Does Levothyroxine Cause Hair Loss?

When you start noticing thinning hair, it’s normal to wonder if something you’re doing is causing it. While the most common type of hair loss, male pattern baldness, is largely inevitable (thanks to good ’ol genetics), some medications can cause hair changes.

If you’re taking thyroid medication, particularly levothyroxine, you might be wondering, Does levothyroxine cause hair loss? And if so, how can I prevent hair loss while taking levothyroxine?

We won’t make you read a novella to find your answer. Yes, levothyroxine can cause hair loss — it’s usually not permanent, though.

But there’s a little more to it than that. Here, we’ll discuss the link between levothyroxine and hair loss, plus what you can do to treat it.

Levothyroxine is a medication used to treat low thyroid levels (hypothyroidism), which happens when the thyroid gland doesn’t make enough thyroid hormones. The drug is a synthetic form of the thyroid hormone thyroxine (T4) naturally produced by the body.

Levothyroxine is a generic medication. Brand names for it include:

• Synthroid®

• Levoxyl®

• Unithroid®

• Tirosint®

• Levo-T®

Okay, but does levothyroxine cause hair loss? It can, unfortunately. Keep reading for insight.

Levothyroxine can cause hair loss. Prescribing information from the FDA (U.S. Food and Drug Administration) specifically notes that partial hair loss might happen during the first few months of treatment.

But as mentioned, excess shedding from levothyroxine is usually temporary.

Hypothyroidism, Hyperthyroidism, Autoimmune Disorders, and Hair Loss

Here’s the ultimate catch-22, though: Hypothyroidism, the very condition levothyroxine treats, can also cause hair loss.

Research shows that people with an underactive thyroid may experience hair loss or prolonged shedding known as telogen effluvium (hair loss due to stress, illness, or injury). The condition might also leave you with dry, brittle, or lackluster hair.

Autoimmune conditions can cause hair loss too. One called alopecia areata is known to result in thinning hair.

You might also experience hair loss if you have the opposite thyroid condition: an overactive thyroid (hyperthyroidism). This condition causes shedding and reduces hair’s tensile strength, making it more prone to breakage and hair loss.

You can learn more about the connection between the thyroid and hair loss in our guide to thyroid hair loss.

How Levothyroxine and Hair Loss Are Connected

There isn’t much research clearly illustrating the link between levothyroxine and hair loss.

But one theory is that as the medication balances your hormone levels and your hair shifts out of the resting (telogen) phase of the hair growth cycle — that it was unnaturally in as a result of hypothyroidism — and back into the anagen (or growth) phase, there can be a period of shedding before hair starts regrowing.

Counterintuitively, shedding can also happen when beginning a hair loss treatment, like finasteride. But as you continue taking it, you’ll start seeing results.

You’d think the hair loss would stop once you’ve corrected low thyroid levels. But actually, some people find that their hair loss remains or even gets worse after they start taking levothyroxine.

The better news is that this hair loss usually resolves within a few months, and you should see normal growth from there on out.

Hair loss can indicate that your levothyroxine dose is too high, especially if it doesn’t resolve on its own within a few months.

One study looked at a child with hypothyroidism experiencing anagen effluvium (a rare type of rapid scalp hair loss that occurs after exposure to a certain medication or chemical) after starting levothyroxine. After adjusting the dosage, the hair loss stopped.

If hair loss from levothyroxine doesn’t improve within a few months, talk to your healthcare provider about lowering the dosage. Elevated heart rate and fatigue are two common signs the dosage of your medication for thyroid disease is too high.

On the other hand, you want to be sure you’re getting enough levothyroxine. Foods high in calcium, like milk, cheese, and other dairy products, can affect how your body absorbs the medication.

Medical providers often recommend taking levothyroxine on an empty stomach and waiting at least 30 minutes before eating.

Other Side Effects of Levothyroxine

Besides hair loss, levothyroxine side effects can include:

• Irregular heartbeat

• Nervousness or irritability

• Vomiting or diarrhea

• Chest pain

• Sleep problems (such as insomnia)

• Shortness of breath

• Hives

• Tremors

• Fever or sweating

• Leg cramps

• Muscle weakness

• Heat intolerance

• Headache

• Change in appetite or weight loss

• Changes in menstrual period

Keep scrolling to find out how you can prevent levothyroxine-related hair loss.

You may not be able to totally prevent hair loss while taking levothyroxine, but you can do some things to slow or reverse hair loss.

Unlike male pattern baldness (androgenetic alopecia), levothyroxine hair loss (or thyroid-related hair loss) isn’t caused by the male hormone dihydrotestosterone (DHT). So popular hair loss treatments like finasteride, which targets DHT, aren’t much help in this scenario.

Fortunately, other hair loss treatments can help you out.

Minoxidil

Minoxidil doesn’t work on hormones like finasteride. But that’s precisely why it can address many types of hair loss, including those caused by illness or medication.

This treatment is a vasodilator, meaning it widens hair follicles and brings oxygen and blood flow to the scalp.

We offer minoxidil liquid solution and minoxidil foam, both at 5% strength. Topical minoxidil is over-the-counter and FDA-approved for hair loss.

There’s also oral minoxidil, which requires a prescription and isn’t FDA-approved specifically for hair loss. However, the oral version is sometimes used off-label to treat excess shedding and can be an option if you’re not interested in a topical product.

Hair Loss Shampoo and Conditioner

Shampoo and conditioner can’t magically regrow all your lost hair. Still, it can make a big difference in your hair’s appearance, particularly in terms of volume and thickness.

Our thickening shampoo is made with saw palmetto, which research shows slows hair loss and boosts hair regrowth. Like finasteride, it’s also a DHT blocker — so it may not be the best choice for hair loss from medication, but if you suspect male pattern baldness is also at play, it’s a great place to start.

Our volumizing shampoo and conditioner plump hair at the root so it looks fuller, which can be especially helpful if you have diffuse hair loss (thinning all over).

Our thickening conditioner with niacinamide can help build keratin, an essential protein that makes up hair.

Lifestyle Adjustments

Though hair loss is sometimes unavoidable, there are steps you can take to reduce the risk of further hair loss.

Lifestyle tweaks you can make that may improve hair fall include:

• Eating a balanced diet

• Managing stress

• Taking supplements to address nutritional deficiencies

For instance, very low levels of zinc or biotin could cause hair loss. Blood tests can identify any deficiencies.

If you’re taking biotin and have hypothyroidism, definitely tell your healthcare provider. The B vitamin can sometimes interfere with tests that measure thyroid hormone levels.

Does levothyroxine cause hair loss? It might.

But excess shedding could also be because of the thyroid problems levothyroxine is treating. Research shows that 33 percent of people with hypothyroidism experience hair loss.

Here’s what to keep in mind about levothyroxine hair loss:

• Levothyroxine is very helpful in correcting thyroid imbalances, including those thyroid disorders that lead to shedding. But it won’t magically stop hair loss overnight. Some people may even notice their hair loss gets worse on levothyroxine before it gets better.

• While levothyroxine can cause temporary hair loss, the issue typically resolves within a few months as your body adjusts to the medication. If hair loss persists, consult your healthcare provider about potentially adjusting your dosage.

• Various treatments, such as minoxidil, can help mitigate hair loss caused by levothyroxine. Using volumizing shampoos and conditioners might also improve the appearance of thinning hair while you address the underlying issue.

• Maintaining good overall hair health involves managing medication side effects and addressing underlying thyroid issues. To support hair regrowth and minimize further hair loss, check in regularly with your healthcare provider and follow their guidance on how to take your medication.

Interested in learning more about the link between certain drugs and hair loss? Check out our guide to medications that can cause hair loss.

And if hair loss is persistent or you’re looking to treat hair loss from levothyroxine, we have prescription hair loss treatment options available online following a virtual consultation with a licensed healthcare professional.