Can trazodone cause hair loss? It is a question raised by some patients prescribed this antidepressant, and one worth examining carefully. Trazodone is a serotonin antagonist and reuptake inhibitor (SARI) licensed in the UK for depression, and occasionally used off-label for insomnia. While alopecia does appear in the UK Summary of Product Characteristics as an adverse reaction, it is listed as 'frequency not known' — meaning robust data are limited. This article reviews what the current evidence shows, how drug-induced hair loss can occur, what other factors may be involved, and what steps to take if you notice hair thinning whilst taking trazodone.

Trazodone and Hair Loss: What the Evidence Shows

Alopecia is listed in the UK SmPC for trazodone as an adverse reaction of 'frequency not known', but no robust clinical trial data confirm a causal relationship between trazodone and hair loss.

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Trazodone is a serotonin antagonist and reuptake inhibitor (SARI) licensed in the UK for the treatment of depression. At lower doses, it is sometimes used off-label to help with insomnia, though this is not an approved indication in the UK. It works by blocking certain serotonin receptors and inhibiting the reuptake of serotonin, helping to regulate mood and sleep. Like all medicines, it carries a profile of potential side effects — and hair loss is occasionally reported by patients taking it.

According to the UK Summary of Product Characteristics (SmPC) for trazodone, alopecia is listed as an adverse reaction with a frequency categorised as 'not known' (meaning it cannot be estimated from the available data). It is not among the commonly reported side effects. Post-marketing surveillance data and isolated case reports suggest that, for a small number of individuals, there may be a possible association between trazodone and hair loss, but the evidence base remains limited.

There is no robust clinical trial data confirming a causal relationship between trazodone and hair loss. When hair loss is reported in patients taking trazodone, it is often difficult to determine whether the medicine itself, the underlying condition being treated, or other concurrent factors are responsible. Clinicians and patients should therefore approach this topic with measured caution — acknowledging the possibility without overstating the risk.

How Common Is Hair Loss as a Side Effect?

Hair loss cannot be assigned a standard frequency category for trazodone; it is not among the commonly reported side effects, which include drowsiness, dry mouth, dizziness, and nausea.

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Based on the current UK SmPC for trazodone, alopecia is listed as an adverse reaction of 'frequency not known' — meaning a reliable frequency estimate cannot be made from the data available. It is not possible to assign it a standard pharmacovigilance frequency category on current evidence. For reference, those categories are:

• Very common: affects more than 1 in 10 people

• Common: affects 1 in 10 to 1 in 100 people

• Uncommon: affects 1 in 100 to 1 in 1,000 people

• Rare: affects 1 in 1,000 to 1 in 10,000 people

• Very rare: affects fewer than 1 in 10,000 people

More commonly reported side effects of trazodone include drowsiness, dry mouth, dizziness, and nausea. The MHRA's Yellow Card reporting scheme allows patients and healthcare professionals in the UK to report suspected adverse drug reactions; while alopecia has been submitted as a report in association with trazodone, such reports indicate a suspected association only — they do not confirm causality.

Some other antidepressants have also been associated with hair thinning in case reports and post-marketing data, though this is not well established as a class effect and should not be generalised without supporting evidence. Patients who are concerned about this potential side effect should be reassured that the available data do not suggest hair loss is a frequent occurrence with trazodone. Nevertheless, any new or worsening hair loss during treatment should be discussed with a GP or prescribing clinician.

Why Some Medicines Can Affect Hair Growth

Drug-induced hair loss most commonly occurs via telogen effluvium, where a pharmacological stressor pushes follicles into the resting phase, causing diffuse shedding two to four months later.

To understand why certain medicines might contribute to hair loss, it helps to understand the normal hair growth cycle. Hair follicles cycle through three phases: anagen (active growth), catagen (transition), and telogen (resting and shedding). Disruptions to this cycle — whether caused by illness, nutritional deficiency, hormonal changes, or medicines — can result in increased shedding or thinning.

Drug-induced hair loss typically occurs through one of two mechanisms:

• Anagen effluvium: Occurs when a drug directly disrupts active hair growth, most commonly seen with chemotherapy agents.

• Telogen effluvium: A more diffuse shedding that occurs when a physiological or pharmacological stressor pushes a large number of follicles prematurely into the resting phase. This type is more commonly associated with psychiatric medications and typically begins two to four months after the triggering event. It is non-scarring and usually reversible once the underlying cause is addressed.

In the case of trazodone, the mechanism by which it might theoretically contribute to hair loss is not established. It has been suggested, speculatively, that serotonergic activity could influence hair follicle cycling, as serotonin receptors have been identified in human hair follicles — however, this remains an area of ongoing research and should not be taken as a confirmed clinical finding. No direct causal mechanism linking trazodone to hair loss has been demonstrated in clinical studies, and patients should be aware that any such association, if real, is likely to reflect an uncommon individual response rather than a predictable pharmacological effect.

What to Do If You Notice Hair Thinning on Trazodone

Do not stop trazodone abruptly; consult your GP, who will take a full history, rule out other causes such as thyroid dysfunction or iron deficiency, and review your full medication list.

If you notice increased hair shedding or thinning after starting trazodone, the most important first step is not to stop your medication abruptly. Discontinuing antidepressants without medical guidance can lead to discontinuation symptoms and a return of the underlying condition being treated. Always speak to your GP or prescribing clinician before making any changes to your medication.

When you consult your doctor, they will likely:

• Take a thorough history to establish the timeline of hair loss in relation to when trazodone was started

• Rule out other causes, including thyroid dysfunction, iron deficiency, and other common and treatable conditions

• Review your full medication list, as other prescribed or over-the-counter medicines may be contributing

• Consider blood tests based on clinical assessment — in UK primary care, this typically includes a full blood count (FBC), serum ferritin, and thyroid-stimulating hormone (TSH); further tests such as vitamin D, vitamin B12, or zinc levels are ordered only if there are specific clinical reasons to suspect a deficiency

The following features should prompt prompt medical review or referral to a dermatologist:

• Scarring, inflammation, or pain on the scalp

• Rapid or extensive hair loss

• Signs of androgen excess (for example, irregular periods, acne, or unwanted facial hair in women)

• Diagnostic uncertainty after initial assessment

If trazodone is suspected to be the cause after other factors have been excluded, your doctor may discuss whether a dose adjustment or a switch to an alternative antidepressant is appropriate. In many cases, drug-induced telogen effluvium is self-limiting and hair regrowth occurs once the triggering factor is addressed. You can also report suspected side effects directly to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

Other Factors That May Contribute to Hair Loss

Hair loss is multifactorial; thyroid disorders, iron deficiency, hormonal changes, androgenetic alopecia, and other medications are common causes that should be investigated before attributing thinning to trazodone.

It is essential to consider that hair loss is a multifactorial condition, and in many cases where a patient on trazodone notices thinning, the medicine may not be the primary cause. Depression and anxiety themselves are associated with physiological stress responses that can trigger telogen effluvium. The very condition for which trazodone is prescribed may therefore be a contributing factor to hair changes, independent of the medication.

Several other common causes of hair loss should be considered and investigated:

• Thyroid disorders: Both hypothyroidism and hyperthyroidism can cause diffuse hair thinning and are relatively common in the UK population

• Iron deficiency: One of the most frequent reversible causes of hair loss, particularly in women of reproductive age; serum ferritin is the most sensitive marker in primary care

• Hormonal changes: Postpartum hair loss, menopause, and polycystic ovary syndrome (PCOS) are well-recognised triggers

• Androgenetic alopecia: The most common form of hair loss overall, with a strong genetic component

• Nutritional deficiencies: Deficiencies in vitamin D, zinc, or biotin may contribute to hair loss in some individuals, though these are investigated only when clinically indicated rather than routinely. Note that high-dose biotin supplements can interfere with certain blood tests — including thyroid function tests — and you should always inform your healthcare professional if you are taking any supplements, as this may affect the interpretation of results (MHRA Drug Safety Update)

• Other medications: Beta-blockers, anticoagulants, retinoids, and certain hormonal contraceptives are among the medicines more firmly associated with hair loss in the BNF and clinical literature

Lifestyle factors such as significant weight loss, crash dieting, high psychological stress, and certain hairstyling practices can also contribute. A holistic assessment by a GP — and referral to a dermatologist if needed — is the most effective way to identify the true cause and guide appropriate management. Addressing any underlying conditions often leads to meaningful improvement in hair health over time.

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