Mouth sores on rapa

MK mentioned that mouth sores are sometimes a side effect of rapa & showed up in some of the people in the survey they did.

Apparently, mouth sores can be caused by various things, of which the common ones seem to be canker sores & cold sores. Cold sores are a herpes infection, canker sores are some kind of ulcers (so saith Mayo via google).

For the people who had them, are they canker sores, cold sores or do you think they are something else? I’m just curious. I didn’t get them & have no personal experience to go on.

Thanks, Beth


I get them once in a while. Usually 1 at a time, a day after a dose. They take a day or two to go away as I recall. They do not hurt or even sting when eating/drinking. My tongue finds them somehow. I haven’t had anything like them since I had braces as a kid. As long as they go away quickly I am unconcerned.

1 Like

Yes - usually the rapamycin-related sores are what are called “Apthous Ulcers” and are pretty common on rapamycin; I think about 30% or more of us get them at least once. And yes, the common term for these is “canker sore”.

I’ve seen Peter Attia recommend Debacterol as the best way to address these sores, when people get them.

But they usually clear up after a few days. I’ve had one only once at around 6mg/ dosing once per week, and never again despite testing much higher doses. So I’m not sure the cause.

You can see past discussions on this topic,

Here: Cold sores raging early on into rapa

Here: Rapamycin: How to handle mouth sores

Here: Got my first ever herpes labialis / canker sore


I don’t get either. I get blood blisters in my mouth.

1 Like

I took my first 1mg dose this past week and got very small white bumps in my mouth, primarily on my gums in the front of my mouth. None of them hurt, but are these likely the mouth sores people speak of? They are much smaller than canker sores and are not painful.