Diagnosing Low Testosterone
The speaker stresses the importance of a comprehensive blood panel beyond just total testosterone. Key markers include free testosterone (which can be affected by SHBG), FSH and LH (to assess pituitary function), estradiol (as estrogen plays a role in male health and can be elevated in obesity), thyroid hormones, and prolactin (to rule out pituitary adenomas). The diagnostic threshold of 300 ng/dL for total testosterone is acknowledged as a guideline, but the speaker emphasizes that it's an arbitrary number and that individual symptoms and androgen receptor sensitivity (CAG repeats) are equally important. Some individuals may feel unwell even with levels above 300 if their receptors are less sensitive, while others feel great at 350 due to sensitive receptors. The diagnostic criteria typically require two morning readings below 300 ng/dL.
Checking multiple hormone levels helps identify the root cause of low testosterone, which could range from pituitary issues (FSH, LH, prolactin) to thyroid dysfunction or estrogen imbalance. Estradiol is important because obesity can increase estrogen, and suppressing it unnecessarily can negatively impact libido.
I've had guys in my clinic that have an estrogen of 100. We don't immediately go, 'You know what? I'm going to block your estrogen before starting testosterone.'
If you are going to the doctor, what you want to look for is total testosterone, free testosterone, FSH, LH. Unusual for a guy to have his estrogen checked, but we always check an estradiol. And believe it or not, everything is not testosterone-related. You have to check your thyroid and even a prolactin level.

