What Type of Magnesium Is Best?

The Short Answer

The best magnesium depends entirely on your goal: glycinate for sleep, citrate for constipation, and L-threonate for brain health. There is no single "perfect" magnesium for everyone.

You should actively avoid magnesium oxide. It is the most common form found on drugstore shelves, but it has a pathetic 4% absorption rate and is practically guaranteed to cause digestive distress. If you want to dive deeper into the top brands, check out our guide on the Best Magnesium Supplement.

Why This Matters

Magnesium is the master mineral responsible for over 600 biochemical reactions in your body. It regulates everything from your heartbeat and muscle contractions to your brain's neurotransmitter production. Without enough of it, your biological engine runs rough.

Up to 75% of Americans are chronically deficient in magnesium. Modern industrial farming has severely depleted our soil quality, meaning even a perfect organic diet might not provide enough. While we usually advocate trying to Get Everything From Food, magnesium is one of the few exceptions where supplementation is often necessary.

Taking the wrong form is a complete waste of money. Because the supplement industry is poorly regulated, brands pad their margins by using the cheapest elemental magnesium available. You end up flushing your money down the toilet—often literally, as cheap magnesium pulls water into your intestines and causes diarrhea.

What's Actually In Your Magnesium Supplement

Different forms of magnesium are simply elemental magnesium bound to a "carrier" molecule. This carrier dictates how well the mineral absorbs and where it goes in your body.

• Magnesium Glycinate — Bound to the calming amino acid glycine. It is highly bioavailable, won't cause diarrhea, and is the absolute best Magnesium For Sleep and anxiety.
• Magnesium Citrate — Bound to citric acid. It absorbs fairly well but actively pulls water into your bowels, making it the perfect choice for constipation but risky for daily use. Read more in our Magnesium Glycinate Vs Citrate breakdown.
• Magnesium L-Threonate — Bound to threonic acid. This is the only form proven to cross the blood-brain barrier, making it the top choice for cognitive function and focus.
• Magnesium Malate — Bound to malic acid, which is involved in your body's energy cycle. It is highly recommended for morning use, chronic fatigue, and muscle pain.
• Magnesium Oxide — Bound to oxygen. It has a laughable 4% absorption rate and acts almost exclusively as a harsh laxative.

What to Look For

Green Flags:

• "Fully Chelated" on the label — This means the magnesium is securely bound to its carrier amino acid, guaranteeing it will survive your stomach acid and actually absorb.
• Third-party testing — Look for certifications ensuring the product is free of heavy metals and accurate in its dosing. Understanding Third Party Tested Meaning is vital for safe supplementation.

Red Flags:

• Magnesium Oxide as the first ingredient — Brands often hide this cheap ingredient in "magnesium complexes." If oxide is listed first, put the bottle back.
• Proprietary blends — If the label says "Magnesium Blend" but doesn't tell you exactly how much of each form is included, they are hiding cheap ingredients behind a fancy label.

The Best Options

We prefer brands that prioritize high-absorption chelated forms and independent testing. For a deep dive into brand reliability, see our evaluation of whether Is Thorne Good.

The Bottom Line

1. Match the form to your symptoms. Use glycinate for relaxation, citrate for digestion, and malate for muscle energy.

2. Read the ingredient list carefully. Never pay premium prices for supplements that use magnesium oxide as their primary ingredient.

3. Take it at the right time. Take energizing malate in the morning, and take calming glycinate about an hour before bed.

FAQ

When is the best time to take magnesium?

It depends entirely on the form you are taking. Take magnesium glycinate right before bed to improve your sleep architecture, but take magnesium malate in the morning since it supports cellular energy production.

Can you take too much magnesium?

Yes, but the primary side effect is simply diarrhea. The tolerable upper intake level for supplemental magnesium is 350mg per day for adults. For a full breakdown of toxicity risks, read Can You Take Too Much Magnesium.

Which magnesium is best for anxiety?

Magnesium glycinate is the gold standard for stress relief. Because it is bound to glycine—an inhibitory neurotransmitter that calms the central nervous system—it offers a synergistic relaxing effect. Read our complete guide on Magnesium For Anxiety for specific dosing protocols.