L-lysine
Also called: Lysine, lysine HCl
An essential amino acid you get from protein foods. It's mostly used to help prevent cold sore outbreaks.
Medical Disclaimer
Supplements can interact with medications and aren't right for everyone, especially during pregnancy or breastfeeding, or with a chronic condition. Ask your provider before you start.
Studied for
- Cold sores (mixed evidence, mainly for prevention)
- Low protein intake on a plant-based diet
- Calcium absorption (limited evidence)
- Stress and anxiety, paired with arginine (limited evidence)
Found naturally in
- Meat, poultry, and fish
- Eggs and dairy
- Beans, lentils, and tofu
- Quinoa
Label red flags
- Cold sore blends where lysine is a small amount in a proprietary mix
Check with a provider
- Kidney disease
- Taking large amounts of calcium, since lysine increases how much calcium you absorb
- Taking aminoglycoside antibiotics (such as gentamicin). Lysine may add to their effect on the kidneys.
- Pregnancy or breastfeeding (high doses aren't well studied)
- Stomach upset or diarrhea can happen at high doses
Usually found in cold sore and immune formulas, lip balms, amino acid blends. Browse the Lesher Wellness store
Parts of the body it affects
Explore what each area does and the conditions that can affect it.
Skin
Your skin is your largest organ and a major immune barrier. Rashes, patches, and color changes are often the first visible signs of an autoimmune condition.
Blood & immune system
Blood carries oxygen and nutrients, and white blood cells defend you from infection. In autoimmune disease, that defense system targets your own tissues.
Illustrations: Servier Medical Art, CC BY 4.0
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Dr. Lesher is a Naturopathic Doctor who focuses on autoimmune and chronic conditions in women. Since 2020, she's helped hundreds of patients stop managing symptoms and start healing.