4 Best Lysine Supplements (2026) · Expert Reviewed

Q: What is the best lysine supplement for cold sores?

For cold sore prevention, look for a supplement delivering at least 1,000mg of L-lysine per serving. Quantum Health Super Lysine+ provides 1,500mg plus immune-supporting herbs and has the longest track record for cold sore use. Peak Performance L-Lysine + Monolaurin offers a unique dual-action approach combining lysine with monolaurin's antiviral properties.

Q: How much lysine should I take daily?

For general immune support and cold sore prevention, 1,000mg daily is the minimum effective dose established in clinical research. During active cold sore outbreaks, some practitioners recommend increasing to 2,000-3,000mg daily in divided doses. For general health, 500-1,000mg daily is sufficient.

Q: Does lysine actually work for herpes and cold sores?

The evidence is mixed but suggestive. The original Griffith et al. (1987) trial found 1,000mg daily L-lysine significantly reduced recurrence of herpes simplex. A 2017 review noted that while individual trials show benefit, the overall evidence base is limited by small study sizes and methodological variation. Many clinicians still recommend it given the favorable safety profile.

Q: Can I take lysine with other supplements?

Yes. L-lysine is generally safe to combine with most supplements. It pairs well with vitamin C and zinc for immune support. Avoid taking very high doses simultaneously with arginine supplements, as they compete for the same transport mechanisms. Lysine may also support calcium absorption.

Q: Are there side effects from lysine supplements?

L-lysine is well-tolerated at typical supplement doses (1,000-3,000mg daily). Rare side effects include mild GI discomfort, nausea, or diarrhea at higher doses. Very high doses (over 10g daily) have been associated with kidney issues in animal studies. Stick to recommended doses and consult your doctor if you have kidney disease.

Q: Peak Performance L-Lysine 1000mg + Monolaurin 500mg: Can Peak Performance L-Lysine + Monolaurin interact with antiviral medications?

Both lysine and monolaurin have antiviral properties that could theoretically interact with prescription antivirals. If you take acyclovir, valacyclovir, or other antiviral medications, consult your doctor before combining them with this supplement. No serious interactions have been documented at these doses.

Q: Peak Performance L-Lysine 1000mg + Monolaurin 500mg: Is this lysine + monolaurin combo safe during pregnancy?

L-lysine is an essential amino acid found in food and is generally considered safe. However, the monolaurin component has limited pregnancy safety data. Pregnant or breastfeeding women should consult their healthcare provider before taking this combination formula.

Q: Peak Performance L-Lysine 1000mg + Monolaurin 500mg: What side effects might occur with Peak Performance L-Lysine + Monolaurin?

L-lysine at 1000mg is well-tolerated by most adults. Mild GI discomfort, nausea, or diarrhea may occur in some users. Monolaurin at 500mg may cause mild digestive symptoms as well. Start with one serving to assess tolerance.

Q: Peak Performance L-Lysine 1000mg + Monolaurin 500mg: Does this product contain common allergens?

Peak Performance L-Lysine + Monolaurin is formulated in capsule form and is third-party tested for purity. Check the label for specific allergen statements regarding gluten, soy, dairy, and tree nuts, as manufacturing facility cross-contamination warnings may apply.

Q: Peak Performance L-Lysine 1000mg + Monolaurin 500mg: Can I take this supplement long-term for cold sore prevention?

L-lysine has been used for long-term herpes simplex prophylaxis in clinical studies lasting months. The 1000mg dose matches the Griffith et al. protocol used for ongoing prevention. Long-term use at this dose is generally well-tolerated, though periodic reassessment with your doctor is advisable.

Supplement Science Editorial Team

Best Lysine Supplements (2026)

Lab Tested, Evidence Ranked

Supplement Science Editorial Team·Evidence-Based Supplement Research

Published Apr 10, 2026

This content is for informational purposes only and does not constitute medical advice. Consult your healthcare provider before starting any supplement. Full disclaimer

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We reviewed 18 L-lysine supplements across dose adequacy, form, purity, clinical backing, and value per serving. Our picks span standalone lysine capsules and combination formulas, prioritizing products that deliver the 1,000mg+ clinical dose studied for cold sore prevention and immune support.

As an Amazon Associate, we earn from qualifying purchases. Some links below are affiliate links — this doesn't affect our editorial independence or product ratings. How we evaluate products

4+ products evaluated · Ratings based on published research, not commissions

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How We Evaluate

Every product is scored against these weighted criteria. Our ratings reflect clinical evidence and product quality, not commission rates.

Dose Adequacy

30%

Clinical studies on L-lysine for herpes simplex prevention use 1,000-3,000mg daily. Products providing at least 1,000mg per serving score highest, as this is the minimum effective dose established in controlled trials.

Formula Quality and Synergy

25%

Purity of L-lysine form, absence of unnecessary fillers, and meaningful synergistic ingredients. Combination formulas must include ingredients with independent clinical evidence rather than pixie-dusted additions.

Third-Party Testing

20%

Independent lab verification of identity, potency, and contaminants. Important for amino acid supplements where identity testing confirms the correct isomer (L-lysine vs D-lysine) is present.

Clinical Evidence Alignment

15%

How well the product's dose and form match the protocols used in published clinical trials. Products matching the 1,000mg dose from the Griffith et al. herpes prophylaxis trial score highest.

Value per Serving

10%

Cost per serving at the clinical dose. L-lysine is an affordable amino acid — premiums should be justified by third-party testing, combination ingredients, or superior manufacturing.

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Supplement Guide

L-Arginine

Bottom line: L-Arginine at 3-6 g/day modestly lowers blood pressure via nitric oxide, but L-Citrulline is often preferred for sustained NO elevation.

Condition Guide

Immune Function

References

Griffith RS, Walsh DE, Myrmel KH, Thompson RW, Behforooz A (1987). Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Dermatologica. DOI PubMed
Chi CC, Wang SH, Delamere FM, Wojnarowska F, Peters MC, Kanjirath PP (2015). Interventions for prevention of herpes simplex labialis (cold sores on the lips). Cochrane Database of Systematic Reviews. DOI PubMed
Tomblin FA, Lucas KH (2001). Lysine for management of herpes labialis. American Journal of Health-System Pharmacy. DOI PubMed