Safety Profile
Known Safety Concerns
- High doses may increase renal calcium excretion -- kidney stone risk
- Nausea and diarrhoea above 10 g/day
- May interact with arginine absorption at high doses
- Generally very safe at supplement doses up to 3 g/day
Contraindications
- High doses may increase renal calcium excretion -- kidney stone risk
- Nausea and diarrhoea above 10 g/day
Interactions
Information not yet available for this ingredient profile.
Evidence and Scientific Findings
Ingredient Overview
L-lysine is an essential amino acid used primarily for herpes simplex virus suppression and collagen synthesis support. Well tolerated at standard doses. At very high doses (over 10 g/day) may cause GI distress and elevate cholesterol. High lysine intake increases renal calcium excretion — relevant for individuals with kidney stones.
Biological and Chemical Classification
- Scientific Name
- L-Lysine hydrochloride
Mechanism of Action
Information not yet available for this ingredient profile.
Clinical Evidence of Effectiveness
Information not yet available for this ingredient profile.
Pharmacokinetics
Information not yet available for this ingredient profile.
Recommended Dosage
Information not yet available for this ingredient profile.
SETI — Scientific Evidence Transparency Index
Executive Summary — Ingredient Assessment
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or RCT)
- Main clinical benefit observed: Metabolic
- Evidence consistency: High consistency across studies (100%)
- High doses may increase renal calcium excretion -- kidney stone risk
- Nausea and diarrhoea above 10 g/day
- May interact with arginine absorption at high doses
- Generally very safe at supplement doses up to 3 g/day
The available scientific evidence for L-Lysine indicates notable safety signals that warrant caution. Use should be considered carefully and monitored, particularly in sensitive populations or alongside other medications.
Total SETI Score
High risk| Evidence quality | 10/40 |
| Evidence consistency | 20/20 |
| Safety signals | 0/20 |
| Study recency | 10/10 |
| Evidence transparency | 10/10 |
Evidence Summary
- 10 studies reviewed
- 0 high-quality studies (meta-analysis or systematic review)
- 0 studies identified benefits or no safety concern (GREEN)
- 10 studies reported limited or advisory safety evidence (YELLOW)
Evidence Policy
Only peer-reviewed scientific literature indexed in PubMed or comparable databases is included in this evaluation. Commercial websites, blogs, and marketing materials are excluded. All references include direct traceable links to source documents.
Last updated: 25 მარ 2026, 12:48
Evidence Distribution
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Observational / other LOW evidence YELLOWA dual-function molecule enables stable four-electron conversion and Zn deposition for high-capacity aqueous Zn-I(2) batteries. ↗Zhang H et al.. A dual-function molecule enables stable four-electron conversion and Zn deposition for high-capacity aqueous Zn-I(2) batteries.. Chem Sci. 2026. PMID:41669750.PMID 41669750 ↗Journal Chem SciYear 2026Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/41669750/
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Observational / other LOW evidence YELLOWBeneficial effects of u03b5-polylysine on growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in broilers fed a lysine-deficient diet. ↗Huang W et al.. Beneficial effects of u03b5-polylysine on growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in broilers fed a lysine-deficient diet.. Poult Sci. 2025. PMID:39793239.PMID 39793239 ↗Journal Poult SciYear 2025Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/39793239/
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Observational / other LOW evidence YELLOWMicro-Nanofiber Three-Dimensional Antibacterial Sponge with Wetting/Pore Dual Gradient for Rapid Liquid Infiltration and Uniform Retention in Diapers. ↗Wei D et al.. Micro-Nanofiber Three-Dimensional Antibacterial Sponge with Wetting/Pore Dual Gradient for Rapid Liquid Infiltration and Uniform Retention in Diapers.. ACS Appl Mater Interfaces. 2025. PMID:39611352.PMID 39611352 ↗Journal ACS Appl Mater InterfacesYear 2025Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/39611352/
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Observational / other LOW evidence YELLOWComposite antibacterial hydrogels based on two natural products pullulan and u03b5-poly-l-lysine for burn wound healing. ↗Cui W et al.. Composite antibacterial hydrogels based on two natural products pullulan and u03b5-poly-l-lysine for burn wound healing.. Int J Biol Macromol. 2024. PMID:39069059.PMID 39069059 ↗Journal Int J Biol MacromolYear 2024Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/39069059/
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Observational / other LOW evidence YELLOWMetabolic engineering combined with site-directed saturated mutations of u03b1-keto acid decarboxylase for efficient production of 6-aminocaproic acid and 1,6-hexamethylenediamine. ↗Wang T et al.. Metabolic engineering combined with site-directed saturated mutations of u03b1-keto acid decarboxylase for efficient production of 6-aminocaproic acid and 1,6-hexamethylenediamine.. Biotechnol Bioeng. 2024. PMID:38956978.PMID 38956978 ↗Journal Biotechnol BioengYear 2024Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/38956978/
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Observational / other LOW evidence YELLOWCombining directed evolution with high cell permeability for high-level cadaverine production in engineered Escherichia coli. ↗Liu X et al.. Combining directed evolution with high cell permeability for high-level cadaverine production in engineered Escherichia coli.. Biotechnol J. 2024. PMID:38472088.PMID 38472088 ↗Journal Biotechnol JYear 2024Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/38472088/
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Observational / other LOW evidence YELLOW[A new biosynthesis route for production of 5-aminovalanoic acid, a biobased plastic monomer]. ↗Kang Y et al.. [A new biosynthesis route for production of 5-aminovalanoic acid, a biobased plastic monomer].. Sheng Wu Gong Cheng Xue Bao. 2023. PMID:37212232.PMID 37212232 ↗Journal Sheng Wu Gong Cheng Xue BaoYear 2023Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/37212232/
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Observational / other LOW evidence YELLOWCarbon nanogels exert multipronged attack on resistant bacteria and strongly constrain resistance evolution. ↗Mao JY et al.. Carbon nanogels exert multipronged attack on resistant bacteria and strongly constrain resistance evolution.. J Colloid Interface Sci. 2022. PMID:34742090.PMID 34742090 ↗Journal J Colloid Interface SciYear 2022Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/34742090/
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Observational / other LOW evidence YELLOWInvestigation of the Effect of Nanocrystalline Calcium Carbonate-Substituted Hydroxyapatite and L-Lysine and L-Arginine Surface Interactions on the Molecular Properties of Dental Biomimetic… ↗Goloshchapov D et al.. Investigation of the Effect of Nanocrystalline Calcium Carbonate-Substituted Hydroxyapatite and L-Lysine and L-Arginine Surface Interactions on the Molecular Properties of Dental Biomimetic Composites.. Biomimetics (Basel). 2021. PMID:34940013.PMID 34940013 ↗Journal Biomimetics (Basel)Year 2021Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/34940013/
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Observational / other LOW evidence YELLOWUnusual Aggregates Formed by the Self-Assembly of Proline, Hydroxyproline, and Lysine. ↗Koshti B et al.. Unusual Aggregates Formed by the Self-Assembly of Proline, Hydroxyproline, and Lysine.. ACS Chem Neurosci. 2021. PMID:34406754.PMID 34406754 ↗Journal ACS Chem NeurosciYear 2021Study type Observational / otherEvidence strength LOW evidencePubMed link https://pubmed.ncbi.nlm.nih.gov/34406754/
Score Transparency
0 of 10 approved references (score saturates at 10). More peer-reviewed studies = stronger evidence base.
Method: Q = number of approved references ÷ 10 (capped at 1.0)
Limited — mostly case reports or animal studies
Method: L = mean study-level weight across approved references. Level 1 (meta-analysis / systematic review) = 1.0; Level 2 (RCT) = 0.8; Level 3 (cohort/case-control) = 0.6; Level 4 (case report) = 0.4; Level 5 (animal / in-vitro) = 0.2.
Mixed or neutral — roughly equal benefit and risk signals
Method: D = (sum of risk-scored references − sum of benefit-scored references) ÷ total evidence score, then scaled from [−1, 1] to [0, 1]. 0.0 = pure benefit; 0.5 = neutral; 1.0 = pure risk.
One or more monitoring-level safety signals active
Method: S = 0.5 (neutral baseline) + sum of active signal severity deltas ÷ 10. Severity deltas: Critical = +2.0, High = +1.5, Moderate = +1.0, Low = +0.5. Capped at 1.0.
Final GIRI Score for L-Lysine. Risk level thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
Full methodology & data sources
The GIRI Score is computed entirely from structured data — no editorial scoring or subjective weighting is applied at any step.
- References: Only approved references are counted. Each reference is assigned an evidence level (L1–L5) and a direction (risk / neutral / benefit) by the reference manager or AI classifier.
- Safety Signals: Sourced from regulatory agencies (FDA, EMA, Health Canada, TGA, and others) and pharmacovigilance databases. Only active signals count toward the score.
- Formula version: GIRI Score v3.7.0 — Q × L × D × S × 10.
- Limitations: The score reflects published evidence and recorded signals as of the last update date. It is not a clinical risk assessment and should not replace advice from a qualified healthcare professional.
Risk Level Classification
Based on available regulatory signals and scientific evidence, this ingredient presents a low safety concern under normal conditions of use.
0–3.0
3.0–5.5
5.5–7.5
7.5–10
The score pin shows exactly where this ingredient falls on the fixed risk scale.
What drove the Low classification for L-Lysine
A score of 2.5 places this ingredient in the Low band. Thresholds: Low 0–3.0 · Moderate 3.0–5.5 · High 5.5–7.5 · Critical 7.5–10.
0 approved references.
Limited — mostly case reports or animal studies (Level 4–5).
Neutral or mixed — benefit and risk signals roughly balanced.
No active signals — S component is at neutral baseline (0.5), contributing no extra risk weight.
No major regulatory restrictions or advisories recorded across monitored jurisdictions (FDA, EMA, Health Canada, TGA, and others).
How are the Low / Moderate / High / Critical thresholds defined?
The four risk levels are fixed score bands. A score is assigned to exactly one level based on where it falls:
| Level | Score | Meaning |
|---|---|---|
| LOW | 0.0 – 2.9 | Sparse or predominantly beneficial evidence. No active safety alerts. |
| MODERATE | 3.0 – 5.4 | Mixed signals — some risk alongside benefit. Caution at high doses or in sensitive groups. |
| HIGH | 5.5 – 7.4 | Multiple studies or regulatory alerts documenting adverse effects. Professional oversight recommended. |
| CRITICAL | 7.5 – 10 | Regulatory restrictions in one or more major jurisdictions. Serious documented harm. Avoid without specialist supervision. |
Thresholds are fixed constants (GIRI_Score_Utils::LEVEL_THRESHOLDS). They do not change per ingredient and are never subject to editorial adjustment.