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Over the past year we’ve seen a marked rise in clients contacting Opti Laboratories with concerns about thinning eyelashes or eyebrows after starting weight-loss injections such as Wegovy, Ozempic or Mounjaro. While these medications have been genuinely life-changing for many people, a small number of users do report unexpected changes in their hair health including their lashes and brows.
Although this can be worrying, the good news is that most cases are temporary, reversible, and linked to factors that can be addressed.
In this article, I will explain what the latest research shows, why lash and brow shedding can occur, and what steps you can take to protect your eyelashes and eyebrows during GLP-1 therapy.
Drugs like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro) promote rapid, and in some cases dramatic, weight reduction. While this is often what is sought, there can be downsides. Rapid weight loss is known to cause nutrient deficiencies, systemic stress or alterations to hormone levels.
These factors working together can disrupt the normal hair growth cycle. This is most often seen as telogen effluvium which is a temporary, non-scarring form of hair loss that affects the scalp and, in some cases, the eyebrows and eyelashes.
No. In almost all cases it is temporary and reversible. If the cause of any imbalance is found and corrected, lashes and brows often begin to recover within 2 to 3 months, but full regrowth can take 6 months without any assistance.
There have been recent studies trying to quantify the effect of weight loss injections on hair loss.
A study published in the Journal of the American Academy of Dermatology (September 2024) explored whether semaglutide, under the brand Ozempic, might contribute to hair loss when used for weight reduction. Early clinical trials at higher doses (2.4 mg weekly) noted hair loss in about 3% of participants versus 1% with placebo.
This new analysis looked at real-world patient data from 78 different hospitals and clinics in America. The researchers found that:
A paper in the Journal of the European Academy of Dermatology (January 2025) looked at hair shedding in people using Ozempic or Mounjaro for both diabetes and weight loss. They analysed FDA reports from 2022 and 2023 to find that that reports of hair loss were more common than expected, at least compared to information from earlier clinical trials. The mechanism is still unclear. The paper highlights animal studies that suggest GLP-1 receptors are found in hair follicles, but also concede that it may be telogen effluvium secondary to the restricted nutritional state and the systemic stress from weight loss. The authors highlight that the overall risk appears low and good nutrition may help reduce the risk.
These findings suggest that Ozempic does not greatly raise the risk of hair loss for the average user, though certain individuals may still experience shedding during therapy.
A limitation is that it does not address the important question of whether weight loss injections accelerate hair loss that would have happened had the user not started the injections.
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The research findings reflect what we have seen with some of our clients.
One client had been using our service to grow her eyelashes and eyebrows for a number of years, then noticed that the results had started to weaken. She also noticed that her scalp hair had thinned a little. It turned out that she had recently started Mounjaro. She managed to improve her lashes again by taking a series of basic supplements to ensure that she was always getting the required micronutrients to support hair growth, as well as trying to maximise the nutrient load of the small meals she was having.
We had another client that was using Ozempic that noticed that her eyelashes and particularly her eyebrows were thinning. It turned out that there were some days in which she barely ate anything. The irregularity of food intake was likely to have been causing a great deal of stress to her body.
With both of these examples, some slight adjustments helped while still allowing for weight loss to occur.
These are before and after photos of real Opti Laboratories customers.
Low levels of nutrients such as iron, zinc, vitamin C, biotin or vitamin D significantly weaken hair follicles. When using weight loss injections it is possible to miss some of these key dietary requirements due to the reduced appetite.
Sudden changes can stress the body and this stress can push hair follicles prematurely into the shedding (exogen) phase of the hair cycle.
GLP-1 receptor agonists may influence thyroid and sex hormone balance, both important for hair growth. Evidence is still scanty. A 2024 review highlights that, although controversial, there is evidence that thyroid hormone levels can be altered by weight loss jabs. A recent review paper from November 2025 shows a rise in bioavailable testosterone, but drew no conclusions on free testosterone.
Inadequate protein or energy availability is one of the strongest triggers of hair loss, including lash and brow shedding.
You should always speak to your prescribing doctor if you experience:
▪️Sudden lash or brow thinning
▪️Patchy brow loss
▪️Scalp shedding that continues beyond 3 or 4 weeks
▪️Symptoms of thyroid imbalance (fatigue, cold intolerance, thinning outer eyebrows)
▪️Signs of nutrient deficiency
To help understand the underlying cause your doctor would want to ask you questions about your diet and any other changes to your lifestyle since starting the weight loss jabs. If you have a food diary then that could prove useful. The doctor may then arrange for tests. Depending on your symptoms and individual circumstance, these may include:
▪️Thyroid function tests
▪️Iron and ferritin levels
▪️Vitamin D levels
▪️Certain vitamin B levels
Our clinically proven, prescription strength growth treatment has been our gold standard treatment since we started in 2007.
Trusted by over 15,000 clients.
Each pack includes the treatment and the applicators, which lasts most people three months with careful usage.
Once any underlying medical or nutritional cause has been addressed, many people want to regrow their lashes and eyebrows.
Opti Laboratories are the eyelash and eyebrow growth experts.
Our clients include individuals recovering after:
▪️Thyroid related brow loss
▪️Chemotherapy related eyelash thinning
▪️Cosmetic over plucking
▪️Eyelash and eyebrow loss from radiotherapy
▪️Thinning eyelashes due to medications
However, we also help a lot of people that simply want longer eyelashes and thicker eyebrows too.
Based in the UK and led by a team of British doctors, we have helped thousands of clients since 2007.
We continue to innovate. Our award-winning daytime lash and brow serum, the first in the world to offer UV protection for lashes and brows, supports growth and helps protect fragile follicles during your recovery.
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