Magnesium L-threonate
Magnesium threonate, Magtein
Forms: Magtein is the patented ingredient; also sold in blends with phosphatidylserine and other nootropics. Other magnesium salts have their own cards.
Other esters and forms: Magnesium, Magnesium aspartate, Magnesium carbonate, Magnesium chloride, Magnesium citrate, Magnesium gluconate, Magnesium glycinate (bisglycinate), Magnesium hydroxide, Magnesium lactate, Magnesium malate, Magnesium orotate, Magnesium oxide, Magnesium sulfate (Epsom salt), Magnesium taurate
Magnesium bound to threonic acid, marketed for memory and sleep. It raised brain magnesium in rats; human trials are small and mostly industry-funded.
Legal status: Sold freely as a supplement; some products are registered OTC medicines; not prohibited in sport.
What it gives
What people use it for and what the sources report. Strength is a general category from the literature: mild, clear or strong.
Purpose
Taken for memory, focus and sleep. The claims come from rat studies of brain magnesium and synapses. It contains relatively little magnesium by weight, so it is not a practical way to replace sweat losses or correct a deficiency.
What people seek and what studies show
In rats it raised brain magnesium and improved learning and memory. Human trials are small and company-funded: cognitive scores improved in 44 older adults; in 100 younger adults overall cognition and some self-rated sleep measures improved, but tracker-measured sleep did not. No independent replication; no data on sleep, recovery or performance in athletes.
Effects
Evidence: Limited human data — some human studies, small or short
Sought effects by goal (as reported)
Possible side effects
Possible does not mean certain: whether they appear depends on dose, duration, individual response and monitoring. Below — what to watch for and how to notice it early.
2 possible side effects
level · how often it is reportedWhat the levels mean
Level: general category from the literature, not your personal risk
How often
- common
- reported often
- possible
- reported in some people
- rare
- reported occasionally
How to lower the risks
For 1 of 2 possible side effects there are specific ways to lower the chance: everyday measures, supplements and options a doctor may consider. For the rest — general advice. No measure removes a risk completely.
Low-level side effects
How each option helps (2)
- Working with a doctor — Assesses persistent vomiting or severe belly pain (possible pancreatitis or gallstones) and adjusts prescribed GLP-1 treatment when nausea persists.
- Pancreatin + dimeticone (Pankreoflat) — May ease heaviness and gas after meals; can cause nausea or diarrhea. Not for pork or cow's milk protein allergy (anaphylaxis reported) or early acute pancreatitis.
Check-ups and blood tests
Which tests and check-ups to do and when. This is a guide — agree the exact schedule with a sports physician.
Myth & fact
“Threonate is the only magnesium that reaches the brain and makes you smarter.”
Brain uptake was shown in rats. Memory gains in humans come from a few small company-funded trials and have not been independently confirmed.
Combinations
No specific combination notes for this substance yet. The stack check still adds up side effects that several substances share.
Sources
Possible side effects by body system, combinations, how to lower the risks and which tests to do — free.
Open the stack check