Can a Vegetarian Diet Cause Hair Loss?

A vegetarian diet does not directly cause hair loss. However, a poorly planned one can create nutritional gaps that disrupt the hair growth cycle and trigger diffuse shedding. The good news is that once you identify and correct the deficiency, hair typically recovers.

Why nutritional deficiencies hit hair follicles first#

Hair follicles are among the most metabolically active tissues in your body. They need a steady supply of micronutrients, amino acids, and energy to cycle through their growth phases. When intake falls short, your body directs resources to vital organs first. Hair production gets deprioritised, and follicles shift prematurely into their resting phase. The result is telogen effluvium (diffuse shedding), which typically appears 2 to 3 months after the nutritional shortfall begins.

This delay is one reason people often don't connect the shedding to their diet. They changed their eating habits months earlier and assume the problem must lie elsewhere.

The nutrients most likely to be low#

Most vegetarian diets are rich in fruit, vegetables, and wholegrains. What they can fall short on are nutrients that are concentrated in meat and fish. Four are particularly relevant to hair.

Iron#

Iron deficiency is the most common nutritional cause of hair loss in the UK, and vegetarians are at higher risk because plant foods contain non-haem iron, which is absorbed far less efficiently than the haem iron found in red meat. Phytates in wholegrains and legumes can reduce absorption further.

A useful practical step: eat iron-rich plant foods alongside a source of vitamin C. Studies show vitamin C can increase non-haem iron absorption — under realistic dietary conditions, research suggests a 2 to 3-fold improvement is achievable, though the effect varies depending on the meal composition and the amount of vitamin C consumed. Pair lentil soup with a squeeze of lemon, or eat spinach alongside red pepper.

For hair health specifically, some evidence suggests that serum ferritin (stored iron) below 30 mcg/L may be enough to impair the hair cycle, even when haemoglobin is still normal — though it is worth noting that this threshold varies across studies and is not a universally agreed clinical cut-off. NHS labs typically flag ferritin only when it drops below 15 mcg/L, so you can have a meaningful deficiency for hair purposes without being formally anaemic. It is worth asking your GP for a specific ferritin result, not just a full blood count.

Vitamin B12#

B12 is found almost exclusively in animal products. Vegetarians who eat eggs and dairy regularly may get adequate amounts, but those who avoid these foods are at real risk. B12 deficiency develops slowly because the body stores it for years, but once it sets in, it affects cell division throughout the body, including in hair follicle matrix cells.

Vegans face a higher risk than lacto-ovo vegetarians and should supplement B12 directly, as fortified foods alone are often insufficient.

Zinc#

Zinc supports the proteins that make up each hair strand. Vegetarian diets tend to be lower in zinc because plant sources (pumpkin seeds, hemp seeds, legumes) contain phytates that bind to zinc and reduce how much you absorb. Low zinc is associated with telogen effluvium and, in severe cases, a moth-eaten pattern of scalp hair loss.

Vitamin D#

Vitamin D deficiency is extremely common in the UK. The government recommends that everyone supplements 10 micrograms daily from October to March, and many people remain deficient year-round. Vitamin D receptors are present in hair follicle cells, and research links low vitamin D to impaired follicle cycling. It is not a dramatic cause of hair loss on its own, but it is a relevant contributor, particularly during UK winters.

Protein#

Hair is made almost entirely of keratin, a protein. Vegetarian diets that rely heavily on carbohydrates and are low in legumes, dairy, eggs, or soy can fall short on total protein intake. Aim for a varied protein intake across the day.

A practical food source guide#

Getting tested: which blood tests to ask for#

If you are noticing increased shedding, ask your GP for a specific panel rather than just a general health check. The tests most relevant to hair loss in vegetarians are: serum ferritin, full blood count, vitamin B12, folate, vitamin D (25-OH), and TSH (thyroid stimulating hormone, to rule out thyroid dysfunction, which can cause identical symptoms).

Some GPs will run the full panel; others may need prompting. If access is difficult, private testing services like Medichecks offer a combined deficiency panel for around £70 to £100, which can be useful if you want results quickly.

If your ferritin is low, your GP can prescribe iron tablets on the NHS. Over-the-counter ferrous sulfate is also available from most pharmacies and can be a cost-effective option while you wait for an appointment — speak to the pharmacist, who can advise on the appropriate dose and formulation for your situation.

What to expect once deficiencies are corrected#

Hair regrowth after correcting a nutritional deficiency is slow. Shedding typically continues for 4 to 6 weeks after you start treatment, because follicles already shifted to the resting phase will still shed. New growth becomes visible at around 3 months, and meaningful density improvement takes 6 to 12 months. Patience is essential, and serial ferritin tests every 3 months can help confirm you are on track.

Is your hair loss definitely dietary?#

Not all hair loss in vegetarians is down to nutrition. Male pattern baldness (androgenetic alopecia) is driven by genetics and the hormone DHT, not diet. It produces a characteristic pattern of recession at the temples and crown, rather than the diffuse, all-over shedding typical of telogen effluvium. Thyroid conditions, scalp disorders, and significant life stress can also cause shedding that overlaps with nutritional hair loss.

If your shedding is patterned rather than diffuse, or if blood tests come back normal, the cause is likely not dietary. For men with pattern hair loss, clinically proven treatments are available at Totiva's hair loss service (currently available for men only).

Should you take a hair supplement?#

Many hair supplements are built around biotin (vitamin B7). Biotin deficiency is genuinely rare, and there is no good evidence that supplementing it helps hair growth in people who are not deficient. It is also worth being aware that high-dose biotin (typically above 5 mg per day) can interfere with thyroid and troponin blood test results — an MHRA-flagged safety concern. Most hair supplements contain doses well below this level, but it is worth checking the label and informing your GP or pharmacist if you are taking biotin before having blood tests.

The supplements worth considering as a vegetarian are vitamin D (10 mcg daily as a minimum), vitamin B12 if you are vegan, and iron or zinc only if a blood test confirms you are low. Targeted supplementation based on tested deficiencies beats a broad-spectrum hair pill every time.

FAQs#

How long does it take for hair to grow back after fixing a deficiency? Expect shedding to slow within 6 to 8 weeks of correcting the deficiency, with new growth visible at around 3 months. Full density recovery takes 6 to 12 months. Retest your levels at 3 months to confirm they are improving.

Does going vegan carry a higher risk than being vegetarian? Yes. Vegans have a strictly higher risk of B12 deficiency because they avoid all animal products, including eggs and dairy, which are reliable vegetarian B12 sources. Vegans should supplement B12 directly, as the NHS also advises. Vitamin D3 supplements for vegans need to be derived from lichen rather than lanolin, so check the label.

Can stress make diet-related hair loss worse? Yes. Stress and nutritional deficiency can both independently trigger telogen effluvium, and they compound each other. People who change their diet during a stressful life period, such as moving house, a new job, or illness, are at higher combined risk. Addressing both where possible gives the best outcome.