Metformin is a medication that doctors prescribe to treat type 2 diabetes and polycystic ovary syndrome. Some people have concerns that this drug may cause hair loss, but little evidence supports that claim.

Doctors typically prescribe metformin as a first-line treatment for people with type 2 diabetes. Alongside diet and exercise, metformin can help a person control their insulin and blood sugar levels.

Doctors sometimes also prescribe metformin for people with polycystic ovary syndrome (PCOS). Raised insulin and blood sugar levels are common symptoms of PCOS, and metformin can help reduce them.

In this article, we explore the possible relationship between metformin and hair loss, as well as relevant research. We also describe some of the treatment options for reducing the impact of hair loss if it does occur.

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Metformin may play an indirect role in hair loss.

On rare occasions, people have reported a link between metformin and thinning hair or hair loss. However, it is unclear whether metformin is directly responsible for this issue or if other factors play a role.

For example, a 2017 case report in Current Drug Safety described how a 69-year-old man with type 2 diabetes suddenly lost his eyebrows and eyelashes.

The man took a combination of metformin, and another diabetes medication called sitagliptin.

Doctors used clinical tests to rule out any systemic or skin diseases that might be contributing to hair loss. The authors of the report concluded that there was a possible association between the medication and hair loss.

However, as this case study involved just one person, it is difficult to move from these findings to a general trend suggesting a significant relationship between metformin and hair loss.

Metformin might also reduce the risk of hair loss in people who take it to treat PCOS, according to a randomized clinical trial from 2016.

As hair loss can be a symptom of PCOS, treating the condition can reduce its effects.

Another possibility is that metformin may indirectly contribute to hair loss in people with diabetes.

Research from 2016 suggests that taking metformin long-term can cause B-12 deficiency and anemia. Hair loss is a potential symptom of both of these conditions.

According to Dr. Jill Crandall, Professor of Medicine at Albert Einstein College of Medicine in New York, metformin might reduce the gut's ability to absorb vitamin B-12. This reduced absorption may explain why people experience symptoms of B-12 deficiency.

In addition to hair loss, other vitamin B-12 deficiency symptoms include:

  • depression
  • digestive issues, such as constipation or bloating
  • fatigue
  • irregular heartbeat
  • lightheadedness
  • loss of balance
  • memory loss
  • numbness or tingling of the skin
  • shortness of breath
  • vision loss
  • weakness

Mild deficiencies may not cause any symptoms.

A doctor may advise that people who are taking metformin should increase their intake of B-12-rich foods or take B-12 supplements to treat or prevent this deficiency.

Alternatively, they may recommend getting shots of B-12 that bypass the gut and enter the bloodstream directly.

Here, read about how to safely stop taking metformin.

Other potential causes of hair loss may relate to a person's medical condition rather than the use of metformin to treat it.

These include the following health problems.

High blood sugar

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High blood sugar can increase the risk of hair loss.

A buildup of sugar in the blood can damage blood vessels and organs throughout the body. Healthy blood vessels are necessary for transporting oxygen and nutrients to each part of the body, including the hair follicles.

If the hair follicles do not receive enough oxygen and nutrients, this can affect the growth of hairs. More hair may fall out, or new hair may grow at a slower rate than usual.

Type 1 diabetes can also increase the risk of a person developing alopecia areata. In people with this condition, the immune system mistakenly attacks the hair follicles, causing hair to fall out in patches.

People with type 2 diabetes often have insulin resistance, which means that the cells in their body do not respond to insulin appropriately.

One 2014 study reports a link between insulin resistance and a type of alopecia, or hair loss.

PCOS

Females with PCOS have abnormally high levels of androgens, which doctors refer to as male hormones. Occasionally, this hormonal imbalance can cause a type of hair loss. It may also cause excess facial hair and acne.

People with PCOS might also experience hair loss due to high levels of sugar in the blood.

Here, learn everything you need to know about PCOS.

Stress

Living with a long-term medical condition, such as diabetes, can cause stress.

According to the American Diabetes Association, stress can directly increase blood glucose levels, making diabetes symptoms worse. In addition, people who experience stress may be less likely to follow their diabetes care plan.

PCOS can also cause emotional stress, which can further affect hormone levels in the body. These hormonal changes may cause or contribute to thinning hair.

Metformin may cause several side effects. It is best to speak to a doctor about any side effects that last for more than a few days.

Anyone who experiences severe side effects when taking metformin should seek immediate medical attention.

Common side effects

The most common side effects of metformin are:

Less common side effects

Less often, people taking metformin may experience:

  • muscle pain
  • dizziness or lightheadedness
  • rash
  • excess sweating
  • a metallic taste in the mouth
  • chills
  • flu-like symptoms
  • flushing

Rare side effects

In rare cases, metformin may cause anemia. The symptoms of anemia can include:

  • drowsiness
  • loss of concentration
  • loss of strength
  • sleep problems, such as difficulty sleeping or increased sleepiness

Severe side effects

In severe cases, metformin may cause lactic acidosis.

Lactic acidosis is a dangerous complication that causes a buildup of lactic acid in the body. This can lead to diabetic coma and might even be fatal for some people with extremely high levels of lactic acid.

It is vital to call 911 immediately if any of these reactions occur when taking metformin.

People may be able to reverse or slow down hair loss using medications, surgery, and home remedies. However, this is not always possible,

Sometimes, a person may need a combination of treatments. Treatment options include:

Medications

Some drugs can treat hair loss. These include minoxidil (Rogaine), which is an over-the-counter (OTC) medication. The treatment takes at least 6 months to work, and a person must apply it to their scalp daily.

Finasteride (Propecia) is a prescription medication for males who experience hair loss. It is available in pill form, and a person needs to take it on an ongoing basis to see significant results.

Some females with PCOS may experience relief from hair loss if they take birth control pills.

If a particular medication causes hair loss, a doctor may recommend an alternative treatment. It is essential to consult a doctor before stopping any prescription drug.

Hair transplant surgery

People with permanent hair loss may wish to consider a hair transplant.

During this procedure, a surgeon or dermatologist will remove tiny sections of skin from other parts of the individual's head or body. They will then implant the hair follicles from this skin onto the areas.

A person may require multiple sessions to achieve satisfactory results. Hair transplantation is often an expensive option.

Home remedies

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Relaxation techniques, such as meditation, may help reduce stress and the risk of hair loss.

People may be able to reverse or prevent further hair loss by doing the following:

  • Reducing stress. Stress is a common cause of thinning hair, although this type of hair loss is usually temporary. Yoga, meditation, and deep breathing exercises can all be beneficial for stress relief.
  • Checking for nutrient deficiencies. A deficiency in B-12 or other nutrients, such as iron, can cause hair loss. A doctor can use a blood test to check a person's levels of these nutrients.
  • Avoiding damaging hair treatments. Tight hairstyles, including braids and ponytails, can pull on the hair and contribute to hair loss. Heat treatments, such as straightening or curling, also damage the hair and may cause it to break off.
  • Treating underlying conditions. A doctor can help establish a treatment plan for diabetes, PCOS, and other disorders that may contribute to hair loss. A person should follow the treatment plan carefully to prevent balding and other complications.
  • Exploring ways to hide hair loss. Some people may want to disguise their hair loss by using certain styling techniques. Others may prefer to shave the rest of their head to hide balding patches or cover thinning areas with a scarf or wig.

When to see a doctor

Individuals who notice sudden or excessive hair loss should seek consultation with a doctor.

This symptom may indicate an underlying medical condition, or it may be a side effect of an OTC or prescription medication.

The doctor will recommend treatments, lifestyle adjustments, and natural remedies that may help prevent or reverse a person's hair loss.

Takeaway

Doctors prescribe metformin to treat high levels of blood sugar and insulin in people with type 2 diabetes or PCOS.

In rare cases, there may be a link between hair loss and taking metformin. It is also possible that metformin may cause hair loss indirectly. Taking metformin long-term may increase the risk of vitamin B-12 deficiency, which can sometimes cause hair loss.

However, it is also possible that hair loss in people taking metformin is a result of a health condition rather than the medication.

Treatments for hair loss include medications, hair transplant surgery, and home remedies.

Q:

What are the other side effects of metformin?

A:

Some common side effects include bloating, flatulence, diarrhea, weakness or fatigue, and a metallic taste.

These often become less bothersome as your body adjusts to the metformin dose but can be unpleasant to deal with. If these, or other side effects described above, persist, or become worse, contact your doctor.

Alan Carter, PharmD Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.