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How long does it take for suprep to work?

88 Answers

Official Answer by 3 Sep 2018

Suprep is a type of osmotic laxative that is used for cleansing the colon before a colonoscopy procedure in adults. Thorough cleansing of the colon is essential as it allows your doctor to see the mucosal lining of your colon.

The length of time it takes for Suprep to act and the duration of the action appear to be quite variable. Some people have a bowel movement within minutes while others take hours. Make sure you drink the entire bowel prep solution. You can tell when your bowel is ready for the procedure when your stool is clear, yellow, light and liquid.

If you have not had a bowel movement within three hours of drinking your prep call your doctor. You may need another laxative.

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Votes: +0
Marvell 27 Dec 2010

It's unfortunate that no one has responded. I don't know of anyone who has used it so can't comment either. If you have already used it please let us know of the effects, if you don't mind.

Votes: +4
highrider69 14 Nov 2016

I had to take this for a colonoscopy, it doesn't taste too bad but it drains your electrolytes, make you feel weak. You don't feel that hungry but it takes about 3 hours to flush your system. The second dose is worse because now you know the taste. If you are a diabetic, be careful controlling your sugar.

Maggie56 16 Dec 2016

1st dose... 50 minutes before it began to work. Felt bloating, mild cramping and nausea.

Cgillil2 17 Mar 2017

I just took this about 20 minutes ago and results were immediate. Started off with stomach grumbles and then in no time, had my first movement. Reaction times differ for other individuals, but anywhere from 45 minutes to 2 hours are common

Bobs-your-uncle 30 Mar 2017

First colonoscopy, first Suprep. For me it started working within 10 minutes and I am in the process right now. Will comment on the length later. This has caused me to be very nauseous, chilled and shaky. The Suprep is sweetened with Splenda and that made it difficult for me to get it down. Friends tell me this is better than the older PEG solution.

Carolynwhite 24 Apr 2017

Well I used & it took me 6 hours for it to work. I suggest you get big girl panties pull-ups I kid you not. Once it started I couldn't make it to bathroom before I went on myself in floor walls commode in my bed I was mad as hell. I've had colonoscopy before & didn't use this one. I want use it again believe me. I was still going pooing when time for my presedure. Needless to say I have to redo all over ugh I could scream

beautyfirst 21 Jul 2017

I just took the prep and it only took an hour to work maybe because I don't have a gallbladder

Ellieirish 21 Sep 2017

I took my first dose at 6:00 pm. Added a Crystal Light Lemonade packet, that helped with the taste. I experienced cramping and full action at about 1 hour after I took it. By 10:00 pm, it seemed to calm down. But it was pretty draining.

Dmmjsellers 26 Oct 2017

It took over 90 minutes to begin working for me. Suprep didn't taste terrible. Sweet but salty. At least it wasn't thick and gloppy.

smlauderman 27 Oct 2017

Started drinking it at 6:00. Effects in full force before 7:00. Continuing beyond 2 hours. Tastes horrible!

Ellieirish 27 Dec 2017

For me, it started to take effect about 45 minutes after I took it. I had some cramps, lots of chills, and the flushing out was intensive. By the time I went to bed, around 11:00 after taking it at 6:00, I was able to get sleep. The second dose wasn’t as bad tasting and the effect seemed milder. The dosage is exactly the same, by the way, same bottle and there’s no indication which to take first.

Several things I learned. Eat a prep diet starting 48 hours before your colon prep. That really helped. I avoided all fiber, red meat, gassy veggies, and fruit for the two or three days before. I drank and drank. Prep your bottom with Desitin cream BEFORE you take your first dose. Have cooling wipes on hand and in the bathroom at the ready. On the day before, the all clear liquid diet is not that bad. I found gummy bears in clear and yellow were allowed and that was awesome.


I ate just the strained chicken broth from a really good restaurants chicken noodle soup and that was way more satisfying than a canned broth dinner. I had jello and Italian ice in lemon at the ready, and I wasn’t even hungry enough for them. I also used pineapple crystal light right in the cold prep liquid, used a straw and washed it down with ice water.

The thing I most learned: the colonoscopy itself was a breeze! Best sleep I ever had and I was treated so well. Good luck!

Meta-ridley 29 Mar 2018

Im doing it now and man is it fast! Started working 12 min after i took it. Taste pretty nasty but is do-able. Im in my 3rd hour but its starting to taper off. I dont have cramps with it at all. (Thankgod) some people took an hr to get started. Pity

Sunnynights68 3 Aug 2018

My dr had me do a liquid Diet all day then do the Suprep at 6 PM. Within 10 minutes I was on the toilet. 20 Minutes later and I’m unable to leave. I’m hoping this will taper off at some point. No stomach pain or nausea though I think the liquid diet helped with that

GG_65 3 Aug 2018

Thanks everyone I survived mine time was 30 minutes after I stayed on toilet for 3 hours I kid you not lol... everytime I got up I was back on so I just stayed there :-)... after 3 hours I was good to stay off for a few minutes slept from 2 a.m-3 got up took my shower started the other bottle at 4 a.m and was going in no time then I went after I got to the hospital like 7x and when they were getting ready to do the procedure I said oh no I have to go againtheysaid no worries if you do we will suction it up UGH & that was the last thing I remember ... they said they had to give me enough knock out medicine for 2 people because I kept moaning (I don't recall any of it THANKFULLY LOL... and upon them trying to wake me up I told them & my sister to leave me the F alone and let me sleep :-( (I also don't recall that THANKFULLY) after all is said & done the drink part was the worst and I had the endoscopy also but they said my colon looked healthy so I am good there and should be getting the biopsy results soon HOORAY it's over and done with lol

naildriver 5 Jan 2011

It took 7 minutes before the first urge to go then stayed in the restroom for 30 minutes. After the initial 30 minutes I made 2 more short trips in the next 30 minutes.

Votes: +6
Irish264 17 Nov 2016

Thanks, I'm taking this tonight and couldn't remember

Relic54 9 May 2017

Took at 3 pm, 4 1/2 hours later still going. Just gurgling no cramps. Second scope used ducolax & miralax first time. This prep is better for me. Don't expect much rest .

Dmmjsellers 27 Oct 2017

Not sure if my question actually showed up. I've read everyone's comments and now that my colonoscopy is over, I thought I'd share my comments. Suprep was not that bad for me. Yes, it tastes like salty KoolAid. But at least it's not thick and goopy. First dose at 7pm and I mixed it with clear Gatorade2. It took over an hour and a half to even feel the urge to go. Maybe because I actually only had liquids all day. I had no cramps at all. I did not spend hours in the bathroom and did not have terrible urgency either. I got some rest and set my alarm for 6am. The 2nd dose was more difficult to get down and I felt nauseous but didn't throw up. I went a few more times and then rested some more before having to be at the office at 12:30. I actually had a nightmare there weren't enough bathrooms in the waiting room! But it was fine. If you get anything out of these posts it's that everyone is different and I guess depending on what is in your system when you start will determine how long it takes to come out.

Txhazleeyez 7 Nov 2018

I'm drinking it now and its working fast. I put in some Crystal Light Lemonade in mine it don't taste that bad.

atlcdn 12 Mar 2011

For me it was within minutes... for the 4 pm one and the 4 am one. There are no words to describe the taste, so I won't even try. The good news is that there was none of that awful cramping with hours and hours of being stuck in the bathroom. It was much easier on the body... It just wasn't as bad after taking it... after about 3 hrs I was not in the bathroom very much at all... Much, much better than the preps in the past.
As usual, the meds given to me at the time of the procedure did not make me sleep or even make me sleepy so it was uncomfortable for me... but I can handle just about anything after the prep... :-) What was found was removed and I am soooooo glad it's over for another five years... yay!

Votes: +3
Jeriandjeff 6 Jan 2018

I found I described it as a lemon cough syrup that's exactly how it tasted to me which is still gross but easier than I thought it would be and I used extra cold water where every time my husband was drinking down the syrup he would take a drink of cold water on the side to keep the taste out of his mouth but it's so easy

Jeriandjeff 6 Jan 2018

I found I described it as a lemon cough syrup that's exactly how it tasted to me which is still gross but easier than I thought it would be and I used extra cold water where every time my husband was drinking down the syrup he would take a drink of cold water on the side to keep the taste out of his mouth but it's so easy

Jhumphrey6455 7 Mar 2018

I am doing my first colonoscopy prep. I had great reservations about the prep. However, I found the solution to be fine. Just tasted like salty lemon water. No smell either. It took affect in about 30 minutes. I had about 4 bowel movements before taking the second dose. It also wasn’t any concern getting to the toilet. Not that bad.

jrm2fla 30 Jun 2011

I started taking the Suprep mixture at 5:40pm as directed, taking large sips every 10 minutes for an hour until I drank the whole cup (the bottle of Suprep plus water up to the 16 oz. mark.) As advised, I sucked on hard butterscotch candy and Altoids (original mint flavor) to get the taste out of my mouth. My wife warned me about the process. I thought it woud start working in 15-25 minutes. Instead, by the time I drank 9/10 of the cup, at about 6:30pm, it was working (about 50 minutes.) The effect is like diarrhea. As directed, over the next hour, I drank an additional 32 oz. of water. I kept going intermittently for over 90 minutes. It was best not to leave the bathroom during that time. I had my laptop so I just watched a Netflix movie to keep distracted. Now it is 8:30pm and I have not gone for a while. I was able to move to the bed but I am ready to sprint to the bathroom if need be! I have to repeat the process to tomorrow morning early, before my 12 noon colonoscopy.


Happy happy joy joy. I noted that Apprehensive did not submit a post later to tell of his / her experience. Oh well. Good luck to any of you who go through it.

Votes: +4
GG_65 27 Jul 2018

I am having a colonoscopy in 2 hours I drank the prep for the 1st time at 5 pm yesterday YUCK... at 4 this morrnin started he 2nd ... it took 30 min after the 1st I was in the bathroom for 3 hours I have 20 min to finish the 2nd but haven't been to the bathroom yet but feel it may be coming on UGH... mine however was not clear by the time I was done hoping it is by the time it kicks in and hoping I don't have issues on way to get it done it's 20 min away lol good Luck to any & ALL who has to have this done

jmed4144 31 Jan 2012

The length of time it takes for Suprep to act and the duration of the action appear to be quite variable. Most other reports are of much more immediate action. In my wife's case, taking the first dose at 5pm Sunday it did not produce any effect until AFTER the second dose at 3am (10 hours). The bowel movements continued for about 1-1/2 hours until about 5am. Thinking that all was over by 6am we left home for the procedure - about an hour drive - no problem. However, the second dose kicked in while in the waiting room about 8am (5 hours), not pleasant - but fortunately that was over in about 1/2 hour. The good news is that the Dr. reported that the prep was very good.


Our experience must be a record for length of delayed action. However, the Dr. did not seem to be greatly surprised. My wife, a retired nurse, followed the suggested dietary restrictions and the dosage instruction religiously. Perhaps those who have some issues with constipation should expect longer delays between taking Suprep and experiencing the bowel movements.

As unpleasant as it my sound, wearing "Depends" (and taking a spare) on the trip to the procedure may save some greater embarasment.

Votes: +5
ohjeezthatguy 9 Jul 2018

Looks like I might be in the same boat. 3 hours in and I'm getting cramps and noises but no "end results". I did have a fair amount of fiber last week, so I think I'm partially cleaned out from that. Usually it takes me between 3 to 5 hours before this prep work med all of the sudden hits me... but hard to say this time around. I usually take magnesium citrate, or morning enemas if it's a sigmoidoscopy, but this time they had me do the SuPrep route.

ohjeezthatguy 23 Sep 2018

Update on mine, it took about 6 hours before I started to go... but wow is all I can say. I was on the toilet for the next 1 and a half hours, with only 2 to 5 minute small breaks in-between blowing the lid off my toilet. There goes another ozone layer above my house. :(

I would go, clean up, lay back in bed on my side, and just as I would get slightly comfortable... time to go again. I went like 16 times total within a 10 hour time frame. I was thoroughly empty after round 2 of my Suprep. I managed to take both full doses, but needed the bathroom twice before my colonoscopy (thankfully in the waiting area and not after getting in my gown and bed).

End result: best checkup ever! Doc said I was in the best remission I've ever been in. Even the ulcers had healed over some. Looks like the high carb diet worked for me and cutting out more fats and trigger foods.

goldenbloom 7 Jul 2012

It takes about 20 minutes so don't go far from the bathroom. The first bottle was so horrible to drink but I found the secret --- the second bottle I mixed with very cold bottled water and drank it through a straw. Soooo much better because you could hardly taste or smell it. Works for about 3 hours so be ready. Good luck.

Votes: +2
muzzypat 12 Aug 2012

Just got done with 1st round. Smelled like fruity cough syrup. Mix well with COLD water. Use a straw and get it as far back into your mouth as possible to avoid a lot of taste buds. Then drink 2 more 16oz glasses of cold water. The cold water helps to wash the somewhat strange taste away. No nausea, no cramping, just cold from all of the cold water. Feel like I'm cleaned out and it's about 1.5 hrs since starting. Hope this helps. A whole lot better than GoLytely. I go through this again at 4 a.m.

Votes: +2
plenk 18 Feb 2013

For me it took about 4 hours before it started working after the first dose. I had a lot of uncomfortable cramps starting about an hour after the first dose and continuing through 5 hours afterwards.

Votes: +2
Ccakes 28 Mar 2013

For me as well, I'm going on four hours. I took it (suprep) at 2:00pm as instructed. About 45 min later I had a Normal bowel movement. Just now at 5:45 had a very tiny normal bowel movement. Lots of cramps and some nausea. Sipping on chicken broth right now and cramping. Hopefully it will really kick in b/c I'm not really looking forward to taking this again at 6am! The taste is supposed to be berry flavored but I thought it tasted like concentrated grape, and I love grape but not this... Hope it works soon...

plenk 28 Mar 2013

The 2nd dose is what really cleaned me out. This wasn't near as immediate as the GoLYTELY prep.

Dave120462 16 Mar 2013

I really don't understand all the stuff about the taste. It really wasn't that bad it tasted like cough medicine to me. Being on the toilet was the bad part. I drank my first dose at 3pm about 8 minutes later I felt a strange feeling in my stomach at 20 minutes in I was going to the bathroom. My sister said it wasn't that bad her problem was having to drink all the water. I on the other hand didn't have problems with the water part. All I can say is drink only what they tell you to. I can drink and drink so I kept going. Oh yeah and after you take your first dose if you think you have gas you should run to the bathroom lol

Votes: +3
cbrenk 2 May 2013

I took the suprep at 6:00 pm and it had no effect (except some mild cramping and headache). I took it again at 4:00 am and I am still waiting for an effect 2 hours later! Headache is worse.
I may have to cancel the colonoscopy. I had a similar experience 2 years ago and I'm surprised my doctor didn't try giving me something different. I guess this stuff works well for 99% of people and I'm one of the 1%.

Votes: +2
Mharlow92 1 Sep 2016

For me... 37 minutes!!! From my last swallow of the 16 oz of water after my first bottle... 37 minutes to action. Then after the second bottle and another 16 oz of water... Round two. It started tapering off after probably 2 hours of the last dose. Thank God. This is my first experience with a colon flush and lemme tell ya... Suprep don't play!!!

Votes: +1
Pinkpeonies 11 Sep 2016

I started my first bottle at 5pm, with instructions to drink that mixed with water up to the 16 oz. mark and then 32 more oz. of water within the next hour. It's now 6:30pm and I'm almost done with the 32 oz. The stuff began working within 15-20 minutes (granted, I'd been having bouillion in the afternoon so that was also salty and probably began the flushing process). The stuff made me nauseous almost right away but I managed to hold it off for over half an hour. At some point, I threw it up (it's disconcerting enough when your poop sounds like pee; it's even worse when the force of vomiting has an effect at the other end at the same time... and it tastes just as bad coming up as it did going down). There's go to be an easier way to do this--I know there is because I've had to do bowel prep for abdominal surgery in the past and never got as sick as I did with this stuff. Yuk. Not looking forward to waking up at 3am to start all over again with the 2nd bottle.

Votes: +3
gristd 19 Jun 2017

How did your scope go. I'm having similar problems. I took first dose at 5 pm. Did have any results other than severe nausea. Took second dose at 10pm and immediately had to excite too bathroom it's now midnight, still going but nothing is clear. I'm not sure if this is the first dose going thru. I really can't do this prep again. I've suffered two anxiety attacks. This is horrible. I know it's late, but I hope your answer. Thanks for letting me vent. I hope I didn't gross you out. Also, we're they able to get a good scope in your case

becca30 28 Sep 2017

I did my first dose at 4 pm today I had my first bowel movement with 20 minutes after taking it I have to take my second dose at 8 pm today . The taste is awful to me this is my second colonoscopy ever done I don’t want to drink this crap again

Nan Moore 1 Nov 2018

Took the first dose at 725Pm. Had a slight round of diarrhea an hour later. At 915 it began in earnest and for the next hour it was constant. Not looking forward to my 2AM dose but hopefully since most everything is thru I can still get a bit of sleep before the procedure at 9.

Ctx2 12 Sep 2016

First round. 5 pm. The flavor tasted like amped up Sweetarts. Nothing but stomach cramps until 7 pm. Then I stayed in the bathroom for ONE hour straight. Every time I thought it was over, nah. I finally was able to go to bed at 10 pm. Next round at 2:30. Five minutes after finishing the rumbling started and here we go again (no pun intended). It's 3:41 am and I am surprised my system even has anything left, but I'm still hanging out in the bathroom. Oddly, I was freezing during this time and it is rare for me in the Summer/early Fall to ever be cold.

Votes: +1
Cbbesh 15 Feb 2017

This is pretty much my experience. I was not expecting to feel cold, but I am very chilled and a little dizzy.

Gaylemae 20 Sep 2016

Within 10 minutes of starting first dose, I was on the bathroom for about an hour straight. It feels like liquid coming out, and my stomach was pretty distended. No cramps or gas but I wound up having to use a paper towel between my cheeks to not leak when rushing to sit. Didn't do 2nd bottle. Taste was horrible, got chills, don't dare cough unless on toilet

Votes: +2 free discount card

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