What Is Slow Mag Magnesium and What Type of Magnesium Is in It?

SlowMag Mg is a US dietary supplement whose magnesium comes from magnesium chloride, delivering 143 mg of elemental magnesium per two-tablet serving.

Magnesium chloride is the compound doing the work in the flagship SlowMag Mg tablet, and knowing that matters more than the brand name on the bottle. The US label pairs 143 mg of elemental magnesium with 238 mg of calcium in every two-tablet dose, a combination the manufacturer pitches at muscle, nerve, and heart support. Read the panel once and two things become clear: what you’re actually swallowing, and where the numbers get confusing.

What Type of Magnesium Is in SlowMag?

SlowMag Mg uses magnesium chloride as its magnesium source, not magnesium oxide, citrate, or glycinate. The US label lists magnesium chloride directly, alongside calcium and chloride, in a 60-tablet bottle built around a two-tablet serving.

The full per-serving breakdown, per the label record filed with the NIH Dietary Supplement Label Database:

• Magnesium: 143 mg (36% Daily Value)
• Calcium: 238 mg (24% Daily Value)
• Chloride: 416 mg (12% Daily Value)

Those 60 tablets equal 30 labeled servings, so a bottle lasts about a month at one serving daily. The label directs two tablets once or twice daily, or as a physician advises.

Why the Magnesium Chloride Number Confuses People

The 143 mg figure refers to elemental magnesium, not the weight of the magnesium chloride compound itself. That gap trips up plenty of label readers, and it’s worth understanding before you compare products.

Magnesium chloride weighs considerably more than the magnesium it supplies, so a tablet can contain a large amount of the compound while reporting a smaller elemental number. The US label sidesteps the confusion by reporting elemental magnesium outright. A separate non-US Slow-Mag tablet is described as containing 535 mg magnesium chloride equivalent to 64 mg elemental magnesium per tablet, a completely different formulation and labeling convention. Don’t swap one spec for the other.

The branding has also branched. A SlowMag Magnesium Glycinate Calm + Stress slow-release product exists in a 50-count size, and its magnesium form is magnesium glycinate, not chloride. Two products, two different magnesium types, one shared name family. Check the panel every time rather than assuming.

If you’re weighing which magnesium form suits your needs, this comparison of magnesium options for slow COMT walks through the practical differences.

Who Should Be Careful With SlowMag?

Magnesium supplements are generally well tolerated, but magnesium chloride can cause diarrhea or bowel discomfort, and kidney function changes the risk picture entirely. People with impaired kidneys should talk to a doctor before starting, because reduced clearance can let magnesium build up.

Calcium and magnesium can also interfere with how some medications absorb, including certain antibiotics, thyroid medicine, and osteoporosis drugs. The US label excerpt doesn’t publish a full interaction schedule, so read your bottle and ask a pharmacist about anything you take regularly. The manufacturer’s SlowMag Mg product information covers the intended positioning, and the NIH label record is the authoritative panel to verify current numbers.

One more practical note: taking two tablets twice daily without checking total magnesium from other supplements can push you past what you intended. Add up every source first.

SlowMag Quick Reference

Keep these points straight and the label stops being confusing:

• Magnesium source is magnesium chloride, with calcium added.
• 143 mg elemental magnesium per two-tablet serving — not 143 mg of compound.
• 60 tablets per bottle equals 30 servings.
• Labeled dose is two tablets once or twice daily.
• Kidney disease or regular prescriptions? Get medical advice first.
• Magnesium glycinate appears under similar branding — read the panel.