- Is there a link between weight loss and hair loss?
- Why does hair loss start weeks after weight loss?
- What causes hair loss during weight loss?
- Does Ozempic (semaglutide) cause hair loss?
- How much weight loss increases the risk of hair loss?
- Is hair loss due to weight loss temporary?
- How can you prevent hair loss during weight loss?
Hair loss during weight loss is more common than many people expect. If you notice hair loss when losing weight, you are not alone. Many people experience hair thinning and weight loss at the same time.
What makes this confusing is that hair loss does not usually happen straight away. In many cases, it starts weeks or even months later.
In most situations, this is caused by telogen effluvium. This is a temporary type of hair loss where the body reacts to a change, such as rapid weight loss, stress, or nutritional deficiencies (Malkud, 2015).
In practice, this often happens in people who lose weight quickly, for example after a strict diet or medical treatment. The good news is that, in many cases, this process is temporary and the hair will recover over time.
Is there a link between weight loss and hair loss?
Yes, there is a clear link between weight loss and hair loss.
Hair loss when losing weight is not a side effect, but a natural response of the body. When you lose weight, your body must adjust to these changes.
During this process, the body sets priorities. Essential functions continue as normal, but less important processes, such as hair growth, may slow down for a while.
Research shows that hair loss often happens after situations such as
- Changes in diet
- Surgery
- Illness
- Or physical stress (Malkud, 2015; Bariatric study, 2020).
This is why hair thinning and weight loss are often seen together. Hair loss when losing weight is therefore a normal, temporary response to the body.
Why does hair loss start weeks after weight loss?
Many people feel that their hair loss happens suddenly. However, there is almost always a delay between the cause and when the hair falls out.
This is due to the hair growth cycle, which has three main stages:
- The growth phase (anagen)
- The transition phase (catagen)
- And the resting phase (telogen).
In telogen effluvium, more hairs than usual move from the growth phase into the resting phase at the same time. These hairs do not fall out immediately, but around 8 to 12 weeks later (Malkud, 2015).
With this type of hair loss, the hair usually thins evenly across the scalp. It does not cause clear bald patches, but rather a general thinning of the hair.
This is how hair loss develops after weight loss:
- When you start losing weight, your body may experience stress or a lack of nutrients.
- As a result, hair stops growing earlier and moves more quickly into the resting phase.
- The actual hair loss only becomes visible a few months later.
In many cases, you may already notice changes in your body in the first few weeks or months, such as looser clothes or a slimmer appearance. Hair loss, however, tends to appear two to three months later. This is why many people do not immediately connect it to their weight loss.
What causes hair loss during weight loss?
Hair loss during weight loss is usually caused by a combination of factors, such as rapid weight loss, nutritional deficiencies, and stress in the body.
Rapid weight loss as a trigger
The speed of your weight loss plays an important role. Rapid weight loss is seen by the body as a form of stress. As a result, hairs can move more quickly from the growth phase to the resting phase.
This effect is clearly seen in bariatric surgery, a medical treatment for people with severe obesity. It is also known as weight loss surgery. Hair loss often becomes visible only a few months after the procedure (Bariatric study, 2020). Hair loss is common in this situation and clearly shows that rapid weight loss is an important trigger.
Nutritional deficiencies
During weight loss, you may develop deficiencies in important nutrients. The most important are:
- Protein: needed to build hair
- Ferritin (iron): important for healthy hair growth
- Zinc: supports the hair cycle
If your body does not get enough of these nutrients, hair growth becomes less of a priority (Almohanna et al., 2019).
Reduced intake and absorption (double mechanism)
With some types of weight loss, more is happening in the body. This can occur, for example, when using certain medications.
You may have a reduced appetite, which means you eat less. You may also experience digestive issues, also known as GI symptoms. GI symptoms are problems in your digestive system, such as:
- Nausea
- Bloating
- Diarrhoea
- Stomach pain
Because of these symptoms, you often eat less and your body may also absorb nutrients less effectively. This means two things are happening at the same time.
- You are taking in fewer nutrients, and your body is using the nutrients it does receive less efficiently.
- This increases the risk of deficiencies and, as a result, hair loss (Wilding et al., 2021).
In addition, it is important to know that during weight loss you do not only lose fat, but also muscle mass. This means the body has fewer building blocks available, such as proteins. Since hair is partly made up of protein, this can contribute to hair loss.
Long-term physiological stress
Weight loss can last for a long period of time. If your body receives less energy and fewer nutrients for weeks or months, it continues to adapt.
As a result, the body can enter a kind of “energy-saving mode”. The energy from food is used to keep essential functions working properly, while processes such as hair growth become less of a priority. Hair may stop growing sooner, which can cause hair loss to last longer. It may also take more time for your hair to recover.
In addition, nutrient deficiencies often continue over a longer period. This means the body has fewer building blocks available for new hair. As a result, hair loss may not only start later, but it can also take longer for your hair to grow back.
Does Ozempic (semaglutide) cause hair loss?
Ozempic is a medication that helps with weight loss. It belongs to a group of medicines known as GLP-1 receptor agonists.
GLP-1 is a hormone in your body that affects your appetite and digestion. Medications like Ozempic enhance this effect. As a result:
- You feel full more quickly
- You feel less hungry
- You eat less without trying
People who use this medication often lose a significant amount of weight, sometimes more than 10 to 15% of their body weight. Weight loss often starts within the first few weeks, while hair loss usually appears 2 to 3 months later. Because of this delay, many people do not immediately connect the two (Wilding et al., 2021).
It is important to know that hair loss is not a direct side effect. The cause is indirect. It mainly happens due to:
- Rapid weight loss
- Reduced food intake
- Changes in the body
The medication itself does not cause hair loss, but the effects it has on the body can lead to it.
How much weight loss increases the risk of hair loss?
Not everyone who loses weight will experience hair loss. However, the risk becomes higher when you lose a large amount of weight quickly over a short period of time. Research shows that hair loss is more likely when you lose around 10 to 15% of your body weight, especially if this happens rapidly (Wilding et al., 2021).
When using GLP-1 medication, such as semaglutide (Ozempic), this is not uncommon. In studies, 69% of participants lost more than 10% of their body weight, and around 50% lost more than 15% (Wilding et al., 2021).
This shows that large and rapid weight changes occur in many people. As a result, the risk of hair loss is more widespread than often assumed.
Is hair loss due to weight loss temporary?
In most cases, hair loss starts two to three months after you have lost weight. It may become slightly worse for a short time before it stabilises. Once the body returns to balance, the hair usually begins to grow again. This recovery process often takes three to six months (Malkud, 2015; Bariatric study, 2020).
However, it is important to understand that recovery does not happen automatically for everyone. If the underlying cause, such as nutritional deficiencies or ongoing stress, remains, hair loss may continue for a longer period.
How can you prevent hair loss during weight loss?
Hair loss during weight loss cannot always be prevented, but you can reduce the risk. The most important thing is to make sure your body continues to receive enough nutrients and is not put under too much stress too quickly.
By paying attention to your diet and the pace of your weight loss, you help your body stay in balance. This also supports healthy hair growth.
Make sure you get enough protein
Protein is an important building block for your hair. Hair is largely made up of keratin, which is a type of protein.
If you do not get enough protein, your body has fewer building blocks available for new hair. As a result, hair growth may slow down and hair loss can increase (Almohanna et al., 2019).
During weight loss, it is therefore especially important to eat enough protein, so your body continues to receive these essential nutrients.
Pay attention to iron (ferritin)
Iron plays an important role in hair growth. In the body, iron is stored as ferritin. If your ferritin levels are too low, this can affect the hair growth cycle. Hair may fall out more quickly or grow back less effectively (Almohanna et al., 2019).
Because iron deficiency is not always immediately noticeable, it may be helpful to have your levels checked if you are experiencing hair loss. You can contact your general practitioner for this.
Avoid extreme calorie restriction
Eating very little or losing weight too quickly can put the body under pressure. This is seen as a form of stress.
With extreme calorie restriction, the body does not receive enough energy and nutrients. As a result, less essential processes, such as hair growth, are temporarily reduced (Almohanna et al., 2019).
It is therefore better to lose weight slowly and gradually. This gives your body time to adjust and reduces the risk of hair loss.
When supplements can be useful
Supplements can help, but only if there is a deficiency. If your body is already getting enough nutrients, additional supplements usually have little effect on hair loss. They do not address the underlying cause (Almohanna et al., 2019).
It is therefore important to first look at your diet and any possible deficiencies. Supplements can then be a useful addition, but they are not a replacement for a good foundation.
Resources
Almohanna, H. M., Ahmed, A. A., Tsatalis, J. P., & Tosti, A. (2019). The role of vitamins and minerals in hair loss: A review. Dermatology and Therapy, 9(1), 51–70.
Courcoulas, A. P., et al. (2017). Weight change and health outcomes at 3 years after bariatric surgery among individuals with severe obesity. JAMA, 317(24), 2419–2429.
Malkud, S. (2015). Telogen effluvium: A review. Journal of Clinical and Diagnostic Research, 9(9), WE01–WE03.
Mechanick, J. I., et al. (2020). Clinical practice guidelines for the perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures. Endocrine Practice, 26(11), 1349–1415.
U.S. Food and Drug Administration (FDA). (2021). Ozempic (semaglutide) injection, for subcutaneous use: Prescribing information.
Wilding, J. P. H., Batterham, R. L., Calanna, S., Davies, M., Van Gaal, L. F., Lingvay, I., et al. (2021). Once-weekly semaglutide in adults with overweight or obesity. The New England Journal of Medicine, 384(11), 989–1002.
This information does not replace professional medical advice. If in doubt, always consult a doctor or specialist.
