Causes of Hair Loss in Men: What You Need to Know Before a Hair Transplant
In this ZMDHair video, double board-certified surgeon Dr. Hootan Zandifar walks through the primary reasons men experience hair loss—starting with the most prevalent culprit and covering several other conditions that must be evaluated before any treatment plan is created.
Dr. Zandifar is board-certified by both the American Board of Otolaryngology–Head & Neck Surgery and the American Board of Facial Plastic Surgery, UCLA-trained, and a member of the American Society of Hair Restoration Surgery, making him uniquely qualified to diagnose and address the full spectrum of hair-loss causes.
- Androgenetic alopecia (male pattern baldness), driven by DHT, is the most common cause of hair loss in men.
- Other causes—including stress-induced telogen effluvium, autoimmune conditions, and low thyroid levels—must be identified and ruled out.
- A proper medical workup before an FUE hair transplant helps ensure the right treatment is chosen for each individual patient.
- Donor-area follicles used in FUE are generally DHT-resistant, supporting durable results in androgenetic alopecia cases.
Androgenetic Alopecia: The Leading Cause of Male Hair Loss
As Dr. Zandifar explains, the most common cause of hair loss in men is androgenetic alopecia—widely known as male pattern baldness. The hormone testosterone produces a byproduct called dihydrotestosterone (DHT), which causes the hair follicles on the top of the scalp to miniaturize, thin, and eventually stop producing visible hair. Because this process is driven by genetics and hormones, it tends to follow a predictable progression across the crown and hairline.
Understanding whether a patient’s hair loss is androgenetic is a critical first step before considering an FUE hair transplant. Follicles harvested from the back and sides of the scalp—the donor area—are typically resistant to DHT, which is why transplanted hair can maintain long-term growth in areas previously affected by male pattern baldness.
Other Medical Causes That Must Be Ruled Out
Dr. Zandifar emphasizes that several other conditions can also cause hair loss and need to be properly worked up and ruled out. These include telogen effluvium, a form of stress-induced shedding; seborrheic or autoimmune-related alopecia conditions; and hormonal imbalances such as low thyroid levels (hypothyroidism). Each of these has a distinct mechanism and may require medical management rather than—or in addition to—a surgical solution.
- Telogen effluvium: Diffuse shedding triggered by physical or emotional stress, illness, or nutritional deficiency.
- Autoimmune alopecia: Conditions where the immune system targets hair follicles, such as alopecia areata.
- Thyroid dysfunction: Low thyroid hormone levels can disrupt the normal hair-growth cycle and cause widespread thinning.
Why a Thorough Evaluation Matters Before FUE
A comprehensive consultation is essential because performing an FUE hair transplant on a patient with an undiagnosed medical cause of hair loss could produce suboptimal results. If an underlying condition like hypothyroidism or an autoimmune disorder is driving the shedding, addressing that condition first may slow or halt further loss—changing the treatment plan significantly.
At ZMDHair, Dr. Zandifar’s evaluation process is designed to identify the root cause of each patient’s hair loss before recommending any surgical or non-surgical intervention. Only once androgenetic alopecia is confirmed as the primary driver—and other causes are excluded—can a personalized FUE plan be developed with confidence in long-term outcomes.
Full Video Transcript
the most common cause of hair loss in men is a condition that we call androgenetic alopecia or basically we call that male pattern boldness it's where the hormone testosterone has a byproduct called dihydrotestosterone that causes the hairs in the top of the head to thin and eventually regress now there are other causes of hair loss as well things like tilen fluvium where stress induced hair loss is noted there are conditions like seratic hair loss or other alopecia conditions that are autoimmune there are hormone conditions such as uh low thyroid levels that can cause hair loss and all of these need to be worked up and ruled out but the most common cause of hair loss in men is uh that male pattern bous hair loss that we see and we know very well
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Frequently Asked Questions
- What is DHT and why does it cause hair loss?
- Dihydrotestosterone (DHT) is a byproduct of testosterone. In men genetically predisposed to androgenetic alopecia, DHT causes follicles on the top of the scalp to shrink over time, producing progressively thinner hair until growth stops.
- Can stress really cause hair loss?
- Yes. As Dr. Zandifar notes, telogen effluvium is a recognized form of stress-induced hair loss. Significant physical or emotional stress can push a large number of follicles into a resting phase simultaneously, leading to noticeable shedding weeks to months later.
- Do I need blood tests before a hair transplant consultation?
- A thorough evaluation—which may include blood work to assess thyroid levels and other hormonal markers—helps rule out medical causes of hair loss. Dr. Zandifar reviews each patient's history to determine which workup is appropriate before recommending treatment.
- Is FUE effective for male pattern baldness?
- FUE is a well-established surgical option for men whose hair loss is primarily androgenetic. Because donor follicles from the back and sides of the scalp resist DHT, they can continue to grow after being transplanted into thinning areas, provided the patient is a suitable candidate.
