Most magnesium makes Crohn's worse. Here's what doesn't.

The short answer: Magnesium deficiency is common in Crohn's disease — but most standard magnesium supplements can worsen diarrhea and gut symptoms. The three forms most likely to be tolerated by a Crohn's gut are magnesium glycinate, magnesium malate, and magnesium L-threonate. Always introduce slowly and in conversation with your gastroenterologist or care team.

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I made a mistake with my son's supplements about two years into his Crohn's journey.

I knew — as a naturopath — that magnesium was important. Muscle function, sleep, nerve signaling, inflammation regulation. The research is solid. And I also knew that people with Crohn's and IBD are at higher risk of deficiency, because of malabsorption, because of the gut lining being compromised, because of the dietary restrictions that come with managing a flare.

So I added magnesium to his routine. Confidently.

Within days, his symptoms were worse. More urgency. More cramping. More time in the bathroom.

What I'd forgotten — or rather, what I hadn't applied carefully enough to his specific situation — was that the form of magnesium matters enormously. The supplement I'd chosen had magnesium oxide in it. One of the cheapest, most common forms. Also one of the most poorly absorbed. And one of the strongest natural laxatives you can take.

For a healthy gut, that might just mean a loose stool. For a Crohn's gut? It can trigger a cascade.

## Why Is Magnesium Deficiency So Common in Crohn's?

The Crohn's & Colitis Foundation notes that nutrient deficiencies — including magnesium — are among the most common complications of IBD. This happens for several reasons working against each other at once.

First, the inflamed gut lining absorbs nutrients less efficiently. Magnesium is absorbed primarily in the small intestine — which is often the most affected section in Crohn's disease. Second, diarrhea (a hallmark symptom of active disease) causes significant magnesium loss. Third, some medications used in Crohn's management can affect magnesium levels. And fourth, many people with Crohn's restrict their diet significantly during flares, cutting out foods that would otherwise be good magnesium sources — like nuts, seeds, and legumes.

Key takeaway: In Crohn's, magnesium deficiency isn't a lifestyle issue — it's a structural consequence of the disease itself, and it deserves clinical attention.

Symptoms of low magnesium can include muscle cramps, poor sleep, fatigue, headaches, and heightened anxiety — all of which can overlap with Crohn's symptoms, making it easy to miss.

## What Makes a Magnesium Form 'Gut-Friendly'?

Not all magnesium supplements are created equal. The key difference is how well each form is absorbed — specifically, whether it gets taken up in the gut before it reaches the colon.

Forms with low absorption rates (like magnesium oxide) draw water into the bowel as they pass through — which is exactly why they're used as laxatives. For someone with Crohn's, this is counterproductive at best and actively harmful during a flare.

Higher-absorption forms are bound to compounds (like amino acids or organic acids) that the gut can take up more readily. Less magnesium reaches the colon unabsorbed. Less osmotic effect. Gentler on the system.

## The 3 Forms Worth Discussing With Your Care Team

These are the three I look at first when supporting someone with Crohn's who needs magnesium — and what I now use thoughtfully for my son, in consultation with his medical team.

1. Magnesium Glycinate

This is the form I reach for most often. Magnesium is bound to glycine, an amino acid, which significantly improves absorption and dramatically reduces the laxative effect. It's one of the most well-tolerated forms for sensitive guts. Glycine itself has calming properties, which can support sleep — something many people with Crohn's struggle with. If someone in your family has Crohn's and needs magnesium support, this is usually the first conversation worth having with your naturopath or GP.

2. Magnesium Malate

Bound to malic acid (found naturally in fruit), magnesium malate is another highly bioavailable form with a gentler gut profile. It's often associated with energy production and muscle recovery — which makes it particularly relevant given the fatigue that's so common in IBD. Some people find it slightly more energising than glycinate, so it's worth taking earlier in the day.

3. Magnesium L-Threonate

This is the newest of the three and the most research-backed specifically for brain and nervous system support. It's been shown to cross the blood-brain barrier more effectively than other forms. For people with Crohn's who experience brain fog, anxiety, or the cognitive effects of chronic illness — which are real and underreported — this form is worth knowing about. It's typically the most expensive, but a small dose goes further.

What to avoid: Magnesium oxide and magnesium sulfate (Epsom salts, when taken orally) have the strongest laxative effects and the poorest absorption rates. Magnesium citrate sits in the middle — better absorbed than oxide, but still has a notable laxative effect that makes it tricky for Crohn's guts.

## How to Introduce Magnesium Safely With Crohn's

Even the gentler forms need to be introduced carefully. Here's what I always recommend — and what I did with my son:

- Start low. Begin with half the standard dose and build up slowly over 2-3 weeks.

- Take with food. This reduces the chance of any gut irritation.

- Time it right. Glycinate works well at night (the glycine supports sleep). Malate is better in the morning or early afternoon.

- Watch for changes. Any increase in urgency, cramping, or loose stools is a signal to reduce the dose or try a different form.

- Tell your GI team. This is always the most important step. Magnesium can interact with some medications, and your gastroenterologist should know what you're taking.

My husband — who's been in deep remission for over 20 years after three surgeries in his younger years — uses magnesium glycinate regularly. It took some trial to find the right dose, but it's been a consistent part of his routine for years now, always alongside his medical care.

## Common Questions

Can magnesium supplements trigger a Crohn's flare?

Certain forms — particularly magnesium oxide and citrate — can worsen diarrhea and cramping in people with Crohn's. This isn't a flare in the clinical sense, but it can significantly increase symptoms. Choosing a highly absorbable form (glycinate, malate, or threonate) and starting with a low dose reduces this risk considerably.

How do I know if I'm magnesium deficient with Crohn's?

A simple blood test (serum magnesium) can give you a baseline, though it doesn't always reflect total body stores. Symptoms like muscle cramps, poor sleep, fatigue, and headaches can also be indicators. Ask your GP or gastroenterologist to check your levels at your next appointment.

Is it safe to take magnesium with Crohn's medication?

Magnesium can interact with some medications, including certain antibiotics and medications used in IBD management. Always check with your pharmacist or GI team before adding any supplement to your routine.

What's the best magnesium dose for someone with Crohn's?

This varies depending on the individual, their current levels, their disease activity, and their medications. There's no universal answer — which is exactly why working with your care team matters. As a starting point, many naturopaths begin with 100-150mg of elemental magnesium from a gentle form like glycinate and adjust from there.

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This is the kind of thing I wish someone had handed me a guide for when my son was first diagnosed. The supplement world is overwhelming, and most of the advice online doesn't account for the specific challenges of a Crohn's gut.

You're not doing anything wrong if you've tried magnesium before and it made things worse. You just needed a different form.

Here's the plan: bring this to your next appointment, ask for your magnesium levels to be checked, and if supplementation is appropriate, start with glycinate at a low dose.

As always — this supports your medical care. It doesn't replace it.

— Kate

The Crohn's Method