When Treatment Makes Low T Even Lower

Feb 27, 2015

Can Treatment Cause Low T to go Lower?As a urologist who specializes in testosterone deficiency, I can assure you that the last thing a man wants is even lower T readings after he’s begun treatment. I see this maybe four or five times a year, and it baffles patients and non-expert physicians alike. Yet there’s usually an explanation, as one recent patient of mine illustrates.

This guy was in his late thirties and had seen his primary-care physician complaining about low libido, fatigue, lack of motivation, irritability and difficulty building muscle mass — all the classic Low T symptoms. The doctor checked his testosterone twice. Normal readings are between 400 and 1,200 nanograms per decileter; this guy was at 246 and 285. His doctor prescribed Testim, a topical testosterone cream.

Two weeks later, the patient’s number had dropped to 228 — so his physician prescribed Androgel, a topical gel. Two weeks later, the number was lower still. Confused, the doctor punted — and sent the patient to me.

I knew there could be only two possible explanations. The first entailed learning when the guy’s T level was being measured. Most testosterone creams and gels should be applied in the morning after a shower; the testosterone takes two to three hours to absorb, so peak T arrives around four to five hours after application. Measurable testosterone, however, falls precipitously once absorption is complete. So if a doctor is checking a patient, say, 18 hours after application, he’ll probably record a low number.

This wasn’t the case here, though; this patient’s tests had been drawn several hours after application. So I shifted my focus to the second possible explanation: his dosage.

Here’s why. A man’s testicles produce a finite amount of testosterone. When he undergoes testosterone-replacement therapy (TRT) of any kind, his testicles actually stop producing the hormone; even small amounts of synthetic T will trigger this “negative feedback” and shut down the body’s natural production. So if the amount of topical testosterone prescribed is lower than the amount of testosterone the testicles were producing, a man’s T will drop once therapy begins.

This patient, then, was in no-man’s land. The dosage he’d been prescribed was inadequate to correct his low testosterone, but it was more than enough to suppress his own production of it. I increased his Androgel dosage, and a few weeks later we took his readings about five hours after morning application. His level had increased to 920 ng/dL — and that’s performance any man can be perfectly happy with.