Do Over-the-Counter Sleep Aids Really Work?

Getting the right amount of good-quality sleep is essential to your health. Most adults should be regularly getting around 7 hours of sleep every night. And teenagers and children need even more sleep to stay healthy. 

However, many people find getting a full night’s sleep to be challenging. In fact, around 50 to 70 million people in the U.S. have persistent problems with sleep. These sleep problems are often referred to as insomnia, which includes problems with falling asleep, staying asleep, or both. 

Sometimes, you can make lifestyle adjustments that might help with your sleep. These might include limiting caffeine, creating a comfortable sleep environment, and sticking to a bedtime routine. If these adjustments don’t work, you might consider trying a sleep aid. 

There are several sleep aids that are available over-the-counter (OTC). But do they really work? We’ll discuss the effectiveness of OTC sleep aids below.

What are the options for OTC sleep aids?

Deciding between different OTC sleep aids at your pharmacy can be overwhelming. But you may be surprised to learn that many products contain similar ingredients. Check the label of each sleep aid to find out which ingredients it contains. If you’re unsure, speak to your pharmacist. Keep in mind that some combination products may contain ingredients you don’t need (e.g., cough suppressant).

Most commonly, you’ll see either diphenhydramine or doxylamine on the label. And melatonin and CBD are often found in “natural” options. Below, we’ll review what you should know about each of these ingredients.

Diphenhydramine

Diphenhydramine (Benadryl) is a common ingredient in OTC sleep aids. It’s an antihistamine that’s used to treat allergy symptoms, like sneezing or itching. One of the main side effects of diphenhydramine is sleepiness. Because of this, it’s commonly used to help with sleep problems.

Diphenhydramine is available OTC in many different dosage forms, including:

• Tablet

• Capsule

• Oral liquid

• Chewable tablet

• Fast-dissolving tablet

For allergies, it’s sold under the brand name Benadryl. But it can be found in sleep formulations like Unisom SleepMelts and ZzzQuil. It’s also available in combination medications that can help with pain symptoms such as Aleve PM, Advil PM, and Tylenol PM.

Doxylamine

Doxylamine (Unisom SleepTabs) is also an antihistamine, so it works similarly to diphenhydramine for allergies. It can also make you sleepy, which is why it’s commonly used in sleep aid formulations.

Doxylamine is available OTC as a tablet or capsule, oral liquid, and chewable tablet. For sleep, it’s sold under the brand Unisom SleepTabs. Remember to check the label since not all Unisom products contain doxylamine. And if you’re having trouble sleeping due to being sick, it can be found in combination cold and flu products like Vicks NyQuil Cold and Flu Relief. 

Melatonin

Melatonin is a chemical that your body produces naturally to help regulate your sleep and wake cycles. OTC melatonin is a synthetic version. Melatonin products may be helpful for people experiencing jet-lag or difficulty falling asleep at a normal time (delayed sleep-wake disorder). But there’s not enough evidence that shows it helps with chronic insomnia.

Melatonin is available OTC in many different dosage forms, including:

• Tablet

• Fast-dissolving tablet

• Powder for dissolving in liquid

• Oral liquid

• Gummies

• Cream

• Gel

• Transdermal patch

You can find melatonin on its own and in products like Emergen-Zzzz Nighttime Sleep Aid. 

Cannabidiol (CBD)

You may find CBD in some OTC sleep aids. CBD is a chemical derived from the cannabis sativa plant. It can be taken orally, applied topically or transdermally, or inhaled.

CBD doesn’t give most people the feeling of being “high” like THC. THC is another chemical derived from the same plant. But some studies suggest that CBD might help with sleep. Since this is a relatively new treatment for sleep problems, more research is needed to see if it’s truly an effective sleep aid.

It’s important to know that the CBD products you see on the shelf or online haven’t been approved by the FDA. And the FDA doesn’t consider these products to be dietary supplements, either. Some companies illegally market CBD products as unapproved treatments for certain conditions. So, you’ll want to talk to your healthcare provider before giving these products a try.

Do OTC sleep aids work?

In 2017, the American Academy of Sleep Medicine (AASM) published a summary of how well several different sleep aids work for insomnia. That same year, the American Academy of Family Physicians (AAFP) also published a review. So, what did they say?

Diphenhydramine was found to shorten the amount of time it took to fall asleep by an average of 8 minutes. And people taking it stayed asleep for an average of 12 minutes longer than people taking placebo (dummy pill). But they had no improvement in the quality of sleep compared with placebo.

Melatonin was found to shorten the time it took to fall asleep by 9 minutes. There was a small improvement in the quality of sleep compared with placebo.

Doxylamine hasn’t been studied as much as diphenhydramine for sleep. But specific formulations, like Unisom, have been approved by the FDA as a nighttime sleep aid. 

The verdict

AASM doesn’t recommend diphenhydramine or melatonin for sleep onset or sleep maintenance in people with insomnia. AAFP doesn’t recommend doxylamine for the same uses, either. But they do recommend controlled-release melatonin if you have trouble falling asleep.

OTC sleep aids might still be recommended by your healthcare provider if you’re experiencing short-term sleep problems. And if you’re pregnant, diphenhydramine or doxylamine are generally considered to be safe options for sleep.

There are several small studies that suggest CBD might help people with sleep problems. As mentioned above, more research needs to be done to prove that it works. Keep in mind that CBD products haven’t been approved by the FDA.

Are OTC sleep aids safe?

As with most medications, OTC sleep aids can have side effects and potentially interact with other medications. This is also true for supplements that promote sleep. Make sure your healthcare provider and pharmacist have your current medication list to check for interactions.

Side effects

The reason antihistamines, like diphenhydramine and doxylamine, are used for sleep is because they can make you feel drowsy. But they can also cause other side effects, such as dry mouth, blurred vision, and fatigue. These side effects can be severe if you’re over 65 years old.

Melatonin can cause side effects like headache, dizziness, and nausea. It can also make you feel groggy the following morning. CBD can cause side effects such as fatigue, diarrhea, and low appetite.

Interactions

Avoid taking diphenhydramine or doxylamine-containing products with alcohol. That’s because it can make the side effects of these medications worse. And both medications can interact with other medications that cause drowsiness, including opioids, benzodiazepines, and sleep medications.

Melatonin can interact with several medications. A few examples include seizure medications, blood thinners, and other sleep medications.

CBD also has the potential to interact with several different medications. Examples include citalopram (Celexa), topiramate (Topamax), and warfarin (Coumadin, Jantoven). 

When would a prescription sleep aid be recommended?

If you’re experiencing sleep problems, hopefully they’ll only last a short period of time. Times of stress, sickness, and travel can affect your sleep. Even though these OTC sleep aids are easily accessible, it doesn’t mean they should be taken on a regular basis.

Speak with your healthcare provider if you’ve been taking diphenhydramine or doxylamine-containing medications for 2 weeks or more. Melatonin products are typically taken for up to 6 months for adults (3 months for children). It’s possible that you’re experiencing a health issue that’s causing your sleep problems that your provider should check out.

We don’t have as much information about how long it’s safe to take CBD. That’s because there haven’t been many studies. If you’re taking CBD regularly to help with sleep, let your healthcare provider know. This is especially true if you have any other health problems, or take any other medications.

If you have insomnia that doesn't respond to OTC sleep aids, or if you’re using them regularly, your provider might want you to try a prescription medication. 

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Written by:

Sarah Lobello Pearson, PharmD

Sarah Pearson is a practicing pharmacist with over 10 years of experience in the field. She received her doctorate in pharmacy from the University of Georgia in Athens, GA.

Edited by:

Alyssa Billingsley, PharmD

Alyssa Billingsley, PharmD, is the director of pharmacy content for GoodRx. She has over a decade of experience as a pharmacist and has worked in clinical, academic, and administrative roles.

Reviewed by:

Christina Aungst, PharmD

Christina Aungst, PharmD, is a pharmacy editor for GoodRx. She began writing for GoodRx Health in 2019, transitioning from freelance writer to editor in 2021.

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