Efficacy of Lysine Hydrochloride containing medicines for cold sores

We initiated targeted compliance reviews of selected listed medicines containing Lysine Hydrochloride to verify whether sponsors had appropriate evidence to support their cold sore-related claims.

We found that the evidence provided by the sponsors was inadequate to support the cold sore-related claims. Consequently, all sponsors removed the unsupported claims from their medicines and their advertisements.

If you are a sponsor of a listed medicine containing Lysine Hydrochloride that makes claims regarding cold sores, you are encouraged to:

• review your supporting evidence using the Evidence Guidelines; and
• re-assess how your product is presented and ensure all claims—especially those related to cold sores—are accurate, truthful, and not misleading.

For more details, please visit the Compliance and education for listed medicines page.