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Hair Loss on a low carb and keto diet

Hair loss is a common issue that comes up frequently for people who are losing weight following a ketogenic diet or a low carb lifestyle

So, let’s talk about the causes - the actual causes, not the Facebook opinions!

  1. Telogen Effluvium. (TE)

The most common cause of hair loss on a low carb or ketogenic diet is a process called Telogen Effluvium. (TE)

To understand this process, we need to know how hair works.

Hair growth follows a cycle. Every hair is at a different phase and this is random throughout our whole scalp.

Each hair follicle goes through these three phases

  1. Anagen: actively growing hair this is 4-6 years for scalp hair
  2. Catagen: in-between phase of 2–3 weeks when growth stops and the follicle shrinks,
  3. Telogen: resting phase which lasts 1–4 months

The majority of our hair is in the growing phase. (Anagen)

So, at any one time, you will have hair in the growing phase, the in-between phase and then the resting phase.

At the end of the resting phase, the hair is shed and new hair grows. It is normal to shed about 100 hair a day.

However, a significant shock to the system moves the hair from the growing phase to the resting phase. Meaning we have more hairs in the resting phase. 2-3 months after the shock all the resting hairs begin to shed, so instead of losing 100 hairs a day, we can lose up to 500.

Significant shocks include rapid weight loss in any form, whether this is keto, low carb, weight loss surgery or the new weight loss medications such as Ozempic, Saxenda and Wegovy. They can all cause Telogen Effluvium.

Hair loss from Telogen Effluviam comes in big clumps. Hairbrushes are full, and drain holes get clogged.  

Other causes of TE include

  • Childbirth
  • Illness with a fever
  • Surgical operations
  • Accidents
  • Psychological stress
  • Long haul flights with jetlag

The condition is usually self-limiting meaning that when the stressor is removed, the hair growth returns to its natural state. This can take 6-9 months for hair thickness to return to pre-shock levels.

  1. Protein Deficiency.

This is actually quite rare There are many companies selling supplements to help with hair loss, praying on our insecurities around hair loss. Hair loss from protein deficiency requires severe protein deficiency seen in people that are starving. That being said, at Real Life Medicine, we like to prioritise protein in our diet as it is the building block of so many of our biological processes and has the highest satiety factor (meaning it keeps you full for longer!)  Collagen is a form of protein and is used extensively throughout our body to make skin, bone and cartilage. There are many products/supplements that claim to prevent or improve hair loss with collagen. However, if you are eating meat, fish chicken skin, and bone broth along with Vit C containing foods such as leafy greens, then you won’t need a collagen supplement.

  1. Vitamin and Mineral Deficiencies

If you are following a low carb real food diet using our build a plate formula, you are unlikely to have vitamin deficiencies with the exception being Vitamin D

Vitamin D.

Vit D deficiency is common in temperate climates due to a lack of sun exposure. It is also common in obesity, insulin resistance and those women with lipoedema. Vitamin D is thought to have a role in hair cycling. There seems to be an increased risk of Telogen Effluvium in people with low Vitamin D. Link to Vit D blog

Iron Deficiency

This is a cause of hair loss, though usually not due to a low carb or ketogenic diet. The best form of iron that our body absorbs more easily is found in red meat. Iron deficiency is common in women with heavy periods, pregnant women, vegetarians and non-red meat-eaters. It is important to get iron levels checked. If they are severely low, investigation of the cause and supplementation may be necessary


Zinc deficiency is rare but can lead to hair loss. Zinc deficiency is uncommon in people eating a low carb or keto diet. The highest forms of zinc are found in oysters, red meat and poultry all of which are eaten on a low carb real food diet.


Biotin is also known as Vit B7, B8 or Vitamin H. It is a very popular supplement to take for hair loss but there is no evidence that supplementing people with normal biotin levels is at all helpful in hair loss. It is often advised by people in FB groups to take biotin but it’s also important to note that biotin alters the results of many pathology tests, especially thyroid tests.

Biotin is readily available in our diet and found in eggs, nuts and legumes. It is also made by bacteria in the large bowel. People at risk of biotin deficiency are pregnant and breastfeeding women, people with gastrectomies and colectomies, and severely malnourished people

  1. Thyroid function

Both hyperthyroidism and hypothyroidism can cause hair loss. Neither of these is related to a low carbohydrate or ketogenic diet but both conditions are reasonably common. Hair growth returns when the underlying thyroid problem is corrected.

  1. Female and male pattern hair loss

These conditions are common and women can experience either male or female pattern hair loss. The causes are unknown but there is likely a genetic link and hormonal imbalance. These conditions can be managed but need an accurate diagnosis by medical doctors first. This often involves a visit to a dermatologist.

Neither of these conditions is related to a low carb or keto diet.

Treatment of hair loss on a low carb or keto diet

In summary, the most common cause of hair loss on a low carb or ketogenic diet is telogen effluvium (TE) which is caused by rapid weight loss. The vast majority of TE starts 2-3 months after the weight loss and will resolve by itself 6-9 months later.

Things you can do to minimise the risk of TE are to ensure your Vitamin D levels are normal. Ensure your diet is based on whole foods with good quality protein and vegetables. The slower the weight loss, the lower the risk of hair loss.

Unless you are deficient in particular vitamins and/or minerals, supplements are of no use and can cause you harm. The exception here is people with sleeve gastrectomies and other conditions that cause malabsorption.

Please don’t take advice from Facebook forums. We know people are trying to help but honestly, sometimes their advice is harmful. The supplement industry is unregulated and can make misleading claims. In particular biotin and collagen are unlikely to help with hair loss, are expensive, and biotin interferes with pathology testing results.

If you are concerned about hair loss, please see your doctor for an accurate diagnosis and appropriate treatment.


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