Metformin is a prescription medication for the treatment of type 2 diabetes and polycystic ovary syndrome (PCOS). Some people are worried that this drug may cause hair loss, but there is little evidence to validate this concern.

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

Doctors sometimes also prescribe metformin for people with PCOS. Raised insulin and blood sugar levels are common with PCOS, and metformin can help lower them.

In this article, we explore the possible relationship between metformin and hair loss. We also describe some of the treatment options for this symptom.

Does metformin cause hair loss?

On rare occasions, people have reported a link between metformin and thinning hair or hair loss. However, it is unclear if metformin is 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 was taking a combination of metformin and another diabetes medication called sitagliptin.

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

Metformin, vitamin B-12, and hair loss

Another possibility is that metformin may cause hair loss indirectly. Research 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 may reduce the gut's ability to absorb vitamin B-12. This reduced absorption may explain why people experience symptoms of 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.

Some researchers believe that doctors should consider routinely testing people who take metformin for vitamin B-12 deficiencies.

A doctor may advise people who are taking metformin to increase their intake of foods rich in B-12 or take B-12 supplements to treat or prevent this deficiency. Alternatively, they may recommend getting B-12 shots, which bypass the gut and enter the bloodstream directly.

Other possible causes of hair loss

Other potential causes of hair loss may relate to a person's medical condition rather than to metformin use. These include:

High blood sugar

A buildup of sugar in the blood can damage blood vessels and organs throughout a person's body. Healthy blood vessels are necessary to transport oxygen and nutrients to each part of the body, including the hair follicles.

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

Type 1 diabetes can also increase a person's risk of 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. Some studies report a link between insulin resistance and a type of alopecia, or hair loss.

PCOS

Females with PCOS have abnormally high levels of male hormones called androgens. Occasionally, this hormonal imbalance can cause a type of hair loss. It may cause excess facial hair and acne, too.

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

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 are experiencing 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.

Other side effects of metformin

Metformin may cause several side effects. It is best to speak to a doctor about any side effects that persist for more than a few days. Anyone who experiences severe side effects should seek immediate medical attention.

Common side effects

The most common side effects of metformin are:

• diarrhea
• nausea and vomiting
• gas
• weakness or fatigue
• stomach upset
• headache

Less common side effects

Less often, people taking metformin may experience:

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

Rare side effects

In very 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

Serious side effects

In severe cases, metformin may cause coma, seizures, or lactic acidosis. It is vital to call 911 immediately if any of these reactions occur.

Treatments and natural remedies for hair loss

People may be able to reverse or slow down hair loss using medications, surgery, and home remedies. Sometimes, a combination of treatments is necessary. 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. It comes in pill form, and a person needs to take it on an ongoing basis to maintain results.

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

If a particular medication is causing hair loss, a doctor may recommend an alternative treatment. It is essential to always 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 balding areas.

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

Home remedies

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 relieving stress.
• 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. Heated treatments, such as straightening or curling, also damage the hair and can cause it to break off.
• Treating underlying conditions. A doctor can help establish a treatment plan for diabetes, PCOS, and other disorders that may cause hair loss. A person should follow the treatment plan carefully to prevent balding and other complications.
• Discussing medications and supplements with a doctor. Some medications and supplements can cause hair loss as a side effect. Anyone with concerns should discuss all medication and supplement use with a doctor and inquire about alternatives.
• Exploring ways to hide hair loss. Certain styling techniques can help disguise hair loss on a temporary or permanent basis. People can shave the rest of their head to hide balding patches or cover thinning areas with a scarf or wig. If hair loss is due to a specific medical condition, a person's insurance may cover its treatment.

When to see a doctor

Individuals who notice sudden or excessive hair loss should see a doctor. This symptom may indicate an underlying medical condition, or it may be a side effect of an OTC or prescription medication.

A doctor can recommend treatments 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. Some people are concerned that hair loss is a potential side effect of metformin treatment.

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 their health condition rather than the medication.

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