Magnesium L-Threonate vs Phosphatidylserine
Two 'brain-specific' cognitive supplements whose entire human evidence case rests on a single small, often industry-linked trial each.
Short answer
Neither magnesium L-threonate nor phosphatidylserine needs a prescription, and both have human data, so the goal decides it. Magnesium L-threonate is marketed for memory and brain magnesium; phosphatidylserine is the choice for readers interested in cognitive decline, memory and stress/cortisol.
Magnesium L-Threonate
Magtein
The 'raises brain magnesium and memory' story rests on one 2010 rat study plus one small industry-linked human trial; for repletion, cheap glycinate/citrate work just as well.
Full Magnesium L-Threonate evidence reviewPhosphatidylserine
PS
The strongest human data comes from older trials using bovine-brain-derived PS, which is no longer sold (BSE concerns); the soy-derived PS on shelves today is chemically different and has a thinner, weaker trial record of its own.
Full Phosphatidylserine evidence reviewMagnesium L-Threonate vs Phosphatidylserine: head to head
- FDA status / approved use
Magnesium L-Threonate
Dietary supplement; not an approved treatment for any conditionPhosphatidylserine
Sold as a supplement; FDA allows only a qualified health claim with a disclaimer- Marketed for
Magnesium L-Threonate
Memory, brain magnesiumPhosphatidylserine
Cognitive decline, memory, stress/cortisol- Outcome areas
Magnesium L-Threonate
Cognitive function / memoryPhosphatidylserine
Cognitive function / memory; Mood / anxiety / stress- Evidence grade
Magnesium L-Threonate
Clinical dataPhosphatidylserine
Clinical data- How it works
Magnesium L-Threonate
Magnesium salt designed to raise magnesium in the brain specificallyPhosphatidylserine
Membrane phospholipid concentrated in neurons that supports neurotransmitter release- Route and dosing
Magnesium L-Threonate
Oral powder; about 144 mg elemental magnesium per day, often splitPhosphatidylserine
Oral supplement; trials used 300 or 600 mg daily- Headline human result
Magnesium L-Threonate
Improved a cognitive test composite (p = 0.003, Cohen's d = 0.91) over 12 weeks in a small, industry-linked 2016 RCTPhosphatidylserine
No memory benefit vs placebo with soy-derived PS at 300 or 600 mg daily in a 12-week RCT of 120 older adults- Strongest evidence
Magnesium L-Threonate
MMFS-01 RCT, J Alzheimers Dis 2016Magnesium L-Threonate evidence reviewPubMed 26519439Phosphatidylserine
Bovine-PS cognitive decline RCT, Aging Clin Exp Res 1993Phosphatidylserine evidence reviewPubMed 8323999- Key safety signal
Magnesium L-Threonate
Loose stools at high intake; can accumulate with reduced kidney function; binds some antibiotics and thyroid hormonePhosphatidylserine
Generally well tolerated; mild gastrointestinal upset is the most common complaint- How it is obtained
Magnesium L-Threonate
Over the counter as a dietary supplementPhosphatidylserine
Over the counter as a dietary supplement
| Magnesium L-Threonate | Phosphatidylserine | |
|---|---|---|
| FDA status / approved use | Dietary supplement; not an approved treatment for any condition | Sold as a supplement; FDA allows only a qualified health claim with a disclaimer |
| Marketed for | Memory, brain magnesium | Cognitive decline, memory, stress/cortisol |
| Outcome areas | Cognitive function / memory | Cognitive function / memory; Mood / anxiety / stress |
| Evidence grade | Clinical data | Clinical data |
| How it works | Magnesium salt designed to raise magnesium in the brain specifically | Membrane phospholipid concentrated in neurons that supports neurotransmitter release |
| Route and dosing | Oral powder; about 144 mg elemental magnesium per day, often split | Oral supplement; trials used 300 or 600 mg daily |
| Headline human result | Improved a cognitive test composite (p = 0.003, Cohen's d = 0.91) over 12 weeks in a small, industry-linked 2016 RCT | No memory benefit vs placebo with soy-derived PS at 300 or 600 mg daily in a 12-week RCT of 120 older adults |
| Strongest evidence | MMFS-01 RCT, J Alzheimers Dis 2016Magnesium L-Threonate evidence reviewPubMed 26519439 | Bovine-PS cognitive decline RCT, Aging Clin Exp Res 1993Phosphatidylserine evidence reviewPubMed 8323999 |
| Key safety signal | Loose stools at high intake; can accumulate with reduced kidney function; binds some antibiotics and thyroid hormone | Generally well tolerated; mild gastrointestinal upset is the most common complaint |
| How it is obtained | Over the counter as a dietary supplement | Over the counter as a dietary supplement |
marks a row where the two differ. “Not established” marks a cell the available evidence does not answer. Evidence grades come from our evidence matrix, which grades each molecule on the human data for the use it is marketed for.
- Clinical data:
- Tested in humans — but investigational, discontinued, or proven only on a surrogate marker (not the marketed outcome).
Our verdict
Magnesium L-threonate's 'raises brain magnesium and memory' story rests on one 2010 rat study plus one small, industry-linked human trial — for general magnesium repletion, cheap glycinate or citrate forms work just as well at a fraction of the cost. Phosphatidylserine's strongest data used bovine-brain-derived PS, discontinued after BSE concerns; the soy-derived form sold today is a different molecule with its own thinner, older trial record. Both are cases where a genuinely evocative mechanism outran the actual human trial base.
Magnesium L-Threonate fits if
You specifically want the brain-targeted magnesium claim, though for general repletion a cheaper form works as well.
Phosphatidylserine fits if
You want the cognitive-specific compound, understanding today's soy-derived version isn't the one the strongest historical trials tested.
Magnesium L-Threonate vs Phosphatidylserine: common questions
- Is either magnesium L-threonate or phosphatidylserine FDA-approved?
- No. Magnesium L-threonate is a dietary supplement; not an approved treatment for any condition. Phosphatidylserine is sold as a supplement; FDA allows only a qualified health claim with a disclaimer.
- Which has stronger human evidence, magnesium L-threonate or phosphatidylserine?
- Neither clearly. Both have human clinical data. The key source for magnesium L-threonate is MMFS-01 RCT, J Alzheimers Dis 2016; for phosphatidylserine, it is Bovine-PS cognitive decline RCT, Aging Clin Exp Res 1993.
- What are the main safety concerns with magnesium L-threonate and phosphatidylserine?
- For magnesium L-threonate, watch for loose stools at high intake; can accumulate with reduced kidney function; binds some antibiotics and thyroid hormone. Phosphatidylserine is generally well tolerated; mild gastrointestinal upset is the most common complaint.
Key studies behind each
Magnesium L-Threonate
- Slutsky I, Abumaria N, Wu LJ, et al. (2010). Enhancement of learning and memory by elevating brain magnesium. Neuron. PubMed 20152124
- Liu G, Weinger JG, Lu ZL, Xue F, Sadeghpour S. (2016). Efficacy and Safety of MMFS-01, a Synapse Density Enhancer, for Treating Cognitive Impairment in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial. J Alzheimers Dis. PubMed 26519439
- Kirkland AE, Sarlo GL, Holton KF. (2018). The Role of Magnesium in Neurological Disorders. Nutrients. PubMed 29882776
- Alateeq K, Walsh EI, Cherbuin N. (2023). Dietary magnesium intake is related to larger brain volumes and lower white matter lesions with notable sex differences. Eur J Nutr. PubMed 36899275
Phosphatidylserine
- Cenacchi T, Bertoldin T, Farina C, et al. (1993). Cognitive decline in the elderly: a double-blind, placebo-controlled multicenter study on efficacy of phosphatidylserine administration. Aging (Milano). PubMed 8323999
- Jorissen BL, Brouns F, Van Boxtel MP, et al. (2001). The influence of soy-derived phosphatidylserine on cognition in age-associated memory impairment. Nutritional Neuroscience. PubMed 11842880
- Monteleone P, Maj M, Beinat L, et al. (1992). Blunting by chronic phosphatidylserine administration of the stress-induced activation of the hypothalamo-pituitary-adrenal axis in healthy men. European Journal of Clinical Pharmacology. PubMed 1325348
- Parker AG, Gordon J, Thornton A, et al. (2011). The effects of IQPLUS Focus on cognitive function, mood and endocrine response before and following acute exercise. Journal of the International Society of Sports Nutrition. PubMed 22017963
The full evidence reviews
- Magnesium L-Threonate (Magtein): does the 'brain magnesium' actually work?
A real preclinical mechanism — but the 'raises brain magnesium + sharpens memory' story rests on one 2010 rodent study and one small, industry-linked human trial. For plain repletion, cheap glycinate works fine.
Updated August 2026
- Phosphatidylserine: Evidence for Memory, Cortisol, and Cognitive Health
A membrane phospholipid with real biology, older positive cognition data on a form you can no longer buy, and a weaker case for the soy-derived version sold today.
Updated August 2026