Asian Journal of Research and Reports in Endocrinology

Testosterone is frequently described as an aggression-promoting hormone, yet this shorthand obscures a literature in which effects are small, context-dependent and sometimes prosocial. This critical narrative review evaluates evidence linking endogenous testosterone, competition-related hormonal change and experimental testosterone administration with aggressive behaviour and social decision-making. Literature accessible through PubMed/MEDLINE, PubMed Central, the Directory of Open Access Journals and DOI-linked scholarly records was examined, with backward and forward citation searching used to identify influential and contradictory studies. The synthesis distinguishes baseline associations from within-person reactivity and pharmacological causation, and integrates behavioural, endocrine and neuroimaging evidence. Baseline testosterone shows, at most, a weak positive association with aggression, while competition-related changes are somewhat more informative but remain contingent on motivation, outcome interpretation and social context. Experimental administration does not produce a general increase in aggression, cooperation, risk taking or competitive choice. Instead, testosterone appears to alter the salience and expected value of status-relevant actions. Depending on the incentives and meanings embedded in a situation, this can support retaliation, threat approach and status consumption, but also fairness, reciprocity, strategic generosity and prosocial learning. Frontolimbic modulation, especially altered coordination between amygdala and prefrontal systems, provides a plausible mechanism, although neural findings are based on restricted samples and heterogeneous dosing protocols. Cortisol, dominance motivation, self-construal, sex, social rank and provocation may moderate effects, but many interaction findings are underpowered and vulnerable to analytical flexibility. The evidence therefore supports a context-sensitive social-regulatory account rather than a deterministic androgen–aggression model. Progress requires preregistered multisite experiments, harmonised pharmacokinetic and assay procedures, repeated within-person measurement, stronger computational models and ecologically valid designs that include women, diverse cultures and life-course variation.