Does weight loss medication cause hair loss?

Reviewed by Dr Sabah Salman

How common is hair loss after losing weight?

Losing weight can be very good for your health. The benefits can include improved heart health, a reduced risk of developing type two diabetes, a better sex drive, and improved mental health. However, losing weight can also come with some unexpected side effects, such as hair loss.

Hair loss shouldn’t happen if you’ve only lost a few pounds, but it can sometimes be seen in people who have lost a lot of weight.

This article talks though the causes of hair loss during a weight loss journey. We also talk about hair loss and weight loss injections, and if there’s a link.

What causes hair loss after a large weight loss?

Extreme weight loss and/or crash diets

Extreme or rapid weight loss can cause temporary, and usually reversible, hair loss (telogen effluvium). This type of hair loss usually occurs after stressful events, such as illness or childbirth. It happens because the body prioritises essential functions over hair growth.

If your weight loss is unintentional, it’s important you talk to your doctor. Unintentional weight loss can be described as unexpected weight loss without changing your diet or exercise routine. It can be caused by a health condition, not getting the right nutrients, or a combination of things.

Nutrient deficiencies and calorie restriction

Some vitamin and mineral deficiencies can cause temporary hair loss (telogen effluvium),for example, a vitamin D deficiency or an iron deficiency. If you’ve not been getting enough nutrients when losing weight, your doctor might recommend changing your diet to make sure you’re getting what you need, and that you’re not ‘crash dieting.’ A supplement could also be an option.

If you’re on weight loss medication, it’s likely your appetite will have reduced. Because of this, it’s important you eat balanced and nutritious meals. Avoid ultra-processed foods and refined carbohydrates where you can.

Protein deficiency

A lack of protein in the diet can also cause telogen effluvium. If you’re not getting enough protein during your weight loss journey, this could be the reason you’re noticing some hair loss.

When trying to lose weight (with or without weight loss medication), make sure you’re getting some lean protein in your diet. As well as helping to prevent hair loss, protein will keep your energy levels up and maintain muscle mass. Good sources of lean protein include chicken without the skin and white fish.

Do weight loss injections cause hair loss?

Weight loss injections include Mounjaro® and Wegovy®. If you’re on weight loss medication and have noticed hair loss, this could be because you’re losing weight quickly. Rapid weight loss can cause temporary hair loss (telogen effluvium) as an indirect side effect of treatment.

Wegovy® studies

A Wegovy® study reported that 3% of adults experienced hair loss. However, only 1% experienced hair loss when taking a placebo (a ‘fake’ treatment). Hair loss is currently listed a side effect in the patient information leaflet.

Mounjaro® studies

Hair loss is also listed in Mounjaro®’s patient information leaflet as a side effect. In a study, around 5% of patients reported hair loss using a 5 – 15mg dose. This is compared to less than 1% using a placebo.

Will hair loss during weight loss treatment be permanent?

It’s unlikely to be permanent. Hair loss caused by rapid weight loss is usually a temporary side effect. Telogen effluvium is likely to get better on its own over a few months.

To support hair growth, make sure you:

• Eat a balanced diet
• Practice gentle hair care
• Manage stress  

Hair loss treatment during your weight loss journey

If you’re worried about hair loss, you should talk to your GP. You can also start an online consultation from our men’s hair loss or women’s hair loss clinics. If suitable, our clinicians will prescribe medication.

If your hair loss is due to weight loss, biotin capsules could be an option. Biotin capsules (for men and women) are daily vitamins. They can be effective if your hair loss is due to a biotin (vitamin H or B-7) deficiency, which is often the case when losing weight.

References

https://www.nhs.uk/conditions/unintentional-weight-loss/ 
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5315033/
https://www.drugs.com/medical-answers/ozempic-wegovy-mounjaro-cause-hair-loss-3575019/
https://www.medicines.org.uk/emc/files/pil.15481.pdf
https://www.bad.org.uk/pils/telogen-effluvium/