Semaglutide or tirzepatide medications, better known as brand names like Ozempic, Mounjaro and Wegovy, are used as treatments for type-2 diabetes or obesity. As they become more widespread as a weight management tool, there have been ever increasing reports of users experiencing hair loss as a side effect.
Some evidence points to hair loss as a possible effect of these medications, while others say completely the opposite: they could actually be beneficial for hair growth.
We’ll get into the different theories and what the existing clinical evidence says about each. But here’s the big picture: healthcare providers are emphasizing the need for more research so patients can be properly informed about potential side effects, including hair loss, and so any issues that pop up during treatment can be addressed in the right way.
How do weight loss medications work?
Semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro) belong to a class of medication called Glucagon-like peptide-1 (GLP-1) agonist(GLP-1 RAs). They imitate a naturally occurring hormone to lower blood sugar levels in patients, helping them feel less hungry and digest food more slowly, which aids weight loss as people tend to eat less.
How common is hair loss from weight loss medications?
Not common enough to be included in the patient safety leaflet for Ozempic or Wegovy, though it is listed as a ‘common’ side effect (may occur in up to 1 in 10) of Mounjaro. However, as the use of these medications becomes more widespread, reports of hair loss associated with their use are becoming louder on social media.
Most studies look at the incidence of adverse events which affect patient’s quality of life or adherence to the medication (like vomiting and diarrhoea) and might overlook hair loss.But hair loss can be tough to deal with and shouldn’t be brushed off by prescribers as unimportant.
So far, a few studies have looked specifically at hair loss as an adverse event linked to the use of semaglutides or tirzepatide for weight loss. A systematic review in 2025 of five studies, taking into account a total of 2905 patients using weight loss medication, found mixed outcomes. Three of the studies suggested these medications had a positive effect on hair growth, while two reported hair loss as an adverse event associated with their use. And in a large clinical trial of more than 2,000 Wegovy users, three percent experienced hair loss compared with one percent of the placebo group. Although not definitive, these findings suggest that hair shedding does occur in a subset of patients.
Telogen effluvium
One of the most common culprits behind sudden hair shedding is telogen effluvium, a temporary form of hair loss triggered by significant stress on the system. This kind of “shock loss” can be set off by illness, childbirth, surgery… or yes, rapid weight loss.
Because GLP-1 RA medications often lead to dramatic drops in weight, the stress of this on the body can disrupt the hair cycle. This theory is supported by a study, which found that Wegovy users who lost more than 20% of their body weight reported more hair loss than those who lost less.
Another key trigger for telogen effluvium is nutrient deficiency. Since these medications reduce appetite, some people end up eating too little to meet their daily nutritional needs, especially if they’re also dealing with side effects like nausea or vomiting. GLP‑1 medications don’t prevent nutrient absorption, but they do make it easier to under‑eat, which can lead to low levels of vitamins and minerals important for hair growth (like iron, biotin, and zinc.
This is why researchers are calling for better nutritional support for people using GLP‑1 RAs. Patients undergoing bariatric surgery (aka gastric sleeves or bands), who lose weight at similar rates, receive close monitoring and detailed micronutrient guidance. GLP‑1 users typically don’t, even though their needs may be similar when food intake drops significantly.
Hormonal changes
Some early evidence suggests weight loss injections might actually help reverse hair loss. A case report of a man who used tirzepatide for a year and saw increased hair density within six months. The idea behind this improvement is the role weight loss drugs play in improving conditions linked to hair loss, like obesity and insulin resistance. So, while reports like this are interesting, they’re far from conclusive.
On the other hand, some think the impact of GLP-1 agonists on the hormonal cycle, particularly on the thyroid which is essential in regulating the hair cycle, could negatively impact the proper functioning of the hair cycle and lead to hair loss. Potentially, they could increase the chances of androgenetic alopecia (male pattern baldness), which may persist even after discontinuation.
Again, more robust trials are required to provide clinical evidence to support these hypotheses, before any definitive conclusions can be drawn.
Is hair loss permanent?
If hair loss is caused by telogen effluvium, it is unlikely to be permanent.
Once the underlying trigger is corrected, hair growth tends to resume as normal. It could take up to 6 months for hair to start regrowing, and even longer for the regrowth to become noticeable. So, once nutritional deficiencies are addressed by eating a balanced diet, and your body adjusts to weight loss, your hair should start growing again as normal.
How to avoid hair loss with weight loss injections
As the medications themselves aren’t thought to cause hair loss, it may be possible to reduce your chances of losing hair by being mindful of the following:
Lose weight slowly and steadily
Hair loss is more common on higher doses and with drastic reductions in body weight. It might be tempting to lose weight as quickly as possible, but losing weight gradually is better for your overall health and reduces the risk of losing hair. Avoid extreme calorie restriction.
Speak to a medical professional
Always follow the guidance of your prescriber. Regular check-ins are essential for monitoring side effects and weight loss and adjusting your dosage accordingly.
Pay attention to what you’re eating
When appetite is low, nutrient-dense foods become especially valuable because they provide key vitamins and minerals even when portions are small. This supports not only hair health but also energy levels and overall wellbeing. And if you’re struggling to meet your nutrient needs through food alone, adding a high‑quality supplement can help fill the gaps.
Source List
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