Free DHT Test · Blood

If you have ever wondered why your testosterone level looks normal but you still notice symptoms tied to androgens, the answer often lies one step downstream. Most testosterone in your blood is bound to proteins and locked away from your tissues. The small fraction that escapes those proteins gets converted into a more potent hormone that actually does the work in your prostate, skin, and hair follicles.

Free DHT (free dihydrotestosterone) measures the unbound, biologically active portion of that downstream hormone. It is an exploratory marker without standardized clinical cutpoints, and most published research has measured total DHT rather than the free fraction specifically. That said, the free fraction is what reaches your cells, so tracking it gives you a window into androgen activity that total testosterone alone cannot show.

What Free DHT Actually Measures

DHT is a steroid hormone, made when an enzyme called 5-alpha-reductase converts testosterone into a more powerful androgen. DHT binds the androgen receptor more tightly than testosterone and is the dominant driver of androgen action in the prostate, scalp, beard, and genital skin. Most of the DHT in your blood does not come directly from a gland. It is produced locally in tissues and spills into circulation.

Like other sex steroids, DHT travels in your blood mostly bound to carrier proteins (sex hormone binding globulin and albumin). The free fraction is small but biologically meaningful, because only unbound hormone is generally thought to enter cells. This is the same logic behind measuring free testosterone instead of total testosterone when binding proteins are altered.

Heart Disease Risk

Cardiovascular signals from DHT do not point in one direction. In a study of 3,690 older men, those with higher plasma DHT had lower deaths from ischemic heart disease and lower all-cause mortality compared to men in the middle of the range. The same cohort showed higher DHT predicted a lower risk of stroke, though not heart attack.

A meta-analysis of large studies in men found a U-shaped pattern: both very low and very high DHT levels were linked to higher all-cause and cardiovascular mortality, with the lowest risk somewhere in the middle. In a study of 974 older men, higher DHT also tracked with less insulin resistance and lower risk of developing diabetes. In contrast, a small study of 43 patients with severe aortic valve narrowing found that higher serum DHT was tied to more heart muscle thickening and scarring, suggesting that in already-diseased hearts, high androgen exposure may worsen remodeling.

Prostate Health

DHT is the central androgen driving prostate growth, and 5-alpha-reductase inhibitors that block its production are standard treatment for benign prostatic hyperplasia (BPH, an age-related enlarged prostate). The relationship with prostate cancer death is more nuanced than the popular story suggests. In a prospective cohort of 2,400 men, higher baseline DHT was linked to a lower long-term risk of prostate cancer death, regardless of whether men had cancer at the start.

A review of clinical data also concluded that modest increases in circulating DHT during testosterone or DHT therapy have not been clearly tied to more prostate disease or cardiovascular harm, though long-term safety data remain limited. The takeaway: blood DHT is not a one-to-one readout of prostate cancer risk, and intratumoral DHT inside cancer tissue is what drives disease biology.

Liver Cancer Risk in Men

One of the more concerning signals comes from the Liver Cancer Pooling Project, which analyzed 1,043 men and found that higher pre-diagnostic levels of androgens, including DHT, were associated with increased risk of liver cancer. This is a direction-specific risk that runs counter to the older-men mortality data and matters most for men with other liver risk factors like fatty liver disease, heavy alcohol use, or chronic hepatitis.

Bone, Frailty, and Body Composition

In 1,128 older men from the Cardiovascular Health Study, higher DHT was linked to lower hip fracture risk and higher lean body mass. Data from the European Male Ageing Study covering 3,369 community-dwelling older men found that higher androgen levels (including DHT) were associated with less worsening of frailty over time, though the effect weakened after adjusting for body weight. In a study of 1,943 adults, women with higher calculated free DHT had a lower risk of developing chronic kidney disease.

PCOS and Metabolic Phenotype in Women

DHT in women is a different story. In a PCOS (polycystic ovary syndrome) cohort of 310 women, free DHT and free testosterone were higher than in controls, while total DHT did not differ. The most useful pattern was a high ratio of total testosterone to DHT, which was strongly linked to obesity, insulin resistance, impaired glucose tolerance, and metabolic syndrome. A smaller study of 30 PCOS women confirmed that this ratio tracks insulin resistance and worse blood sugar control.

What this means for you: if you are a woman being evaluated for PCOS or unexplained androgen symptoms, free DHT alone is not the diagnostic answer. Total and free testosterone remain the first-line tests recommended by guideline bodies. Free DHT, paired with testosterone, may help characterize your metabolic phenotype rather than make the diagnosis.

Symptomatic Men With Normal Testosterone

In a study of 2,041 men evaluated at andrology clinics, those with normal total testosterone but symptoms of low androgen (low libido, fatigue, mood changes) had worse symptom scores when their DHT was lower. The authors concluded that DHT testing is not appropriate for primary screening, but it can add information once standard testosterone testing has come back normal and symptoms persist. This is the clearest scenario in men where measuring DHT changes how you think about your situation.

Reconciling the Mixed Signals

Free DHT is not a simple "good number, bad number" marker. Higher DHT in older men generally tracks with better outcomes (lower mortality, less stroke, fewer hip fractures, less frailty), while higher DHT in specific contexts (men with liver risk factors, women with PCOS, hearts already affected by aortic stenosis) can flag worse outcomes. The most useful framework: think of free DHT as a phenotype indicator that needs to be interpreted alongside your sex, age, and other health conditions, not as a universal target you are trying to push higher or lower.

Reference Ranges

Free DHT does not have standardized clinical cutpoints in major guidelines. Most published reference data are for total DHT, and assays vary widely between labs. The values your lab reports (typically in picograms per milliliter, a unit for very small concentrations) reflect the analytical range of the specific test method used. Some labs measure free DHT directly using equilibrium dialysis or similar techniques; others calculate it from total DHT, sex hormone binding globulin, and albumin.

Because of this variation, compare your results within the same lab over time rather than against a universal target. A single number is far less useful than seeing your trajectory across multiple draws.

When Results Can Be Misleading

• Assay limitations: older immunoassays for DHT can cross-react with testosterone and produce inaccurate readings. Liquid chromatography-tandem mass spectrometry (a more accurate lab technique that separates and identifies hormones individually) is the more reliable method for measuring DHT.
• Calculated vs measured free DHT: if your lab calculates free DHT from total DHT and binding proteins rather than measuring it directly, the result depends on how accurate the underlying inputs are. Validation of these calculations is less robust than for free testosterone.
• Recent intense training: in 28 male and female athletes, high-volume training periods shifted DHT levels measurably, particularly in women. A single reading just after a heavy training block may not reflect your usual level.
• Acute illness: a study of 160 patients hospitalized with COVID-19 found low testosterone and DHT correlated with disease severity. Acute illness can transiently lower androgens, so testing during or shortly after a significant infection can mislead.

Tracking Your Trend

Free DHT moves with your testosterone status, your binding proteins, your activity level, and your health. A single value tells you very little. A trend over time, paired with how you feel and your other lab markers, tells you much more. If you are starting testosterone replacement, a 5-alpha-reductase inhibitor like finasteride, or any other hormone-altering therapy, get a baseline first.

Retest 3 to 6 months after any change to medication, training, or lifestyle that could move androgens. Once you have established a stable pattern, retest at least annually. Use the same lab and same assay each time, since differences in method can be larger than the actual biological change you are trying to detect.

Decision Pathway for Abnormal Results

If your free DHT is unusually high or low, the next step is rarely to act on the number alone. Pair it with total and free testosterone, sex hormone binding globulin, estradiol, and LH (luteinizing hormone, the pituitary signal to the testes). For men, that combination tells you whether the issue starts in the brain, the testes, or in tissue conversion of testosterone to DHT. For women being evaluated for PCOS or hirsutism, add total and free testosterone, DHEA-S, and androstenedione, and look at the testosterone-to-DHT ratio rather than DHT alone.

If you are a man with hypogonadal symptoms but normal testosterone and a low DHT, an endocrinologist or andrologist is the right specialist. If you are a woman with elevated free DHT and metabolic features (insulin resistance, irregular cycles, weight gain), a reproductive endocrinologist is more appropriate. For men with significantly elevated DHT and known liver disease or family history of liver cancer, surveillance imaging of the liver is worth discussing with a hepatologist.