How Do Sleeping Aid Tablets Work?

Medically approved by
Dr Earim Chaudry
Last updated
22nd March 2022

In 30 seconds

As many as two-thirds (67%) of adults don’t get the shut-eye they need. This has led to sleeping aid tablets becoming one of the most commonly used medications in the UK, with more than one in 10 people using them to improve the quality of their sleep. So, how do they work? Typically, sleeping aid tablets make you feel drowsy, reducing the time it takes to fall asleep.

What Are Sleeping Aid Tablets?

Sleeping aid tablets are exactly what they sound like: tablets designed to help you sleep. They can generally be grouped into two categories: 

  • Milder, over-the-counter sleep aids that promote sleepiness, and
  • Stronger prescription tablets that are designed explicitly as sleeping aids. 

However, they all have the same thing in common — they affect the part of the brain that causes drowsiness and helps you fall (and stay) asleep. If you find that you can’t sleep (for any number of reasons), you may consider taking a sleeping aid tablet before bed.

Do Sleeping Aid Tablets Actually Work?

Yes, they do — and recent research backs up the effectiveness of sleep aid tablets in treating mild and chronic insomnia. 

A study published in the BMJ looked at the results of 13 trials submitted to the FDA for approval of sleep aids Eszopiclone (Lunesta), Zaleplon (Sonata), and Zolpidem (Ambien). It focused on the time it took to fall asleep after taking one of the drugs. The analysis showed that those who took sleeping pills fell asleep around 22 minutes faster than those who didn’t. 

Yet, despite the strong evidence to suggest the usefulness of sleep aid tablets, there remains some debate. Some researchers have concluded that, while sleeping aid tablets do help people fall asleep, they owe some of their benefits to a placebo effect

So, How Do Sleeping Aid Tablets Work?

The way sleeping aid tablets do the job can depend on the type you’re using — over-the-counter or prescription. Let’s take a look at both options.

1. Over-the-Counter Sleeping Aid Tablets 

While not specifically designed for inducing drowsiness, some sleeping aid tablets do so as a side effect. This makes them common short-term options for those struggling with sleeplessness caused by stress or jet lag. 

The most popular option tends to be antihistamines. Available over-the-counter (OTC) from pharmacists or supermarkets, they’re mainly used to treat symptoms of hay fever and other allergic reactions. They cause drowsiness by blocking the actions of against histamine, a chemical produced by the body’s central nervous system that causes many of the symptoms of allergies, such as a runny nose or sneezing. 

Milder forms of insomnia can also be treated effectively with over the counter sleep tablets, including Nytol and Benadryl, that contain the active ingredient diphenhydramine (a kind of an antihistamine). 

Some other OTC sleeping aid tablets contain natural ingredients such as valerian and lavender. While there’s some debate over the effectiveness of these herbal sleep supplements, certain studies have demonstrated their usefulness. In particular, valerian — a tall, flowering grassland plant — is thought to reduce the amount of time it takes to fall asleep.

Note: Some antihistamines are sold as “non-drowsy,” so if you want to try an OTC antihistamine as a sleep aid, avoid those ones, such as Loratadine (sold as the brand name Clarityn).

2. Prescription Sleep Medication 

If you’re experiencing chronic insomnia, you should avoid taking mild sleeping pills, if possible. 

This is because they’re not very effective in treating more severe sleep disorders, and they can still cause unpleasant side effects, including unwanted sleepiness in the morning the next day. 

Prescription sleeping aid tablets may be more appropriate if your insomnia is persistent. These tablets directly affect the nervous system by binding with the GABA receptors in the brain, which help control our level of alertness. They work by stimulating drowsiness or relaxation, causing sedative effects and promoting sleep. 

Benzodiazepines are among the most commonly prescribed sleep medicines for insomnia. They include Lorazepam, Triazolam, Temazepam and Diazepam. 

Since these drugs affect the GABA receptors, they can have other effects, including reduced anxiety, muscle relaxation, feelings of euphoria, and poor memory. While Benzodiazepines are sometimes the right option for people with disrupted sleep, they should be taken with caution. Tolerance and even addiction can develop, which means they’re not suitable for long-term use. 

Some sleep aid tablets only target specific GABA receptors, achieving better, safer, and faster results. Some of the most commonly used selective GABA medications include Lunesta (eszopiclone) and Zolpidem.

Another Prescription Option: Sleep-Wake Cycle Modifiers

One of the emerging prescription sleep aid options is sleep-wake cycle modifiers.  

Ramelteon (Rozerem) acts on the natural body clock — the circadian rhythm, which influences our sleep-wake cycle. The sleep-wake cycle is partly controlled by the hypothalamus in the brain. Ramelteon binds to the melatonin receptors in this area, and this helps to promote sleep.

Read more: What Are the Strongest Sleeping Pills? 

Are There Any Side Effects of Sleeping Aid Tablets?

When taking sleeping aid tablets, it’s essential to consider their potential side effects. Certain over-the-counter medications can cause dry mouth, memory loss, daytime sleepiness, and an increased risk of falls, so always read the label before using them. 

Researchers also suggest that these drugs may be particularly risky for older patients (over-65s). Younger people aren’t advised to take diphenhydramine for more than two weeks since tolerance can develop, and effectiveness will diminish.

Meanwhile, GABA medicines used to treat insomnia can also have potential side effects, but these tend to be mild. They include memory disturbances, behaviour changes before sleep, and hallucinations. 

And because sleep-wake cycle modifiers (like Ramelteon) are limited to a single part of the brain, they have fewer side effects than many other sleeping aid tablets. Moreover, its risk of addiction is thought to be zero. This makes it a popular option for those with sleep disturbances, particularly older adults with chronic insomnia. 

Keep in mind that because this medication acts on the part of the brain that controls hormones, it may affect hormone levels if taken for long periods. This can reduce sex drive in men and make it more difficult for women to fall pregnant.

Key Takeaways

Having trouble sleeping? Sleeping aid tablets could be the answer. They can deliver a good night’s sleep by promoting feelings of drowsiness and helping you fall asleep faster. Most of them do this by interacting with a particular part of your brain or impacting your hormone levels.

Want to try a natural sleep supplement with ingredients designed to help you drop off? Manual has you covered. Find out more here.


Are Sleep Aid Pills Bad for You?

No, sleep aid pills aren’t bad for you, but they can result in some unpleasant side effects, including dry mouth, constipation, and daytime drowsiness. They should only be used as a short-term measure to tackle sleep problems, including insomnia. Long-term, relaxation techniques like mindfulness and meditation, regular exercise, and practices like cognitive behavioural therapy (CBT) can help.


  1. – As many as 16 million UK adults* are suffering from sleepless nights as a third (31%) say they have insomnia. –

While we've ensured that everything you read on the Health Centre is medically reviewed and approved, information presented here is not intended to be a substitute for professional medical advice, diagnosis, or treatment. It should never be relied upon for specific medical advice. If you have any questions or concerns, please talk to your doctor.

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