L-Serine
Research reviewed: Up until 03/2026
L-Serine is a dietary supplement with 6 published peer-reviewed studies involving 94 participants, researched for ALS / Motor Neuron Disease, Hereditary Sensory Neuropathy, Alzheimer's Disease & Cognitive Function and 1 more areas.
Evidence at a Glance
Strength is scored by study design, sample size, study type, and outcomes
ALS / Motor Neuron Disease
ModerateHereditary Sensory Neuropathy
ModerateAlzheimer's Disease & Cognitive Function
ModerateSleep Quality & Circadian Rhythm
ModerateResearch Visualised
Visual breakdown of the clinical data.
Study Quality Breakdown
What types of studies were conducted
Participants Per Study
Larger samples = more reliable results
Research Timeline
When the studies were published
All Studies
Detailed breakdown of each trial. Click to expand.
ALS / Motor Neuron Disease
To evaluate the safety of L-serine for ALS patients at varying doses.
Study Type
Randomized, double-blind, Phase I clinical trial
Purpose
To evaluate the safety of L-serine for ALS patients at varying doses.
Dose
Oral twice-daily: 0.5g, 2.5g, 7.5g, or 15g per dose (up to 30g/day)
Participants
20 patients with probable or definite ALS, ages 18-85, disease duration <3 years, FVC ≥60%
Duration
6 months
Results
L-serine was generally well tolerated. L-serine did not accelerate functional decline as measured by ALSFRS-R scores. Exploratory analysis suggested the possibility of a dose-related slowing of disease progression. 30g/day was safe and well-tolerated.
How They Measured It
ALSFRS-R scores, forced vital capacity, blood/urine/CSF sampling, comparison with historical placebo controls from 5 prior ALS trials
Hereditary Sensory Neuropathy
To evaluate L-serine supplementation in patients with hereditary sensory and autonomic neuropathy type 1 (HSAN1).
Study Type
Randomized controlled trial with open-label extension
Purpose
To evaluate L-serine supplementation in patients with hereditary sensory and autonomic neuropathy type 1 (HSAN1).
Dose
400 mg/kg/day oral L-serine
Participants
18 enrolled, 16 completed; ages 18-70 with symptomatic HSAN1
Duration
2 years (1 year randomized + 1 year open-label extension)
Results
L-serine group showed significant improvement in CMTNS vs placebo (-1.5 units, p=0.03). Deoxysphinganine levels dropped 59% in L-serine group vs 11% increase in placebo (p<0.001). No serious adverse effects related to L-serine.
How They Measured It
Charcot-Marie-Tooth Neuropathy Score version 2 (CMTNS), plasma sphingolipid levels, epidermal nerve fiber density, electrophysiology, patient-reported measures
Alzheimer's Disease & Cognitive Function
To study the effect of combined metabolic activators (CMA) including L-serine on cognitive functions in Alzheimer's disease patients.
Study Type
Randomized, double-blinded, placebo-controlled Phase II trial
Purpose
To study the effect of combined metabolic activators (CMA) including L-serine on cognitive functions in Alzheimer's disease patients.
Dose
12.35g L-serine + 1g nicotinamide riboside + 2.55g N-acetyl-L-cysteine + 3.73g L-carnitine tartrate; once daily for 28 days, then twice daily to day 84
Participants
Alzheimer's disease patients (treatment and placebo groups)
Duration
84 days
Results
Significant decrease of ADAS-Cog score on day 84 vs day 0 (P=0.00001, 29% improvement) in the CMA group. Significant improvement vs placebo in patients with higher baseline ADAS-Cog scores (P=0.0073). Improved hippocampal volumes and cortical thickness on MRI.
How They Measured It
ADAS-Cog score, MRI (hippocampal volumes, cortical thickness), plasma metabolomics and proteomics
Sleep Quality & Circadian Rhythm
To investigate the effects of L-serine ingestion on human sleep quality.
Study Type
Two randomized, double-blinded, crossover studies
Purpose
To investigate the effects of L-serine ingestion on human sleep quality.
Dose
L-serine administered 30 minutes before bedtime
Participants
Study 1: 45 healthy subjects dissatisfied with sleep; Study 2: additional participants with objective measurements
Duration
Single-night assessments
Results
Sleep initiation (p=0.02) and sleep maintenance (p=0.008) significantly improved during L-serine intake vs placebo. Actigraphy showed reduced number of nighttime awakenings (trend toward significance).
How They Measured It
Ogri-Shirakawa-Azumi sleep scale (Study 1), St. Mary's Hospital questionnaire and actigraphy (Study 2)
To investigate whether intake of L-serine before bedtime prevents circadian phase delay in real-life conditions.
Study Type
Double-blind, placebo-controlled field study
Purpose
To investigate whether intake of L-serine before bedtime prevents circadian phase delay in real-life conditions.
Dose
3.0g L-serine 30 minutes before bedtime
Participants
33 healthy university students (16 L-serine, 17 placebo)
Duration
2 weeks intervention after 1-week baseline
Results
DLMO was significantly delayed in the placebo group (p=0.02) but not in the L-serine group. Significant difference in DLMO changes between groups (p=0.04). L-serine prevented the circadian phase delay typically seen during autumn/winter.
How They Measured It
Dim light melatonin onset (DLMO) from saliva samples, sleep/wake logs, light exposure monitoring
To examine whether L-serine enhances light-induced circadian phase resetting in mice and humans.
Study Type
Experimental trial (animal and human components)
Purpose
To examine whether L-serine enhances light-induced circadian phase resetting in mice and humans.
Dose
L-serine administered before bedtime (specific human dose not detailed)
Participants
Healthy male students (mean age 22.2 years)
Duration
Acute assessment
Results
L-serine administration enhanced light-induced phase shifts in mice by 1.86-fold (P<0.05). In humans, L-serine ingestion produced significantly larger circadian phase advances compared to placebo following morning light exposure.
How They Measured It
Dim-light melatonin onset (DLMO) from saliva samples in humans; wheel-running activity in mice
Frequently Asked Questions
Common questions about L-Serine research
There are currently 6 peer-reviewed studies on L-Serine (L-Serine), involving 94 total participants. Research covers Neurological health, Mental health, Sleep. The overall evidence strength is rated as Strong.
The evidence is currently rated as "Strong Evidence". This rating is based on study design quality (randomisation, blinding, placebo controls), sample sizes, study types (6 human studies), and reported outcomes.
L-Serine has been researched for: Neurological health, Mental health, Sleep. Each area has its own body of evidence which you can explore in the study breakdowns above.
Yes, 6 out of 6 studies are human trials. Human trials carry more weight in our evidence scoring system.
