Winners Have More Testosterone

Researchers were able to predict the winners of rugby matches by measuring testosterone levels before the games. Yes, before. Is testosterone a predictor of victory? Read on for the answers.

What is success? The answer depends on what we are talking about, but in sports, success means winning. Yeah, for some of us who play in recreational leagues success means drinking beer in the dugout and hanging out with friends, but for serious athletes, the bottom line is victory. We can measure this pretty simply by our W-L record. But what if we could measure it before we even compete? And what if those results gave us the time to alter our preparation enough to change a future L into a W instead? Wouldn’t you want to know about it?

Well it turns out this is at least partially possible. A recent study in the Journal of Strength and Conditioning examined the hormone changes in rugby athletes the week prior to competition and then compared the results of the test to the results of the games. It looks like we can predict with some reliability what the outcome of a game is going to be in a team sport before the game even starts.

The researchers looked at two hormones in particular. Testosterone was one, a hormone of anabolism and other sports related attributes like aggressiveness. The other was cortisol, the hormone of catabolism and stress.

In response to exercise, both hormones are typically elevated, but prior to a game the results are different. In the week prior to a win, absolute and relative testosterone was substantially elevated in athletes on the winning team. In fact, testosterone was relatively elevated in the winners by about 27% more than the losers. Cortisol, by contrast, was not significantly different between the winning team or the losing team. Both sides had a reduction in cortisol of between 22 and 25%.

How can this be? Precognition? Time travel? Probably not. More likely these results reflect the mental state of the athletes. It seems the anticipation of winning has a beneficial effect on our hormones. So, is this important to us? It can be easy in this situation to confuse cause and effect. It’s not likely that the increase in testosterone contributed much to the actual victory, but rather the athletes believed they would win because they knew it was likely. And sure enough, they won because they were better than the other team.

However, there are practical outcomes for this study. First, researchers used a simple salivary testosterone test. Anyone can do this, and it might be a good way for coaches and teams to get an accurate measurement of their team’s self-confidence going into a match. It might also be a good argument for the use of sports psychology to improve a team’s perception of their odds or, at the very least, more work in the areas needed for victory.

Second, while the increase in testosterone might not have caused the wins in the study, it sure as hell didn’t hurt. We all know that a natural testosterone boost of nearly 30% is great for athleticism, and we now know it can be achieved just by being well prepared for winning. And winning then increases our confidence further. It’s an upward spiral that’s worth examining by any team.


1. Blair Crewther, et. al., “The Workout Responses of Salivary-Free Testosterone and Cortisol Concentrations and Their Association With the Subsequent Competition Outcomes in Professional Rugby League,” Journal of Strength & Conditioning Research, 27:2 (2013)

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