What does it mean when you have a low tsh but you also have a low t4?

Thyroid labs: Hi. See an endocrinologist. Make sure it's a free T4 (not a TOTAL T4). If you have low TSH and a low free T4, that's compatible with pituitary disease causing hypothyroidism (so called "secondary hypothyroidism"). IF you have that (not saying you do), you need to be checked for pituitary problems and other pituitary deficiencies (adrenal, most promptly); If u have secondary hypothy, CHECK ADRENALS