Walk down the supplement aisle and you'll see "magnesium" on dozens of labels — followed by some impossible-to-pronounce suffix. Glycinate, threonate, citrate, oxide, malate, taurate. They're not interchangeable. Each form has different absorption, different tissue distribution, and different uses.
What magnesium does in the body (briefly)
Magnesium is involved in over 300 enzymatic reactions, including muscle and nerve function, blood pressure regulation, blood glucose control, and protein synthesis. Most adults are mildly deficient — modern diets struggle to deliver the recommended 300-400mg daily.
The four forms that matter
Magnesium glycinate
Magnesium bound to glycine (an amino acid). Highly bioavailable, gentle on the stomach, and the glycine portion has its own calming, GABA-supportive effects.
- Best for: Sleep, anxiety, muscle tension, restless legs
- Take: Evening, 1-2 hours before bed
- Side note: Most-recommended form for people new to supplementation. Hardest to overdo.
Magnesium L-threonate
Magnesium bound to threonic acid. Patented research shows it crosses the blood-brain barrier more efficiently than other forms — meaning more of the magnesium reaches brain tissue.
- Best for: Cognitive function, memory, brain fog, age-related cognitive support
- Take: Morning or evening
- Note: Substantially more expensive than other forms. Worth it specifically for brain-focused use cases.
Magnesium citrate
Magnesium bound to citric acid. Well-absorbed but has a notable laxative effect at moderate to high doses.
- Best for: Constipation, occasional digestive sluggishness
- Take: Morning, with water
- Caution: If you're not specifically trying to address constipation, you'll find out the hard way at higher doses.
Magnesium oxide
The cheapest form, most common in budget multivitamins. Poorly absorbed (around 4% bioavailability) and predominantly used as a laxative in clinical settings.
- Avoid for: Most supplementation goals — you absorb very little of it
- Use for: Acute heartburn (acts as antacid)
Other forms worth knowing
- Magnesium taurate: Bound to taurine. Cardiovascular-supportive due to the taurine component.
- Magnesium malate: Bound to malic acid. Often recommended for fibromyalgia and chronic fatigue.
- Magnesium chelate (multiple): Marketing term, not specific. Usually means glycinate or another amino-acid chelate.
How NTX products use magnesium
eimele Sleep Glow uses magnesium glycinate as its primary mineral component (combined with L-theanine and a small dose of melatonin) — chosen specifically because glycinate's gentleness and the glycine's own calming effects make it the ideal sleep support form.
Practical takeaways
- Sleep / anxiety → glycinate
- Brain / cognitive → threonate
- Constipation → citrate
- Heart / cardiovascular → taurate
- Multipurpose / new to supplementation → glycinate
- Avoid → oxide unless you specifically want a laxative
Frequently asked questions
Can I take multiple forms? Yes — total daily magnesium intake (across all forms + food) is what matters. RDI is 300-400mg.
Will magnesium make me sleepy in the daytime? Glycinate at moderate doses won't typically. High doses might cause subtle drowsiness.
How long until I notice an effect? Acute effects (relaxation, sleep onset) often within days. Chronic effects (muscle tension, recovery, mood) within 4-8 weeks.