Testosterone and Aggression: The Relationship

Testosterone and Aggression
Medically approved by
Dr Earim Chaudry
Last updated
26th August 2020

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Does testosterone cause aggression? Whilst, along with machismo and lust, aggressive behaviour is something conventionally associated with the male hormone, there is no straightforward scientific link between testosterone and aggression.
However, this is not to say that there is no link at all. There seems to be evidence, for example, that testosterone is increased in contexts of competitiveness and that more testosterone is present in more aggressive people. This is not to say that testosterone causes aggression, however.
Crucially, though, testosterone is much more important for developing your physical characteristics – including your sexual organs, your body hair and your muscle mass – than any specific “manly” behaviour.

Testosterone and Aggression

Testosterone is perhaps the most famous of the male sex hormones. But as happens with things we do not fully understand, there are lots of things – from fast cars to competitiveness – with which it is conventionally associated.

One of these is aggression. As a tendency to actual physical violence, or else as a competitiveness, machismo, or belligerence, aggression has long been linked – anecdotally and colloquially – to this male hormone. In fact, testosterone is even sometimes known as the “aggression hormone”.

But does testosterone cause aggression really? In this article, we’re going to take a look – and consider some of the other things that testosterone may well cause too.

Does Testosterone Cause Aggression? The Evidence

The trouble with testosterone is that many of us believe that we know what it does already. From increasing competitiveness to building strength, from boosting sex drive to enhancing levels of confidence and energy, testosterone is a hormone whose “masculine” effects we take for granted.

But do we really understand them? According to one study in the journal, Nature, our beliefs about what this hormone does have powerful effects in themselves – but they don’t necessarily correspond to reality. In the study, 121 women were required to play a game, before which some were given testosterone and others a placebo. However, those who were told that they had taken the hormone were on the placebo, whilst those on testosterone were unaware. This way, scientists could test the difference between the expectations and the reality of the hormone’s effect.

The results were interesting. Those who thought they had taken testosterone played much more aggressively. However, those who had actually taken testosterone played much more generously and fairly than the others. Following the study, one of the researchers said, “It is a folk hypothesis that testosterone causes aggression”.

But Does Testosterone Increase Aggression at All?

This “folk hypothesis”, however, does have some scientific support. According to one review of studies from 1991, testosterone is strongly linked to aggression in animals, whilst, in humans, aggressive encounters themselves have been seen to have an effect on levels of testosterone too. Similarly, more aggressive people have been found to have higher levels of testosterone, whilst testosterone increases during aggressive sports, too.

Whilst they suggest that there is some link between testosterone and aggression, what these studies fail to do is to confirm that testosterone causes aggression. In fact, studies have not been able to identify clearly that such a causal relationship exists at all.

According to one 2004 study – which investigated the effect of testosterone supplements on anger, hostility, aggression, irritability, and sexual function – aggressive behaviour did not change after treatment. A smaller study found that small changes in euphoria, irritability, and confusion resulted from high doses of testosterone. However, the likelihood of psychiatric episodes did too.

From the evidence, it seems like the idea that testosterone causes aggression may well be a “folk hypothesis” after all.

What Does Testosterone Do?

Testosterone may not have the effect we believed. This is not to say that it has no impact on our behaviours at all. In fact, there is good reason why people believed what they did for so long.

For example, whilst aggression itself doesn’t seem to be causally linked to testosterone, studies have found that other social responses may be affected by the hormone. Research has suggested, for instance, that testosterone promotes behaviours that enhance social dominance. One study found that, among young teenagers, testosterone was actually linked to higher social dominance but lower aggression.

As a result, scientists are beginning to reach the tentative conclusion that testosterone plays a role in producing behaviours that increase your ability and motivation to achieve and maintain social status. However, it remains unclear precisely how this works.

The Effects of Testosterone

Beyond the ground-breaking studies into the effects of testosterone on our social behaviours, we do know the concrete impacts of the hormone on physical processes within the male body. Produced in the testes of men, testosterone plays a role in the regulation of sex drive, the composition and distribution of fat and muscle, in the production of red blood cells, and in the growth of body hair.

Yet, the function of testosterone changes across our lifetimes. Whilst, when we are young, the hormone enables the development of our sexual organs and our body structure, as we age its role becomes more regulatory – focusing on the maintenance of our sperm health and our bone mass.

As a result, throughout our lives, the levels of testosterone that we have tends to decrease, at a rate of about 1% per year. 

What is Low Testosterone?

This decline, however, can be more radical in some than in others – and can lead to a condition known as low testosterone, or Low-T.

Much more common in the elderly and in those who are overweight, Low-T can have serious effects on the male body, on your mood, and on your sexual health. Some symptoms of low testosterone include irritability, a low sex drive, fatigue, and changes in body composition. It can also lead to hair loss and erectile dysfunction too.

However, there are natural ways to increase your testosterone. And you needn’t worry about increasing your aggression either.

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Key Takeaways

Testosterone is a hugely important chemical in our bodies, affecting – among many other things – our body composition and sex drive. But does testosterone cause aggression? The science says probably not: no direct link between testosterone and aggression has yet been found.

However, what testosterone does seem to do is influence our behaviour linked to social dominance. The hormone appears to make us strive to be more socially dominant and to help us maintain that dominance once we have achieved it.

References

  1. Nature – Prejudice and truth about the effect of testosterone on human bargaining behaviour: https://www.nature.com/articles/nature08711

  2. Nature – Testosterone link to aggression may be all in the mind: https://www.nature.com/articles/news.2009.1131

  3. John Archer (1991). The influence of testosterone on human aggression: https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.2044-8295.1991.tb02379.x

  4. Menelaos L. Batrinos (2012). Testosterone and Aggressive Behavior in Man: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3693622/

  5. Daryl B. O’Connor, John Archer, Frederick C. W. Wu (2004). Effects of Testosterone on Mood, Aggression, and Sexual Behavior in Young Men: A Double-Blind, Placebo-Controlled, Cross-Over Study: https://academic.oup.com/jcem/article/89/6/2837/2870329

  6. T P Su 1, M Pagliaro, P J Schmidt, D Pickar, O Wolkowitz, D R Rubinow (1993). Neuropsychiatric effects of anabolic steroids in male normal volunteers: https://www.ncbi.nlm.nih.gov/pubmed/8492402

  7. Yukako Inoue, Taiki Takahashi, Robert P. Burriss, Sakura Arai, Toshikazu Hasegawa, Toshio Yamagishi & Toko Kiyonari (2017). Testosterone promotes either dominance or submissiveness in the Ultimatum Game depending on players’ social rank: https://www.nature.com/articles/s41598-017-05603-7

  8. B Schaal 1, R E Tremblay, R Soussignan, E J Susman (1996). Male testosterone linked to high social dominance but low physical aggression in early adolescence: https://www.ncbi.nlm.nih.gov/pubmed/8885586

  9. Men’s Health – Testosterone and the struggle for higher social status: https://onlinelibrary.wiley.com/doi/pdf/10.1002/tre.372

  10. Harvard Men’s Health Watch – Harvard Men’s Health Watch: https://www.health.harvard.edu/newsletter_article/Testosterone_aging_and_the_mind

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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