L-serine is an amino acid essential for the synthesis of phosphatidylserine, which is a component of the membrane of brain cells (i.e., neurons). It can be produced in the body, including the brain, but an external supply from the diet is essential in maintaining necessary levels. Although preclinical studies suggest L-serine may inhibit inflammation in the brain, levels of L-serine in humans do not appear to be associated with dementia or cognitive decline. Because L-serine is a naturally occurring amino acid, supplementation is likely safe in moderation.
No clinical studies have tested whether L-serine can prevent age-related cognitive decline or dementia, though one trial is underway now. Our search identified:
No clinical studies have tested whether L-serine can improve cognitive functions or prevent age-related cognitive decline. Studies examining levels of L-serine have not reported any correlations with cognitive function .
L-serine is essential for the synthesis of lipids called phosphatidylserine that make up the cell membrane of neurons . It is also essential for growth of neuronal processes. However, it is not clear whether L-serine supplements directly increase L-serine levels in the brain. In a study on traumatic brain injury in small mammals, L-serine treatment helped to protect brain tissue and improve recovery of neurological functions by inhibiting inflammation . Such protective effects have not been confirmed in humans yet.
A phase 2 clinical trial testing the effects of L-serine in early-stage Alzheimer's patients is currently underway . There have been several studies examining cerebral spinal fluid and blood serum levels of L-serine in people with Alzheimer's, but no clear differences with healthy people have been found, nor any correlations between L-serine levels and cognitive functions . Postmortem studies also showed that L-serine levels in the brain were comparable between Alzheimer's disease patients and healthy people .
Preclinical studies suggest L-serine may benefit those exposed to the neurotoxin beta-methylamino-L-alanine (BMAA) . Our cells can mistake BMAA for L-serine and misincorporate it into proteins, which can lead to cell death and may increase biological markers of Alzheimer's . Laboratory studies indicate that L-serine may prevent misincorporation of BMAA and cell death . However, it is unclear whether L-serine affects biological markers of Alzheimer's in the absence of such neurotoxins.
No clinical studies have tested the safety of L-serine supplementation in healthy adults. In a phase 1 safety trial in 20 ALS? patients, L-serine treatment (0.5-15.0 g, twice daily) for 6 months was generally well-tolerated and appeared to be safe . Two patients withdrew from the trial due to gastrointestinal side effects but no other adverse events or changes in routine blood tests measures were observed.
NOTE: This is not a comprehensive safety evaluation or complete list of potentially harmful drug interactions. It is important to discuss safety issues with your physician before taking any new supplement or medication.
L-serine is a naturally occurring dietary amino acid. It is abundant in soy products, sweet potatoes, eggs, meat, and some edible seaweed. L-serine is also sold as a dietary supplement in capsule and powder forms. The dose used in an ongoing Alzheimer's trial is 15 grams, twice daily, in the form of gummies . Most supplements come in the form of 500 mg capsules.
Information on the Phase 2 study testing L-serine in early Alzheimer's disease at the Dartmouth Hitchcock Medical Center on ClinicalTrials.gov.