How Long Does It Take for Magnesium Citrate to Work?

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    Magnesium Citrate is both a laxative and a supplement. The time it takes to work varies based on how much you’re taking and when you’re taking it.

    What is magnesium citrate?

    Magnesium citrate is a magnesium supplement that is one part magnesium salt and one part citric acid. Magnesium is an essential element that helps to maintain nerve and muscle function, supports a strong immune system, helps to keep bones and teeth strong, keeps the heartbeat steady, and is necessary for the production of energy in the body. Citric acid, a flavor enhancer commonly used in the restaurant industry, increases the bioavailability of the magnesium, making its absorption into the digestive system easier and more abundant.

    How does magnesium citrate differ from other forms of magnesium?

    The main difference between magnesium citrate and magnesium in its other forms concerns absorption, particularly along the digestive tract. The body is only able to absorb a small percentage of the magnesium in most other magnesium supplements. But the combination of magnesium and citric acid creates a more highly absorbable form of magnesium supplement, thereby increasing magnesium absorption along the digestive tract.

    Magnesium citrate's role in the body

    Magnesium is the fourth most abundant mineral in the human body. It is classified as an essential mineral, one that cannot be made by the body but instead must come from food sources or supplements. Magnesium citrate is a specific form of a magnesium supplement. Magnesium deficiency is one of the most prevalent nutrient deficiencies affecting the world’s population. The role of magnesium citrate is to aid the body’s magnesium absorption.

    What is magnesium citrate used for

    Magnesium citrate is most commonly known as a “saline laxative”, which is to say, a salt laxative used to enable bowel movements or clean the colon prior to a colonoscopy. It can also be used as a regular form of magnesium supplementation. If preparing for a colonoscopy, it is important to follow your physician’s instructions exactly as written.

    Potential downsides from taking magnesium citrate

    Magnesium citrate pulls water into the intestines from other areas of the body. It is important to drink plenty of water when taking it as well as throughout the day in order to prevent dehydration and electrolyte imbalances.

    It can also cause stomach cramps, a rumbling feeling in the stomach, intestinal gas, nausea, vomiting, loose stools, and diarrhea. These side effects are generally mild and easily remedied. Drinking alcohol when taking magnesium citrate may worsen diarrhea and other gastrointestinal side effects.

    How to use magnesium citrate

    Magnesium can typically clear and excrete through your body within 24 hours, which is part of the reason magnesium deficiency is so common. In order to reach and maintain optimal magnesium citrate intake, it should be taken consistently to ensure your magnesium levels are within the normal range.

    Follow the directions of your physician or the recommendations on the label when supplementing with magnesium citrate. It can usually be taken with or without food depending on your reason for taking it.

    Magnesium citrate can be taken at any time of the day, unless your physician has a specific recommendation that meets your needs. Try to take it the same time each day without missing any days.

    If using a powdered form of magnesium citrate, it generally works faster when mixed with warm water. Drink plenty of water when supplementing with magnesium citrate to avoid potential dehydration.

    If you are using magnesium citrate to increase the level of magnesium in your blood, you may want to start with smaller doses to avoid digestive discomfort, or a different form that is absorbed more easily with less chance for discomfort, such as magnesium glycinate, hydroxide from Irish seawater, or chloride.

    How long does it take magnesium citrate to work?

    How quickly magnesium citrate works depends on the dose, the supplement delivery method, the length of time you are taking it, and the reason for supplementing. If you are taking a tablet, consistency with low-dose, longer-term supplementation is the key to maximizing effectiveness. You may begin to notice improvements after about a week of supplementation, but do not waiver from your dose as directed. If you are using transdermal magnesium it works instantly due to the quick absorption through the skin, which bypasses the digestive system.

    How long until magnesium citrate will make you poop?

    If you are taking magnesium citrate for bowel movement support, you could feel the effect anywhere from 30 minutes to 6 hours after taking it. If you have loose stools, it is important that you stay hydrated to avoid dehydration. If you are taking magnesium citrate as part of a colonoscopy prep routine, you will likely feel the effects within an hour, and they will continue for an extended period of time. Carefully follow the instructions given to you by your physician.

    The recommended dietary allowance (RDA) of magnesium is between 200-420mg per day, depending on your age, gender, and general health status. The type of magnesium and even the particular brand you’re taking may also impact the dosage. When in doubt, check with your physician about the best dosage for your needs.

    Can you take magnesium citrate daily?

    It is safe to take magnesium citrate on a daily basis as long as you are following the proper recommended dosage. If you plan on taking it long-term, discuss with your physician. If you are taking magnesium citrate as a laxative, it is probably not a good idea to do so on a regular basis.

    When is it best to take magnesium citrate?

    The best time to take magnesium citrate is a matter of personal preference, unless you are instructed to take it at a specific time by your healthcare provider. If you are taking it on a daily basis, it is best to take it at or about the same time every day, for consistency and to avoid taking multiple doses too closely together. If you are using magnesium citrate for bowel support, time your use so that you have sufficient access, and alone time, to use the restroom adequately.

    Potential side effects and risks for taking magnesium citrate

    Magnesium citrate may cause gastrointestinal issues including nausea, vomiting, gurgling stomach, bloat, gas, loose stools, and diarrhea. It may also lead to dehydration if you are not drinking enough water while supplementing. Some of the side effects can be eliminated by simply reducing the dosage and slowly returning to the prescribed level. More is definitely not better when it comes to supplementation.

    Who shouldn't take magnesium citrate?

    People who are pregnant or lactating, and people who have kidney issues should not take magnesium citrate without speaking with their physician. If you are taking any medications, it is always important to speak with your healthcare provider.

    Final takeaways

    Magnesium citrate is an over-the-counter magnesium supplement that is often thought of as a “saline laxative” because it relieves occasional constipation and is used to clear out the intestines as part of a colonoscopy prep. It can also be used to supplement magnesium levels in an effort to maintain optimal levels. High doses of magnesium citrate may cause digestive distress including diarrhea, loose stools, nausea, cramps, vomiting, abdominal pain, and dehydration. Follow the recommended dosage carefully and always consult your physician when beginning a new supplement program.

    Care/of has an excellent article that is a simple guide to Citrate of Magnesia.

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    Dr. Carla Montrond Correia ND, CNS
    Medical Content Manager
    Dr. Montrond-Correia is a licensed naturopathic physician and a certified nutrition specialist (CNS). She holds degrees from University of Bridgeport, Georgetown University, and University of Saint Joseph, and supplemented her education with internships in the health and wellness space. She's focused on research, herbal medicine, nutrigenomics, and integrative and functional medicine. She makes time for exercise, artistic activities, and enjoying delicious food.
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