OTC Sleep Aids: What Works, What Risks, and When to Stop

It’s 2 a.m. again. Your mind won’t shut off. You’ve tried counting sheep, turning off your phone, even drinking chamomile tea. So you reach for that bottle of pills you bought at the pharmacy last month-the one labeled “sleep aid.” It’s easy. It’s cheap. And it worked… once. But now you’re wondering: is this still safe? How long can you keep doing this?

Over-the-counter (OTC) sleep aids are everywhere. You’ll find them next to the cough syrup, in the back of your medicine cabinet, even in bulk packs at warehouse stores. In 2023, Americans spent more than $600 million on these products. They promise quick relief for a bad night’s sleep. But here’s the truth most labels won’t tell you: these aren’t cures. They’re temporary fixes-with real risks.

What’s Actually in These Pills?

Most OTC sleep aids fall into two buckets: antihistamines and supplements. The antihistamines-like diphenhydramine (Benadryl, Sominex) and doxylamine (Unisom SleepTabs)-were never meant to help you sleep. They were made to stop runny noses and itchy eyes. The drowsiness? That’s just a side effect. These drugs block histamine, a chemical in your brain that keeps you alert. Knock that down, and you feel sleepy.

Then there’s melatonin. Unlike antihistamines, melatonin is a hormone your body naturally makes to signal it’s time to sleep. Supplements try to mimic that signal. But here’s the catch: melatonin supplements aren’t regulated like real drugs. A 2017 study found that 26 out of 31 brands had melatonin levels that were way off from what was on the label-some had less than 20% of what they claimed, others had nearly five times more.

Other common ingredients? Valerian root, chamomile, magnesium. These are herbal and often labeled as “natural.” But “natural” doesn’t mean safe or effective. There’s little solid evidence they help with chronic sleep problems. And because they’re sold as supplements, manufacturers don’t have to prove they work before selling them.

What Are the Real Side Effects?

Let’s be clear: these aren’t harmless. Antihistamine-based sleep aids are part of a drug class called anticholinergics. These drugs interfere with acetylcholine, a brain chemical involved in memory and muscle control. Long-term use? That’s linked to a higher risk of dementia. One 2015 study tracking over 3,400 people for more than seven years found that those who took these drugs regularly had a 54% higher chance of developing dementia.

Short-term side effects are just as troubling. About 32% of users report dry mouth. Around 24% get constipated. Blurred vision affects 18%. And for men over 50, urinary retention is a real risk-your bladder can’t empty properly. These aren’t rare. They’re common.

For older adults, the dangers multiply. The American Geriatrics Society lists diphenhydramine and doxylamine as “potentially inappropriate” for people over 65. Why? Because these drugs increase fall risk by 50%. A stumble at night can mean a broken hip-and that can change your life forever.

Melatonin has its own list of problems. Daytime drowsiness hits nearly half of users. Headaches? Common. Vivid dreams or nightmares? Reported by 68% of users in one review. Higher doses (above 5mg) can cause nausea, dizziness, and even nighttime waking. In kids, it’s been linked to bedwetting. And the NHS warns that melatonin can cause unexplained pain in arms or legs-if that happens, stop taking it.

How Long Can You Really Use Them?

The FDA says: don’t use OTC sleep aids for more than two weeks straight. The Cleveland Clinic agrees. So does the Sleep Foundation. Yet a 2022 survey found that 38% of users go past that limit. Nearly 1 in 5 use them for more than a month.

Why does that matter? Because your body adapts. You build tolerance. What once helped you fall asleep in 20 minutes now takes 45. So you take more. Or you start taking it every night. That’s when rebound insomnia kicks in. When you finally stop, your sleep gets worse than before. About 30% of people who use these for more than two weeks experience this.

Even melatonin, which seems gentle, can cause dependency. A 2021 study found that 25% of daily users developed tolerance after just 10 days. Suddenly, they can’t sleep without it. That’s not a supplement-that’s a crutch.

Who Should Avoid These Completely?

Some people shouldn’t touch OTC sleep aids at all.

If you have sleep apnea, these pills can be dangerous. They relax your throat muscles even more, making breathing interruptions worse. That’s not just uncomfortable-it’s life-threatening.

Pregnant women? Avoid them. Diphenhydramine is classified as Category B-no proven harm in humans, but not enough studies to say it’s safe. Melatonin? Virtually no safety data for pregnancy. The NIH’s LactMed database says: skip it.

People with liver or kidney disease? Your body can’t clear these drugs the way it should. That means higher concentrations build up in your system, increasing side effects.

And if you’re over 65? The Beers Criteria, the gold standard for safe prescribing in older adults, says: avoid first-generation antihistamines entirely. The risks far outweigh any tiny benefit.

What Actually Works Better?

There’s a better way. And it doesn’t involve pills.

Cognitive Behavioral Therapy for Insomnia, or CBT-I, is the first-line treatment recommended by the American Academy of Sleep Medicine. It’s not magic. It’s not quick. But it works. Studies show 70-80% of people who complete CBT-I see lasting improvements. No side effects. No dependency. Just better sleep habits.

What does CBT-I involve? It teaches you how to:

• Stop lying in bed awake for hours
• Reset your internal clock with consistent wake-up times
• Reduce anxiety around sleep
• Use your bed only for sleep and sex-not scrolling or watching TV

It’s available online, through apps, or with a therapist. Many insurance plans cover it now. And unlike pills, the benefits stick around long after you stop.

Other proven non-drug strategies? Limit caffeine after noon. Get sunlight within 30 minutes of waking. Keep your bedroom cool and dark. Avoid screens an hour before bed. These sound simple-but they’re backed by science.

When Should You See a Doctor?

If you’ve tried OTC sleep aids for more than two weeks and still can’t sleep, it’s time to talk to a doctor. Not because you’re weak. Because your body is telling you something’s wrong.

Chronic insomnia affects about 10% of adults. It’s not just “not sleeping well.” It’s trouble falling asleep, staying asleep, or waking too early-at least three nights a week for three months or more. That’s a medical condition. And it’s often linked to anxiety, depression, chronic pain, or hormonal changes.

Your doctor can help you figure out the root cause. Maybe you need a sleep study. Maybe you have restless legs. Maybe your thyroid is off. OTC sleep aids won’t fix any of that.

And if you’ve been using these for months? Don’t quit cold turkey. Talk to your doctor. Stopping suddenly can make rebound insomnia worse. They can help you taper off safely.

The Bottom Line

OTC sleep aids aren’t evil. Sometimes, they help. A single night of jet lag? One dose of melatonin might get you back on track. A stressful week? A low dose of diphenhydramine might give you a few good nights.

But they’re not for regular use. Not for long-term sleep problems. Not for older adults. Not for people with other health conditions.

The real problem isn’t that these products exist. It’s that we treat them like solutions instead of short-term tools. We reach for them like candy-because they’re easy, cheap, and everywhere. But sleep isn’t a problem you can dose your way out of.

Good sleep comes from routine, environment, and mindset-not a pill. If you’re still struggling after two weeks, don’t reach for another bottle. Reach for a doctor. Or a sleep therapist. Your brain will thank you.