Q. I had chicken pox as a child and shingles as an adult. I have gotten the Shingrix vaccine. For an occasional cold sore, I use acyclovir, but I take L-lysine daily for prevention. Has anyone studied this as an alternative prevention against Alzheimer’s disease?

As I understand it, the herpes virus might be a contributing factor. Since L-lysine is available without a prescription in the U.S., it could be an alternative to antiviral drugs for many people.

A. The link between herpes virus infection and AD is tantalizing, but it has not yet been firmly established. What we know about L-lysine is that it can help reduce outbreaks of cold sores due to herpes (Viruses, June 2, 2023). According to the scientists, the effective dose of this dietary supplement is at least 1 gram per day. We found no studies of L-lysine being used to prevent AD.

L-lysine is an essential amino acid. Another amino acid, arginine, counteracts the antiviral action of lysine. L-lysine appears to be more effective if people reduce their intake of arginine from legumes, nuts and meat like turkey, chicken or pork.

It was smart of you to get vaccinated against shingles. The varicella zoster virus that causes both chicken pox and shingles has also been implicated in AD. Studies in Wales and Australia indicate that older people vaccinated against shingles are less likely to develop AD than their neighbors who were not vaccinated (Nature, April 2, 2025; JAMA, April 23, 2025).

Q. A while back, your column provided an answer to a man who woke up too early and couldn’t get back to sleep. There are medications that are supposed to help, like sublingual zolpidem. It contains the same ingredient as Ambien and is taken under the tongue. I am taking zolpidem as a pill that I swallow with water. What’s the difference between sublingual zolpidem and what I am taking?

A. We recently received a comment from a reader who occasionally puts a piece of a zolpidem tablet under the tongue to fall asleep. The sublingual formulation is specifically designed to help people get back to sleep after waking in the middle of the night. The dose is 1.75 milligrams for women and 3.5 milligrams for men. Those over age 65 should take the 1.75 milligram dose.

Learn more about zolpidem and other strategies for insomnia in our “eGuide to Getting a Good Night’s Sleep.” It can be found under the Health eGuides tab at www.PeoplesPharmacy.com.

In their column, Joe and Teresa Graedon answer letters from readers. Write to them in care of King Features, 300 W. 57th Street, 41st Floor, New York, NY 10019, or email them via their website: www.PeoplesPharmacy.com.