High testosterone levels correlate with a weakened immune system
the verdict
CONTESTED
the evidence cuts both ways
confidence 39/100
While many experimental studies in birds and mammals support the immunocompetence handicap hypothesis by showing that testosterone can suppress certain immune measures, other research highlights that these effects are highly context-dependent, variable across species, and sometimes contradicted by natural observations.
The evidence we hold leans leans supported
How this was weighed
official record 3x · fact-check 2x · hedged 1x · crowd & reference 1x
Testosterone and oxidative stress: the oxidation handicap hy · peer-reviewed · supports · weight 2 · 2006
Testosterone treatment is immunosuppressive in superb fairy– · peer-reviewed · supports · weight 2 · 2000
Androgens and the Immunocompetence Handicap Hypothesis: Unra · peer-reviewed · supports · weight 2 · 2004
Testosterone-mediated trade-offs in the old age: a new appro · peer-reviewed · supports · weight 1.6 · 2009
Energetic reserves, leptin and testosterone: a refinement of · peer-reviewed · supports · weight 1.3 · 2007
Developing a transcriptomic framework for testing testostero · peer-reviewed · supports · weight 1.05 · 2020
Complex effects of testosterone level on ectoparasite load i · peer-reviewed · supports · weight 1.05 · 2024
Stress, testosterone, and the immunoredistribution hypothesi · peer-reviewed · refutes · weight 2 · 1999
No evidence for the immunocompetence handicap hypothesis in · peer-reviewed · refutes · weight 1.6 · 2018
Functionally opposing effects of testosterone on two differe · peer-reviewed · refutes · weight 1.6 · 2010
Associations between testosterone and immune activity in all · peer-reviewed · refutes · weight 1.05 · 2021
Evidence for · 8
Testosterone and oxidative stress: the oxidation handicap hypothesis
2006 · cited by 356
Experimental elevation of testosterone decreased cell-mediated immunity in zebra finches.
Evidence against · 4
Stress, testosterone, and the immunoredistribution hypothesis
1999 · cited by 246
Argues that the foundational assumption of testosterone-induced immunosuppression is flawed and proposes an immunoredistribution hypothesis.
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More for · 7
Testosterone treatment is immunosuppressive in superb fairy–wrens, yet free–living males with high testosterone are more immunocompetent
2000 · cited by 274
Testosterone treatment decreased the likelihood of a primary antibody response in captive superb fairy-wrens.
Androgens and the Immunocompetence Handicap Hypothesis: Unraveling Direct and Indirect Pathways of Immunosuppression in Song Sparrows
2004 · cited by 219
Testosterone implants suppressed both cell-mediated and humoral immune responses in song sparrows.
Testosterone-mediated trade-offs in the old age: a new approach to the immunocompetence handicap and carotenoid-based sexual signalling
2009 · cited by 71
Old male red-legged partridges exhibited increased immunosuppression when treated with testosterone.
Energetic reserves, leptin and testosterone: a refinement of the immunocompetence handicap hypothesis
2007 · cited by 35
Leptin administration attenuated testosterone-induced immunosuppression in zebra finches, supporting the trade-off model.
Developing a transcriptomic framework for testing testosterone-mediated handicap hypotheses.
2020 · cited by 6
Transcriptomic reanalysis of bird studies revealed conserved molecular signatures of immunosuppression following testosterone treatment.
Complex effects of testosterone level on ectoparasite load in a ground squirrel: an experimental test for the immunocompetence handicap hypothesis.
2024 · cited by 2
Male ground squirrels with experimentally increased testosterone exhibited higher tick loads.
Maternal Androgens in Dominant Meerkats (<i>Suricata suricatta</i>) Reduce Juvenile Offspring Health and Survivorship.
2024 · cited by 2
High prenatal androgen exposure in meerkats resulted in increased juvenile parasitism and decreased immunocompetence.
More against · 3
No evidence for the immunocompetence handicap hypothesis in male humans
2018 · cited by 92
Found that free testosterone levels were positively correlated with influenza post-vaccination response in healthy human males.
Functionally opposing effects of testosterone on two different types of parasite: implications for the immunocompetence handicap hypothesis
2010 · cited by 52
Demonstrated that testosterone has functionally distinct and opposing effects on different parasite species rather than causing a general immunosuppression.
Associations between testosterone and immune activity in alligators depend on bacteria species and temperature
2021 · cited by 4
Found that testosterone-mediated immunosuppression in alligators depends heavily on temperature and specific bacterial species.