Why Does Benadryl Make You Sleepy?

Histamine is involved in causing allergy and cold symptoms. It also plays a role in wakefulness. When Benadryl blocks histamine, it takes away its stimulation of wakefulness. Many people experience this as drowsiness and can use Benadryl to sleep.

How long does Benadryl drowsiness last?

The effects of diphenhydramine last from four to six hours. Benadryl in the injectable form has a rapid onset of action. When used as a night-time sleeping aid, the usual dosage of Benadryl is 50mg at bedtime.

Is it OK to take Benadryl as a sleep aid?

Although antihistamines like Benadryl will make you feel sleepy, they're not a great choice when it comes to treating insomnia. Not only can they affect your sleep quality, but they'll also become less effective very quickly, meaning you may not notice any benefits if you use them often.