Unisom SleepTabs Review

unisom sleep tabs packet and pill

For the last two weeks, I’ve been trying Unisom SleepTabs – an antihistamine over the counter sleep aid that’s widely available in the United States.

I sometimes test new sleep aids for short periods, but before taking Unisom I hadn’t taken any for a month. My system was clear, my sleep not so great, so it was a good time to try it.

I also traveled to England in the second week, so it was a good opportunity to see if it would help with jet lag and sleeping away from home.

In summary, I found Unisom SleepTabs were effective in helping me sleep. However, the effect lessened as the days rolled by, and the hangover effect also increased.

The first night

My first impression was that the Unisom SleepTabs are tiny, which makes them easier to swallow than some of the oversized (in my opinion) sleep aids out there. They have a faint taste, but it’s not too strong or unusual.

I took one and read my book in bed to see if I could detect any sedation. And I believe I started to feel drowsier than I normally would after around 30 minutes.

I turned out the light and fell asleep pretty quickly afterwards – I’d say within 5 to 10 minutes, which is good for me.

Only one waking in the night

I woke up once 3 hours after taking the SleepTab to go to the bathroom. I felt a little groggy, but was able to safely navigate my house and return to sleep.

I again fell asleep quickly, and didn’t wake again until 7 hours later. So far so good then.

Side effects the next morning

I woke up feeling mostly refreshed from getting 7 hours’ sleep, just with a slightly fuzzy head. It was similar to what I’ve experienced with other anti-histamine sleep aids, so didn’t surprise me.

Other than that, there were no discernable side effects after the first night.

The rest of the week

I was quite impressed with how well the Unisom SleepTabs worked on the following nights.

I seemed to sleep well on most nights of the first week. On two nights, I woke up a few times, but fell asleep relatively quickly again.

Only on one night did I wake up for a longer period in the night. But for me, 6 out of 7 nights with 7+ hours’ sleep is a good result.

The downside is that the hangover effect increased as the week progressed. By the end of the week, it seemed noticeably worse than the first couple of nights.

It would take a couple of hours to clear up completely in the morning. And although that’s still acceptable for me, it was concerning that the effect was building.

The second week

I traveled from the U.S. back to the U.K. at the end of the first week to visit family and friends.

Interestingly, I stayed one night in a house with cats, which I’m allergic to. I also spent a couple of nights in a friend’s house which is notoriously dusty, and I’m allergic to house dust mite too!

As expected, the antihistamine did its traditional job of preventing me from sneezing and sniffling my way through the night in their houses.

As for my sleep, the sedation was still there but did start to reduce in effectiveness I thought. Tolerance develops when using antihistamines for sleep, and this was exactly what was happening.

More noticeable side effects

Towards the end of the second week, the next day hangover was very obvious. I was waking up feeling quite groggy, and it would take a couple of hours or longer for it to totally clear.

I also started to get a dry mouth, which would last pretty much all day. So for me, that was a clear sign that it was time to stop taking them.

Would I take Unisom SleepTabs again?

If was experiencing serious sleep problems, I would take them again for a couple of nights, but no longer.

They worked very well at the start, helping me fall asleep faster and stay asleep. And there were no serious side effects.

However, I definitely wouldn’t use them for more than a couple of nights at a time. For me, the tolerance built quite quickly, and the hangover effect along with it.

But overall, compared to many other over the counter and prescription sleep aids, I thought they were effective and relatively easy to take for a short period.

Further information

Unisom Sleeptabs ingredients

unisom sleeptabs ingredients shown on the box

According to the patient information on the pack I bought in the U.S. the ingredients are:

  • Doxylamine Succinate 25 mg (the active antihistamine ingredient that can cause drowsiness)
  • Dibasic calcium phosphate
  • FD&C blue no. 1 aluminum lake
  • Magnesium stearate
  • Microcrystalline cellulose
  • Sodium starch glycolate

Who shouldn’t take it

photo of the warnings that are written on a box of unisom sleeptabs

Unisom advise that you consult a doctor if any of the following apply to you:

  • You have a breathing problem, like asthma, emphysema or chronic bronchitis
  • You have glaucoma
  • You have trouble urinating due to an enlarged prostate gland
  • You’re taking any other drugs
  • You’re pregnant or breastfeeding

They also issue these warnings:

  • Don’t give it to children under 12 years old
  • Don’t drink alcohol at the same time
  • Only take it at bedtime
  • Stop taking them and consult a doctor if you have any side effects
  • If your sleep problems continue for more than 2 weeks, you should speak to a doctor

If you’d like to double check the current advice, you can find the above information on the Unisom website Sleeptabs factsheet page.

You can also find information about the safety on the drugs.com factsheet. That site includes more about interactions with other drugs and conditions.

Elderly people and antihistamines

One point that isn’t included in the Unisom factsheet is that some medical sites state that elderly people should be more careful when taking antihistamines.

This is partly because they have anticholinergic activity. So elderly people with preexisting conditions related to anticholinergic activity should check with their doctor first.

If unsure of this point, elderly people might benefit from erring on the side of caution and checking with a doctor before taking Unisom.

Possible side effects

According to the Unisom website Q&A section, side effects can include:

  • Dry mouth
  • Dizziness
  • Memory problems

Medical websites, like Mayo Clinic and WebMD, list additional side effects:

  • Headache
  • Constipation
  • Stomach upset
  • Blurred vision
  • Worse coordination
  • Dry mouth, nose or throat
  • Irregular or fast heartbeat
  • Ringing in the ears
  • Mental or mood changes (e.g. hallucinations, confusion, irritability)
  • Easy bruising/bleeding

Is it really safe?

Despite the somewhat scary list of possible side effects, most people tolerate Unisom well in short periods. And it’s considered GRAS/E (Generally Recognized as Safe and Effective) by the FDA.

Again though, if you experience any of these side effects, stop taking it and seek medical advice.

Your views

Have you taken Unisom SleepTabs before? What was your experience? Please let me know in the comments below!


  1. Hi,
    I took Unisom once on Friday night around 8:30 and slept great. I didn’t take it on Saturday or Sunday night and haven’t been able to sleep a wink. Not a minute. Could this be an effect of the unisom? I’ve never had a problem is severe before.

    • Hi Ada
      It’s kind of impossible to say really. I know sleep aids can sometimes lead to what they call rebound insomnia, but I’m not sure after just one night. Whether you had some other reaction to it that made your sleep worse rather than better is also impossible to say.

  2. I have been using Unisom before back in the Philippines. I am an insomniac too as well. I usually take it for the next night or even in the following morning to catch up it helps. And I tell you it works. That was about 20 years ago. Now I am trying it here in the US. If I cannot sleep at night, can I take it during 4- 5 am so that I can catch up with the sleep. (or did you experience it)

    • Hi Jay
      Thanks for sharing your experience. Personally, I wouldn’t take sleep aids at that time in the morning, unless your sleep pattern is one where it’s normal for you to sleep all through the morning. But this is a personal choice!

  3. I’ve been taking Unisom the past 4 nights and have been sleeping great! Is it ok to continuously take it ? I’ve had sleeping problems the last couple of months.

  4. Unisom has always worked very well for me. I am now working the graveyard shift and am having a very hard time adjusting to sleeping during the day. Wish I could take these every night but I am worried about health effects. If I could do four days a week that would be great but I know two or three days would be the safer bet. Gonna ask my pharmacist and/or doctor what they think.

    • Hi Robert
      Thanks for sharing your thoughts. Shift work is hard, I know – especially if you have sleep problems anyway. I’d personally not want to take an anti-histamine sleep aid for long periods of time due to the side effects accumulating. But this is a personal choice. Let’s see what your doc days!

  5. Hi Ethan it’s good to hear they worked. I haven’t tried the Unisom brand of Doxylamine but I have tried the Kirkland brand but it did nothing for me – I bought them off eBay so I’m not sure if they were the real deal or fake, the pills and bottle looked legit but you can never be sure. I live in the UK and it’s not possible to buy these from a pharmacy unlike in the US which is a shame. I have tried Promethazine which worked well for me and usually got about 5 hours before waking which is a miracle for me – from what I hear Doxylamine is just as strong as a sedative so I’m thinking the Kirkland Doxylamine I bought online were fake or a bad batch as I wasn’t drowsy whatsoever. Steve.

    • Hi Steve
      Were they tiny blue pills with a slightly bitter taste?
      I haven’t heard of fake Kirkland, and can’t imagine there would be a big market for them anyway! So for me, the most likely explanation is that they just didn’t work for you personally. The sedative effect of these anti-histamines won’t be equal for everyone. And like you say, for some people they will do nothing.

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