L-Lysine
L-Lysine
An essential amino acid important for collagen synthesis, immune function, and particularly effective at preventing and treating cold sores (herpes simplex).
L-Lysine is an essential amino acid that must be obtained from diet or supplements. It's a key building block for collagen synthesis and plays important roles in immune function, calcium absorption, and hormone production. Lysine is best known for its ability to prevent and reduce cold sore outbreaks by competing with arginine, which HSV needs to replicate. It's often deficient in vegetarian diets as grains are low in lysine.
Mechanisms of Action
Arginine Competition
Competes with arginine to inhibit HSV
Collagen Synthesis
Essential for collagen production
Calcium Absorption
Enhances calcium uptake
Recommended Dose
500-3000mg daily; higher for active outbreaks
Loading: For active cold sores: 3000-6000mg/day in divided doses
Optimal Timing
- Empty stomach for better absorption
- Divided doses throughout day
- Away from high-arginine foods
Can be taken without food
Best Form
L-Lysine HCl (capsules or powder)
Alternatives: L-Lysine tablets
L-Lysine HCl is standard and well-absorbed. Available as powder, capsules, or tablets.
Duration
Minimum: 4 weeks
Optimal: 12 weeks
Cycling: Not required
Note: Best absorbed on empty stomach. Reduce arginine-rich foods (nuts, chocolate, seeds) during outbreaks.
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Cold Sore Prevention
Reduced frequency and severity of outbreaks
Collagen Support
Supports skin, bone, and tissue health
Immune Support
General immune function support
Well-studied for HSV prevention; effective at 1-3g/day
May need supplementation as grains are low in lysine
Who Should NOT Take This
- Lysinuric protein intolerance (rare genetic disorder)
Drug Interactions
May enhance calcium absorption
Possible Side Effects
Tip: Take with food if needed; reduce dose
Tip: Reduce dose
Warnings
- Very high doses may affect calcium balance
- Effectiveness depends on maintaining low arginine intake
Top studies from 40+ peer-reviewed papers
Hou XW et al. • Investigative ophthalmology & visual science (2021)
“This review summarizes potential biomarkers and metabolic pathways, providing insights into new pathogenic pathways for this microvascular complication of diabetes.”
Key Findings:
- This review summarizes potential biomarkers and metabolic pathways, providing insights into new pathogenic pathways for this microvascular complication of diabetes.
- Published in Investigative ophthalmology & visual science (2021)
- Further research warranted to confirm findings
Sloun BV et al. • Nutrients (2020)
“The extracted information is publicly available and can serve multiple purposes such as computational modeling.”
Key Findings:
- Oral ingestion of most individual AAs induced an insulin response, but did not alter glucose concentrations in healthy participants.
- Specific AAs (i.e., leucine and isoleucine) co-ingested with glucose exerted a synergistic effect on the postprandial insulin response and attenuated the glucose response compared to glucose intake alone in healthy participants.
- Oral AA ingestion as well as intravenous AA infusion was able to stimulate an insulin response and decrease glucose concentrations in T2DM and obese individuals.
- The extracted information is publicly available and can serve multiple purposes such as computational modeling.
Fornaro M et al. • Molecular psychiatry (2025)
“The Author(s), under exclusive licence to Springer Nature Limited.”
Key Findings:
- Change (Standardized Mean Difference = SMD) in total symptomatology and acceptability (Risk Ratio = RR) were co-primary outcomes.
- High heterogeneity (tau2 = 0.10, I2 = 55.9%) and global inconsistency (Q = 40.79, df = 18, p = 0.002) emerged without publication bias (Egger's test, p = 0.42).
- Sarcosine improved negative symptoms (SMD = -0.65, 95%CI = -1.10; -0.19).
- N-acetylcysteine improved negative symptoms (SMD = -0.90, 95%CI = -1.42; -0.39)/general psychopathology (SMD = -0.76, 95%CI = -1.39; -0.13).
Hullar MA et al. • The American journal of clinical nutrition (2025)
“In healthy humans, diet impacts microbial metabolism and enzymatic activity but not the overall diversity of the gut microbiome.”
Key Findings:
- Overall community structure measured by alpha and beta diversity was not significantly different across the diets, although diet did significantly increase the abundance of 13 of 161 genera (Padj < 0.05) and 5 species in the LGL diet and 7 species in the HGL diet.
- In healthy humans, diet impacts microbial metabolism and enzymatic activity but not the overall diversity of the gut microbiome.
- This emphasizes the relevance of dietary components in activating expression of specific bacterial genes and their impact on host metabolism.
- This trial was registered at clinicaltrials.gov as NCT00622661.
Laky B et al. • Nutrients (2024)
“In conclusion, this multi-nutrient supplement might not only stabilize the progression of lumbar osteochondrosis, but it might also potentially even increase IVD volumes as detected on MRIs.”
Key Findings:
- Despite no significance regarding the distribution of Pfirrmann grade changes (improvement, no change, worsening; p = 0.259), in the supplement group, one patient achieved a three-grade improvement, and worsening of Pfirrmann grades were only detected in the placebo group (9.1%).
- Disc degeneration according to Pfirrmann classifications remained stable during the 3-month intervention in both groups.
- Furthermore, in-depth evaluations of MRIs showed significantly higher 3D-measured volume changes (increase) in the supplement (+740.3 ± 796.1 mm3) compared to lower 3D-measured volume changes (decrease) in the placebo group (-417.2 ± 875.0 mm3; p < 0.001).
- In conclusion, this multi-nutrient supplement might not only stabilize the progression of lumbar osteochondrosis, but it might also potentially even increase IVD volumes as detected on MRIs.
Study Type Distribution
Goals This Supplement Supports
Related Goals
This information is for educational purposes only and is not intended as medical advice. Always consult a qualified healthcare provider before starting any supplement.