You got your testosterone tested. The number came back somewhere in the grey zone — not catastrophically low, not clearly fine — and the doctor either shrugged or the clinic immediately offered you a subscription. Neither response was useful.
That gap between a number and a diagnosis is where most men make a poorly informed decision in one direction or the other. The TRT industry fills it with before-and-after marketing. Conventional medicine often fills it with nothing. This article is an attempt to fill it with the actual evidence.
Why the obvious approach fails
Why the obvious approach fails
The standard entry point for most men is a single total testosterone test, usually ordered because of fatigue, low libido, or mood changes. The result comes back, gets compared to a lab reference range, and a conclusion is drawn. Either the number is “normal” and the conversation ends, or it’s flagged as low and some form of testosterone is proposed. Both responses can be wrong.
A single total testosterone number tells you very little without context. Sex hormone-binding globulin binds to testosterone and renders it biologically inactive. A man with a total testosterone of 500 ng/dL and very high SHBG can have worse functional testosterone availability than a man reading 340 with low SHBG. Strict low-fat or low-cholesterol dietary patterns have been shown to raise SHBG and reduce free testosterone by up to 18% — meaning some men are inadvertently suppressing their own functional testosterone while eating what they’ve been told is healthy. The total number obscures this entirely.
The TRT clinic approach skips past the diagnostic question for commercial reasons. The conventional medicine approach sometimes skips past it from a lack of specialist knowledge or time. The result is the same: the man treats a number instead of a problem.
The diagnostic gap
The diagnostic gap
The diagnostic gap is the distance between what your blood test shows and what is actually causing your symptoms. Closing that gap is the only thing that makes the TRT decision make clinical sense. Every tool in this article is aimed at closing it before you put anything in your body.
Map the whole axis, not just the endpoint
Map the whole axis, not just the endpoint
Testosterone is produced at the end of a chain. The hypothalamus signals the pituitary, which releases LH and FSH, which signal the testes to produce testosterone. A problem anywhere in that chain produces a low testosterone reading, but the appropriate response differs entirely depending on where the breakdown is.
A full diagnostic panel should include total testosterone, free testosterone, LH, FSH, SHBG, and estradiol. This is not complicated to request and it takes one blood draw. If your LH is low alongside low testosterone, the signal problem is upstream — at the pituitary or hypothalamus — and adding exogenous testosterone treats the symptom while leaving the cause completely untouched. If your LH is high and testosterone is still low, the testes themselves are the problem, which is a different clinical situation entirely. Get the full picture before anyone talks to you about replacement.
Test in the morning, before 10am, because testosterone follows a diurnal rhythm and afternoon draws can read 20-30% lower than morning levels. One ambiguous result should trigger a second test 4-6 weeks later before any clinical decision is made.
Understand what exogenous testosterone actually does to LH
Understand what exogenous testosterone actually does to LH
This one is poorly explained by most TRT providers, and it matters. When you inject or apply testosterone from outside the body, your hypothalamus and pituitary detect the elevated levels and reduce their own signalling through negative feedback. LH production drops, often to near zero within weeks. Your testes, no longer receiving the signal to produce testosterone, shrink in size and lose their productive function. This is why testicular atrophy is a predictable, documented side effect of TRT, not a rare one.
For most men, this is reversible after discontinuing TRT, though recovery time varies and can take months. For some men — particularly those who use TRT for extended periods without co-administration of something like hCG to maintain testicular stimulation — the recovery is incomplete. If you genuinely need TRT, this is a reason to ask your prescriber explicitly what the plan is to preserve testicular function during treatment, and to view any provider who doesn’t raise this point with appropriate scepticism.
There is also a libido question here that the industry rarely discusses honestly. Raising testosterone through exogenous means does not reliably improve libido, because libido tracks LH signalling more closely than it tracks testosterone levels. This is a documented phenomenon, not a fringe claim. Men who go onto TRT and find their numbers normalise without any improvement in sex drive are often told to wait, or to adjust dose, when the more accurate explanation is that they’ve suppressed the very pathway that drives desire. If libido is your primary complaint, this is a clinically important distinction. Investigate LH and FSH before assuming more testosterone is the answer.
Read the cardiovascular risk data correctly
Read the cardiovascular risk data correctly
The cardiovascular risk debate around TRT is genuinely unsettled and frequently misrepresented in both directions. Several early observational studies raised concerns about increased cardiovascular events in men using testosterone therapy, and these were widely reported. Later studies, including the TRAVERSE trial published in 2023, found no significant increase in major cardiovascular events in men with hypogonadism receiving TRT compared to placebo, over a median follow-up of around 33 months. The picture is not a clean bill of health — TRT does raise haematocrit, which thickens the blood and increases clotting risk, and this needs monitoring — but the catastrophist framing of TRT as a cardiac time bomb is not supported by current evidence.
The lesson from hormone research more broadly is to weight randomised controlled trial data above observational data. Observational studies that appear to show a strong effect from hormone therapy have repeatedly failed to replicate under controlled conditions, because they cannot adequately account for which men get prescribed hormones in the first place — a selection bias that tends to favour healthier, higher-socioeconomic-status individuals. When you read a headline about TRT and heart risk, ask what kind of study it was before you absorb the conclusion.
The questions to bring to your doctor
The questions to bring to your doctor
If you’re going to have a productive clinical conversation, these are the specific questions that will move it forward. First: can I get a full panel including free testosterone, LH, FSH, SHBG, and estradiol, with a morning draw? Second: given these results, where in the HPG axis does the problem appear to be? Third: if we proceed with TRT, what is the protocol for monitoring haematocrit, PSA, and estradiol during treatment? Fourth: what is the plan to preserve testicular function — and is hCG or an equivalent being considered? Fifth: what is the exit strategy if I want to discontinue, and what does recovery typically look like?
A provider who can’t or won’t engage with these questions is not necessarily incompetent, but they are not the right provider for an informed clinical decision.
The honest caveat
The honest caveat
This framework will not help you if your testosterone is genuinely, unambiguously low — below 250 ng/dL on two separate morning draws, with symptomatic hypogonadism — and you’ve already ruled out reversible causes like obesity, sleep apnea, or chronic stress. In that situation, the diagnostic gap is already closed. The question is no longer where the problem is but whether the risks and logistics of TRT are acceptable to you. The tools above are for the far more common situation of ambiguous results and incomplete diagnostics, not for confirmed, classic hypogonadism. They are also not a substitute for a clinician who actually knows this area — they are a framework for identifying whether the clinician in front of you does.
What to do tomorrow morning
What to do tomorrow morning
If you haven’t yet had a full panel, call your GP or a men’s health specialist today and specifically request total testosterone, free testosterone, LH, FSH, SHBG, and estradiol — and ask to have the draw done before 10am. If you have had results already, pull them out and check whether LH and free testosterone were included. If they weren’t, you don’t have enough information to make this decision yet, and that’s the only place to start.
