The Claim
Administration of cortisol at plasma concentrations mimicking ACTH-induced levels suppresses testosterone levels in normal adult males by abolishing or flattening the nocturnal rise in testosterone, demonstrating a direct physiological interaction between cortisol and testosterone in the endocrine system.
What the research says
Supports is higher
Support is ahead, but a single strong opposing study can change this.
These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.
When cortisol is administered at levels naturally produced during stress, it reduces testosterone levels in adult men by preventing the normal nighttime increase in testosterone.
See the scientific wording
Administration of cortisol to normal adult males, at plasma concentrations mimicking those induced by ACTH treatment, suppresses testosterone levels by abolishing or flattening the nocturnal rise in testosterone, indicating a direct physiological interaction between these two hormones in the endocrine system.
High levels of cortisol block the brain's signal that tells the pituitary to release LH at night. Without this signal, the testes do not produce the usual nighttime surge of testosterone, so testosterone levels stay flat instead of rising.
What the research says
1 studyStudy: Cortisol-induced suppression of plasma testosterone in normal adult males.
When scientists gave men extra cortisol—the stress hormone—their usual nighttime boost in testosterone disappeared. This means high cortisol directly stops testosterone from rising at night, just like the claim says.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.