What causes hair loss in men is one of the most commonly searched health questions in the UK, and for good reason — hair loss affects millions of men at some point in their lives. The most frequent culprit is androgenetic alopecia, or male pattern baldness, driven by genetics and the hormone DHT. However, medical conditions, nutritional deficiencies, medications, and lifestyle factors can all play a role. Understanding the underlying cause is the essential first step towards finding the most appropriate management or treatment.

Common Causes of Hair Loss in Men

Androgenetic alopecia is the most common cause of hair loss in men, but nutritional deficiencies, chronic stress, scalp conditions, traction alopecia, and lifestyle factors such as smoking can also contribute.

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Hair loss in men is extremely common and can arise from a wide range of causes, some entirely natural and others linked to underlying health conditions. Understanding the root cause is essential before considering any form of management or treatment.

The most prevalent cause is androgenetic alopecia, commonly known as male pattern baldness. This hereditary condition accounts for the vast majority of hair loss in men and is driven by a combination of genetic predisposition and the effects of androgens (male hormones) on hair follicles. It typically begins at the temples or crown and progresses gradually over years.

Beyond genetics, other recognised contributing factors include:

• Nutritional deficiencies – low iron or ferritin stores are associated with disrupted hair cycling; links between vitamin D or zinc deficiency and hair loss exist but the evidence is less consistent, and testing is generally only recommended where there is a clinical reason to suspect deficiency

• Chronic stress – physical or emotional stress can trigger a temporary condition called telogen effluvium, where large numbers of hairs enter the resting phase simultaneously

• Scalp conditions – such as seborrhoeic dermatitis or tinea capitis (scalp ringworm); tinea capitis is uncommon in adults but should be considered when hair loss is accompanied by scaly, inflamed patches, and requires confirmation by mycology (skin scrapings or brush samples) before treatment with systemic antifungals

• Traction alopecia – repeated mechanical tension on the hair from tight hairstyles, headwear, or helmets can cause gradual follicle damage and is potentially preventable

• Lifestyle factors – smoking has been associated with hair thinning in observational studies; a link with excessive alcohol consumption has also been suggested, though the evidence for both is limited and these should be regarded as possible associations rather than established causes

Some daily hair shedding is entirely normal. It is when shedding becomes noticeably excessive, or when thinning follows a distinct pattern, that further investigation may be warranted. Identifying the cause early can make a meaningful difference to the range of management options available.

How Male Pattern Baldness Develops Over Time

Male pattern baldness develops as DHT causes progressive follicular miniaturisation in genetically susceptible men, typically following the Norwood–Hamilton scale from temple recession to a horseshoe-shaped band of remaining hair.

Male pattern baldness (androgenetic alopecia) is a progressive condition that develops gradually, often beginning in a man's twenties or thirties, though it can start earlier. It is estimated to affect approximately 50% of men by the age of 50, making it one of the most common dermatological conditions in the UK.

The underlying mechanism involves dihydrotestosterone (DHT), a potent androgen derived from testosterone through the action of the enzyme 5-alpha reductase (predominantly type II). In genetically susceptible individuals, DHT binds to receptors in hair follicles on the scalp, causing them to miniaturise over time. This process — known as follicular miniaturisation — results in progressively finer and shorter hairs. In advanced cases, follicles may become so miniaturised that they produce only fine vellus-like fibres or cease to produce visible hair altogether, though they are not necessarily completely inactive.

The pattern of hair loss typically follows a recognised sequence, often described using the Norwood–Hamilton scale:

• Stage 1–2: Slight recession at the temples

• Stage 3–4: More pronounced recession and thinning at the crown

• Stage 5–6: The two areas of thinning begin to merge

• Stage 7: Only a horseshoe-shaped band of hair remains at the sides and back of the scalp

Not all men will progress through every stage, and the rate of progression varies considerably between individuals. Importantly, the hair follicles at the back and sides of the scalp are generally resistant to DHT, which is why hair in these areas tends to be retained. This biological distinction underpins the rationale for hair transplant surgery, where DHT-resistant follicles are relocated to areas of thinning.

Medical Conditions and Medications That Can Cause Hair Loss

Thyroid disorders, alopecia areata, iron-deficiency anaemia, and lupus can all cause hair loss, as can medications including anticoagulants, chemotherapy agents, retinoids, and some antidepressants.

While male pattern baldness is the most common cause of hair loss in men, a number of medical conditions and prescribed medications can also lead to significant hair thinning or shedding. Recognising these causes is important, as addressing the underlying condition may lead to hair regrowth.

Medical conditions associated with hair loss include:

• Alopecia areata – an autoimmune condition in which the immune system mistakenly attacks hair follicles, causing patchy hair loss. In more severe forms, it can progress to total scalp hair loss (alopecia totalis) or loss of all body hair (alopecia universalis)

• Thyroid disorders – both hypothyroidism and hyperthyroidism can disrupt the hair growth cycle, leading to diffuse thinning

• Iron-deficiency anaemia – a well-recognised cause of telogen effluvium

• Diabetes mellitus – an association between diabetes and hair loss has been reported, though the precise mechanism is not fully established; it may relate to metabolic or autoimmune factors rather than a direct effect on scalp circulation

• Lupus and other autoimmune conditions – can cause scarring or non-scarring hair loss depending on the type

If scaly, inflamed, or crusted patches are present alongside hair loss, mycology (skin scrapings or a brush sample) should be considered to exclude tinea capitis, particularly if there is associated lymphadenopathy. Suspected scarring alopecia — characterised by permanent follicle destruction — warrants prompt dermatology referral.

Medications that have been reported to cause hair loss include:

• Certain antihypertensives (e.g., some beta-blockers — association reported but uncommon)

• Anticoagulants such as warfarin and heparin

• Chemotherapy agents, which commonly cause diffuse hair loss (chemotherapy-induced alopecia)

• Retinoids, including isotretinoin, used for skin conditions

• Some antidepressants, mood stabilisers (e.g., lithium, sodium valproate), and antithyroid drugs

• Anabolic steroids

The strength of association varies between medicines; the BNF and individual Summary of Product Characteristics (SmPCs) provide the most reliable information on frequency. If hair loss begins shortly after starting a new medication, it is important not to stop the medicine without first consulting a GP or prescribing clinician, who can assess whether the timing suggests a causal link and discuss alternatives if appropriate.

If you experience a suspected side effect from any medicine, you can report it to the MHRA via the Yellow Card Scheme at yellowcard.mhra.gov.uk.

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When to See a GP About Hair Loss

See a GP if hair loss is sudden, patchy, accompanied by scalp inflammation or systemic symptoms, or is causing significant psychological distress, as these features may indicate an underlying condition requiring treatment.

Many men accept gradual hair thinning as a natural part of ageing and never seek medical advice. However, there are certain circumstances in which consulting a GP is strongly advisable, as hair loss can occasionally signal an underlying health condition that requires treatment.

You should consider seeing a GP if:

• Hair loss is sudden or rapid, rather than gradual

• You notice patchy or irregular hair loss rather than a typical receding pattern

• Hair loss is accompanied by other symptoms, such as fatigue, weight changes, skin changes, or joint pain

• There is scalp inflammation, redness, scaling, pain, pustules, or crusting in areas of hair loss — these features may suggest scarring alopecia (such as lichen planopilaris or folliculitis decalvans) or an inflammatory fungal infection (kerion), which require urgent assessment

• Hair loss is causing significant psychological distress or affecting quality of life

• You are losing hair from eyebrows, eyelashes, or other body areas

• Hair loss began shortly after starting a new medication

• You have extensive or rapidly progressive alopecia areata, which merits timely specialist assessment

It is also worth seeking advice if you are unsure whether your hair loss is following a typical male pattern or something less common. GPs are well placed to carry out an initial assessment, arrange relevant blood tests, and refer to a dermatologist if necessary.

The psychological impact of hair loss should not be underestimated. Research has shown that hair loss can contribute to reduced self-esteem, anxiety, and depression in some men. NHS Talking Therapies (formerly IAPT) services offer a range of evidence-based psychological therapies and may be appropriate for those significantly affected. A GP can help signpost patients to the right support.

Diagnosis and Assessment on the NHS

GPs diagnose male pattern baldness clinically; where another cause is suspected, targeted blood tests including FBC, ferritin, and thyroid function are arranged, with dermatology referral for atypical or scarring presentations.

When a man presents to his GP with concerns about hair loss, the assessment will typically begin with a thorough clinical history and physical examination. The GP will ask about the pattern and duration of hair loss, family history, recent illnesses or stressors, dietary habits, and any medications being taken.

For straightforward male pattern baldness, no investigations are usually required, and the diagnosis is made clinically based on the characteristic pattern of hair loss.

Where the history or examination suggests another cause, the GP may arrange targeted blood tests, which commonly include:

• Full blood count (FBC) – to check for anaemia

• Serum ferritin and iron studies – to assess iron stores

• Thyroid function tests (TFTs) – to rule out thyroid dysfunction

Vitamin D, zinc, and hormonal tests (such as testosterone and sex hormone-binding globulin) are not routinely indicated but may be considered where there is a specific clinical reason to suspect deficiency or hormonal abnormality.

If scaly or inflamed patches are present, mycology (skin scrapings or a brush sample sent for microscopy and culture) should be arranged to exclude tinea capitis.

If the presentation is atypical — for example, patchy loss, features suggesting scarring alopecia, or associated systemic symptoms — a referral to a dermatologist should be made. Suspected scarring alopecia or a severe inflammatory tinea (kerion) warrants urgent referral to prevent permanent follicle loss.

Dermatologists have access to specialist diagnostic tools, including dermoscopy (a non-invasive technique to examine the scalp and follicles in detail) and, in some cases, scalp biopsy to examine follicular architecture under a microscope. Guidance from NICE CKS (Alopecia areata) and the Primary Care Dermatology Society (PCDS) supports a structured approach to investigation, ensuring that treatable causes are not missed. Waiting times for NHS dermatology referrals can vary by region, and some patients choose to seek private assessment to expedite diagnosis.

Treatment Options Available in the UK

Licensed UK treatments for male pattern baldness include topical minoxidil (over the counter) and oral finasteride 1 mg (prescription-only); hair transplant surgery is available privately from CQC-registered clinics.

The treatment of hair loss in men depends on the underlying cause. For male pattern baldness, several evidence-based options are available in the UK, ranging from over-the-counter products to prescription medicines and surgical procedures.

Licensed medical treatments include:

• Minoxidil (e.g., Regaine® for Men 5% solution or foam) – available over the counter, minoxidil is applied directly to the scalp once or twice daily as directed. Its precise mechanism is not fully understood, but it is thought to prolong the anagen (growth) phase of the hair cycle; vasodilatory effects on the scalp may also play a role. It is most effective when started early and must be used continuously to maintain results — hair loss typically resumes within months of stopping. Common side effects include initial increased shedding (usually temporary), scalp irritation or dryness, and occasionally unwanted facial hair growth. The MHRA has approved it for androgenetic alopecia in men. Always read the SmPC before use.

• Finasteride 1 mg (e.g., Propecia®) – a prescription-only oral tablet taken once daily. It works by inhibiting 5-alpha reductase type II, thereby reducing DHT levels in the scalp. Clinical trials have demonstrated it can slow hair loss and promote regrowth in a significant proportion of men. It is not suitable for everyone. Key safety information includes:

• Sexual side effects (reduced libido, erectile dysfunction, ejaculatory disorders) have been reported; in some men these have persisted after stopping treatment (post-finasteride syndrome). Patients should be counselled about this risk before starting.
• Psychiatric effects including depression, anxiety, and suicidal ideation have been reported. Patients should be advised to stop treatment and seek medical help promptly if they experience mood changes.
• The MHRA 2024 Drug Safety Update reinforces these warnings and requires that patients receive a patient alert card at the time of prescribing.
• Finasteride lowers PSA levels by approximately 50%; this should be taken into account when interpreting PSA results used in prostate cancer screening.
• Women who are pregnant or may become pregnant must not handle crushed or broken tablets, as finasteride can be absorbed through the skin and may harm a male foetus.
• Always refer to the current SmPC (available via the EMC) for full prescribing information.

Treatments that are not licensed for androgenetic alopecia in the UK — including oral minoxidil and dutasteride — may be used off-label in specialist settings; patients should be made aware of their unlicensed status.

Surgical options:

• Hair transplant surgery – techniques such as follicular unit transplantation (FUT) and follicular unit extraction (FUE) are available privately in the UK. These procedures relocate DHT-resistant follicles from the back of the scalp to areas of thinning and can produce natural-looking, long-lasting results in suitable candidates. Hair transplantation is a cosmetic procedure and is not funded by the NHS. Patients should choose a Care Quality Commission (CQC)-registered clinic and ensure the procedure is performed by a suitably qualified clinician on the GMC specialist register. As with any surgical procedure, there are risks including infection, scarring, and variable results; a thorough consultation with a qualified specialist is essential before proceeding.

For other causes of hair loss, treatment is directed at the underlying condition — for example, levothyroxine for hypothyroidism, or iron supplementation for deficiency. Alopecia areata may be managed with topical or intralesional corticosteroids. JAK inhibitors represent a newer treatment approach for severe alopecia areata: ritlecitinib has received a UK marketing authorisation for this indication, and baricitinib has been evaluated in this context; prescribing is specialist-led and subject to current NICE technology appraisal guidance and local commissioning decisions. Patients should discuss eligibility with their dermatologist.

It is important to have realistic expectations: no treatment can guarantee full regrowth, and early intervention generally yields the best outcomes. If you experience a suspected side effect from any treatment, report it to the MHRA via the Yellow Card Scheme at yellowcard.mhra.gov.uk.

Frequently Asked Questions