Is Taking Melatonin and Benadryl Together Safe?

The short answer is no.

Medically reviewed by Mary Choy, PharmD

Benadryl (diphenhydramine) is an over-the-counter (OTC) antihistamine for allergies and sleep.

Melatonin is a hormone that regulates the body's circadian rhythm (the sleep-wake cycle). It's also available as a dietary supplement. Like Benadryl, it's often used for sleep disturbances like insomnia (trouble falling or staying asleep).

There's some controversy over whether these two medicines are safe to take together. Read on for recommendations.

<p>Antonio_Diaz / Getty Images</p> Young female in pink pajamas taking medicine or vitamins before bed at night

Antonio_Diaz / Getty Images

Young female in pink pajamas taking medicine or vitamins before bed at night

Can You Take Benadryl and Melatonin?

The short answer is no unless your healthcare provider recommends it and carefully monitors you.

These medicines are both sedating and can cause similar side effects, such as:

Discussing your sleep concerns with a healthcare provider is best if one sleep medicine isn't doing the trick, rather than adding more medicines.

Benadryl in Older Adults & Chronic Conditions

Benadry is not recommended for everyone.

As a general rule, older adults should not take Benadryl. This is because it can make you too drowsy and cause cognitive impairment, falls, and bone fractures.

Benadryl is also not recommended for people with the following conditions:

Why Do Benadryl and Melatonin Make You Sleepy?

Benadryl is a first-generation antihistamine, an allergy medicine that blocks histamine receptors in the body. Unlike newer antihistamines, older ones like Benadryl enter the brain and are known to cause drowsiness by affecting the central nervous system (CNS).

Melatonin causes sleepiness by activating melatonin receptors in the body. This helps restore the sleep-wake cycle and induces sleep.

Uses of Benadryl and Melatonin

Benadryl is commonly taken as a sleep aid and for conditions like the following:

Melatonin is primarily for insomnia. Some people also use melatonin for the following conditions, though there's not much evidence to support it:

Dietary Supplements

Supplement use should be individualized and vetted by a healthcare professional, such as a registered dietitian nutritionist (RD or RDN), pharmacist, or healthcare provider. No supplement is intended to treat, cure, or prevent disease.

Dosages of Benadryl and Melatonin

Benadryl can be taken every four to six hours for allergy symptoms at the following doses:

  • Adults and children over 12: 25–50 mg

  • Children 6 to 12: 12.5–25 milligrams (mg)

Benadryl can be taken as a sleep aid at the following dose:

  • Adults and children over 12: 25–50 mg at bedtime.

Melatonin is effective for insomnia at the following daily dosages according to clinical trials:

  • Older adults: 1–6 mg; note that the American Academy of Sleep Medicine recommends no more than 2 mg daily for this population

  • Adults: 1–5 mg

  • Children: 0.5–3 mg


Benadryl is often abused. Even though it's an OTC medicine, it should be kept out of reach of children and pets.

Taking too much Benadryl can be fatal. Overdoses can cause:

In case of overdose, call the Poison Control helpline at 1-800-222-1222 or visit the Poison Control website for more information.

Melatonin is not likely to cause toxicity when taken for short periods of time, even at high doses. Case reports suggest that a melatonin overdose can cause hypotension (low blood pressure).

Follow the manufacturer's recommended dose and discuss your treatment goals with a healthcare provider in order to maximize safety before taking either Benadryl or melatonin.

Long-Term Effects of Benadryl and Melatonin

Long-term studies of Benadryl's effects are lacking. Taking Benadryl long term may increase the risk of dementia.

Research shows that people develop tolerance for Benadryl quickly, meaning that higher doses are needed over time to produce the same effect. People may become tolerant to Benadryl's sleep-inducing effects in as little as three days.

As for melatonin, although daily doses of less than 5 mg seem safe for most people, we don't know much about using it long term. More scientific research is necessary before melatonin can be recommended for chronic use.

Choosing a Supplement

In the United States, the Food and Drug Administration (FDA) does not regulate supplements the way it regulates prescription drugs. That means some supplement products may not contain what the label says.

When choosing a supplement, look for third-party tested products and consult a healthcare provider, registered dietitian nutritionist (RD or RDN), or pharmacist.

Alternatives for Better Sleep

Discuss your concerns with a healthcare provider before self-treating if you're having trouble sleeping. Your provider can screen for treatable issues that may keep you at night.

Many underlying conditions can cause insomnia, including:

Treating these conditions can help with sleep.

Before trying OTC or prescription remedies for insomnia, keep in mind that behavioral therapies have proved to help. Some of these include:

  • Sleep hygiene, practices like exercising during the day, going to sleep at the same time each night, and turning off electronics before bed

  • Relaxation training, such as breathing strategies, yoga, or meditation to minimize stress

  • Cognitive behavioral therapy, which is recommended first before any pharmacological treatment

Other OTC products that can help with sleep include:

Prescription medications approved for insomnia are associated with significant side effects. Many have been designated controlled substances because you can become dependent on them. Some prescription medicines for sleep include:

  • Ambien (zolpidem)

  • Belsomra (suvorexant)

  • Halcion (triazolam)

  • Lunesta (eszopiclone)

  • Restoril (temazepam)

  • Rozerem (ramelteon)

  • Sonata (zaleplon)


Melatonin and Benadryl are popular sleep aids that are available without a prescription.

Generally, they shouldn't be taken together because both can cause side effects such as an excess sedative effect and daytime sleepiness, which makes activities like driving a car or operating other heavy machinery dangerous.

Keep in mind that a proper nighttime routine and cognitive behavioral therapy are the gold standards for insomnia and should be tried before medications are taken. Before self-treating, discuss sleep issues with your healthcare provider for specific recommendations.

Frequently Asked Questions

Can you take Benadryl with melatonin?

You shouldn't take Benadryl and melatonin together. Together, they can cause drowsiness and daytime sleepiness, making driving a car or operating other heavy machinery dangerous.

What should not mix with melatonin?

Caffeine and some prescription medicines can increase the levels of melatonin in the body and may increase side effects like fatigue or headache. These medicines include:

Melatonin can lower blood pressure, so keep an eye on yours if you take blood pressure-lowering medicines. Signs of low blood pressure (hypotension) include dizziness, blurry vision, and fatigue.

What should not mix with Benadryl?

If you take Benadryl for sleep, take caution when taking OTC sleep aids or cold and flu combination products. Benadryl is a common ingredient in these medicines.

Benadryl should not be taken with other anticholinergic drugs due to an increased risk of side effects like constipation and dizziness.

If you take Benadryl, avoid other sedating medicines such as the following:

Read the original article on Verywell Health.