L-Serine
Also known as: Serine, L-Ser
Randomised trials report that high‑dose oral L‑serine (400 mg/kg/day) reduced disease progression measures and pathogenic deoxysphingolipids in HSAN1. Small n‑of‑1 trials in rare GRIN2B loss‑of‑function disorders showed individual improvements in some children but mixed overall results. Several randomised, placebo‑controlled trials used L‑serine as a major component of combined metabolic activator formulations that reported faster recovery from mild‑to‑moderate COVID‑19 and improved cognitive scores in Alzheimer’s disease, but effects cannot be attributed solely to L‑serine within those mixtures.
Last reviewed: 2026-10-14 · 4 indexed studies
Set your location for accurate regulatory status
Saved on this device — no sign-in needed.
Overview
L‑serine is a non‑essential amino acid available as an oral supplement. Human trials have tested L‑serine alone for hereditary sensory and autonomic neuropathy type 1 (HSAN1) and in multi‑component metabolic formulations for conditions such as COVID‑19 and Alzheimer’s disease; evidence for benefit is condition specific and often from combined formulations.
Mechanism & Function
Mechanism of Action
In the included abstracts L‑serine is characterised as a metabolic precursor relevant to sphingolipid metabolism (lowering toxic deoxysphingolipids in HSAN1) and as a precursor to d‑serine which modulates N‑methyl D‑aspartate receptor function in GRIN2B disorders. In the combined metabolic activator trials it is a major component intended to support mitochondrial and antioxidant metabolic pathways, though individual contribution is not isolated in those studies.
Physiological Role
Precursor for sphingolipids and for d‑serine (a modulator of NMDA receptors); implicated in cellular metabolic and antioxidant pathways in the context of combined metabolic supplementation.
Primary Pathways
Performance / Health Relevance
Direct performance or ergogenic effects are not demonstrated in the supplied human trials; evidence pertains to specific clinical neurological and recovery outcomes rather than athletic performance.
Evidence Review
No meta-analyses or systematic reviews indexed for this ingredient yet.
Dimensions marked N/A have no indexed evidence of that class. They are shown as unavailable rather than scored.
Practical Use & Dosage
- Minimum Effective Dose
- Not established from isolated‑ingredient trials for most indications; clinical benefit in HSAN1 was observed at 400 mg/kg/day.
- Optimal Range
- Not established. Trials used doses such as 400 mg/kg/day (HSAN1) and 12.35 g per dose within a combined formula (AD trial; given once daily then twice daily).
- Upper / Caution Level
- Not established. High oral doses up to ~400 mg/kg/day (~28 g/day for a 70 kg adult) were used and reported without serious adverse effects in the HSAN1 trial.
- Timing
- Varied by trial; HSAN1 dosed daily, Alzheimer’s combined formula given once daily then twice daily in later weeks.
- Best Format
- Oral powder/capsule as used in trials; often administered as part of a combined metabolic formula in some studies.
- Bioavailability
- No specific human bioavailability data reported in the provided abstracts.
- Absorption Considerations
- Not specified in the provided abstracts.
Safety & Interactions
Side Effects
- •No serious adverse effects reported in the HSAN1 trial (per abstract)
- •Adverse events not detailed in the provided abstracts for other trials
Contraindications
- Not specified in the provided abstracts
Drug Interactions
- •Not specified in the provided abstracts
Who Should Avoid
- •Not specified in the provided abstracts
Monitoring
For clinical use in HSAN1, plasma sphingolipid levels were an outcome measure in the trial; trials report monitoring but specific monitoring guidance is not provided in the abstracts.
Frequently Asked Questions
Auto-generated from indexed evidence — dosage, safety, interactions, and more.
When is L-Serine typically used or indicated?
L-Serine is most commonly used for: Neurological support, Support for inherited sphingolipid disorders, Adjunct in multi‑nutrient metabolic therapies. Precursor for sphingolipids and for d‑serine (a modulator of NMDA receptors); implicated in cellular metabolic and antioxidant pathways in the context of combined metabolic supplementation.
How does L-Serine work?
In the included abstracts L‑serine is characterised as a metabolic precursor relevant to sphingolipid metabolism (lowering toxic deoxysphingolipids in HSAN1) and as a precursor to d‑serine which modulates N‑methyl D‑aspartate receptor function in GRIN2B disorders. In the combined metabolic activator trials it is a major component intended to support mitochondrial and antioxidant metabolic pathways, though individual contribution is not isolated in those studies.
What is the recommended dose of L-Serine?
The optimal range is Not established. Trials used doses such as 400 mg/kg/day (HSAN1) and 12.35 g per dose within a combined formula (AD trial; given once daily then twice daily).. with a minimum effective dose of Not established from isolated‑ingredient trials for most indications; clinical benefit in HSAN1 was observed at 400 mg/kg/day.. Best taken: Varied by trial; HSAN1 dosed daily, Alzheimer’s combined formula given once daily then twice daily in later weeks.. Upper / caution level: Not established. High oral doses up to ~400 mg/kg/day (~28 g/day for a 70 kg adult) were used and reported without serious adverse effects in the HSAN1 trial..
What are the side effects of L-Serine?
Reported side effects include: No serious adverse effects reported in the HSAN1 trial (per abstract); and Adverse events not detailed in the provided abstracts for other trials. Monitoring: For clinical use in HSAN1, plasma sphingolipid levels were an outcome measure in the trial; trials report monitoring but specific monitoring guidance is not provided in the abstracts.
Does L-Serine interact with medications?
Known or theoretical interactions: Not specified in the provided abstracts. Always check with a clinician before combining with prescription medication.
Who should avoid L-Serine?
L-Serine is generally not recommended for: Not specified in the provided abstracts; and Not specified in the provided abstracts.
How strong is the evidence for L-Serine?
Evidence level: Moderate (overall score 64/100), based on 4 indexed studies on SuppIndex.
Research & References (4)
Combined Metabolic Activators Accelerates Recovery in Mild-to-Moderate COVID-19.
Randomised phase 2 and phase 3 trials of a combined metabolic activator (containing L‑serine plus N‑acetyl‑L‑cysteine, nicotinamide riboside and L‑carnitine tartrate) in ambulatory patients with mild‑to‑moderate COVID‑19 compared to placebo.
Combined metabolic activators improve cognitive functions in Alzheimer's disease patients: a randomised, double-blinded, placebo-controlled phase-II trial.
Randomised, double‑blind, placebo‑controlled phase II trial administering a combined metabolic activator with L‑serine as the major component (one dose contained 12.35 g L‑serine) to patients with Alzheimer’s disease, assessing cognitive outcomes and safety.
Potential benefits of l-serine in children with GRIN2B loss-of-function variants: Randomized n-of-1 trials.
Randomised, double‑blind, placebo‑controlled n‑of‑1 trials of oral L‑serine in four children with GRIN2B loss‑of‑function variants, assessing individual patient outcomes over two 6‑month cycles.
Randomized trial of l-serine in patients with hereditary sensory and autonomic neuropathy type 1.
Randomised, placebo‑controlled trial in patients with hereditary sensory and autonomic neuropathy type 1 (HSAN1) comparing oral L‑serine 400 mg/kg/day to placebo for 1 year, with an open‑label extension.
Related Ingredients
Other top-rated ingredients in Amino Acids.
L-Leucine
82/100Essential BCAA that activates mTORC1 via Sestrin2 sensing, driving phosphorylation of S6K1 and 4E-BP1, initiating cap-dependent translation and muscle protein synthesis.
Beta-Alanine
78/100A rate-limiting precursor to carnosine (β-alanyl-L-histidine) synthesis, enhancing intramuscular pH buffering capacity during high-intensity anaerobic exercise.
EAA Blend
78/100Free-form blend of 9 EAAs (Leu, Ile, Val, Lys, Met, Phe, Thr, Trp, His) at evidence-based ratios; bypasses gastric digestion for rapid plasma aminoacidaemia.
Research Overview
Moderate EvidenceCite this ingredient
One-click citation export in APA, MLA, Chicago, BibTeX, or HTML. The URL below is stable and safe to link.
Stable URL
https://thesuppindex.com/ingredients/l-serine
SuppIndex. (2026). L-Serine: Evidence summary, dosage and clinical studies. Retrieved October 16, 2026, from https://thesuppindex.com/ingredients/l-serine
Based on 4 indexed studies · Evidence level: Moderate.
Goal Ratings
Stack Compatibility
L‑serine has been administered as part of multi‑component metabolic activator formulations in clinical trials; effects observed in such trials cannot be attributed to L‑serine alone.