Why losing weight can cause hair loss - and what to do about it

How rapid weight loss affects your hair

Beyond shedding pounds, rapid weight loss can also reduce muscle mass and bone density, and contribute to nutritional deficiencies if your diet isn't well balanced. What you might not realise, however, is that it can also lead to temporary hair loss.

With the rise of weight loss medicines, more people are losing weight faster than ever before. As a result, some may associate sudden hair shedding or thinning with these treatments. However, hair loss is thought to be linked to rapid weight loss itself, rather than the medications.

Sobia Qasim

How your diet can affect your hair health

During any weight loss journey, it's important to pay attention to the nutritional value of the foods you eat, not just their calorie content. While creating a calorie deficit can help you lose weight, your body still needs a wide range of vitamins, minerals, and other nutrients to function properly.

If your diet lacks these essential nutrients, you may lose weight but miss out on the nourishment your body needs to support everything from energy levels to muscle maintenance and healthy hair. That's why focusing on a balanced, nutrient-rich diet is just as important as reducing calories if your goal is to improve your overall wellbeing.

Qasim says that one of the biggest mistakes people make is underestimating how vital nutrition becomes during weight loss.

"The best way to reduce your risk is to make nutrition a priority from the start of treatment,” she explains. “Even if your appetite is reduced, it's important to eat enough protein and ensure you're getting key nutrients such as iron, zinc, vitamin D, and B vitamins - all of which are essential for healthy hair growth. Avoiding crash dieting and aiming for steady, sustainable weight loss can also help minimise shedding."

How to support healthy hair during weight loss

The good news is that there are ways to help reduce the impact of weight loss on your hair, even if you've already noticed some increased shedding.

Qasim explains that, in most cases, this type of hair loss is temporary. By continuing to nourish your body with enough calories, protein, and essential nutrients, your hair has a good chance of recovering over time.

She recommends the following tips to help reduce hair shedding during weight loss.

Prioritise protein and key nutrients

Hair is primarily made from protein, so ensuring you eat enough each day is essential for supporting healthy growth. It’s also important not to overlook nutrients such as iron, zinc, vitamin D, and B vitamins, which all play a role in maintaining healthy hair. If your appetite has decreased, try to make every meal count.

Focus on sustainable weight loss and gentle hair care

Rapid weight loss is more likely to trigger temporary shedding, so taking a slower, more sustainable approach can help reduce your risk. While your hair is more fragile, avoid excessive heat styling, bleaching, harsh chemical treatments, and tight hairstyles that can cause additional stress.

Know when to seek medical advice

Hair grows slowly, so recovery takes time, and it may be several months before new growth becomes noticeable. However, Qasim stresses not to dismiss persistent or severe hair loss as a side effect of weight loss, as this should be checked by a healthcare professional.

“These could point to an underlying condition such as iron deficiency, thyroid disease, or another nutritional deficiency that needs investigating,” says Qasim.

If you've noticed your hair thinning after losing weight quickly, there's no need to panic. In most cases, this type of hair shedding is short-lived. By following the advice above, eating a balanced, nutrient-rich diet, and keeping an eye out for any warning signs, your hair is likely to recover over time.