Whether or not fasting is necessary prior to hormone testing depends on what hormones are being tested and what method of testing is used (i.e., blood, saliva, urine). Call your doctor if you are unsure about the fasting requirements for your hormone test. Most hormone tests do not require fasting.
Saliva Test
If using a saliva hormone test kit, you will need to fast overnight and apply the test before eating anything in the morning to avoid contamination of the saliva.
Growth Hormone
Fasting is necessary prior to growth hormone testing. You will be asked to fast for 10 to 12 hours before testing.
Sex Hormones
No fasting is required for hormone tests that test the levels of binding globulin, follicle stimulating or luteinizing hormone. You may be asked to fast prior to hormone testing for progesterone.
Thyroid Hormones
No fasting is required for hormone tests that check thyroid hormones, including the thyroid-stimulating hormone and parathyroid hormone.
Cortisol
Hormone testing for cortisol may require a short fast, usually between two and three hours before testing. Adrenocortical hormone tests may require an overnight fast.