Magnesium
Magnesium citrate
4.0 (843 owner comments)
RegularityPain & cramping
“Today I would take some magnesium citrate, because wherever is fermenting in your gut needs to be released not stuck up inside of you.”
What owners report →Medical disclaimer: GutVerdict summarizes what people say about supplements on Reddit. It is not medical advice, and nothing here is meant to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the Food and Drug Administration. Talk to your doctor or pharmacist before starting a supplement, especially if you are pregnant, take medicines, or have a medical condition. New, severe or worsening symptoms (such as blood in the stool, weight loss, fever, or night-time symptoms) need a doctor, not a supplement. Full disclaimer.
Magnesium · tablets or capsules
Magnesium oxide: What People With IBS Report on Reddit
Illustration, not a product photo.
A poorly absorbed magnesium salt with a strong osmotic effect in the bowel.
4.0 GutVerdict score
279 owner comments (113 with a clear rating) from r/Constipation, r/SIBO, r/IBS, r/Microbiome, r/Supplements, November 2025 to October 2026. Top 20% of the 36 rated supplements.
Owner sentiment3.9
Recommendations3.0
Tolerability4.7
ValueNot rated
Value is not rated: the example products differ too much in dose to compare cost fairly. How we score.
The short version
Magnesium oxide is rated about average among the supplements we track: 4.0/5. Of 113 rated owner comments, 97 were positive, 5 mixed and 11 negative; 10 mention an unwanted effect. People talk most about regularity and bloating & gas.
Reddit comments are self-reported and unverified. They tell you what people noticed, not whether a supplement works or is safe for you.
Not all magnesium acts the same; read which magnesium form owners use for regularity. Read which gut supplements need extra caution first. There is a separate ranking of what people with SIBO rate highest.
What it is
- A 2021 placebo-controlled trial compared magnesium oxide and senna for chronic constipation.[PubMed]
- The 2023 AGA-ACG constipation guideline discusses magnesium oxide among osmotic options.[PubMed]
Safety and interactions
- The NIH upper limit for supplemental magnesium is 350 mg a day for adults unless a doctor advises more; people with kidney disease are at higher risk of magnesium build-up.[NIH Office of Dietary Supplements]
- Magnesium can interfere with some antibiotics and bisphosphonates; space doses apart.[NIH Office of Dietary Supplements]
Supplements can interact with medicines. Talk to a doctor or pharmacist first, especially if you are pregnant, take prescription medicine, or have red-flag symptoms. See supplement safety and interactions.
Reports by symptom
| Context | Rated owner comments | Positive | Negative | Unwanted effects |
|---|---|---|---|---|
| IBS-C & constipation | 78 | 67 | 7 | 7 |
| SIBO | 36 | 31 | 4 | 1 |
| Bloating & gas | 15 | 15 | 0 | 0 |
| Pain & cramping | 15 | 11 | 4 | 2 |
| IBS-D & loose stools | 6 | 5 | 1 | 1 |
| After antibiotics | 3 | 3 | 0 | 0 |
What Reddit owners say
Commonly praised
- Regularity: 10 owner comments
- Bloating & gas: 9 owner comments
- Fast-acting: 5 owner comments
Common complaints
- Side effects: 8 owner comments
- Pain & cramping: 3 owner comments
- Regularity: 3 owner comments
4/5“Now at 32 I have not had an attack like this in almost a year whilst taking 400mg of magnesium oxide every night before bed..”
4/5“The Micromag looks like all magnesium oxide (I may be mistaken), to give the higher percentage of magnesium inside each molecule, but this is a grey area for me because I don't know what that would do in the body.”
4/5“Magnesium oxide at bedtime helped me tremendously.”
1/5 Pain & crampingRegularity“I take a daily magnesium oxide supplement every night before bed.”
1/5 Taste & texture“You need to stir it and drink quickly to stop all the magnesium oxide powder sinking to the bottom of the glass.”
+30 more owner comments
4/5 Bloating & gasGentle“I've used magnesium oxide in the past and worked perfect for me.”
4/5“Mag oxide helps me - I take the Walmart brand, Equate I think.”
4/5 GentleRegularity“I have found pretty good regular motility on Heather’s Tummy Fiber but when I feel backed up I take 3-4 (recommended dosage is 4) capsules of Oxy-Powder (about once every 10 days) which is magnesium oxide.”
4/5“No other magnesium or magnesium oxide products have worked like this one.”
4/5 Bloating & gas“Taking high does Mag oxide stopped helping.”
4/5“I’ve been using 400 mg of magnesium oxide daily for years(4 years or so).”
4/5 Fast-acting“I'm taking magnesium oxide before bed and that's helping me go the next day.”
4/5 Regularity“I just recently found out magnesium oxide has done wonders for me.”
4/5 Cost“All you need is a magnesium oxide powder for a bowel flush tbh.”
4/5“I'm taking magnesium oxide mag07, and it's helping me get cleared out.”
5/5“I take 400mg magnesium oxide daily and works wonders!”
4/5“Mag oxide works better for me.”
4/5“I use Ozonated Magnesium Oxide now and it works much better and was recommended by my GP and the gastroenterologist who did my colonoscopy.”
4/5“You could try some magnesium oxide. That worked well for me.”
4/5“The recommended daily dose on the powdered form I occasionally use measures out as 1.6g magnesium oxide.”
4/5 Gentle“Sometimes I crave chocolate and I know that's linked to magnesium, MagO7 magnesium oxide has been gentle and I take 1 pill before bed it usually works the best day.”
4/5 Fast-actingSide effects“Idk I usually use Mag07 by NBPure, it’s magnesium oxide, way better for this and it’s smooth, doesn’t upset stomach.”
2/5 RegularitySide effects“Mag oxide isnt absorbed as well BUT is helpful for migraines and for bowel regularity.”
4/5 Fast-actingRegularity“I wake up early & drink Hot water & Gatorade while left side laying with deep belly breathing magnesium oxide before bed helps too it’s not intense or anything just helps give a normal bowel movement the next morning”
4/5 CostPain & cramping“I used to buy magnesium o7 and it worked but is expensive - so I tried an experiment and bought magnesium oxide and it works as well, if not more effectively as the mag o7.”
4/5 Stool form“Metagenics motility has helped me, I use with magnesium oxide and from the day I started taking my stools started to for normal shape and consistency and it's helped get past incomplete emptying it's not a laxative it helps move things through the system”
3/5 Side effectsTaste & texture“I was having magnesium oxide mixed in a glass of water for a couple of years.”
5/5“Mag oxide 1000 mg , and two ginger/artichoke pills first am have been a game changer for me”
2/5 Pain & crampingRegularity“One recent change, I had terrible gastroenteritis for about a week and as a result I stopped taking a magnesium oxide supplement that my GI doc had recommended for constipation.”
5/5“For constipation a ton of mag oxide was a game changer for me.”
4/5“I take 400mg of magnesium oxide every night and have had great luck!”
5/5“But honestly I took that Dada dudes advice from here and Dr janel advice with 1300 mg mag oxide night and morning and I have felt amazing.”
4/5“I take magnesium oxide every night and some betaine HCL with most meals.”
4/5 Bloating & gas“You've probably already tried this but, magnesium oxide helped me a ton with the brain fog, dizziness, muscle twitchiness, and most importantly it reduced my morning bloat.”
4/5“Ahh yeah I actually had been taking magnesium oxide before.”
Example products
These are examples of Magnesium oxide products sold on Amazon. They are not ranked by Reddit and the score above is for the ingredient, not a specific product. Check the label for dose and other ingredients.
Example product · not Reddit-scored
Nature Made Magnesium Oxide Extra Strength 400 mg, 60 Softgels
$11.72 on Amazon (price as of 2026-11-03). Prices change; check Amazon for the current price.
Example product · not Reddit-scored
Rugby Magnesium Oxide 400 mg Tablets, Dietary Supplement, Gluten-Free
$5.89 on Amazon (price as of 2026-11-03). Prices change; check Amazon for the current price.
Research to read
Published studies (we list them so you can read the evidence yourself; inclusion is not an endorsement):
- Am J Gastroenterol 2021: Senna Versus Magnesium Oxide for the Treatment of Chronic Constipation: A Randomized, Placebo-Controlled Trial.
- Gastroenterology 2023: AGA-ACG Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation.
FAQ
What do people with IBS say about Magnesium oxide on Reddit?
Across 279 Reddit comments from people who say they have used it, 97 of 113 rated comments were positive and 11 negative, for a GutVerdict score of 4.0/5. These are self-reported experiences, not clinical evidence.
Do people report side effects with Magnesium oxide?
10 of 113 rated owner comments (9%) describe an unwanted effect such as gas, bloating or an upset stomach. Check the safety notes on this page and ask a doctor or pharmacist before starting.
Who talks about Magnesium oxide most?
Most rated owner comments come from people with IBS-C or constipation (78 comments, 67 positive).
Is Magnesium oxide scored on clinical evidence?
No. The score summarizes Reddit owner comments only. Factual statements on this page link to NIH or PubMed sources, and nothing here is medical advice.
Related supplements
Magnesium
Magnesium glycinate
3.7 (264 owner comments)
RegularitySide effects
“Manage stress (I take L theanine and magnesium glycinate and it’s helped me to have a calmer response)”
What owners report →
Digestive enzymes
Digestive enzymes
4.3 (809 owner comments)
Bloating & gasPain & cramping
“I began to take 1 capsule before each meal together with digestive enzymes and my symptoms lessened by about 70-80% in a few weeks.”
What owners report →Comparisons: Magnesium citrate vs Magnesium oxide
Last updated 2026-11-03. Mentions scanned: 737 in 541 threads.