DHT (Dihydrotestosterone) in Men: What a Low or High Result Means

At a Glance

Dihydrotestosterone is the androgen your body makes from testosterone, by an enzyme called 5-alpha-reductase. It binds the androgen receptor more tightly than testosterone does, which is why a smaller amount of it does more.

Two things shape how this result should be read, and both come before any interpretation of the number:

• Check the units. This analyte is reported in ng/dL and in pg/mL, and LOINC lists both for the concept. They differ by a factor of ten. The range stored on this record, 30 - 85 ng/dL, is the same thing as 300 – 850 pg/mL.
• Check whose range you are reading. Published intervals for this test differ substantially between laboratories, and that difference is largest at the bottom end — see below.

How to read your result

The range stored on this record is 30 - 85 ng/dL (300 – 850 pg/mL) and the field is labeled Optimal Result. Treat it as one laboratory's reference interval rather than a target, because a reference interval describes where most of a population falls, not where you should aim to be.

It is worth knowing how much these intervals vary. Mayo Clinic Laboratories, running this test by mass spectrometry, publishes for males over 19: 112 – 955 pg/mL — which is 11.2 – 95.5 ng/dL.

The two disagree most at the bottom. A man at 200 pg/mL (20 ng/dL) is below the range stored here and inside Mayo's. That is not a contradiction to resolve — laboratories genuinely publish different intervals, depending on method and on the population they were derived from. It is a reason to read the range printed on your own report rather than any range you find elsewhere, this one included.

What this test is actually used for

This is a narrower test than it looks, and knowing its intended uses explains most of what follows. The laboratories that run it name two:

Evaluating a possible 5-alpha-reductase deficiency — a rare inherited condition in which the enzyme that makes DHT from testosterone does not work normally. The informative measurement there is not DHT alone but the ratio of testosterone to DHT, so the two are interpreted together.

Monitoring treatment with a 5-alpha-reductase inhibitor — finasteride or dutasteride. These drugs block the enzyme, so they lower DHT by design, and if you take one a low result is the expected result. What is being monitored is the biochemical effect, not whether the treatment is helping you. Finasteride's prescribing information records serum suppression within 24 hours of a dose while assessing clinical benefit over twelve months, and states that the relative contributions of these reductions to the treatment effect "have not been defined".

A single DHT, on its own and outside those two situations, is hard to act on.

If your result is flagged

Being flagged is a comparison with the range stored on this record, which is one interval among several. It is not a diagnosis, and on its own it does not identify a cause.

The first thing to check on a low figure is medication: a 5-alpha-reductase inhibitor. Finasteride and dutasteride are prescribed for hair loss and for prostate enlargement, and both lower DHT substantially — that is how they work.

The direct route to a high figure is more substrate: testosterone treatment can raise DHT, because DHT is made from testosterone. Other anabolic steroids are a different matter — they are not all 5-alpha-reduced and they affect androgen measurements in different ways, so which preparation is involved changes what the result means.

If you remember only one thing

Check the units before anything else — ng/dL and pg/mL differ by ten, and 30 – 85 ng/dL is 300 – 850 pg/mL. Then check whose range you are being compared with, because published intervals for this test differ, most at the lower bound. And if you take finasteride or dutasteride, a low result is the drug's intended biochemical effect — which is not the same as evidence that it is working for you.

Two people, same result

Two men are both reported at 22 ng/dL (220 pg/mL) — below the range stored on this record, so both are flagged low.

The first has taken finasteride for two years for hair loss. His result is consistent with finasteride's expected biochemical effect. 5-alpha-reductase inhibitors lower DHT by blocking the enzyme that makes it, and finasteride's own prescribing information records suppression reaching 65% within 24 hours of a dose. What that figure does not establish is whether the treatment is helping him. The same document assesses benefit by hair count and self-assessment over twelve months, says benefit generally takes three months or more to appear, and states that the relative contributions of these reductions to the treatment effect "have not been defined". But a single low value does not establish its own cause. That finasteride lowers DHT does not mean a given low DHT was produced by finasteride — without a baseline, the formulation, and the rest of the picture, the result is consistent with the drug's effect rather than proof of it. And it does not tell you his hair is responding, nor does it rule out side effects; the label documents adverse reactions occurring despite the intended suppression.

The second takes no medication and had the test on a panel. For him the figure is below this record's interval and inside the interval Mayo publishes for adult men — so the first question is not "why is it low" but "low against which range". The answer is on his own report.

Same number, and for one of them it is a treatment result rather than a finding at all. Nothing in the figure distinguishes them; the medication list does.

What this result cannot tell you

This is the limitation the rest of the page depends on.

It does not measure androgen effect in tissue. Mayo's own documentation says DHT "does not reflect peripheral androgen action" — it is cleared quickly and binds tightly to sex hormone-binding globulin — and names a different compound, 3-alpha,17-beta-androstanediol glucuronide, as the better marker of androgen action in tissue. If what you want to know is what androgens are doing to your scalp, skin or prostate, this number does not report it.

It does not track the prostate. Mayo states plainly that people with benign prostatic hyperplasia or prostate cancer "may not have elevated dihydrotestosterone (DHT) levels". A normal DHT is not reassurance about the prostate, and a high one is not a prostate finding.

It does not fall with age the way testosterone does. Mayo notes DHT levels remain normal with aging despite the decline in plasma testosterone, so a normal DHT in an older man says nothing about whether his testosterone is low.

It is a laboratory-developed test. Both laboratories cited here state the assay has not been cleared or approved by the FDA, which is ordinary for specialised hormone assays and worth knowing.

Common interpretation mistakes

Comparing a pg/mL result with an ng/dL range. A factor of ten. A result of 450 pg/mL looks alarming against "30 – 85" and is 45 ng/dL.

Reading the stored range as a target. It is a reference interval, and published intervals differ, most at the lower bound.

Reading a low DHT on finasteride or dutasteride as a problem. It is the drug's intended biochemical effect. Reading it as proof the drug is working is the mirror error — the blood change happens within a day and clinical benefit is judged over months.

Expecting it to explain hair loss. Androgenetic alopecia is driven by how follicles respond to androgens, not by the blood level, and the blood level does not measure tissue response.

Reading it as a prostate test. The laboratory that runs it says BPH and prostate cancer may occur without elevated DHT.

Reading it without testosterone. The clinically informative measurement in suspected 5-alpha-reductase deficiency is the testosterone-to-DHT ratio, not DHT alone.

Questions your doctor may ask

Do you take finasteride or dutasteride — both lower DHT by design? Do you use saw palmetto or any other supplement? Any testosterone treatment, anabolic steroids or prohormones, and specifically which preparation? Why was this ordered, and what question was it meant to answer? Was testosterone measured at the same time, and what did it show? What units did your laboratory report, and what range did it print? Is there an earlier result from the same laboratory to compare with? And what would change in your care depending on the answer?

Read together with

Testosterone is the one that matters most. DHT is made from it, so a DHT without a testosterone is hard to interpret — and in suspected 5-alpha-reductase deficiency it is the ratio of the two that carries the information.

Sex hormone-binding globulin affects how much of either hormone is free, and DHT binds it tightly.

Luteinising hormone helps separate a testicular cause from a pituitary one when testosterone is low.

3-alpha,17-beta-androstanediol glucuronide, where available, is the marker Mayo names for peripheral androgen action — the thing this test does not measure.

Clinical pearls

Units first: ng/dL and pg/mL differ by ten, and LOINC lists both for this concept.

Published reference intervals for DHT differ substantially, most at the lower bound — read the one on your own report.

The informative measurement in suspected 5-alpha-reductase deficiency is the testosterone-to-DHT ratio.

A low DHT on a 5-alpha-reductase inhibitor is the intended biochemical effect, and not a measure of clinical benefit.

Blood DHT does not reflect androgen action in tissue.

DHT stays steady with age while testosterone falls, so a normal DHT is not evidence of normal testosterone.

Clinical Takeaway

Dihydrotestosterone is the 5-alpha-reduced metabolite of testosterone and a more potent androgen receptor agonist. It is reported in ng/dL or pg/mL — a tenfold difference, both listed under LOINC 1848-1 — and the range stored here, 30 - 85 ng/dL, is 300 – 850 pg/mL. Published intervals differ materially: Mayo publishes 112 – 955 pg/mL for men over 19, so the stored lower bound sits well above theirs, and the reader's own report's range governs. The established uses are narrow: evaluating possible 5-alpha-reductase deficiency, where the testosterone-to-DHT ratio rather than DHT alone is informative, and monitoring 5-alpha-reductase inhibitor therapy, where a low result is the intended biochemical effect rather than evidence of clinical benefit. A blood DHT "does not reflect peripheral androgen action", people with BPH or prostate cancer may have normal levels, and DHT does not decline with age as testosterone does. It is a laboratory-developed test, not FDA-cleared. Read it with testosterone, against the range printed on the report, and with whoever ordered it.

In one sentence

The potent androgen made from testosterone — informative mainly alongside testosterone, and not a measure of what androgens are doing in your tissues.

Bottom line

Check the units, then check whose range you are being compared against — those two steps resolve a large share of surprising DHT results. If you take finasteride or dutasteride, a low figure is the drug's intended biochemical effect — not, by itself, evidence that it is helping. Either way the number belongs with the testosterone result beside it and the clinician who ordered both.

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