Could Weight-Loss Medication Be Causing Your Hair Loss? Here’s What Experts Say

As the use of GLP-1 and other weight-loss medications continues to grow around the world, more people are reporting sudden hair loss during treatment.

However, experts say the medication itself is not always to blame.

According to Dr Kashmal Kalan, Medical Director at Alvi Armani, rapid weight loss is often the real trigger behind temporary hair shedding.

Why hair loss can happen during weight loss

Dr Kalan explains that when the body loses weight quickly, it prioritises essential functions over hair growth.

“Hair shedding during treatment isn’t always caused by the medicine itself. In many cases, it may be the body’s response to losing weight too quickly. Your body reacts as though food is scarce and thinks: ‘Hair isn’t essential. Let’s save energy’.”

Rapid weight loss, whether caused by GLP-1 medication, bariatric surgery, a very low-calorie diet or illness, can trigger temporary hair shedding.

Reduced food intake may also lead to nutritional deficiencies that affect healthy hair growth.

“Think of hair like a houseplant. If you don’t water it enough with the right nutrients, it grows poorly. It doesn’t necessarily die permanently but simply pauses its growth.”

More South Africans are using weight-loss medication

The issue is becoming increasingly relevant in South Africa as more people turn to prescription weight-management medication.

According to Discovery Bank and Visa’s latest SpendTrend report, 14% of surveyed higher-income South Africans use prescribed weight-management medication.

Clinical research has also found that GLP-1 medicines reduced energy intake on a controlled test day by nearly a quarter compared with a placebo, highlighting the importance of maintaining adequate nutrition when appetite decreases.

Looking beyond the medication

Dr Kalan says Alvi Armani is seeing more patients who assume their medication is directly responsible for sudden hair shedding.

Instead, consultations focus on understanding when the shedding started, how quickly weight was lost, whether eating habits changed and if another medical condition may be contributing to the problem.

Nutrient deficiencies may be the real cause

A review of nearly half a million adults receiving GLP-1 treatment found vitamin D deficiency in 7.5% of patients after six months, increasing to 13.6% after 12 months.

For this reason, Dr Kalan says blood tests should be the first step before reaching for supplements.

Routine investigations include vitamin D, vitamin B12, ferritin and thyroid function.

“Ferritin, the protein that stores iron, is one marker I monitor closely. A level below 30 ng/mL, generally considered indicative of low iron stores in adults, is often enough to cause shedding on its own, even though most labs still call that number normal. Most of these patients feel completely fine elsewhere, so there’s no reason for a routine GP visit to pick it up. By the time the hair’s already falling out, we go back and look for what that visit potentially missed.”

Don’t self-prescribe supplements

Some people turn to probiotics or gut-health supplements in the hope of stopping hair loss.

Dr Kalan says these products are only helpful when a diagnosed digestive condition is contributing to nutrient absorption problems.

“If someone has a diagnosed digestive condition, that’s worth treating, and probiotics may have a place. Outside of that, I’d rather see patients pursue tests that can identify what’s missing than a supplement with no clear indication, strain, or dose.”

When to seek medical advice

Dr Kalan advises anyone taking GLP-1 medication to seek medical advice if hair shedding continues for longer than three months, becomes noticeably worse or is accompanied by fatigue or other unexplained symptoms.

“These medications genuinely change lives for the right patient. If your registered health professional recommends continuation, stay on it. Just make sure your body is still getting what it needs.”

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