Rapamycin compounded? Enteric coated?

Dr. Peter Attia podcast The Drive episode 272. #272 ‒ Rapamycin: potential longevity benefits, surge in popularity, unanswered questions, and more | David Sabatini, M.D., Ph.D. and Matt Kaeberlein, Ph.D. - Peter Attia

Near the last 10 minutes he and the guests (Kaeberlein, Sabatini) talk about how compounded rapamycin is likely not bioavailable. Versus noncompounded enteric coated rapamycin. Thoughts? Is the rapamycin offered here enteric pills?


Hi there, yes, that is correct. Essentially, compounded rapamycin would not pass through the intestinal lining due to its acidity in a regular capsule, which is the form that compounded medications typically come in.

The generic medication that we prescribe is chosen based on its bioavailability. The two manufacturers that we work with are both sealed-coated tablets. This is the same medication transplant patients take for their critical conditions (Dr. Miller for example, took generic rapamycin—both Zydus and Glenmark—to manage her stem cell transplant graft vs. host condition).

We’ve tested these brands for bioavailability through a Sirolimus panel that we offer to our patients as part of the protocol. We chose the brands that we prescribe because they had the highest bioavailability of the options available. It effectively had the same bioavailability as Rapamune (both in terms of cmax and tmax). We can send out a Sirolimus panel for you if it is something you’d like to test for during your protocol.​

We don’t prescribe compounded rapamycin (sirolimus) because of the bioavailability issues that Kaeberlein and Attia discussed. Specifically, the raw powder of rapamycin in a capsule is unstable in gastric pH.

1 Like

Excellent thank you Mr. Tawfik. My wife and i will refill our prescriptions today!

Hello! I appreciate the reference on X yesterday, addressed in the podcast, that there is some difference in the bioavailability of Rapa/Sirolimus.

I’d like to be able to test what I am taking…I do believe it is sirolimus but have no idea whether it is compounded, or not.

This is obviously a major issue to resolve - if it’s not bioavailable, then what would be the point?

Thank you for any information you might share about the panel.


Thank you for your response. This is very clear. I have been taking Rapamycin for 6 months. I would like to be able to get an assay to test my levels for Rapamycin and other markers. How do I get this (I was unable to find the assay on the site).

Also, the most recent prescription refill went from a round white tablet to a white triangular tablet with “RD53” stamped on it. This was a bit surprising/confusing. I would have appreciated some sort of communication clarifying that it is the same drug but different manufacturer.


If you message us through the patient portal we can order the sirolimus panel with some instructions on how to time your tests relative to your dose.

This is my FAQ, and concern. Don

I am kind of surprised that I posted this 2 months ago and have not received a response on the forum.

When I started getting Rapamycin from Healthspan back in March, I was getting round white pills which were too small to have enteric coating. According to the recent Peter Attia interview and other sources, this is almost certainly has low bio-availability.

With my latest Rapamycin refill in September, I noticed that the pill had changed and was now a much larger triangular tablet. According to Google, this may be Sirolimus formulated by Dr. Reddy’s Lab. It looks enteric coated but I don’t know for sure.

I am not sure if you get notifications to a response on the board, but in a previous response I let you know that we can make a requisition to get a sirolimus test.

However, my first post on September 25th should address the concern about the coating and bioavailability of the medication. As I mentioned the sealed coated tablets of the manufacturers we prescribe have been tested and had the same bioavailability of Rapamune.

Let me know if I can address any additional concerns you may have.