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Magnesium Glycinate vs Magnesium Sulphate: Which Is the Best Form of Magnesium?

Magnesium is an important mineral involved in over 600 metabolic reactions, including keeping your heart steady, helping you relax at night, energy production, muscle function and stress regulation. Yet, studies suggest that up to two-thirds of the U.S. population doesn’t get enough magnesium from their diet alone.

This is where the various types of magnesium supplements come in. But with so many different kinds of magnesium available — magnesium glycinate, magnesium sulphate, citrate, oxide and more — how do you know which one is right for you?

In this guide, we’ll compare magnesium glycinate and magnesium sulphate, two of the most commonly discussed forms.

Know what you’re looking for? Head there now:

• Understanding Magnesium: Why Does Form Matter?
• What Is the Difference Between Magnesium Glycinate and Magnesium Sulphate?
• Magnesium Glycinate
• Magnesium Sulphate (Epsom Salt)
• Magnesium Glycinate vs Magnesium Sulphate: Key Differences at a Glance
• Which Is Better: Magnesium Sulphate or Magnesium Glycinate?
• What Is the Best Form of Magnesium to Take?

Understanding Magnesium: Why Does Form Matter?

Before diving into the differences between magnesium glycinate and magnesium sulphate, it’s important to understand why the type of magnesium you take matters.

Not all magnesium supplements are created equal. Some are easily absorbed, making them great for daily use, while others are poorly absorbed and mainly used for specific purposes (like relieving constipation).

The key factors that determine how effective a magnesium supplement is include:

1. Bioavailability (How Well Your Body Absorbs It)

Some forms, like magnesium glycinate, are highly bioavailable, meaning your body can absorb and use most of the magnesium. Others, like magnesium oxide, are poorly absorbed, so you’d need much higher doses to get the same benefits, which is not always safe.

2. Side Effects (Especially Digestive Issues)

Some magnesium supplements (like magnesium citrate and sulphate) have a strong laxative effect, which can be useful for constipation but unpleasant if you just want general health benefits. Others (like glycinate) are gentler on the stomach, making them better for long-term use.

3. Additional Benefits (Beyond Just Magnesium)

Some forms, like magnesium glycinate, include glycine, an amino acid that helps with relaxation and sleep. Others, like magnesium sulphate (Epsom salt), are best used topically for muscle relaxation rather than taken orally.

Now, let’s break down magnesium glycinate and magnesium sulphate in detail.

What Is the Difference Between Magnesium Glycinate and Magnesium Sulphate?

While both supplements provide you with magnesium, their chemical structures, absorption rates and uses differ significantly.

Magnesium Glycinate

• Form: Magnesium bound to glycine (an amino acid).
• Bioavailability: Highly absorbable (gentle on the stomach).
• Best for: Sleep, anxiety, stress relief and long-term supplementation.
• Laxative effect? Minimal.

Magnesium Sulphate (Epsom Salt)

• Form: A salt compound (magnesium + sulphur + oxygen).
• Bioavailability: Poor when taken orally; better absorbed through the skin in baths.
• Best for: Muscle relaxation (topically), constipation relief (orally).
• Laxative effect? Strong (when taken internally).

Magnesium Glycinate

What Is Magnesium Glycinate?

Magnesium glycinate is a chelated form of magnesium, meaning it’s bound to glycine, an amino acid. This combination makes it one of the most absorbable and gentle forms of magnesium available.

Magnesium Glycinate Benefits

• Highly bioavailable: Your body absorbs it efficiently, so you get more magnesium per dose.
• Helps with relaxation & sleep: Glycine has calming effects on the brain, making this form great for insomnia and anxiety.
• Reduces anxiety & depression: Studies suggest it may help regulate mood.
• Gentle on the stomach: Unlike magnesium citrate or sulphate, it rarely causes diarrhoea or cramps.
• Helps with muscle recovery and nerve function: Great for athletes or those with muscle cramps and helps with nerve health.

Further Reading: Magnesium Glycinate and Anxiety

Magnesium Glycinate Side Effects

• Rare, but very high doses might cause mild nausea or dizziness.
• Generally considered one of the safest forms for long-term use.

Magnesium Glycinate is Best For:

• People with anxiety, insomnia or chronic stress.
• Those needing a well-absorbed magnesium supplement without digestive upset.
• Athletes or anyone with muscle cramps or tension.

Further Reading: Magnesium Glycinate FAQs Part 1

Magnesium Sulphate (Epsom Salt)

What Is Magnesium Sulphate?

Magnesium sulphate, commonly known as Epsom salt, is a mineral compound of magnesium, sulphur and oxygen. It’s most famous for being used in baths to soothe sore muscles, but it can also be taken orally as a laxative.

Magnesium Sulphate Benefits

• Soothes sore muscles: Many people soak in Epsom salt baths to ease muscle pain and stress.
• Relieves constipation: Doctors sometimes prescribe it for constipation relief before medical procedures, taken orally.
• May help with minor bruises/cuts: Some use it topically for bruises, cuts or skin inflammation.

Further Reading: Magnesium’s Benefits on Muscles

Magnesium Sulphate Side Effects

• Can cause diarrhoea, stomach cramps and dehydration if taken in excess. 
• Skin irritation in some people when used in baths.
• Most of it flushes out of your system before being properly absorbed.
• Risk of overdose if consumed in large amounts, albeit rare.

Magnesium Sulphate is Best For:

• People looking for temporary relief from constipation (short-term use only)
• Topical use (baths, lotions) rather than oral supplementation.
• Those who enjoy Epsom salt baths for muscle relaxation

Magnesium Glycinate vs Magnesium Sulphate: Key Differences at a Glance

Feature	Magnesium Glycinate	Magnesium Sulphate
Absorption	High (well absorbed)	Low (oral)/Moderate (topical)
Best Uses	Sleep, anxiety, daily long-term supplementation	Muscle relaxation, constipation relief
Laxative Effect	Minimal (gentle)	Strong (can cause diarrhoea)
Side Effects	Rare, mild	Diarrhoea, skin irritation, dehydration risk
Forms Available	Capsules, powder	Bath salts, laxative solutions

Which Is Better: Magnesium Sulphate or Magnesium Glycinate?

The answer depends on your needs:

Choose Magnesium Glycinate if you want:

• A daily supplement for overall health
• Better sleep, reduced anxiety, or stress relief
• High absorption without digestive issues.

Choose Magnesium Sulphate if you need:

• Quick relief from constipation (short-term use).
• Muscle relaxation (Epsom salt baths).

Why Avoid Magnesium Sulphate Long-Term?

• Poor absorption when taken orally.
• Strong laxative effect can lead to dehydration or electrolyte imbalance.
• Risk of magnesium toxicity if overused.

What Is the Best Form of Magnesium to Take?

While magnesium glycinate is often considered the best all-rounder, other forms serve different purposes:

Type of Magnesium	Best For	Absorption
Glycinate	Sleep, anxiety, stress	High
Citrate	Constipation, digestion	Moderate-High
Sulphate (Epsom salt)	Muscle relaxation, laxative	Low (oral)
Malate	Energy, fibromyalgia	Moderate
Threonate	Brain function, memory	High (crosses the blood-brain barrier)
Oxide	Cheap	Low

If you’re looking for the best form of magnesium for daily use, magnesium glycinate is a top choice due to its high absorption and calming effects. Learn more about the different types of magnesium.

Further Reading: Magnesium Glycinate vs Magnesium Citrate

End Note

For most people, magnesium glycinate is the best choice because it’s highly absorbable (your body uses it efficiently), it doesn’t cause digestive issues like other forms and it has added benefits for sleep and anxiety thanks to glycine. If this is the one you’re looking to take, try Xandro’s Magnesium Glycinate 500mg!

Magnesium sulphate (Epsom salt) has its uses, especially for muscle baths or short-term constipation relief, but it’s not ideal for daily supplementation.

If you’re not sure which form is best for you, have a chat with your doctor! They can help you pick the right magnesium supplement based on your health needs. Check out our other forms of magnesium comparison blogs!