Why Rapid Weight Loss May Lead to Hair Loss

If you’re on a weight loss journey, you may have experienced a little more hair shedding than usual. While this may feel concerning, it’s a common side effect of treatment and is often temporary. [1, 2]

In this guide, we’ll explore how weight loss and hair health are connected. We’ll break down the science, share what to expect as your body changes and give guidance on how to support your hair during treatment, and beyond.

Article Summary:

• If you lose a lot of weight during a short amount of time, you may experience hair loss. Fortunately, in most cases this is temporary and resolves itself once your body adjusts to your new weight.
• To minimize the risk of hair loss during weight loss treatment, we advise you to follow a “start low, go slow” approach to dosage increases. Steady, sustainable progress is the best way to support both your hair and your long-term weight loss goals.
• Positive lifestyle changes, like eating a nutrient-dense diet, may also support your hair health.

Can weight loss treatment cause hair loss?

Yes, taking certain types of weight loss medication may cause temporary hair loss. [1, 2] But it’s not the medication itself which triggers hair loss: it’s the effect the treatment has on your body.

You’re more likely to experience hair loss if you lose a lot of weight in a short amount of time. [1] This is because your body may interpret sudden, rapid weight loss as a sign of stress. And when your body detects stress, it may temporarily shift focus away from non-essential functions, like growing hair, to conserve energy. [3]

How can weight loss treatment cause hair loss?

Your hair growth works in cycles:

• Anagen (the growth phase)
• Catagen (a short transition phase)
• Telogen (the resting phase)
• Exogen (the shedding phase) [4]

Sudden weight loss may prematurely push a large number of hairs from the anagen (growth) phase into the telogen (resting) phase. [5] This leads to excess shedding a few months later. [6]

The medical term for this condition is “telogen effluvium” (TE).

Hair loss during weight loss treatment: what to expect

On average, we lose around 50-100 hairs from our head each day. [7] However, following rapid weight loss, you may find you shed more. Signs include:

• Increased shedding when you brush your hair, or run your hands through it
• Finding a lot more hair shedding than usual when you wash your hair
• More shed hairs on your pillow each morning
• You may also experience a type of scalp sensitivity called “trichodynia”. Symptoms include tenderness, burning and itching. If you experience any of these symptoms, we recommend you seek medical advice. [6]

TE may occur all over the scalp, which means you’re more likely to notice a general loss of hair volume and thickness than patches of hair loss. [8] And, because of the way that hair growth cycles work, you’re unlikely to notice TE right away. It may take 2-3 months after rapid weight loss to notice any impact on your hair. [6] Acute (non-chronic) TE lasts less than 6 months, but the actual shedding period is often much shorter. [3]

We understand that this side effect of treatment may be concerning for some. But the good news is that this type of hair loss is usually temporary, and your hair should start to grow back a few months later. [8]

5 ways to manage hair loss during weight loss treatment

While it’s not always possible to prevent temporary hair shedding during rapid weight loss, you can still take steps to care for your hair. In fact, you’re likely already practicing many of these healthy habits as part of your health journey.

Focus on steady, sustainable weight loss

When it comes to weight loss, a gentle, gradual approach is best. This is to reduce metabolic stress on your body. Aim to lose around 1-2lbs, or 0.5-1kg a week. [11]

And remember: your body is unique, and so is your weight loss journey. You may experience setbacks, and weight loss “plateaus” (where your weight loss slows or stops, even if you’re still making positive lifestyle choices). This is perfectly normal. Real progress comes from showing up in small but sustainable ways over time. Acknowledge the difficult days, and treat yourself with kindness when things don’t go as planned.

If you have any concerns about your weight loss, or any plateaus you may be experiencing, speak to your healthcare provider. They may be able to provide additional guidance, or adjust your treatment dosage.

Take extra care with your hair

Being gentle with your hair may not minimize TE itself, but it’s a good practice to carry forward. Try to:

• Massage your hair gently as you wash it, and pat it dry with a microfibre towel
• Limit your use of chemical treatments, like bleaching and perming
• Check the ingredients in the products you use. For example, shampoos with certain types of sulfates (like sodium lauryl sulfate (SLS)) may be harder on your hair. [12]
• Avoid tight hairstyles (like high ponytails) that pull on your hair’s roots, and limit your use of heated tools, like curling irons [8]

Optimize your nutrition

While it’s important to take care of our hair from the outside, nourishing it from within will also help. And one of the best ways to support your hair health is by focusing on the foods you eat.

Make sure your diet contains plenty of:

• Protein: Protein (specifically keratin) is the building block of hair. Eating protein-rich foods, high in amino acids, like eggs, salmon, quinoa, chicken and lentils, may support your hair from the inside-out. [13, 14]
• Iron and zinc: Deficiencies in iron and zinc have been linked to hair loss. [3] But research suggests that increasing your intake of these minerals may support healthier hair if you have a deficiency. [15, 16] Red meat (like beef and lamb) is high in zinc, while fortified cereals, soybeans and spinach are good sources of iron. [17] However, don’t take high-dose iron or zinc unless a clinician says you need them, as too much may be harmful. [15]
• B vitamins (like biotin): Research has shown that, if you’re deficient in biotin, taking supplements may support hair growth. However, most people don't need biotin supplements. [15]

Take time for your mind

Whether it’s physical or emotional, any type of stress may negatively affect your hair. [3, 18] And, while it’s sometimes easier said than done, practicing mindfulness and breathing exercises may help to manage any stress you’re experiencing. [19]

Chronic stress may also make it harder to lose weight, which is one of the reasons why supporting your mental wellbeing is such an important part of your weight loss journey. [20]

Drink plenty of water

Drinking enough water is good for your overall health. However, there’s no proof that drinking extra water makes hair grow faster.

But while staying hydrated doesn’t directly support hair growth, it does support other body functions which can. Drinking plenty of water each day helps to support your circulation, which moves essential nutrients through the body. [21] These include the nutrients required to support healthy hair follicles.

The exact amount of water you need to drink each day differs from person to person. [21] What matters is that you stay hydrated. To check if you’re drinking enough, Health Canada advises to watch out for these signs:

• Thirst: If you feel thirsty, or have a dry mouth, try sipping slowly on water.
• Urine: If your urine is dark yellow and smells strongly, you should drink some more water. If you also notice you’re not passing much urine during the day, and when you do it’s dark in colour, you may want to increase your water intake.
• Mood: If you feel tired, irritable or light-headed, have trouble concentrating or experience headaches, you may be dehydrated. [21, 22]

FAQs

Is hair loss from weight loss permanent?

No, fortunately, hair loss which occurs from weight loss is rarely permanent. And, once the underlying cause has been addressed, most of the time TE resolves itself without any treatment. [3, 6]

Should I stop treatment if I experience hair loss?

Hair shedding alone does not always mean you need to stop treatment. But speak to your clinician if you are worried, losing weight very fast or not eating enough.

If you do choose to stop your treatment due to hair loss, remember that the hair shedding won’t stop immediately.

When will my hair grow back?

Once the shedding period (which may last 3-6 months) is over, your hair will enter a new growth phase. [8] However, depending on how quickly your hair grows, it may take time before you notice your hair returning to its usual volume.

We understand that even temporary hair loss may be difficult to come to terms with. During this regrowth period, you may find hair fibre powders and volumizing shampoos support the appearance of thicker, fuller hair.

Will reducing my dosage strength help minimize hair loss?

While some studies have found more hair loss at higher doses, we don’t know for sure that lowering your dose will prevent it. [9] This is why we recommend a treatment pathway which focuses on a “start low, go slow” approach to dose increases. Gradual weight loss is less likely to “shock” the body and cause hair loss.

It’s also worth remembering that hair shedding often starts a few months after rapid weight loss. [6] So lowering the dose later may not stop shedding straight away. Your clinician can help you decide what is best for you.

What’s the difference between telogen effluvium (TE), androgenetic alopecia (AA) and alopecia areata?

“Telogen effluvium” is the medical term for hair loss which occurs after metabolic stress (like rapid weight loss), hormonal changes (like childbirth) or certain types of medication. TE is most often acute (short-lived and sudden), and resolves itself once the underlying cause has been addressed. [3]

“Androgenetic alopecia” (AA) is the medical term for male and female pattern hair loss. It’s caused by a combination of genetics and hormones. [10] Unlike acute TE, AA is a chronic (long-term) and progressive condition, which means it doesn’t resolve itself, and your head hairs gradually become thinner and shorter over time. [23]

As a side effect of weight loss, TE and AA are the most common types of hair loss. TE is most commonly associated with rapid weight loss. [9]

In some cases, TE may lead to an early diagnosis of AA. [8]

“Alopecia areata” is an autoimmune condition, where your immune system attacks your hair follicles. Hair loss may occur in round, oval patches on your scalp. People who live with autoimmune conditions like vitiligo and psoriasis are more likely to experience alopecia areata. [24]

Are women more likely to experience hair loss during weight loss than men?

Yes, research suggests that women are more likely to develop TE. [5, 9]. However, this may also be because women are more likely to navigate bigger hormonal shifts throughout life, like during menopause and after childbirth. [3]

When should I seek medical advice for hair loss?

Acute TE shouldn’t last any longer than 6 months. If you’re still noticing excess shedding after 6 months, we’d advise you to speak to a dermatologist. We also recommend seeking medical advice if you experience any itching, burning or tenderness in your scalp.

If you have any concerns about hair loss as a result of weight loss treatment, we’re here to support you. Whether you’re currently experiencing hair loss, or you’re considering treatment and would like to learn more about what to expect, our Clinical team can help you to find a treatment that is safe and appropriate for you.

Find out which treatment may be suitable for you with MedExpress.

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