Do weight loss injections cause hair shedding?

An increasing number of clients are seeking advice from us due to hair shedding while taking Glucagon-like Peptide (GLP)-1 weight loss injections.

Is hair shedding or thinning a side effect of Wegovy, Saxenda and Mounjaro medications? The short answer is no – it is a more complex picture.

The Evidence

There are many research studies – past and ongoing – of people using GLP-1 injections either for its initial purpose of controlling diabetes, or the more recent application for weight loss.

Studies can be conflicting – one suggesting they may disrupt normal hair follicle cycles, another suggesting they improve insulin sensitivity and enhance scalp blood flow.[1]

Weight loss and hair loss

What does GLP-1 research tell us about its impact on our hair? It confirms there is a correlation, but not necessarily the cause. Most of these studies exist to understand and analyse medication without necessarily analysing each side effect.

Other weight loss programmes not involving GLP-1 injections can also report hair health concerns.

Is it only rapid weight loss that affects hair?

So, is it the amount of weight lost in a specific period? Again, the short answer is no. There is evidence to show that rapid weight loss can also cause changes in the hair, but what is the cause? For each individual, there may be different reasons, and that is the most fundamental question to answer.

Nutrition and hair

A lack of specific nutrients can affect the hair’s growth cycle. See our article here.

For example, low levels of iron, zinc, vitamin D, or protein can all impact hair health.

When trying to lose weight, portions are often reduced, and meals, especially breakfast, can be skipped. These changes can lead to a drop in the nutrients your body absorbs, which may affect your hair.

Should you take supplements? The short answer is not necessarily. It is always best to start with a balanced, nutrient-rich diet. But it is also important to be aware that you may already have deficiencies, some of which could be contributing to hair thinning or loss.

A good place to start is by making sure you don’t skip breakfast. Aim for a protein-rich meal and stay well hydrated throughout the day.

Dr. Jack Moseley has also written a comprehensive book on the impact of weight loss injections on diet and nutrition.[2] He highlights that not everyone taking weight loss medication has a BMI level of over 27 or 30, and that many people are already starting with poor macronutrient levels due to highly processed diets. He also notes that without regular exercise, weight loss can often lead to a loss of muscle mass, not just fat.

This has been emphasised in a 2025 cross-sectional study that showed how patients on GLP-1 were not meeting the daily recommended MyPlate fruit, vegetables, grains, or dairy servings. In addition, they were not meeting adequate protein needs to support lean mass during weight loss. By intake frequency, vitamin D, potassium, choline, magnesium, and iron had the most significant deficits.

So is it all about nutrients?

Nutrients play a key role in the side effects of weight loss, but the short answer is no. While changes in hair health during weight loss may be coincidental, there may be an underlying reason associated with another factor—sleep, stress, other medication, an emerging health condition, or genetics.

This is one reason why we offer genetic hair consultations for specific hair conditions, as they can provide unique insight into your genetics and how we can personalise treatment plans.

What can I do to improve my hair health while I am on GLP-1?

You have made the first step in investing in your general health by committing to your GLP-1 treatment, so before you accept sacrificing your hair health, continue this investment with an initial consultation with one of our professionally trained trichologists. We see many clients anxious about their hair, and we undertake a detailed health review before diagnosing your condition and giving you a personalised treatment pathway that considers your hair, scalp, and health recommendations.

If you have not had any recent blood tests, we can organise those for you before your consultation, giving you a comprehensive understanding of how to address changes in your hair without stopping your weight loss programme. Simply book the Root Cause Clinical hair health blood test 14 working days in advance, which allows you time to get your blood tested beforehand. See our article here.

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Glucagon-like peptide-1 receptor agonist medications and hair loss: A retrospective cohort study. Burke, Olivia et al. Journal of the American Academy of Dermatology, Volume 92, Issue 5, 1141 – 1143, May 2025

Desai, D.D. ∙ Sikora, M. ∙ Nohria, A. GLP-1 agonists and hair loss: a call for further investigation Int J Dermatol. 2024; 63:1128-1130

Dr Jack Moseley – Food Noise, 2025

Johnson B, Milstead M, Thomas O, McGlasson T, Green L, Kreider R and Jones R (2025) Investigating nutrient intake during use of glucagon-like peptide-1 receptor agonist: a cross-sectional study. Front. Nutr. 12:1566498. doi: 10.3389/fnut.2025.1566498