Rapamycin side effect? Diarrhea

Hi Devon,

I had/have the same problem and posted about it here. Diarrhea from rapamycin

I got diarrhea from just a 1mg dose, and it happened every time.

I cut back to 0.25 mg (a quarter of a tablet) and found it manageable. I also seemed to have an improvement when I took probiotics before taking the rapamycin. I also took it with a meal.

I’m now taking 0.5mg twice a week. I don’t get the same severe diarrhea, but there is some sensitivity still.

Another suggestion that has been made is to put the rapa in enteric-coated tablets to bypass the stomach. I haven’t tried this yet but you may find it helpful.

I hope you see an improvement.

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Thank you, dontwakeme, for sharing your experience. Having recently had a Prenuvo full body scan (they found cancer in my husband), done a blood biopsy for cancer, and had a full physical, with all looking good, I’m figuring it is likely attributable to the rapamycin. Plus, I’ve stopped taking it since I have a surgery coming up and the problem has resolved. What I take is sirolimus compounded by a pharmacy Dr. Green works with on Long Island. He wants me to do more blood work to investigate, so I’ll do that but I doubt we’ll find anything out of whack. When I go back on Rapa I’ll go really slowly and take with the probiotics recommended by another person in this group. I really do want to figure out how to tolerate it, as the doctor who prescribed metformin for me for aging benefits has retired and my new doctor doesn’t want to continue it. Take care -

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Legumes - the biggest common thread in all blue zones.

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All oral rapamycin has to be enteric coated, otherwise it won’t work. When you cut the tablet you expose the contents to the acid, so I am not sure if you are really absorbing anything.

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This is my 4th week on Rapamycin, 2mg, 3mg, and 4mg, and at all doses I have had “almost” diarrhea the whole time, slightly more so at 4mg. I’m a 122 lb female if it makes any difference, dose wise. I am hoping over time it will resolve as my body adapts, since it doesn’t seem optimal. Can you share what Dr. Green said if you’ve followed up with him yet?

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Hi Joodles. Your experience is not dissimilar to mine. I went through a battery of stool sample tests and nothing was found, so it likely wasn’t an infection, parasite, or sign of a disease discernible from that kind of testing. I’ve been off the rapamycin for 2 months as I had to have back surgery. The diahrea has resolved during that time. I am planning on going back on it (slowly, like you) once the 3 months of bone healing is past. It will be interesting to see if the diarrhea returns. If it does, I will then follow Dr. Greene’s recommendation of other blood tests. I’ll post about that as it might be helpful to the few others who seem to have this side effect.

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Typically we’ve seen (and I’ve read in clinical studies) that diarrhea is a pretty high probability side effect at very high doses (i.e. 10mg per day or higher). We don’t hear about it too often here at lower doses like you’re using. You may want to to back off and try a slower ramp, eg. stay at 1mg/week or 2mg/week for a few weeks or more, then perhaps increase by 1mg and stay there for 3 or 4 weeks and see how your body handles it.

Some related reading/threads:

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I have delayed my current dose of Rapamycin and intend experimenting with 16mg plus an accelerator as soon as I get to another of my homes. I will of course be monitoring lipids etc although not with my usual 2 labs, but instead another one I use from time to time.

To be honest the varation in my lipids seems to be unlinked to the rapamycin dose.

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Thanks very much for the suggestion and article. I had to look up a lot of what is in the article in order to get a better grasp on it. So it sounds like diarrhea can indicate there is some chance mTORC2 could be activated. Even if not, malabsorption isn’t great so I think I will back down to 1 or 2 mg for awhile. I’ve stayed at 3 mg for the past few weeks, and the diarrhea has improved slightly but it’s definitely not normal, and it’s still constant. My food preferences have changed too but maybe that’s transient and unrelated.

I wonder if there is any relation at all to this and the fact that I can’t stay on a ketogenic diet long term because I get very weak over the course of months (since both involve inhibition of mTOR). I’ve been so curious about this for a long time.

I hope your back surgery goes well. And hopefully the diarrhea won’t return.

How nice of you to ask. The back surgery went super well and I am totally pain free, which is such joy! My diarrhea didn’t completely resolve when I was off rapa for the 2 months surrounding surgery, so I’m working my way through gastroenterology appointments to see if there is anything there. Nothing infectious found in stool samples, and nothing found on MRI of pancreas and stomach. Next, I assume, will be an earlier colonoscopy than planned. But I do still think it is exacerbated by rapa. I went back on 2 mg last week and had two days of it. Plus two nights of sleep disturbance. I so want to be able to take rapa, having one APOE4 gene. Where are you at this point?

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I think sleep disturbance is a symptom of increased autophagy.

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That’s great about your back surgery!!
According the article RapAdmin sent https://www.gastrojournal.org/article/S0016-5085(15)00449-7/fulltext?fbclid=IwAR3GtmAitR4T88YM9QiV8g27bZrqeC79lqPCekFTgNefxr7acO0SBHB3-C0, I’d think that probiotics wouldn’t help rapa induced diarrhea, but I decided to try Florastor Probiotics for Digestive & Immune Health (commonly used for diarrhea) anyway. I skipped one week of rapa because I thought I was getting sick, and the diarrhea resolved, then the next week I went back to my usual 2 mg of rapa plus the probiotics, and so far so good, which I’m puzzled but happy about. I’m hoping to not need to continue taking the probiotics since they are a bit expensive. I purchased a 2 week supply, and I plan to report back if I need to continue taking them. Of note also is that I was also getting overactive bladder much more than I usually do for a few days each week following my dose (sorry so much TMI), so the rapa just seems to affect that whole area. I already know what to do to address the overactive bladder so I just tried to double down on all of those things (I moderately consume coffee/tea/diet soda so it helps if I reduce those things even more, and exercise more).

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I just wanted to chime in to say that you’re not alone! I also started Rapamycin with a dosing schedule of 6mg per week. And like you, I also started getting diarrhea with each dose (usually starting about 24 hours afterward).

The only thing that’s caused it to stop is decreasing my dose. I went down to 3mg / week and recently started going as high as 4mg / week, thankfully without any problems.

It strikes me as so odd to have this as a side effect, though. It seems as though we shouldn’t be having this problem at such a low dose.

In case it provides useful context, I’m 34, very cardio fit, and I don’t typically have any GI trouble or food allergies.

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I used to have pretty bad (explosive) diarrhea around my Rapa dose. However, Metformin and Acarbose also give me diarrhea so I had attributed it to those two.

After two years, I can say my diarrhea has gotten better, but I am still VERY regular. I can go number 2, 3-4 times daily. It’s just not as liquidy or explosive as it was at the beginning.

The diarrhea, is likely a true rapamycin side effect, the same way some people get canker ulcers in their mouths. The entire digestive track, starting with the mouth are just about the fastest turnover tissue in the human body. You replace the epithelial lining of your gut about every five days or so. This is tissue in immediate contact with highly volatile substances in food and digestive juices, so at high risk of injury and infection, and therefore it makes sense to have very fast turnover and replacement, so injury is repaired rapidly and any infection doesn’t have time to get hold. This rapid turnover means high cell growth and replacement, very much keyed up MTOR. Now, if you take rapa and inhibit MTOR, you are going to first hit the highest activity MTOR in this high growth and turnover tissue lining your mouth and digestive system. This results in many people getting mouth sores, as small injuries are not getting healed as fast as usual, and you get “open sores” - as Peter Attia said, when his kid accidentally bumped his head against Peter’s mouth and the teeth caused a small cut, it immediately turned into a sore because rapamycin prevented the fast healing. Now, in the gut, we can experience the same issue, in that as tiny injuries are not healed as fast as usual, but here the reaction by the body is diarrhea - this is the body expelling all foreign substances as fast as possible to prevent the little injuries from becoming infected, it’s a defence mechanism.

Bottom line, rapamycin can absolutely cause diarrhea and mouth sores.

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Although you are right it is not guaranteed to. My single infrequent large doses of Rapamycin do not cause diarrhea.

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When I switched to every 2 weeks from every week, the diarrhea stopped. mTORC2 effect?

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It’s not a reduction in cell turnover that causes the diarrhea. The effect appears to be caused by reduced absorption of salts in the intestines which is a direct result of rapamycin inhibiting the NHE3 transporter on the intestinal cells. This transporter is important for absorbing sodium and water, and when inhibited it results in diarrhea. Rapamycin Inhibition of mTOR Reduces Levels of the Na+/H+ Exchanger 3 in Intestines of Mice and Humans, Leading to Diarrhea - PubMed

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