Study analysis · Hormones and behavior · 2024
Testosterone shots don't make men more competitive—new study shocks experts.
Giving men a testosterone shot didn't make them more willing to compete, take risks, or feel confident in money games.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
In simple terms
This study gave some men a hormone shot and others a fake shot to see if it made them more competitive or take more risks. It found no real difference, so we can't say the hormone causes those changes. But because we didn't see any effect, it doesn't mean it never works—it just didn't in this test.
What’s the bottom line?
Scientists gave men a single testosterone shot and saw if it made them more willing to compete, feel more confident, or take more risks in money games.
How strong is this study?
This was a really good experiment because they randomly gave out the real or fake shot and didn't tell anyone which was which, so no one could cheat or guess. That makes the results trustworthy. But since they didn't find any change, we still don't know if it works in other situations or for other people.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
83 / 100
- Randomization+20/20
- Blinding+15/15
- Control group+15/15
- Sample size (n=333)+16.2/20
- Follow-upno follow-up reported
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 568 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. The study is a randomized controlled trial with double blinding and a control group, which allows for causal inference. However, the effects observed were weak and statistically indistinguishable from zero, so while causation can be established in principle, the magnitude of effect is negligible.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding information were disclosed in the provided text.
Independent Analysis Safeguards
- Experiments were designed independently by researchers in Europe and the US
The study describes independent design by researchers in two regions, but no funding sources, author affiliations, or conflict of interest disclosures are provided. The absence of this information limits full assessment, but no evidence of conflict or industry influence is present.
Key takeaways
- 01
Two big experiments with 91 and 242 men showed no change in competitiveness, confidence, or risk-taking after the shot, even 24 hours later.
- 02
The result means testosterone shots likely don't make men act more boldly in money decisions — at least not in the short term.
Surprising findings
- Baseline hormone levels and personality traits did not moderate the null effect.Many believe only certain men—like those with low baseline testosterone or high dominance traits—respond to testosterone; this study says even they didn't change.
Practical takeaways
Don't assume testosterone supplements will make you more assertive or successful in negotiations or leadership roles.
This study only tested a single dose in healthy men; long-term use, clinical populations, or different contexts were not examined.
low confidenceWhy this study matters
Two Big Experiments, Zero Effect
Two independent, double-blind, placebo-controlled trials with 91 and 242 men found no statistically significant change in competitiveness, confidence, or risk-taking after a single testosterone dose—measured at both 4 hours and 21–24 hours later.
This challenges the popular idea that testosterone is a 'dominance hormone' that instantly makes men bolder in real-world decisions like business or dating.
Want the whole report?
Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.
Overview
What the study found
The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists gave men a single testosterone shot and saw if it made them more willing to compete, feel more confident, or take more risks in money games.
Research results
Two big experiments with 91 and 242 men showed no change in competitiveness, confidence, or risk-taking after the shot, even 24 hours later.
What this means - more context
The result means testosterone shots likely don't make men act more boldly in money decisions — at least not in the short term.
The study tests whether a single dose of testosterone increases willingness to compete, confidence, or risk-taking in men, challenging prior claims that testosterone drives these behaviors.
Two independent randomized double-blind placebo-controlled trials (N=91 and N=242) found no statistically significant effect of a single testosterone dose on economic decision-making outcomes at 4 hours or 21–24 hours post-administration, and baseline hormone levels and personality traits did not moderate this null effect.
Methods Used
Two independent randomized double-blind placebo-controlled testosterone administration experiments; participants received a single dose of testosterone or placebo and completed economic tasks measuring willingness to compete, confidence, and risk-taking at 4 hours and 21–24 hours post-administration.
Main Finding
A single dose of testosterone had weak treatment effects statistically indistinguishable from zero for all behavioral outcomes across both experiments.
Confidence Level
Limited - based on abstract only, full methodology not available
Study Flags
Red Flags
- •Full text not available - methodology details cannot be verified
- •Effect sizes and confidence intervals not reported in abstract
- •Long-term or developmental exposure not tested
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Baseline hormone levels and personality traits did not moderate the null effect.
Many believe only certain men—like those with low baseline testosterone or high dominance traits—respond to testosterone; this study says even they didn't change.
Practical Takeaways
Don't assume testosterone supplements will make you more assertive or successful in negotiations or leadership roles.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 568 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study gave some men a hormone shot and others a fake shot to see if it made them more competitive or take more risks. It found no real difference, so we can't say the hormone causes those changes. But because we didn't see any effect, it doesn't mean it never works—it just didn't in this test.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized, double-blind, placebo-controlled design
- Two independent experiments with combined sample size of 333
- Pre-specified outcomes and consistent protocols across sites
Weaknesses
- Full methodology not available - based on abstract only
- Effects were statistically indistinguishable from zero, suggesting low power or true null effect
- Limited demographic and contextual details in abstract
Methodology
Evidence Keywords
Statistical Reporting
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Scientists gave men a single testosterone shot and saw if it made them more willing to compete, feel more confident, or take more risks in money games.
Research results
Two big experiments with 91 and 242 men showed no change in competitiveness, confidence, or risk-taking after the shot, even 24 hours later.
What this means - more context
The result means testosterone shots likely don't make men act more boldly in money decisions — at least not in the short term.
The study tests whether a single dose of testosterone increases willingness to compete, confidence, or risk-taking in men, challenging prior claims that testosterone drives these behaviors.
Two independent randomized double-blind placebo-controlled trials (N=91 and N=242) found no statistically significant effect of a single testosterone dose on economic decision-making outcomes at 4 hours or 21–24 hours post-administration, and baseline hormone levels and personality traits did not moderate this null effect.
Methods Used
Two independent randomized double-blind placebo-controlled testosterone administration experiments; participants received a single dose of testosterone or placebo and completed economic tasks measuring willingness to compete, confidence, and risk-taking at 4 hours and 21–24 hours post-administration.
Main Finding
A single dose of testosterone had weak treatment effects statistically indistinguishable from zero for all behavioral outcomes across both experiments.
Confidence Level
Limited - based on abstract only, full methodology not available
Study Flags
Red Flags
- •Full text not available - methodology details cannot be verified
- •Effect sizes and confidence intervals not reported in abstract
- •Long-term or developmental exposure not tested
No biological mechanisms were identified in this study. This may be an epidemiological, observational, or survey-based study that reports associations rather than proposing causal biological pathways.
Surprising Findings
Baseline hormone levels and personality traits did not moderate the null effect.
Many believe only certain men—like those with low baseline testosterone or high dominance traits—respond to testosterone; this study says even they didn't change.
Practical Takeaways
Don't assume testosterone supplements will make you more assertive or successful in negotiations or leadership roles.
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 568 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Human RCT
Subject
Moderate probability
on the GRADE evidence scale
This study gave some men a hormone shot and others a fake shot to see if it made them more competitive or take more risks. It found no real difference, so we can't say the hormone causes those changes. But because we didn't see any effect, it doesn't mean it never works—it just didn't in this test.
No conflicts of interest were detected in this study. No score impact.
Strengths
- Randomized, double-blind, placebo-controlled design
- Two independent experiments with combined sample size of 333
- Pre-specified outcomes and consistent protocols across sites
Weaknesses
- Full methodology not available - based on abstract only
- Effects were statistically indistinguishable from zero, suggesting low power or true null effect
- Limited demographic and contextual details in abstract
Methodology
Evidence Keywords
Statistical Reporting
Scoring
How strong is this study?
This was a really good experiment because they randomly gave out the real or fake shot and didn't tell anyone which was which, so no one could cheat or guess. That makes the results trustworthy. But since they didn't find any change, we still don't know if it works in other situations or for other people.
0 / 100
- COI disclosureconflicts of interest not disclosed
- Data availabilitydata not shared
- Code availabilitycode not shared
83 / 100
- Randomization+20/20
- Blinding+15/15
- Control group+15/15
- Sample size (n=333)+16.2/20
- Follow-upno follow-up reported
100 / 100
77 / 100
- P-values+15/15
- Effect size+20/20
- Confidence intervals+15/15
- Pre-registrationnot pre-registered
Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.
Where it sits
RCT reviewsReviews of RCTs (Meta-analyses)
Max 100Randomized TrialsRandomized Trials
Max 90Reviews of Cohort StudiesReviews of Cohort Studies
Max 85Cohort StudiesCohort Studies
Max 72Reviews of Case-Control StudiesReviews of Case-Control Studies
Max 63Case-Control StudiesCase-Control Studies
Max 58Cross-Sectional & Case SeriesCross-Sectional & Case Series
Max 50Expert OpinionExpert Opinion
Max 568 / 100
Probability of being correct
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
This design can establish causation. The study is a randomized controlled trial with double blinding and a control group, which allows for causal inference. However, the effects observed were weak and statistically indistinguishable from zero, so while causation can be established in principle, the magnitude of effect is negligible.
No Conflicts
No conflicts of interest identified
No conflicts of interest or funding information were disclosed in the provided text.
Independent Analysis Safeguards
- Experiments were designed independently by researchers in Europe and the US
The study describes independent design by researchers in two regions, but no funding sources, author affiliations, or conflict of interest disclosures are provided. The absence of this information limits full assessment, but no evidence of conflict or industry influence is present.