Dihydrotestosterone (DHT) Free Serum Biomarker Testing
It measures the unbound (active) fraction of DHT in your blood, with results you can review in PocketMD and order through Vitals Vault/Quest.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
Free dihydrotestosterone (DHT) is the portion of DHT in your bloodstream that is not bound to carrier proteins and is more available to interact with tissues. Because DHT is a potent androgen, even small shifts can matter when you are trying to make sense of symptoms that look “hormonal.”
This test is most useful when your symptoms and your other hormone results do not quite match, or when you are monitoring a treatment that changes androgen signaling. It is also a way to add detail beyond total testosterone alone.
Your result is only one piece of the picture. Interpreting it alongside testosterone, sex hormone–binding globulin (SHBG), and clinical context helps you and your clinician decide what to do next.
Do I need a Dihydrotestosterone Free Serum test?
You might consider a free DHT test if you have signs of higher androgen activity such as scalp hair thinning, persistent acne, increased facial or body hair growth, or changes in libido that are not explained by your total testosterone alone. It can also be helpful if you have symptoms of androgen deficiency (low libido, reduced morning erections, low energy) and your testosterone results are borderline or inconsistent with how you feel.
This test is commonly used when you are evaluating conditions where androgen balance matters, such as suspected polycystic ovary syndrome (PCOS), certain causes of female-pattern hair loss, or when you are trying to understand prostate-related symptoms in the context of androgen therapy. It may also be relevant if you are taking or considering medications that affect 5-alpha reductase (the enzyme that converts testosterone to DHT) or if you are using testosterone therapy and want to understand downstream conversion.
You usually do not need free DHT as a first-line test for general fatigue or weight changes. In many cases, starting with a broader hormone and metabolic workup is more efficient, and then adding free DHT if the initial results raise questions.
Testing supports clinician-directed care and shared decision-making, but it cannot diagnose a condition by itself.
This is a laboratory measurement performed in a CLIA-certified environment; results should be interpreted with your clinician and are not a standalone diagnosis.
Lab testing
Order labs to measure Dihydrotestosterone, Free, Serum
from $375.97 at Quest Diagnostics
About 1 week
Schedule online — results typically within a week
Clear next steps
Guidance included, with follow-up care available
HSA / FSA
Eligible for pre-tax health spending accounts
Get this test with Vitals Vault
If you want to check free DHT without waiting for an office visit, Vitals Vault lets you order the lab and complete the blood draw through the Quest network. You can use this when you are building a baseline, troubleshooting symptoms, or monitoring a change in therapy.
After your results post, PocketMD can help you translate the numbers into plain language and generate a focused list of follow-up questions for your clinician. That is especially useful for DHT because interpretation depends on sex, age, symptoms, and related markers like testosterone and SHBG.
If your result suggests you need a wider view, you can add companion testing (for example, total testosterone, free testosterone, SHBG, estradiol, LH/FSH, or metabolic markers) and trend results over time rather than reacting to a single data point.
- Order online and draw at a Quest location
- PocketMD guidance for next-step questions and retest timing
- Designed for trending results over time, not one-off guesses
Key benefits of Dihydrotestosterone Free Serum testing
- Clarifies androgen activity when total testosterone does not match your symptoms.
- Helps evaluate hair and skin concerns where DHT sensitivity may play a role.
- Supports PCOS and hyperandrogenism workups when paired with other hormones.
- Adds context when you are using testosterone therapy and want to understand conversion to DHT.
- Helps monitor the physiologic impact of 5-alpha reductase inhibitors over time.
- Improves interpretation of borderline results by considering binding proteins and free fractions.
- Makes it easier to plan targeted follow-up testing and retesting intervals with PocketMD support.
What is Dihydrotestosterone (DHT) free serum?
Dihydrotestosterone (DHT) is an androgen made primarily by converting testosterone through an enzyme called 5-alpha reductase. DHT binds strongly to androgen receptors and can have powerful effects in certain tissues, including hair follicles, skin (oil glands), and the prostate.
“Free” DHT refers to the fraction circulating in your blood that is not bound to carrier proteins. Most DHT is bound to proteins such as sex hormone–binding globulin (SHBG) and albumin. The free portion is smaller, but it is often discussed as the more immediately bioavailable fraction.
A free DHT result is not a direct measure of what is happening inside a specific tissue (like a scalp hair follicle). Some people have normal blood levels but higher local conversion or higher tissue sensitivity. That is why symptoms, family history, and companion labs matter.
How DHT relates to testosterone and SHBG
Testosterone is a precursor to DHT, so changes in testosterone can influence DHT, but the relationship is not one-to-one. Enzyme activity (5-alpha reductase), SHBG levels, and medication use can shift how much testosterone converts to DHT and how much is bound versus free. Looking at total testosterone, free testosterone, SHBG, and sometimes albumin helps explain why your free DHT is higher or lower than expected.
Why “free” results can be harder to compare
Reference ranges and units can vary by lab method, and free hormone assays can be more method-sensitive than total hormone tests. The most useful comparison is often your own trend over time using the same lab method, combined with symptom changes and any treatment adjustments.
What do my Dihydrotestosterone Free Serum results mean?
Low free DHT levels
Low free DHT can happen if overall androgen production is low, if conversion from testosterone to DHT is reduced, or if binding dynamics shift so that less DHT is circulating in the free fraction. It may be seen with use of 5-alpha reductase inhibitors, some patterns of hypogonadism, or after changes in testosterone therapy dosing. If you have symptoms of low androgen activity, your clinician will usually interpret this alongside total and free testosterone, LH/FSH, and SHBG to identify whether the issue is production, conversion, or binding.
Optimal (in-range) free DHT levels
An in-range free DHT result generally suggests your circulating free DHT is consistent with the lab’s expected range for your sex and age. If you still have androgen-related symptoms, the next step is often to look for mismatches between hormones and tissues, such as normal blood levels with higher follicle sensitivity, or symptoms driven by other hormones (thyroid, prolactin, estradiol) or non-hormonal causes. Trending can be helpful if you recently changed medications, started or stopped hormonal contraception, or adjusted testosterone therapy.
High free DHT levels
High free DHT may reflect higher androgen production, increased conversion from testosterone to DHT, lower SHBG (which can increase free fractions), or medication and supplement effects. In some people, higher free DHT aligns with acne, oily skin, scalp hair thinning, or increased body hair, but symptoms vary widely. Your clinician may pair this with total testosterone, free testosterone, SHBG, and sometimes DHEA-S and androstenedione to determine whether the pattern suggests ovarian, adrenal, or medication-related drivers.
Factors that influence free DHT
Time of day, recent illness, and lab method can affect results, and free hormone measurements can be especially sensitive to assay differences. Medications are common drivers, including testosterone therapy, 5-alpha reductase inhibitors, some anti-androgens, and hormonal contraception. SHBG changes (from thyroid status, insulin resistance, liver health, and certain medications) can shift the free fraction even if total DHT is unchanged. Age, body composition, and genetics also influence conversion and tissue sensitivity, so your symptoms and trend over time matter as much as a single number.
What’s included
- Dht, Free
- Dihydrotestosterone
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Frequently Asked Questions
What is the difference between DHT and free DHT?
DHT is the hormone itself, while “free DHT” refers to the portion circulating unbound to proteins like SHBG and albumin. Free fractions are discussed as more immediately available to tissues, but they still do not perfectly represent tissue-level activity. Your clinician usually interprets free DHT alongside total androgens and SHBG.
Do I need to fast for a free DHT blood test?
Fasting is not typically required for DHT testing. However, if you are ordering companion tests that do require fasting (such as glucose, insulin, or a lipid panel), it can be convenient to fast so everything is collected under the right conditions. Follow the instructions provided with your lab order.
When is the best time of day to test DHT?
Androgens can show some daily variation, so many clinicians prefer morning testing for consistency, especially when comparing results over time. The most important factor is to test at a similar time of day each time you repeat the lab. If you use testosterone therapy, timing relative to your dose can also matter.
Can finasteride or dutasteride affect free DHT results?
Yes. These medications inhibit 5-alpha reductase and commonly lower DHT levels, sometimes substantially. If you are monitoring response or side effects, it helps to document your dose, how long you have been taking it, and whether you changed anything recently so your clinician can interpret the trend.
Can high free DHT cause hair loss?
Higher DHT can be associated with androgen-sensitive hair follicles and pattern hair loss, but blood levels are only part of the story. Genetics and follicle sensitivity strongly influence whether DHT contributes to hair thinning. If hair loss is your main concern, your clinician may also consider iron status, thyroid labs, and other androgens.
What other labs should I check with free DHT?
Common companion tests include total testosterone, free testosterone, SHBG, estradiol, and sometimes DHEA-S and androstenedione. Depending on your symptoms, LH and FSH can help clarify whether the signal is coming from the brain–gonad axis, and metabolic markers can be useful when SHBG or insulin resistance may be influencing free fractions.
How soon should I retest free DHT after changing a medication or hormone dose?
A typical approach is to wait several weeks after a meaningful change so levels can stabilize, but the best timing depends on the medication, dosing schedule, and your symptoms. If you are monitoring a therapy that directly affects DHT (like a 5-alpha reductase inhibitor), your clinician may choose a consistent interval such as 6–12 weeks. PocketMD can help you plan questions and a retest schedule to discuss with your clinician.