Product Reviews
Lysine Supplements Review

 Initial Posting: 2/6/16 
Lysine Supplements Reviewed by

Choose the Best Lysine Supplement

CL Tests Reveal Which Lysine Supplements Provide the Best Quality and Value

Lysine supplement brands compared in this review
21st Century L-Lysine for Cats Nature Made L-Lysine Source Naturals L-Lysine
Andrew Lessman ProCaps Lysine Pet Naturals of Vermont L-Lysine for Cats Spring Valley [Walmart] L-Lysine
Carlson L-Lysine Puritan's Pride L-Lysine Swanson Free-Form L-Lysine
CVS/pharmacy L-Lysine Rexall L-Lysine Up & Up [Target] L-Lysine
Douglas Laboratories L-Lysine Rite Aid Pharmacy L-Lysine Vitacost L-Lysine
Finest Nutrition [Walgreens] L-Lysine Solaray L-Lysine Vitamin World L-Lysine
GNC L-Lysine Solgar L-Lysine  
21st Century L-Lysine for Cats Andrew Lessman ProCaps Lysine Carlson L-Lysine CVS/pharmacy L-Lysine Douglas Laboratories L-Lysine Finest Nutrition [Walgreens] L-Lysine GNC L-Lysine Nature Made L-Lysine Pet Naturals of Vermont L-Lysine for Cats Puritan's Pride L-Lysine Rexall L-Lysine Rite Aid Pharmacy L-Lysine Solaray L-Lysine Solgar L-Lysine Source Naturals L-Lysine Spring Valley [Walmart] L-Lysine Swanson Free-Form L-Lysine Up & Up [Target] L-Lysine Vitacost L-Lysine
Make sure the lysine supplement you take passed our quality review and is right for you!
Isn't your health worth it?
Lysine (also known as L-lysine and commonly sold in the L-lysine HCl form) is an essential amino acid. Some evidence suggests that it may help prevent and reduce symptoms of cold sores (herpes simplex labialis), genital herpes lesions, and canker sores. Lysine is also commonly recommended to prevent and treat feline herpesvirus 1 in cats. But does lysine work for these uses? Which lysine supplements provide the highest quality and best value?

To answer these questions, recently reviewed the clinical evidence for lysine and purchased and rigorously tested many lysine supplements (including two cat chews) to be sure they contained what they claimed and that tablets would properly break apart for absorption.

Our tests found one product which we consider misleading, providing just 83.2% of the lysine one might expect from its label. Fortunately, we also identified a number of high quality lysine supplements which contained their labeled amounts of lysine and could properly release their ingredients. However, there were significant differences in cost, ranging from just 4 cents to 33 cents for the same dose of lysine, so we identified those providing the best value. We also tested two lysine chews for cats — one of which provided lysine at a much lower cost than the other. 

In this comprehensive review of lysine supplements, you'll get test results and quality ratings for 17 lysine supplements for people (including 7 that passed our voluntary Quality Certification Program) and two popular lysine supplements for cats. You'll also get information about an additional lysine supplement similar to one that passed testing. You'll learn:
    • Which lysine supplements passed or failed testing 
    • How lysine supplements compare on quality and cost and which provide the best value.
    • What lysine can and cannot do for your health, and your cat's health.
    • How to read the labels, so you know how much lysine you can really expect from a product without being fooled.  
    • Lysine dosage for uses including cold sores, genital herpes lesions and canker sores.
    • Concerns, drug interactions, and potential side-effects of lysine.

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Learn More About Lysine Supplements Answers -- for Lysine Supplements Review
Must I take amino acid supplements on an empty stomach? Can I take them with other amino acids or with food to help with swallowing capsules? Get the answer >>

Can lysine, vitamin B-12, or other vitamins or minerals help prevent or reduce canker sores? Get the answer >>

Which supplements can cause diarrhea? Get the answer >>
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