How Long It Takes For Magnesium Citrate To Wear Off

If you've ever been unable to go to the bathroom for days, you know how uncomfortable you can get — and how quickly you want your issue to go away. For most people, magnesium citrate is considered a safe way to combat occasional constipation.

Magnesium citrate is a supplement that features magnesium and leverages citric acid to improve its bioavailability. In fact, citric acid makes an excellent partner to enhance magnesium's absorption rates. According to a 2019 study in Magnesium Research, subjects who were given magnesium citrate showed higher concentrations of magnesium within 24 hours than those who ingested only magnesium.

You can find magnesium citrate as a liquid product, as well as in pills, tablets, softgels, etc. However, it's the liquid version that may leave you wondering, "When will these magnesium citrate effects wear off?" Here's why: When consumed as a liquid, magnesium citrate starts to attract water into your digestive tract. This causes the waste in your bowels to soften, as well as begin to move rapidly out of your body. (In other words, stock up on toilet paper and avoid taking magnesium citrate before going to sleep.) In general, the effects of magnesium citrate in its liquid form should wear off within about four hours. This isn't an exact figure, though.

This doesn't mean you should rely on magnesium citrate if you're having constipation nearly every day. As gastroenterologist Dr. Kyle Staller explained to WebMD, magnesium citrate isn't designed for constipation caused by chronic bowel problems. Nonetheless, it can be taken occasionally as a "rescue" laxative because "when you really can't go, magnesium citrate can be a potent, over-the-counter treatment that can help people go."

In addition to being a fairly dependable way to overcome your more infrequent cases of backed-up bowels, magnesium citrate can also help "clean out" your gastrointestinal system in advance of certain medical visits. For example, doctors frequently tell patients to use magnesium citrate in preparation for colonoscopy and similar procedures. (Getting your first colonoscopy? Know what to expect from a colonoscopy.)

The only issue is that once you feel the full effects of magnesium citrate, you want to be close to a bathroom. And you probably also want to have some indication of when you won't be running to the toilet regularly anymore.

Sometimes, it can take about six hours for magnesium citrate to fully kick in and produce any obvious benefits. Therefore, you probably want to wait until you're no longer having bowel movements before getting in your car or heading out for a long bike ride.

Just be sure that you continue to drink water after taking magnesium citrate unless you're given other directions by a medical professional. After all, you certainly don't want to solve your constipation or go through the (sometimes arduous) process of getting prepared for a colonoscopy, only to experience the nagging warning signs of dehydration.

Of course, you may only want to take magnesium citrate as a daily supplement to make sure you get enough magnesium. In that case, you should take a dose that's small enough not to make you run to the bathroom. How much is too much? You can use the upper limit recommendations from the National Institutes of Health (NIH) as a guideline: 350 milligrams each day, with the expectation that you'll make up the rest of the magnesium you need with food.