Saliva Hormone Variability
Saliva hormone testing is more prone to factors effecting levels compared to serum testing because saliva is not a sterile or homogenous sample, and individual variability exists due to physiological, genetic, and environmental factors.
- Poor oral health: Bleeding gums can contaminate saliva. Hormonal fluctuations, especially in women (during pregnancy, menstrual cycles, or menopause), can make gums more susceptible to inflammation and bleeding. In turn, gum disease might further alter the local balance of these hormones in saliva. Some studies suggest that periodontal disease may reduce testosterone levels in saliva.
- High/low hormone secreters: Some people may have high or low ability to transport and secrete hormones into saliva. The efficiency of hormone transport into saliva varies from person to person based on genetics, gland structure, and function. Some hormones circulate in bound and free forms. Only free (unbound) hormones can diffuse into saliva, and the proportion of free hormone varies between individuals. Some hormones passively diffuse into saliva (e.g., cortisol), while others require active transport. Differences in transport protein expression can affect secretion efficiency. Conditions like diabetes, autoimmune diseases, or salivary gland dysfunction can alter hormone secretion into saliva.
- Hydration and salivary flow rate: Higher saliva production and flow rates can dilute hormone concentrations, while lower saliva production flow rates can lead to higher hormone concentrations.
- Transdermal hormone creams: Hormone levels may be overrepresented in saliva and underrepresented in serum. Progesterone is highly lipophilic and, along with lipophilic inactive ingredients in creams, which may saturate the fat layer below the oral dermis.
- Dose of hormone therapy: Ensure proper dose was administered (i.e., 0.1 mg vs 1.0 mg).
- Timing of hormone therapy: Absorption peaks or lows may be observed depending upon application time related to collection of sample.
- Administration route of hormone therapy: Sublingual or troche hormones, or topical hormones applied to upper body close to the salivary or lymphatic glands, may result in elevated levels in the saliva sample.
- Unknown exposure to hormones and xenohormones: Skin-to-skin or skin-to-surface-to-skin contact may occur, and personal care products with xenoestrogens or xenoandrogens may result in elevated hormone levels.