Wegovy (semaglutide 2.4 mg) is a GLP-1 receptor agonist licensed in the UK for weight management in adults with obesity. Whilst hair loss is not listed as a common adverse effect in the MHRA Summary of Product Characteristics, some patients report increased shedding during treatment. This typically relates to rapid weight loss triggering telogen effluvium rather than the medication itself. Understanding the mechanisms, prevention strategies, and treatment options helps patients manage this temporary concern whilst achieving their weight management goals safely and effectively.

Why Does Wegovy Cause Hair Loss?

Wegovy (semaglutide 2.4 mg) is a glucagon-like peptide-1 (GLP-1) receptor agonist licensed in the UK for weight management in adults with obesity or overweight with weight-related comorbidities. According to the Medicines and Healthcare products Regulatory Agency (MHRA) Summary of Product Characteristics and European Medicines Agency (EMA) assessment reports, hair loss is not listed as a common adverse effect of Wegovy. However, some patients report increased hair shedding during treatment. It is important to understand that there is no official direct link established between semaglutide and hair loss, and the mechanism is not fully understood.

The most plausible explanation relates to the rapid weight loss that Wegovy facilitates rather than the medication itself. Significant caloric restriction and rapid weight reduction can trigger a condition called telogen effluvium, a form of temporary, diffuse hair loss where hair follicles prematurely enter the resting phase of the hair growth cycle. As described in the British Association of Dermatologists' patient information, this physiological stress response typically occurs two to four months after the triggering event, which may coincide with the period of most substantial weight loss on Wegovy.

Additionally, rapid weight loss can lead to nutritional deficiencies if dietary intake is not carefully managed. Inadequate protein, iron, zinc, biotin, and essential vitamins can compromise hair follicle health and contribute to increased shedding. The appetite suppression caused by Wegovy may inadvertently result in reduced nutrient intake if patients do not maintain a balanced, nutrient-dense diet despite eating smaller portions. Hormonal changes associated with significant weight loss may also play a contributory role, though this remains a theoretical mechanism requiring further research. Understanding these potential mechanisms helps inform preventative strategies and reassures patients that hair loss, when it occurs, is typically temporary and reversible.

How Common Is Hair Loss with Wegovy Treatment?

Hair loss is not documented as a common adverse reaction in the Wegovy Summary of Product Characteristics (SmPC) as published by the Medicines and Healthcare products Regulatory Agency (MHRA), nor in the European Medicines Agency (EMA) European Public Assessment Report (EPAR). The clinical trials that supported Wegovy's approval enrolled thousands of participants, but alopecia was not identified as a common adverse event in the published safety data. This suggests that if hair loss occurs, it may affect a relatively small proportion of users and may not be directly attributable to the medication itself.

However, post-marketing experiences suggest that some individuals do experience increased hair shedding whilst taking Wegovy. The true incidence remains difficult to quantify, as hair loss may be multifactorial and not always reported to healthcare professionals or regulatory bodies. It is worth noting that similar reports have emerged with other weight loss interventions, both pharmacological and surgical, reinforcing the hypothesis that rapid weight reduction rather than the specific medication is the primary factor.

Telogen effluvium associated with weight loss typically affects a minority of individuals and is generally self-limiting. According to NICE Clinical Knowledge Summaries, most people who experience this type of hair loss will see regrowth within six to twelve months once the triggering factor resolves and nutritional status is optimised. The absence of hair loss as a documented common adverse effect in the SmPC should provide reassurance, though individual experiences may vary. Patients concerned about hair changes should discuss these with their prescribing clinician to ensure appropriate assessment and exclude other potential causes of alopecia unrelated to Wegovy treatment.

If you suspect your hair loss may be related to Wegovy, you should report this through the MHRA Yellow Card Scheme, which helps monitor the safety of medicines and identify new side effects.

Preventing Hair Loss While Taking Wegovy

Preventing hair loss during Wegovy treatment centres on maintaining optimal nutrition despite reduced appetite and ensuring gradual, sustainable weight loss. Patients should prioritise adequate protein intake, aiming for approximately 1.0 to 1.2 grams per kilogram of ideal or adjusted body weight daily, as protein is essential for hair follicle structure and function. High-quality protein sources include lean meats, fish, eggs, dairy products, legumes, and plant-based alternatives. Even with smaller meal portions, focusing on nutrient-dense foods helps maintain the building blocks necessary for healthy hair growth, as outlined in the NHS Eatwell Guide.

Ensuring sufficient micronutrient intake is equally important. Iron deficiency is a well-established cause of hair loss, particularly in premenopausal women, and rapid weight loss can exacerbate existing deficiencies. Foods rich in iron include red meat, poultry, fish, fortified cereals, spinach, and pulses. Vitamin C enhances iron absorption, so combining iron-rich foods with citrus fruits or vegetables can be beneficial. Zinc, B vitamins, and other micronutrients also support hair health and should be included through varied dietary sources.

Before starting supplements, it's advisable to have appropriate blood tests to identify specific deficiencies. If supplementation is clinically indicated, this should be done under medical guidance. Importantly, if taking biotin supplements, be aware that the MHRA has issued a Drug Safety Update warning that high-dose biotin can interfere with laboratory tests, including thyroid function tests and cardiac markers. Always inform healthcare professionals about any supplements you're taking before blood tests.

Patients may benefit from consultation with a registered dietitian who can provide personalised nutritional advice tailored to their reduced caloric intake whilst on Wegovy. Avoiding crash dieting or excessively rapid weight loss is advisable; a steady reduction of 0.5 to 1 kilogram per week is generally considered safe and sustainable. Adequate hydration, stress management, and gentle hair care practices—such as avoiding excessive heat styling, tight hairstyles, and harsh chemical treatments—can further protect hair during this period. Taking a comprehensive approach to nutrition and self-care significantly reduces the risk of experiencing hair loss whilst achieving weight management goals with Wegovy.

Treatment Options for Wegovy-Related Hair Loss

If hair loss develops during Wegovy treatment, the first step is to address any underlying nutritional deficiencies through blood tests arranged by your GP. A full blood count, serum ferritin, vitamin B12, folate, thyroid function tests, C-reactive protein (CRP), vitamin D, and zinc levels (if clinically indicated) can identify correctable causes. For persistent iron deficiency, coeliac disease screening may be appropriate. If deficiencies are detected, targeted supplementation under medical supervision can help restore normal hair growth. Iron supplementation, for example, may be recommended if ferritin levels are low, though this should only be taken when clinically indicated as excessive iron can be harmful.

For telogen effluvium specifically, the mainstay of management is reassurance and time, as this condition is typically self-limiting according to NICE Clinical Knowledge Summaries. Once the triggering factor—in this case, rapid weight loss—stabilises and nutritional status improves, hair follicles gradually return to their normal growth cycle. Regrowth usually becomes noticeable within three to six months, with full recovery taking up to a year. Maintaining optimal nutrition and managing stress can support this natural recovery process.

Topical minoxidil, available over the counter in the UK, is licensed for androgenetic alopecia but may be considered off-label for persistent hair thinning related to telogen effluvium. Evidence for its use in telogen effluvium is limited, and patients should discuss this option with a healthcare professional before starting treatment. Some patients find that using gentle, nourishing hair care products and scalp treatments provides symptomatic relief and improves hair appearance during the regrowth phase. Biotin supplements are widely marketed for hair health, but there is limited robust evidence supporting their efficacy in individuals without biotin deficiency, which is rare.

In cases where hair loss is severe, persistent beyond twelve months, or associated with scarring or patchy baldness, referral to a dermatologist may be appropriate, as recommended by the British Association of Dermatologists. These features suggest alternative diagnoses such as alopecia areata or scarring alopecias that require specialist assessment and management. Your GP can coordinate appropriate investigations and referrals based on clinical findings and the pattern of hair loss observed.

When to Seek Medical Advice About Hair Loss

Patients experiencing hair loss whilst taking Wegovy should contact their GP if the shedding is excessive, distressing, or accompanied by other concerning symptoms. Whilst mild, diffuse hair thinning consistent with telogen effluvium may not require urgent intervention, certain features warrant prompt medical assessment. These include sudden onset of patchy hair loss, which may indicate alopecia areata; scalp inflammation, scaling, erythema with pustules, or tenderness suggesting infection or inflammatory conditions; loss of eyebrows or eyelashes; and hair loss accompanied by systemic symptoms such as fatigue, weight changes beyond expected Wegovy effects, or mood disturbances that might indicate thyroid dysfunction or other endocrine disorders.

According to NICE Clinical Knowledge Summaries, it is also important to seek medical advice if hair loss persists beyond twelve months despite nutritional optimisation, as this timeframe exceeds the typical recovery period for telogen effluvium. Additionally, if you notice changes in hair texture, such as increased brittleness or changes in nail quality, this may suggest nutritional deficiencies requiring investigation. Women who experience hair loss alongside menstrual irregularities should discuss this with their healthcare provider, as hormonal factors may be contributing.

Your GP can perform a thorough clinical assessment, including examination of the scalp and hair distribution pattern, and arrange appropriate blood tests to exclude underlying medical conditions. They can also review your overall response to Wegovy, assess whether the benefits of continued treatment outweigh concerns about hair loss, and discuss alternative weight management strategies if necessary. In most cases, reassurance and nutritional support are sufficient, but individualised medical advice ensures that any significant underlying pathology is not overlooked.

If you suspect your hair loss may be related to Wegovy, report this through the MHRA Yellow Card Scheme, which helps monitor medication safety. Patients should never discontinue Wegovy without consulting their prescribing clinician, as abrupt cessation may lead to weight regain and loss of metabolic benefits. A shared decision-making approach, weighing the substantial health benefits of weight loss against the temporary and usually reversible nature of hair shedding, helps patients make informed choices about continuing treatment whilst addressing their concerns about hair health.

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