In short
- A diagnostic appointment. The purpose is to answer whether low testosterone is really the cause, not to hand over a prescription.
- Timing decides the result. Blood is taken between 8 and 10 in the morning, fasting, and repeated on separate days.
- One low value proves nothing. Levels fall after poor sleep, after food, and during any acute illness.
- LH and FSH tell you where the problem is. Testicle or pituitary, and that changes everything.
- A clear answer, including no. If testosterone is not the cause, you hear what is.
Treatment Overview
What this appointment is for
Testosterone deficiency needs two things at once: symptoms consistent with it, and a genuinely low morning testosterone confirmed on separate occasions.
A number alone is not a diagnosis, and symptoms alone are not either. Getting this wrong in either direction has consequences, which is why the appointment exists.
Why the timing of the blood test matters so much
Testosterone follows a daily rhythm. It peaks around 8 in the morning and falls to roughly 70 percent of that by 8 in the evening.
- Between 8 and 10 in the morning. It is far easier to tell low from normal when normal is at its highest.
- Fasting. Food, and glucose in particular, lowers the reading acutely.
- Repeated. A low or borderline value is confirmed on a second, sometimes third occasion before any diagnosis is made.
- Not during illness. Acute or subacute illness produces a temporary low reading that means nothing about your baseline.
An afternoon test after a bad night and a coffee shop breakfast is how healthy men end up on lifelong hormone therapy.
What the numbers mean
| Reference | Value |
|---|---|
| Typical laboratory normal range | Roughly 300 to 800 ng/dL, varying by assay |
| Healthy non obese men aged 19 to 39 | 264 to 916 ng/dL by reference methodology |
| Lower limit in non obese men over 60 | Around 219 ng/dL |
Ranges differ between laboratories, which is why the result is always read against the range of the laboratory that produced it.
When free testosterone is worth measuring
Only when a binding protein problem is suspected alongside possible deficiency. The two common causes are obesity, which lowers sex hormone binding globulin, and older age, which raises it.
One technical point that matters: free testosterone measured by the analog method, which is what most commercial laboratories offer, does not correlate with the reference method and gives misleading results. Where a free testosterone is genuinely needed, it is ordered by equilibrium dialysis from a specialist laboratory.
What else gets tested and why
- LH and FSH. High values point to a problem in the testes. Normal or low values point to the pituitary or hypothalamus. The distinction changes the investigation and sometimes requires imaging.
- Prolactin and iron studies, where the pattern suggests a pituitary cause.
- Thyroid function, full blood count, glucose, HbA1c and lipids, because the look alikes are common.
- Semen analysis, only where fertility is the question.
What imitates low testosterone
These produce an almost identical list of complaints and are far more common.
- Obstructive sleep apnoea and chronic short sleep.
- Depression and chronic stress.
- Thyroid disease, iron deficiency and anaemia.
- Poorly controlled blood sugar and obesity.
- Alcohol, and medications including long term opioids and high dose steroids.
If you were already put on testosterone elsewhere
The basis for that diagnosis gets checked. Where the original evaluation does not support it, the recommendation is to stop and re-evaluate about two months later, because staying on it can mask a treatable condition.
Who Is a Good Candidate?
- You have symptoms such as low libido, fewer morning erections, persistent fatigue, low mood or loss of muscle despite training.
- You want a diagnosis before a prescription, including the possibility of no.
- You have type 2 diabetes, osteoporosis or a low trauma fracture, where the likelihood of deficiency is genuinely higher.
- You take long term opioids or high dose steroids, both of which suppress testosterone.
- You were started on testosterone elsewhere and want the diagnosis checked properly.
- You want a prescription based on one afternoon blood test.
- You are currently unwell with an acute or subacute illness. Testing then produces a temporary low result that means nothing.
- You are trying to conceive. Testosterone therapy suppresses sperm production, and this conversation has to happen before anything is started.
- You want testosterone for performance or physique with normal levels. Raising a normal level into the supraphysiological range carries risk and will not be done here.
What Happens During the Consultation
-
1
Symptoms and history
What changed and when, libido and morning erections, energy, mood and concentration, training response, sleep and snoring, alcohol, and every medication you take including anything bought without a prescription.
-
2
Examination
General virilisation, body hair, breast tissue, testicular size and consistency. Weight, waist, body composition and blood pressure, because obesity affects both the diagnosis and the interpretation.
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3
Blood tests done properly
Morning fasting total testosterone between 8 and 10, repeated on a separate day. LH and FSH if it is low. Thyroid, prolactin, iron studies, full blood count, HbA1c and lipids alongside. Free testosterone only where a binding problem is suspected, and only by the correct method.
-
4
The answer
Confirmed deficiency, a look alike condition, or normal results with symptoms that need explaining differently. Whichever it is, you get it plainly, with what the numbers mean and what happens next.
Program Structure & Follow-Up
What happens after the consultation
Three outcomes, and all three come with a plan.
- Confirmed testosterone deficiency. You move to testosterone replacement therapy, with the preparation chosen around your life and a fixed monitoring schedule.
- Another cause found. Sleep apnoea, thyroid disease, iron deficiency, poorly controlled glucose or a medication effect. That gets treated, and testosterone is often unnecessary once it is.
- Normal results. The symptoms are real and still need an explanation, so the work up continues rather than stopping at a normal hormone panel.
Before any treatment starts
- Prostate assessment in men over 50, or over 40 with a first degree relative who had prostate cancer. PSA and examination before, not after.
- Baseline haematocrit, because testosterone raises it.
- A fertility conversation, because treatment suppresses sperm production.
- Personal and family history of blood clots, which matters more than most clinics acknowledge.
If it is not testosterone
Being told no is a useful outcome. Starting testosterone in a man whose real problem is untreated sleep apnoea or depression delays the treatment that would have worked, and adds a therapy he then depends on.
Benefits, Limits & Safety
What a proper diagnosis gives you
- Certainty. Two or three correctly timed morning values are a very different basis than one convenient sample.
- The distinction between a testicular and a pituitary cause, which occasionally uncovers something important.
- Treatment that is likely to work, because the benefits of testosterone are clear when the diagnosis is genuine and much less so when it is not.
The limits
- Symptoms such as fatigue, low mood, reduced strength and increased body fat are non specific. Low libido, fewer morning erections, loss of body hair and small testes are more specific.
- Reference ranges vary between laboratories and there is no single universal cut off.
- Where results are equivocal, the honest answer is sometimes to repeat them rather than to decide.
Safety points from the start
- Population screening is not recommended. Testing is done where there is a reason, not as part of a routine panel.
- Do not test during illness. The result will be low and misleading.
- Never accept a free testosterone by analog assay. It gives misleading information and should not be ordered.
- Previous diagnoses get checked. Testosterone is frequently prescribed to men who never met the criteria.
What you leave with
A confirmed diagnosis, an alternative explanation, or a clear statement that testing was normal and the work up continues. Never a prescription issued on a single convenient sample.
How testing is done
Morning fasting total testosterone between 8 and 10, repeated on separate days, with LH and FSH if low. Thyroid, prolactin, iron, blood count, HbA1c and lipids alongside.
When testing is postponed
During acute or subacute illness, which produces a temporary low reading. Testosterone is also not started before a fertility conversation, or in men seeking it with normal levels.
Cost & Program Investment
Cost depends on which tests your case needs and how many repeat samples are required, so a single number on a website would be misleading. You get the full figure in the consultation before anything is arranged, and there are no charges you have not been told about.
Frequently Asked Questions
Testosterone follows a daily rhythm, peaking around 8 in the morning and falling to roughly 70 percent of that by evening. It is much easier to distinguish low from normal when normal is at its highest, so samples are taken between 8 and 10.
Food, and glucose in particular, lowers serum testosterone acutely. A sample taken after breakfast can read low in a man whose levels are entirely normal.
Levels fluctuate even in the morning, and a single low value is not enough to commit someone to long term hormone therapy. A low or borderline result is repeated on a separate day, sometimes twice.
Most laboratories use roughly 300 to 800 ng/dL, though this varies by assay. In healthy non obese men aged 19 to 39 the reference range was 264 to 916 ng/dL, and the lower limit falls with age to around 219 ng/dL in non obese men over 60.
Only if a binding protein problem is suspected alongside possible deficiency, most often because of obesity or older age. It must be done by equilibrium dialysis. The analog method offered by most commercial laboratories does not correlate with the reference method and should not be ordered.
Where the problem is. High values with low testosterone point to the testes, low or normal values point to the pituitary or hypothalamus. That distinction changes the investigation and occasionally leads to imaging.
Very often. Sleep apnoea, chronic short sleep, depression, thyroid disease, iron deficiency, poorly controlled blood sugar, alcohol and certain medications all produce the same list of complaints and are more common than testosterone deficiency.
Yes. Obesity lowers sex hormone binding globulin, which lowers total testosterone without necessarily lowering the free level. That binding effect is proportional to the degree of obesity and improves with weight loss.
The basis for the original diagnosis gets checked. If the evaluation before treatment does not support it, the recommendation is to stop and re-evaluate about two months later, because continuing can mask a treatable cause.
Yes, it suppresses sperm production. That conversation happens before anything is started, not after, and if you are trying to conceive the approach is different.
It is better to wait. Acute and subacute illness cause a temporary drop in testosterone that has nothing to do with your baseline.
It depends on which tests are needed and how many repeat samples, so a single figure would be misleading. You get the full cost in the consultation before anything is arranged.
Evidence
Where this information comes from
Every figure on this page is taken from the sources below. All of them are free to read, so you can check them yourself.
This page is general medical information and does not replace a personal consultation. Trial results are averages across large groups, not a prediction for any one person.