recovery samples ([TT vs. C] r = -0.53; [fT vs. C] r = +0.21) correlation coefficients were significant (p < 0.05). The findings indicate that exercise does allow the development of a significant negative relationship between C and TT. Interestingly, a significant positive relationship developed between C and fT following exercise; possibly due to an adrenal cortex contribution of fT or disassociation of fT from sex hormone binding globulin. The detected in vivo relationships between C and T, however, were associative and not causal in nature and were small to moderate at best in strength.


    Seems like taking a supplement that blunts cortisol pre-workout would be beneficial to prevent a negative skewing of the C to T ratio- but where could one find such a supplement????

  3. If only there were such a product.....

    By any chance does IGF-2 blunt cortisol pre-workout to prevent a negative skewing of the C to T ratio?

  4. Quote Originally Posted by Lanbane View Post
    If only there were such a product.....

    By any chance does IGF-2 blunt cortisol pre-workout to prevent a negative skewing of the C to T ratio?


  5. Old thread, I know. I thought it was interesting. The study seems to indicate that C/T ratio was negative, but C/fT was improved. Isn't free T what we are all after anyway? And does anyone know how C reduction through supplementation would affect free T?

    Another related question. What does lower testosterone in the blood after exercise really mean? I've seen studies like this for years saying Cort gets raised and Test gets lowered. But does higher Cort really lower Test or are these 2 things just happening at the same time, ie. non-causal? Couldn't lower Test be a byproduct of the body using it all up to repair after exercise and higher Cort due to the stress of exercise? Or does the body not work like that?

  6. Free testosterone is metabolized pretty darn quick - like 30 mins.

    I'd think in the long run lower cort so you have higher testosterone is better than higher cort and higher free testosterone for a mere 30 mins.


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