Rapamycin and A1C

Does anyone have any research on how rapamycin may effect glucose tolerance and A1C. I have been taking 5-6MG 1 x week for 8 months (not cycling off) and in my latest bloodwork for the first time my A1C came in at 5.8, so just above normal and in the “pre-diabetes” category. I believe I read somewhere that over a prolonged period of time that rapamycin was found to create glucose intolerance in mice. I am going to take the next 4 weeks off and then go on a 2 ,month on 1 month off to see if the A1c normalizes. Anyone have any guidance or thoughts?

Thanks for posting this. The news is concerning. But I think it would be helpful if you could post other results you’ve got from the same test going back a ways. Do you have those available? Very helpful to know how much of an outlier this new value is in your own history.

Thanks for responding. Had my records pulled and in 2022 A1C was 5.5 and in 2021 was also 5.5. So not as significant an increase as I thought and may have nothing to do with Rapamycin and may be diet related.

I have been taking Rapamycin for 2 years and my A1C as measured last week was 4.8. I have not seen an uptick in my A1C as of yet,


Hi- This is Shriya from the Healthspan Clinical Team! Elevated blood sugar does sometimes occur on the rapamycin protocol. Rapamycin lowers insulin secretions which is a positive in the context of overall longevity. We’ve noted that elevated doses of Rapamycin can precipitate hyperglycemia as a consequence of diminished insulin secretion. When such reduced insulin levels coincide with a diet rich in carbohydrates, a form of hyperglycemia could possibly emerge in certain individuals. From a lifestyle perspective, a modification involving a decrease in the consumption of simple carbohydrates can help reduce these levels. For some specific cases, the introduction of metformin into the treatment regimen could be a viable strategy for the regulation of these levels. Lastly, there is no harm at all in reducing the frequency of your dosing schedule, so that is something we can implement. If you have concerns about your A1C levels as shown on blood tests, we recommend reaching out to our healthcare team so that we can develop a personalized solution!


My understanding is elevated A1C and lipids occur more often with people doing daily dosing for medical conditions. I’m diabetic and taking 1,000 mg metformin twice a day, and for years before starting rapamycin, my A1C had been high ~ 7.8+, mainly due to poor diet. I’m in my 60s and found that improving my diet was no longer enough to get it under control. I started taking Acarbose (25-50 mg) with each meal and my A1C fell to 5.8 after about 2.5 mos. I started 5 mg/wk of rapamycin after that, and about 6 weeks ago, and my A1C as of last week is even better - 5.4. I plan to keep an eye on it.

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Nice. Hopefully your a1c levels continue to drop. I didn’t realize arcabose had that much affect on lowering a1c levels.

Thanks Shriya, for the great response. I have been on 5mg/week for about 6 weeks and watched my HbA1c go from 5.5 to 5.9. I have also seen my Tryglicerides go from 103 to 193. So I signed up for a CGM (Continous Glucose Monitor) with Levels and read the book “Good Energy” by Dr Casey Means. She describes exactly what you are suggesting. I have noticed Big glucose spikes when eating simple sugars - especially with my nightly glass of 100% Cranberry Juice ritual with 28g of Sugar. I have since started watching my carbohydrates, eating in a 5 hour window with intermittent fasting with a couple 36 hour fasts to kickstart Keytosis. Also ending each shower with at least 1 minute of cold shower, and taking a walk after my largest meal at the end of the day. I have gone from 196 lbs to 182 lbs. I highly suggest everyone take charge of their health by educating themselves so they know the right questions to ask their health provider. My Triglycerides came down in the previous 5 months prior to Rapamycin by giving up alcohol. However, it popped right back up after starting Rapamycin. My take so far is that I was on the edge of pre-diabetes with a prior fasting glucose of 99-100 before my dietary changes. Now my fasting glucose is 85, and it will also crash as low as 62. From what I have learned, the spike in Triglycerides may be hyperglycemia as well as a sign of over-nutrition. Watch for the empty calories and highly processed foods. My goal is longevity, but for that to happen, metabolic health becomes the top priority to control heart health and inflammation. With big changes in lifestyle it as well as changing medications, blood markers seem to be changing rapidly. FYI, I started on Metformin about 9 months ago to control suspected glucose spikes since my last meal is so close to bedtime. Quality sleep is a whole different topic. Read “Why We Sleep” by Matthew Walker.