Saliva has several obvious advantages over blood for testing of hormone levels. For example saliva:
But the most important reason is that saliva is the most accurate method of evaluating your hormone status. Only about 1-5% of the hormones in blood are in the unbound or “free” form. The remaining 95-99% are tightly bound to blood proteins. It is this unbound fraction of hormones that enters tissues throughout your body, including the salivary glands. Hence, salivary hormones are representative of the free or unbound hormones in blood that are "bioavailable" to tissues of your body.
Saliva testing is the most accurate method of evaluating your hormone status, including how hormone replacement therapy, topical hormone creams, diet, herbal therapy, and exercise influence your hormone levels.
Anyone with symptoms involving fatigue, insomnia, stress, immunity problems, blood sugar problems, and weight issues should be tested for cortisol levels as well as “sex” hormones.
Men and women of any age who are having symptoms of hormone imbalances should test for all hormones that may be associated with their symptoms.
Men and women over the age of forty may want to do a baseline test. Frequently imbalances will be detectable for a time period before symptoms gain attention.