L-Lysine
What it is
An essential amino acid studied for preventing cold sores (herpes simplex). Evidence is mixed — some trials show reduced recurrence, others show no benefit. Theory: lysine competes with arginine, which herpes virus needs to replicate. Also supports collagen synthesis and calcium absorption. Very safe at standard doses. Most useful at higher doses (3 g/day) during outbreaks.
Dose
500–3,000 mg/day for cold sore prevention; take on empty stomach; avoid high-arginine foods during outbreaks
Time of day & tips
Take on an empty stomach for best absorption. During cold sore outbreaks, avoid high-arginine foods like nuts, chocolate, and seeds. Can be combined with vitamin C.
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