How do the Active Ingredients in Sleep Aids & Tablets Work?


Getting a good night’s sleep is so important to have a productive day and it is a problem a lot of people struggle with. It is because of this problem, some people turn to sleep aids and remedies for help. In some situations, people rely on them. 

However, how much do you know about your sleep aids? Do you know what you’re taking before you go to sleep? 

In this Chemist Direct article, we look at the key active ingredients and how they work. 

Diphenhydramine in Sleeping Aids 

Diphenhydramine is an antihistamine that has many potential uses. 

It CAN be used to relieve allergy and hayfever symptoms. It can also used for colds. It can be used to relieve rashes, itching, irritated eyes, coughs and sneezing. Diphenhydramine can also be used to prevent nausea, vomiting and other symptoms of motion sickness. 

It is commonly used in over-the-counter medication and is found in a wide range of sleeping pills by leading healthcare brands like Lunox and Nytol

How Diphenhydramine works as a sleep aid is that the antihistamine does two things. 

The first is that it helps decongests and clears your sinuses. This helps you enjoy a good night sleep and prevents you from being disturbed and waking up. 

Also, Diphenhydramine naturally makes you sleepy. When used for allergies and hayfever, it would warn you about this property and you should consider this before taking it. (1, 2, 3)

Promethazine Hydrochloride in Sleeping Aids 

Promethazine is a type of drug which works as an antihistamine and is commonly used to treat allergy symptoms. 

When used for treating hayfever and allergies, it reduces the effects of runny noses, excessive sneezing, irritated eyes and skin and other allergy-related symptoms. Promethazine is also used to prevent motion sickness. 

It has been shown to naturally make people drowsy and is used as an active ingredient in sedatives by brands such as Sominex. Due to its effectiveness as an antihistamine, it helps clears your sinuses for a night of undisturbed sleep. Combined with its natural ability to make people drowsy, it is why Promethazine is an effective sleep aid. (4, 5)

Natural & Alternative Sleep Remedies 

Some people prefer to use a more natural solution for your their insomnia. This could be for several reasons, one is that they are already on other medication that may conflict with a sleeping aid. A natural sleep remedy would use a combination of plant extracts, which will help you become relaxed, reduce stress and calmly drift to sleep. 

Sleep aid brands like Kalm and Sominex Herbal look to natural ingredients to provide that alternative for the public. 

At Chemist Direct, we work with leading healthcare brands to provide our customers with the very best sleep aids, tablets and remedies. Check them out today. 

This article has been medically approved by Superintendent Pharmacist Shilpa Shailen Karia, MRPharmS. - GPhC Reg No: 2087328


  1. Sleep aids: Understand over-the-counter options - Mayo Clinic 
  2. Sleep Aid Tablets - WebMD 
  3. Using Diphenhydramine or Benadryl as a Sleep Aid Insomnia Medication - Very Well Health 
  4. Promethazine (including Phenergan) - NHS 
  5. Promethazine -