Does losartan cause hair loss? This is a question many patients prescribed this common blood pressure medication ask their GP. Losartan is an angiotensin II receptor blocker (ARB) widely used across the UK for hypertension, diabetic nephropathy, and heart failure. Whilst hair loss (alopecia) has been reported in association with losartan in post-marketing data, it is listed as a rare or frequency-unknown side effect in UK product information. This article explores the evidence, explains why some medicines affect hair growth, and outlines what to do if you notice hair thinning whilst taking losartan.

Can Losartan Cause Hair Loss?

Losartan may cause hair loss in a small number of individuals; alopecia is listed as rare or frequency unknown in UK SmPC data, but a definitive causal relationship has not been firmly established.

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Losartan is an angiotensin II receptor blocker (ARB) widely prescribed in the UK for conditions including hypertension, diabetic nephropathy, and — where ACE inhibitors are not tolerated — heart failure, in line with the British National Formulary (BNF) and UK Summary of Product Characteristics (SmPC). It works by blocking the action of angiotensin II, a hormone that causes blood vessels to constrict, thereby helping to lower blood pressure and reduce strain on the heart and kidneys.

Hair loss (alopecia) has been reported in association with losartan in post-marketing data. The frequency category in UK SmPCs for losartan products (such as those listed on the MHRA's Electronic Medicines Compendium) may be recorded as 'rare' (fewer than 1 in 1,000 patients) or, in some product listings, as 'frequency not known' — reflecting that the evidence comes largely from spontaneous case reports rather than controlled clinical trials. Patients and clinicians should check the current SmPC for the specific product dispensed. Regardless of the precise frequency category, alopecia is not a common or expected side effect for most people taking losartan.

It is important to note that hair loss has many potential causes — including stress, nutritional deficiencies, thyroid disorders, and other medications — and it can be difficult to attribute hair thinning to any single factor without a thorough clinical assessment. The association between losartan and hair loss is based on post-marketing signals and case reports; a definitive causal relationship has not been firmly established.

If you are taking losartan and have noticed increased hair shedding or thinning, it is worth discussing this with your GP rather than stopping the medication without advice, as doing so could lead to a rise in blood pressure and have significant cardiovascular consequences.

Overall, the available evidence suggests that losartan may cause hair loss in a small number of individuals, but this is not a common or expected side effect for most patients. A balanced, informed conversation with your prescriber is the most appropriate first step. Further information is available via the NHS Medicines A–Z page for losartan and the BNF monograph.

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How Common Is Hair Loss as a Side Effect?

Hair loss is listed as 'rare' (fewer than 1 in 1,000 patients) or 'frequency not known' for losartan in UK SmPC data, making it far less common than side effects such as dizziness or hyperkalaemia.

Understanding how frequently a side effect occurs helps patients and clinicians weigh the risks and benefits of any medication. Based on UK SmPC data for losartan products (available via the MHRA's Electronic Medicines Compendium), alopecia is listed either as 'rare' (fewer than 1 in 1,000 patients) or with a frequency of 'not known', depending on the specific licensed product. Patients should refer to the patient information leaflet supplied with their medication or check the relevant SmPC for the most accurate frequency data.

By comparison, more commonly reported side effects of losartan, as listed in the SmPC and NHS Medicines A–Z, include:

• Dizziness (particularly on standing, due to blood pressure lowering)

• Hyperkalaemia (raised potassium levels)

• Renal impairment in susceptible individuals

• Fatigue and headache

Post-marketing surveillance — the ongoing monitoring of medicines once they are in widespread use — has generated spontaneous reports of hair loss associated with ARBs as a class, including losartan, via schemes such as the MHRA's Yellow Card programme. However, spontaneous reporting captures suspected reactions rather than confirmed causal links, so the true incidence may differ from clinical trial data.

It is also worth considering that hypertension itself, as well as the physiological stress of managing a chronic condition, can contribute to hair changes over time. Telogen effluvium — a form of diffuse hair shedding triggered by physical or emotional stress — is a well-recognised phenomenon (described by the Primary Care Dermatology Society, PCDS) that can coincide with starting a new medication, making causality difficult to establish.

In clinical practice, many patients who report hair loss whilst taking losartan are found to have an alternative or contributing explanation upon investigation. Nevertheless, the reported association should not be dismissed, particularly if hair loss begins shortly after starting the medication or following a dose increase.

Why Some Medicines Affect Hair Growth

Losartan may theoretically disrupt hair follicle signalling by blocking angiotensin II receptors in dermal papilla cells, though this mechanism is speculative and not confirmed by definitive clinical evidence.

To understand why losartan might affect hair in some individuals, it helps to consider the biology of hair growth. Hair follicles cycle through three phases: anagen (active growth), catagen (transition), and telogen (resting and shedding). Disruption to this cycle — whether through hormonal changes, nutritional deficits, or pharmacological interference — can result in increased shedding or reduced regrowth.

Angiotensin II, the hormone that losartan blocks, has been proposed in some research to play a role in hair follicle biology. It has been hypothesised that angiotensin II receptors may be expressed in dermal papilla cells — the specialised cells at the base of hair follicles that regulate growth — and that blocking these receptors could theoretically alter local signalling within the follicle. However, this mechanism is speculative, is not fully established in peer-reviewed literature, and there is no definitive clinical evidence confirming a clear causal pathway between losartan use and hair loss.

Other antihypertensive drug classes have also been associated with hair loss through different proposed mechanisms. Beta-blockers, for example, are cited in dermatological literature (including PCDS and NICE CKS guidance on alopecia) as a recognised cause of drug-induced hair loss, thought to involve adrenergic receptor pathways. ACE inhibitors — another class acting on the renin–angiotensin system — have similarly been linked to alopecia in rare cases.

Drug-induced hair loss is typically diffuse (affecting the whole scalp rather than discrete patchy areas) and in many cases improves after withdrawal of the causative agent, though timelines vary and full recovery is not guaranteed. This pattern differs from conditions such as alopecia areata or androgenetic alopecia, which have distinct presentations and underlying mechanisms. For further guidance on differentiating causes of hair loss, NICE Clinical Knowledge Summaries (CKS) on alopecia and the PCDS provide useful primary care resources.

What to Do If You Notice Hair Thinning on Losartan

Do not stop losartan without medical advice; instead, see your GP for a medication review and blood tests to exclude other causes such as thyroid dysfunction or iron deficiency.

If you are taking losartan and have begun to notice increased hair shedding, thinning, or changes in hair texture, the most important first step is not to stop your medication without medical advice. Losartan is often prescribed for serious cardiovascular or renal conditions, and stopping it without supervision may lead to a rise in blood pressure and worsened cardiovascular control.

Instead, arrange an appointment with your GP to discuss your concerns. Your doctor may:

• Review your medication history to identify whether the timing of hair loss correlates with starting losartan or a dose change

• Arrange blood tests to rule out other causes — initial investigations typically include a full blood count (FBC), ferritin (iron stores), and thyroid function (TSH); vitamin B12, vitamin D, and coeliac serology may also be considered depending on your history and examination findings

• Consider referral to a dermatologist if the pattern of hair loss is unusual, rapidly progressive, patchy (suggesting alopecia areata), involves eyebrows or eyelashes, or is accompanied by scalp changes such as redness, scaling, or scarring — features that may indicate a condition requiring specialist assessment, as outlined in NICE CKS guidance on alopecia

• Consider a supervised medication switch if losartan is deemed the likely cause and an alternative agent is clinically appropriate

You can also report suspected side effects directly to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk, which helps build the national evidence base for drug safety monitoring.

In many cases, hair loss that occurs during losartan treatment improves over time, even without changing the medication. Maintaining a balanced diet, managing stress, and avoiding harsh hair treatments can support overall hair health. Hair regrowth, even after a contributing factor is addressed, typically takes three to six months to become visible, and outcomes vary between individuals.

Alternative Blood Pressure Medicines and Hair Loss Risk

Calcium channel blockers (e.g. amlodipine) and thiazide-like diuretics (e.g. indapamide) are not prominently linked to hair loss and represent NICE NG136-recommended alternatives where a switch is clinically appropriate.

If your GP determines that losartan is likely contributing to hair loss and a change in medication is appropriate, it is helpful to understand the hair-related side effect profiles of alternative antihypertensive agents. It is important to emphasise that the primary goal of antihypertensive treatment is cardiovascular and renal protection; hair-related considerations may help guide the choice between equally suitable options, but should not override clinical priorities.

NICE guideline NG136 (Hypertension in adults: diagnosis and management) recommends the following approach to first-line treatment:

• ACE inhibitor or ARB for people aged under 55 who are not of Black African or African–Caribbean family origin

• Calcium channel blocker (CCB) for people aged 55 or over, or for people of Black African or African–Caribbean family origin at any age

• Thiazide-like diuretic if a CCB is not tolerated or is unsuitable (for example, due to oedema)

From a hair-loss perspective:

• ACE inhibitors (such as ramipril or lisinopril) act on the same renin–angiotensin system as losartan and have also been associated with rare cases of alopecia. Switching between an ARB and an ACE inhibitor may therefore not resolve the issue in all patients, and ACE inhibitors are not recommended alongside ARBs.

• Calcium channel blockers (such as amlodipine) are not prominently associated with drug-induced hair loss in dermatological literature, including PCDS guidance, and represent a commonly used alternative where clinically appropriate per NG136.

• Thiazide-like diuretics (such as indapamide) are another NICE-recommended option and are not prominently linked to alopecia, though individual responses vary.

• Beta-blockers (such as atenolol or bisoprolol) are cited in dermatological sources, including PCDS and NICE CKS, as a recognised cause of drug-induced hair loss — more frequently than ARBs. Switching to this class would therefore not be advisable if hair preservation is a concern, and beta-blockers are not recommended as routine first-line antihypertensives for uncomplicated hypertension under NG136.

Ultimately, the choice of antihypertensive should be guided by your individual clinical profile — including age, ethnicity, comorbidities, and tolerability — in line with NICE NG136 and BNF guidance. Your GP or a specialist hypertension nurse can help identify the most suitable option, balancing cardiovascular protection with quality-of-life considerations such as hair health.

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