Reading Your Testosterone Panel

A hormone panel is the point at which most people first encounter their own endocrinology, usually as a column of numbers with reference ranges beside them. The ranges are less informative than they look, and the single most common mistake is treating one out-of-range value as a diagnosis.

Why one reading is not enough

Testosterone follows a daily rhythm. It is typically highest in the morning and declines through the day, which is why draw timing is specified rather than left to convenience. It also varies between days in the same person, and it falls transiently during acute illness, after poor sleep, and during periods of significant caloric restriction. For that reason, guidelines generally call for at least two separate morning measurements before low testosterone is diagnosed. A single borderline result taken at 4pm after a bad night is not a finding — it is noise.

Total, free, and why SHBG decides which matters

Most testosterone in circulation is bound to carrier proteins, principally sex hormone-binding globulin and albumin. Only the unbound fraction is available to tissues. That creates a discrepancy worth understanding. Someone with a high SHBG can have a perfectly respectable total testosterone while their free testosterone is low, and they will feel it. Someone with low SHBG — common in insulin resistance — can show the reverse. This is why a useful panel measures total testosterone, free testosterone and SHBG together. Reading any one of them alone invites the wrong conclusion.

LH and FSH locate the problem

Two men can have identical low testosterone for entirely different reasons, and the treatment differs accordingly.

• Low testosterone with high LH points to the testes. The pituitary is signalling hard and not

getting a response. This is primary hypogonadism.

• Low testosterone with low or normal LH points upstream, to the pituitary or hypothalamus.

This is secondary hypogonadism. The distinction is not academic. Enclomiphene works by increasing LH and FSH, so it depends on the testes being able to respond. In primary hypogonadism they cannot, and it will not work.

Estradiol, and why more suppression is not better

Estradiol in men is not a contaminant to be minimised. It has necessary functions in bone density, lipid handling, cognition and libido. Aggressive suppression with an aromatase inhibitor produces its own set of problems — joint pain, low mood, poor libido and, over time, bone loss. Contemporary practice measures it, interprets it alongside symptoms, and reaches for an aromatase inhibitor sparingly. One further technical point: standard estradiol assays are calibrated for female concentrations and are unreliable at male levels. A sensitive assay is the one worth ordering.

Haematocrit is the marker to watch on therapy

Of everything tracked during testosterone therapy, haematocrit is the one that most directly concerns safety. Testosterone stimulates red cell production, and the rise is typically asymptomatic — you will not feel it happening. That is precisely why it is monitored on a schedule rather than in response to symptoms. Where it rises beyond an acceptable range, the response may be a dose reduction, a change of interval, or pausing therapy while it normalises.

The markers people forget

Three results explain a large share of the fatigue and low libido that brings people to a hormone clinic, and none of them are testosterone:

• TSH. Thyroid dysfunction presents almost identically and is straightforward to identify.
• Ferritin. Iron deficiency causes fatigue well before it causes anaemia, so a normal

haemoglobin does not exclude it.

• Prolactin. An elevated prolactin suppresses the reproductive axis and can indicate a

pituitary adenoma. It is treatable, and missing it means treating the wrong thing for years. A panel that omits these is not a thorough panel.

What to take from all this

Your results describe a system, not a score. The useful question is never whether one number sits inside a reference range, but what the pattern across several markers suggests, and whether it matches how you actually feel. That interpretation is the clinician's job, and it is the reason laboratory work comes before a treatment decision rather than after it.