Reviewed by Sarah Law, Naturopathic Nutritionist
Magnesium Glycinate vs Citrate vs Oxide: Which Is Best for Absorption?
- Glycinate is the gentlest and best absorbed for everyday use, ideal for sleep, calm and recovery.
- Citrate absorbs well too, but is mildly laxative, better for digestion and daytime use.
- Oxide is high in elemental magnesium but poorly absorbed (around 4% fractional absorption).
- For consistent daily results, a fully reacted Magnesium Glycinate is the dependable pick.
Not all magnesium is created equal, and the form you choose changes how much actually reaches your cells and how your gut tolerates it. Here is the short version: glycinate for daily use, sleep and stress; citrate for digestion and daytime; oxide mostly to avoid for ongoing use. Below is the detail, with a side-by-side comparison.
The Comparison at a Glance
| Form | Absorption | Best for | Watch-outs |
|---|---|---|---|
|
Glycinate (bisglycinate) |
High, gentle | Daily use, sleep, stress, recovery | Slightly larger dose volume (capsules) |
| Citrate | Good | Digestion, occasional constipation, daytime | Can be mildly laxative; less calming |
| Oxide | Low (~4%) | Short-term constipation relief only | Poorly absorbed; bloating, loose stools |
Over the years I have tested nearly every form of magnesium, some worked brilliantly, others caused discomfort. That is why we use a fully reacted magnesium bisglycinate in our Magnesium Glycinate Capsules: gentle on the gut, well absorbed, and the one I take nightly for deeper sleep and stress balance. It is pure, filler-free and third-party tested in UK GMP and BRC-certified facilities.
Magnesium Glycinate (Bisglycinate)
Magnesium glycinate binds magnesium to the amino acid glycine, creating a chelated compound that is well absorbed and gentle on digestion. Glycine itself promotes calm, which is why people reach for glycinate for sleep and stress relief. It is the go-to form for daily use without digestive discomfort, and the focus of this guide.
Magnesium Citrate
Magnesium citrate is magnesium combined with citric acid. It absorbs well and gently stimulates digestion, which can help with occasional constipation. It is less calming than glycinate, so it suits daytime or post-exercise use. Taken late at night it can be a little too stimulating compared with glycinate.
Magnesium Oxide
Magnesium oxide contains a high percentage of elemental magnesium, but its absorption is very low, with one well-known analysis putting fractional absorption around 4% [1]. Much of it passes through the gut unused and can draw water into the intestines, causing loose stools. It is cheap and common in generic tablets, but not ideal for ongoing supplementation.
Recommended in this guide
The gentle, well-absorbed pick
Magnesium Glycinate (Bisglycinate)
240 vegan capsules · 303 mg elemental magnesium per serving · 2-month supply
About 50p per day, or 40p on subscription
✓ Fully reacted, non-buffered✓ Third-party tested✓ UK GMP & BRC made✓ 2024 Gold Award
Comparing Absorption and Bioavailability
Absorption decides how much magnesium reaches your cells. Oxide is the clear laggard: poorly soluble and poorly absorbed. Organic forms do much better, and for everyday use glycinate combines good absorption with the best digestive tolerance.
- Glycinate: well absorbed and the most tolerable, the best choice for consistent daily supplementation.
- Citrate: good absorption, suitable for occasional use or digestive support.
- Oxide: low uptake and poor solubility, better avoided for long-term use.
"In practice the form matters as much as the dose. I steer most clients toward glycinate for daily use because it absorbs well and rarely upsets digestion. I keep citrate for short-term constipation or daytime use, and I rarely recommend oxide for anything beyond occasional bowel relief."
— Sarah Law, Naturopathic Nutritionist & Functional Practitioner
Dosage and How to Take
The sweet spot for adults is around 200 to 400 mg elemental magnesium daily. Our Magnesium Glycinate Capsules provide about 303 mg per serving, fully reacted and gentle enough for nightly use. Take glycinate in the evening for sleep; if you use citrate for digestion or energy, take it earlier in the day. For all-day, all-round coverage, a multi-form blend like Magnesium Seven combines several forms.
Free Download
Get our Magnesium Dosing Guide (+ 10% off your first order)
A one-page PDF: how to read an elemental magnesium label, which form to match to your goal, and the right dose. We will email it instantly, plus a code for 10% off.
No spam, unsubscribe anytime. UK-based support.
Which magnesium is right for you?
Safety, Testing and Purity
Our magnesium glycinate is fully reacted (no oxide buffer) and made in UK GMP and BRC facilities, with every batch third-party tested for purity and heavy metals. Free from GMOs, gluten, dairy and fillers. For detail, see our Ingredients A to Z entry for Magnesium Glycinate.
Frequently Asked Questions
Which magnesium form absorbs best?
Glycinate and citrate both absorb well and are far ahead of oxide. Glycinate is the gentlest and best for daily use, sleep and stress; citrate suits digestion and daytime use.
Is magnesium glycinate better for sleep?
Yes. The glycine bond promotes calm and supports sleep onset, which is why glycinate is the preferred evening form.
Can I take magnesium glycinate and citrate together?
Yes. Citrate by day and glycinate at night is a common pairing, or use a multi-form blend.
Is magnesium oxide ever useful?
It can help short-term with constipation but is not ideal for ongoing supplementation due to low absorption.
What is the most gentle magnesium supplement?
Glycinate, it is the best tolerated, with minimal digestive disturbance.
References
- Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001;14(4):257-62. PubMed
- Abbasi B et al. The effect of magnesium supplementation on primary insomnia in the elderly. J Res Med Sci. 2012. PubMed
- NIH Office of Dietary Supplements. Magnesium Fact Sheet for Health Professionals. NIH ODS
References verified June 2026.
Ben Law is the founder of Love Life Supplements and host of the Optimised Health Show. With over a decade of experience in clean, science-backed formulation, Ben focuses on filler-free, third-party tested supplements made in the UK. Learn more on the About page.