Supplement Comparison
Magnesium Glycinate vs Oxide: Which Form Actually Absorbs?
We analyzed what top longevity experts — Huberman, Attia, Patrick, Johnson, and Hyman — actually say about magnesium glycinate vs magnesium oxide. Here is where they agree and where they don't.
Strong Consensus
on Magnesium overall
TL;DR — Glycinate for daily use & absorption; Oxide only for its cheap laxative effect
Take glycinate for daily magnesium, sleep, and calm — it's well-absorbed and gentle on the stomach. Magnesium oxide is the cheapest form but poorly absorbed; most of it passes through and acts as a laxative. Oxide is fine for occasional constipation but a weak choice for correcting a deficiency. Attia notes oxide is less absorbed than carbonate.
What Each Expert Actually Takes
Glycinate (+ threonate)
Uses magnesium glycinate and threonate in his sleep cocktail — not oxide.
Prefers carbonate; uses oxide but notes it absorbs poorly
Personally supplements three forms — carbonate (mornings), oxide, and others — and notes carbonate is 'more fully absorbed than oxide, citrate, or glycinate.' Groups oxide among the bowel-speeding forms.
Glycinate (or malate)
Recommends glycinate and malate for bioavailability and daily needs. Does not recommend oxide for meeting daily magnesium.
Not specified
Blueprint stack does not call out a specific magnesium form in analyzed videos.
Glycinate
Recommends glycinate for daily use and sleep, food-first with supplementation to fill gaps.
Key Differences
Absorption
Magnesium Glycinate
Well-absorbed — chelated to glycine
Magnesium Oxide
Poorly absorbed — much of it passes through the gut (Attia ranks it below carbonate)
Best For
Magnesium Glycinate
Daily needs, sleep, calm/anxiety, muscle relaxation
Magnesium Oxide
Occasional constipation — its laxative pull is the main use
GI / Bowel Effect
Magnesium Glycinate
Gentle, well tolerated
Magnesium Oxide
Strong laxative — Attia groups oxide with the bowel-speeding forms
Usable (Elemental) Magnesium
Magnesium Glycinate
Good — most of the dose is actually absorbed
Magnesium Oxide
High on the label, but low absorbed = little usable magnesium
Cost
Magnesium Glycinate
Affordable
Magnesium Oxide
Cheapest form — common in budget/drugstore products
Expert Consensus
Magnesium Glycinate
Recommended by Patrick & Hyman; used by Huberman
Magnesium Oxide
No expert recommends oxide for daily magnesium
What the Experts Said (Direct Quotes)
"I do think magnesium is important. About 40% of the US population doesn't get adequate magnesium intake."
Essentials: Micronutrients for Health & Longevity | Dr. Rhonda Patrick at 19:27
"DNA repair enzymes require magnesium. Magnesium is a co-factor for them. Magnesium is at the center of a chlorophyll molecule — dark leafy greens are a key source."
Essentials: Micronutrients for Health & Longevity | Dr. Rhonda Patrick at 20:26
"The big three are calcium, vitamin D — and when I say vitamin D, I mean D3 — and magnesium. I consider the required daily amounts a minimum."
Navigating bone health: early life influences & strategies for improvement & injury prevention at 86:41
"Magnesium 300 to 500 milligrams daily. These can be supplemented if you can't get this in food."
Navigating bone health: early life influences & strategies for improvement & injury prevention at 87:02
"Magnesium threonate is not the best option for meeting daily magnesium needs. It shouldn't be included as contributing to your recommended daily allowance."
The Science of Magnesium and Its Role in Aging and Disease at 00:30
"Nearly half of the US population has inadequate magnesium intake, primarily due to diets lacking magnesium-rich foods like dark leafy greens."
The Science of Magnesium and Its Role in Aging and Disease at 02:05
"The most prevalent deficiencies include iron, vitamin D, magnesium, and omega-3s — these are the big ones."
My Favorite Supplements for Optimal Health & Longevity | Dr. Mark Hyman at 02:15
"Magnesium or folate may have the ability to affect the function of hundreds and hundreds of different enzymes."
My Favorite Supplements for Optimal Health & Longevity | Dr. Mark Hyman at 06:21
Bottom Line
If your goal is to actually raise your magnesium — for sleep, calm, or correcting a deficiency — glycinate wins easily: it's well-absorbed and gentle. Magnesium oxide is the form you find in the cheapest drugstore tablets, and its defining trait is poor absorption: a lot of it never gets into your body and instead pulls water into the bowel, which is why it works as a laxative (milk of magnesia is magnesium hydroxide, a close cousin). Attia, who uses several forms himself, explicitly ranks oxide below carbonate for absorption. The only real reason to choose oxide is if you specifically want the cheap laxative effect. For everything else — daily needs, sleep, muscle relaxation — use glycinate.
Consensus Protocol — Magnesium
Dosage
300-500mg elemental magnesium daily (Attia: 300-500mg; Patrick: ~400mg; Hyman: 400mg+)
Form
Glycinate or malate for general bioavailability (Patrick). Carbonate for best absorption without GI effects (Attia). Threonate for cognitive focus only — don't count toward daily needs. Citrate/oxide if you want bowel regularity as a side benefit.
Timing
Smaller, frequent doses throughout the day for better absorption. Carbonate in the morning (Attia's protocol). Evening dose for sleep support.
Notes
Standard blood tests for magnesium are unreliable — the body maintains plasma levels by drawing from bones, masking true deficiency (confirmed by both Attia and Patrick). Excessive zinc supplementation can inhibit magnesium absorption. Physically active adults need 10-20% more than sedentary RDA.
Now you know which form. Get the full protocol.
Exact dosages — what each expert recommends, not just which form
Daily schedule — morning vs evening, what to pair with food, what to separate
Expert watchdog — get alerted when an expert changes their recommendation
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