Background: Saliva collection is an easy, non-invasive method to measure hormones.
Methods: Two studies were performed. In the first, a convenience sample of 1,454 males who had submitted saliva for salivary testosterone measurements were studied. In the second study, we intensively studied symptoms and measurements of total testosterone, free testosterone symptoms and measurements of total testosterone, free testosterone and bioavailable testosterone in relationship to salivary testosterone in 127 men. A secondary endpoint was to examine the relationship of salivary testosterone to hypogonadal symptoms in the ADAM and AMS questionnaires.
Results: In the first study, we have shown that salivary testosterone, measured in 1,454 males aged 20 to 89 years, declines by 47% over the lifespan. In the second study, salivary testosterone was strongly correlated with bioavailable testosterone (p < 0.000001) calculated free testosterone (p < 0.00001) and total testosterone (p < 0.002). Salivary testosterone was significantly related to hypogonadal symptoms on the St. Louis University ADAM questionnaire and the Aging Male Survey.
Conclusions: These studies support the use of salivary testosterone as an acceptable assay for screening for hypogonadism. Salivary testosterone is not a better assay than other measures to diagnose hypogonadism.