Is Lysine Safe During Pregnancy?

Cynthia Flynn's picture


Dear Midwife,
I have herpes and to avoid outbreaks, I take large doses of Lysine as soon as I start to feel an outbreak coming on. Also, if I feel a cold coming on, I take large doses of Echinacea to ward off the cold. Are these things safe while pregnant and how much does the dosage matter?


Lysine is not recommended for pregnancy. Acyclovir and valacyclovir are safe for pregnancy and should be prescribed by your midwife or doctor. Echinacea is probably safe, but as with any medication, should be minimized during pregnancy.

-- Cynthia, CNM


Submitted by bugmenot on

What's the basis for your answer? Yogurt has as much lysine as a lysine supplement.

I don't know of any studies on the effects of lysine and pregnancy, but I also don't know of any studies on the effects of antivirals during pregnancy either.

I really don't know what the answer is, but I think if you're going to tell people not to take lysine supplements, you need to say why.

Cynthia Flynn's picture

To be more specific, Acyclovir is Pregnancy category B and is listed as safe for lactation. It has been used for decades without ill effect, and the studies show that it is safe. If a baby is actually born with herpes because their mother was not prophyllaxed during pregnancy, the baby is given IV acyclovir to save its life. Valtrex (valacyclovir) is a newer drug, but it has the same pregnancy profile as acyclovir.

You are right, there are not studies of lysine, so the recommendation is to avoid it in both pregnancy and lactation. But as with all choices, it is up to the mother to decide how she wishes to manage both her pregnancy and any medical problems that might arise.