DHT Test

Your testosterone level gets most of the attention, but testosterone is partly a raw material. In tissues like the prostate, skin, and hair follicles, an enzyme called 5 alpha reductase converts testosterone into DHT (dihydrotestosterone), a hormone that binds the androgen receptor far more tightly. DHT is the real driver behind prostate enlargement, pattern hair loss, and much of the androgen signaling that shapes your body over decades.

A large pooled analysis of over 250,000 person years of follow up found that men with the lowest DHT levels had about 19% higher risk of dying from any cause and 29% higher risk of dying from cardiovascular disease compared to men with DHT in the upper mid range. But risk also rose at the very highest DHT levels, forming a U shaped curve. Knowing your DHT helps you understand your androgen biology in a way that a testosterone test alone cannot.

What DHT Actually Measures

DHT is a steroid hormone, one of the body's most potent natural androgens. Unlike testosterone, which circulates in large quantities and serves as a general purpose androgen, DHT is produced mainly inside target tissues. Your prostate, hair follicles, skin, and liver all contain 5 alpha reductase enzymes that convert testosterone to DHT locally. A fraction of that locally produced DHT leaks into the bloodstream, and that is what this test measures.

This distinction matters. Serum DHT is an imperfect window into what is happening at the tissue level. A randomized trial in 31 healthy men showed that even when serum DHT was raised roughly sevenfold using transdermal DHT gel, the DHT concentration inside the prostate did not change, and prostate gene expression stayed the same over four weeks. So a high blood DHT does not necessarily mean tissues are being overstimulated, and a normal blood DHT does not guarantee tissues are seeing enough.

In women, DHT circulates at much lower levels. Most of it comes from peripheral conversion of adrenal hormones like DHEA (dehydroepiandrosterone) and androstenedione, rather than from ovarian testosterone. Accurate measurement of DHT in women requires a sensitive assay method called LC-MS/MS (liquid chromatography tandem mass spectrometry). Standard immunoassays can give unreliable results at these low concentrations.

Heart Disease and Death Risk

The relationship between DHT and cardiovascular disease follows a U shaped pattern. An individual participant data meta analysis pooling nine prospective cohorts (with 255,830 person years of follow up) found that men in the lowest quintile of DHT (median 0.69 nmol/L, or about 20 ng/dL) had a 19% higher risk of all cause death and a 29% higher risk of cardiovascular death compared to men in the highest quintile (median 2.45 nmol/L, or about 71 ng/dL). Men with very low DHT, below 0.59 nmol/L (about 17 ng/dL), also had increased risk of new cardiovascular events. These associations held after adjusting for age, BMI, smoking, physical activity, blood pressure, diabetes, cholesterol, and kidney function.

A separate study of 3,690 community dwelling men aged 70 to 89 confirmed this pattern. Men with DHT of 1.34 nmol/L (about 39 ng/dL) or higher had lower rates of death from ischemic heart disease. Mid range DHT, roughly around the population median of 1.4 to 1.5 nmol/L (about 41 to 44 ng/dL), was associated with the lowest overall death risk.

If your DHT is in the low range, that is a signal worth investigating alongside your total and free testosterone, your body composition, and your metabolic health. Low DHT rarely exists in isolation; it usually reflects broader androgen insufficiency or metabolic stress.

Prostate Cancer

Despite DHT's role in prostate growth, blood DHT levels do not reliably predict prostate cancer risk. A collaborative analysis pooling 18 prospective studies, including 3,886 prostate cancer cases and 6,438 controls, found no statistically significant association between circulating DHT and overall prostate cancer incidence. There was a slight, non significant trend toward higher DHT associating with more advanced disease at diagnosis, but this did not reach statistical significance after adjustment.

This finding may seem surprising given that blocking DHT production with drugs like finasteride reduces prostate cancer incidence. The explanation is that what matters for prostate cancer is DHT inside prostate tissue, not DHT in the blood. The prostate regulates its own internal DHT levels somewhat independently of what is circulating. A normal or even high blood DHT does not tell you what the prostate is experiencing internally.

Metabolic Health

In a population study of 3,690 older men, those with low DHT (below the 2.5th percentile of 0.49 nmol/L in healthy men) had significantly higher odds of frailty, diabetes, and cardiovascular disease. When both testosterone and DHT were low together, the odds were even higher. Higher BMI, larger waist to hip ratio, dyslipidemia, and diabetes were all independently associated with lower DHT levels.

In women with PCOS (polycystic ovary syndrome), the ratio of testosterone to DHT may carry additional information. A study of 310 women with PCOS found that a high testosterone to DHT ratio, meaning relatively less conversion to DHT, tracked with a worse metabolic picture: more obesity, more insulin resistance, more metabolic syndrome. This ratio is not yet part of standard clinical guidelines, but it suggests DHT may eventually add value to metabolic risk assessment in specific populations.

Hair Loss

DHT is the primary hormonal driver of androgenetic alopecia (male pattern hair loss). In genetically susceptible hair follicles on the scalp, DHT triggers miniaturization, a process where thick terminal hairs gradually become thinner and shorter with each growth cycle until they are barely visible. Finasteride at 1 mg per day was shown in a trial of 1,553 men to significantly increase hair counts by 107 hairs in a standardized area at one year and 138 hairs at two years, compared to progressive loss in the placebo group.

Here again, what matters most is DHT activity at the follicle, not necessarily the number on your blood test. Some men with robust blood DHT levels have no hair loss because their follicles lack the genetic sensitivity. Others lose hair despite unremarkable blood DHT. Still, tracking serum DHT can be useful if you are taking a 5 alpha reductase inhibitor and want to confirm the drug is working systemically.

How DHT Changes with Age

The story of DHT and aging is more nuanced than the straightforward decline seen with testosterone. In the Massachusetts Male Aging Study, a landmark population study of men aged 40 to 70, serum DHT actually rose slightly on longitudinal follow up, even as testosterone and free testosterone fell. A separate cross sectional analysis within the same study found DHT essentially flat across the age range of 39 to 70.

But in men transitioning from their 70s into their 80s and 90s, the picture shifts. A prospective study of 1,025 men with a median age of 75 at baseline found DHT declined at 7.2% per year over 8.6 years of follow up, a steeper drop than testosterone's 2.0% per year decline. In younger healthy men (average age 34), DHT fell by 15.6% over about 12 years. Whether your DHT holds steady or declines with age depends heavily on your overall health, body composition, and the balance of enzyme activity in your tissues.

Ethnic Variation

A study of 1,899 men from the Boston Area Community Health Survey found that Black men had significantly higher DHT levels and higher DHT to testosterone ratios compared to white and Hispanic men, despite similar testosterone levels across groups. The authors concluded that normative ranges for diagnosing androgen deficiency do not need ethnic adjustment, but the finding means your DHT should be interpreted in the context of your own baseline and trend, not just compared to a single universal cutpoint.

Reference Ranges

DHT does not have universally standardized clinical cutpoints the way testosterone does. The best available reference data come from population studies using LC-MS/MS, the gold standard assay method. Your lab may use a different method and report different numbers, so always compare results within the same lab over time.

These ranges come from 394 very healthy men aged 70 to 89 in Perth, Australia, measured by LC-MS/MS. They are orientation for older men, not universal targets for all ages. Younger men generally have higher DHT.

Compare your results within the same lab over time for the most meaningful trend. Ask your lab which assay method they use; immunoassays may be less accurate than LC-MS/MS, particularly at lower concentrations.

When Results Can Be Misleading

Several common situations can make a single DHT reading unreliable.

• 5 alpha reductase inhibitors: Finasteride lowers serum DHT by about 70%, and dutasteride lowers it by 90 to 95%. If you are taking either drug for hair loss or prostate symptoms, your DHT will be profoundly suppressed and cannot be interpreted as reflecting your natural androgen status.
• Obesity and metabolic disease: Higher BMI, diabetes, chronic kidney disease, and chronic liver disease are all independently associated with lower DHT. A low reading in someone with these conditions may reflect metabolic stress rather than primary androgen deficiency.
• Testosterone therapy route matters: Transdermal (skin applied) testosterone causes a disproportionate rise in DHT compared to injected testosterone, because the skin contains high concentrations of 5 alpha reductase. The testosterone to DHT ratio falls from about 10:1 to closer to 2.5:1 with scrotal patches. If you are on testosterone therapy, the route of administration will heavily influence your DHT number.
• Fasting status: Overnight fasting increases morning DHT by about 9 to 16% and reduces variability compared to non fasting samples. For the most consistent results, draw your blood fasting in the early morning.

Tracking Your Trend

A single DHT measurement is a starting point, not a verdict. Given the variability introduced by fasting status, time of day, body composition, and medication use, a trend over multiple readings is far more informative than any one number. Get a baseline reading while fasting in the early morning. If you are making changes, such as starting testosterone therapy, a 5 alpha reductase inhibitor, or a significant weight loss program, retest in three to six months to see how your DHT has responded. After that, annual monitoring is reasonable for most people.

If you are taking finasteride or dutasteride, your DHT will drop dramatically within weeks. A follow up test can confirm the drug is working as expected. If your DHT has not fallen as much as predicted (roughly 70% for finasteride, 90% or more for dutasteride), that warrants a conversation about compliance or drug absorption.

What to Do with an Abnormal Result

If your DHT is low, the first step is context. Check your total testosterone, free testosterone, SHBG (sex hormone binding globulin), and LH (luteinizing hormone) to determine whether the low DHT reflects low testosterone production, altered 5 alpha reductase activity, or elevated binding proteins. Review your medication list for drugs that suppress DHT. Assess your metabolic health: fasting glucose, insulin, BMI, and waist circumference can all contribute to low androgen levels.

If your DHT is unexpectedly high, particularly in a woman, the workup should include testosterone, DHEA sulfate, and androstenedione to identify the source of excess androgens. In men on testosterone therapy, a high DHT is often simply a consequence of the delivery route (especially transdermal) and is not by itself a safety concern based on current evidence. An endocrinologist or urologist can help interpret the pattern and decide whether any action is needed.