Problems falling asleep and staying asleep, known together as insomnia, affect a large number of people and can affect a person’s capacity to function normally greatly. Some people take sleeping pills to feel better and sleep well at night — and melatonin and Benadryl are two common choices.

Melatonin is a hormone that regulates your sleep and waking cycles. On the other hand, Benadryl is an antihistamine that can help relieve allergies and sleep.

But can you take both medications simultaneously to help you sleep?

In this article, we’ll talk about what each drug is and how it works, as well as the risks and benefits of taking them both simultaneously. Now, let’s begin.

What is Melatonin?

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Melatonin is a hormone produced naturally in the pineal gland of the brain. It helps regulate the sleep-wake cycle, also known as the circadian rhythm. [1]

Melatonin levels go up at night as the body gets ready for sleep, and they go down in the morning to wake the body up. Most people take melatonin supplements to help them fall asleep faster, sleep better, and get over jet lag faster.

What is Benadryl?

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Diphenhydramine is sold under the brand name Benadryl. It is an antihistamine that blocks the effects of histamine, a chemical the body produces during an allergic reaction. [2]

It’s often used to treat allergy, cold, or flu symptoms like itching, sneezing, and a runny nose. One of the side effects of Benadryl is drowsiness, making it a popular off-label sleep aid. [3]

Like melatonin, Benadryl is available over the counter in pill, capsule, or liquid form.

How Do Melatonin and Benadryl Work?

Melatonin works by binding to the sleep-wake cycle regulators in the brain. Raising the level of melatonin helps the body fall asleep faster and stay asleep for longer.

On the other hand, Benadryl works by blocking histamine receptors in the body, reducing allergy and cold symptoms. It also has a calming effect, making you tired, which can help those with trouble sleeping.

Can You Take Melatonin and Benadryl Together?

In general, you should talk to a medical professional before combining medications. The risk of adverse effects, including sleepiness, dizziness, and reduced cognitive function, may rise when melatonin is used with Benadryl.

Also, combining these medications might not be safe for everyone since people react differently to medications.

Potential Side Effects of Melatonin and Benadryl

As with any medication or supplement, both melatonin and Benadryl can cause side effects.

Common side effects of melatonin include the following. [2]

  • Headache
  • Nausea
  • Dizziness
  • Sleepiness
  • Irritability

Common side effects of Benadryl are the following.

  • Drowsiness
  • Dry mouth
  • Dizziness
  • Nausea
  • Blurred vision

However, you should contact your doctor immediately if you experience severe or persistent side effects.

Which Medication is Better For Sleep?

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Both melatonin and Benadryl can be effective sleep aids, but which is better depends on your needs.

Melatonin may be a better option if you’re looking for a natural sleep aid that helps regulate your body’s sleep-wake cycle. It can be particularly helpful if you have insomnia or jet lag. [1]

Benadryl may be a better option if you’re looking for quick relief from occasional sleeplessness due to allergies or other factors. However, it’s important to note that Benadryl can be habit-forming and may cause drowsiness the following day.

What are the Risks of Taking Melatonin and Benadryl?

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Taking melatonin or Benadryl can increase the risk of drowsiness and difficulty concentrating. Hence, avoiding driving or operating heavy machinery after taking these medications is important. Additionally, taking too much of either medication can lead to more serious side effects, such as:

  • Rapid heartbeat
  • Shortness of breath
  • Seizures
  • Loss of consciousness

When using medications for sleep, you should follow the recommended dosage guidelines. Taking more than the recommended dose can be dangerous and lead to serious health consequences.

Always talk to a medical professional or pharmacist before using any sleep aid, including melatonin or Benadryl. This is especially important if you have a medical condition, take other medicines, or are pregnant or breastfeeding.

Melatonin and Benadryl can interact with other medications you’re taking and cause unwanted side effects. Plus, they can make you feel groggy and impaired the next day, making it difficult to do your daily activities safely.

Also, it’s important only to take the recommended amount of melatonin or Benadryl. Remember that taking excess doses can increase the risk of side effects and may harm your health.

How Much Melatonin and Benadryl Can You Take?

The dose of melatonin and Benadryl varies depending on your age, weight, and overall health. But typically, the recommended dose of melatonin for adults is between 1-10mg. This is taken 30 minutes before bedtime. [4]

For Benadryl, the recommended dose for adults is 25-50mg, taken every 4-6 hours as needed.

Always follow the recommended dosage guidelines and never exceed the recommended dose.

Can You Build Tolerance to Melatonin and Benadryl?

There is a risk of developing a tolerance to both melatonin and Benadryl. [5] This means that your body may become less responsive to the medications over time, making them less effective at helping you fall asleep.

The slow metabolization of exogenous melatonin may cause melatonin tolerance. [6]

To minimize the risk of developing a tolerance, take these medications only as needed and not regularly.

Bottom Line: Can You Take Melatonin and Benadryl Together?

To sum up, melatonin and Benadryl are medications you can use to help with sleep disorders and insomnia.

These two medications may increase the risk of certain side effects, so you should not take them together. In taking any of these medications, follow the suggested dosage instructions and do not take more than the suggested amount.

Disclaimer: This article is only a guide. It does not substitute the advice given by your healthcare professional. Before making any health-related decision, consult your healthcare professional.

Editorial References And Fact-Checking

  • U.S. Department of Health and Human Services. (n.d.). Melatonin: What you need to know. National Center for Complementary and Integrative Health. Retrieved March 22, 2023, from 
  • Sicari V, Zabbo CP. Diphenhydramine. [Updated 2022 Jul 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:
  • Wong HCG. Long-term use of diphenhydramine. CMAJ. 2015 Oct 6;187(14):1078. doi: 10.1503/cmaj.1150066. PMID: 26438591; PMCID: PMC4592307.
  • Pierce M, Linnebur SA, Pearson SM, Fixen DR. Optimal Melatonin Dose in Older Adults: A Clinical Review of the Literature. Sr Care Pharm. 2019 Jul 1;34(7):419-431. doi: 10.4140/TCP.n.2019.419. PMID: 31383052.
  • Richardson GS, Roehrs TA, Rosenthal L, Koshorek G, Roth T. Tolerance to daytime sedative effects of H1 antihistamines. J Clin Psychopharmacol. 2002 Oct;22(5):511-5. doi: 10.1097/00004714-200210000-00012. PMID: 12352276.
  • Braam W, van Geijlswijk I, Keijzer H, Smits MG, Didden R, Curfs LM. Loss of response to melatonin treatment is associated with slow melatonin metabolism. J Intellect Disabil Res. 2010 Jun;54(6):547-55. doi: 10.1111/j.1365-2788.2010.01283.x. PMID: 20576063.


  • Shaira Urbano, Licensed Pharmacist

    Shaira is a licensed pharmacist (Bachelor of Pharmacy) and an experienced content writer. She enjoys inspiring and informing her readers through research-backed, comprehensive health content. Shaira draws from her personal experience working with real-life patients in a hospital setting and is currently pursuing her passion in writing.


Shaira is a licensed pharmacist (Bachelor of Pharmacy) and an experienced content writer. She enjoys inspiring and informing her readers through research-backed, comprehensive health content. Shaira draws from her personal experience working with real-life patients in a hospital setting and is currently pursuing her passion in writing.