New Peter Attia interview w/Matt Kaeberlein, inferior bioavailability of encapsulated rapa

Has anyone done blood test of bioavaliability when using Indian generic tablets like Rapacan (Biocon) or Siromus (Zydus)? Do they have reasonable bioavailability? (Or at least has anyone seen benefits using these generics? Like reduction of inflamation, etc.)

I hope I can find a lab here in Perth, Australia that are willing to test me without GP prescription. While I find it, does anyone has on hand the blood levels one should ideally reach with Kaeberlein dose: 0.15mg per kg of weight once a week. And how much time after ingestion should I get the blood test?

Many thanks,
Dr. Spin

Just looked on bay. Enteric acid resistant capsules are available there. I think the simple answer is to buy those. (1 size larger than the capsules you have). Put your compounded capsule inside one of those or put the capsule contents inside the enteric capsule. Viola! The sirolimus gets through the stomach acid without degradation and is absorbed in the small intestine. Thoughts anyone?

It has been suggested in several groups/discussions that the generic coated “Amazon-capsules” may not function as intended. (It was among others suggested the capsules are not ‘airtight’ where the two halves meet, and liquid will get in and out of the capsules).


These don’t necessarily work. See this previous discussion that touches on this issue here: Rapamycin enteric coating vs powder bioavailability

and also this thread: Bioavailability of Rapamycin From Compounding Pharmacy

Whatever you do, if you’re using compounding pharmacy rapamycin you probably want to do a sirolimus blood level test a few hours after taking the medicine to validate that its getting into your system: How to get a Rapamycin (sirolimus) Blood Level Test


I’ve not seen any comparison studies. Typically, if there isn’t a benefit to the pharmaceutical company (i.e. a competitive benefit) they aren’t going to do the study. Since there is very limited competition in this segment of the market, I doubt anyone has done the study.

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Since I already have a large quantity of compounded capsules, I ordered some of the empty enteric coated capsules. I’ll fill one and place it in a glass of body temp water with some vinegar (don’t have access to HCl). Interested to see what the dissolution time will be. Not the best science, I know, but it’s a start. I’ll let you folks know.

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I think MAC already did this on another thread and said they dissolved way too fast


A simple solution is to take an over the counter H2 blocker 90 minutes prior totaling rapa
Famotidine 20 mgs costs $ 0.35 per pill
This will suppress stomach acid temporarily an allow got improved absorption of rapa
Famotidine 20mgd is otc

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Interesting suggestion on this - have you tried it?

The famotidine is a good theory that I suggested on an earlier thread, but I don’t know of any data to prove it actually works to increase absorption of rapa capsules. Seems like one’s best bet, with minimal risk, if capsules are all you can get.


Because I am also using compounded capsules, I’ve tried the experiment @Paul_Moss suggested. I put instant coffee in an enteric capsule (from Amazon) and placed the capsule in vinegar (held under the vinegar with a fork) to see how long it would take to spill the coffee. Stomach acid has a pH of 1-2, and 4% vinegar has a pH of ~2.3 (not quite stomach acid but close-ish). After about 2 hrs the instant coffee started leaking into the vinegar. The capsule starts disintegrating on the sharp edge where the larger half overlaps the other half capsule. (BTW, you can read about @MAC’s similar experiment, in the thread “Rapamycin enteric coating vs powder bioavailability”. I think he used delayed release capsules, not enteric, but check out his posts.)


Thanks! Good to know.
And the instant coffee was a really good idea. Easy to visualize!

If taken on an empty stomach in the AM, then it seems like 2 hours ought to be enough time to clear the stomach in most people. I’ll repeat the experiment when my enteric acid resist capsules get here. That’ll take awhile though. Ordered from the US Ebay and I am in Japan.

I hope the enteric capsules and/or famotidine work, but due to the uncertainty I’m going to stick w/tablets. BTW the thing you would not want to do is to use both famotidine and enteric caps, since the enteric caps are made to only dissolve in higher pH, therefore increasing gastric pH w/famotidine would actually cause the caps to open up in the stomach. Maybe the rapa would still be absorbed due to the higher pH, but it would be a waste of enteric caps.

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So WHAT is the bioavailability of the capsules?

Is anyone subscribed to the podcast willing to share some of his AMA’s?

Certainly not all so-called enteric capsules are equal. Seems like you found a good one.

I subscribed to the Peter Attia membership then decided I’d cancel for a while due to the expense, after which they sent me an email with an offer that was dirt cheap, can’t remember exactly how much but it was just a fraction of the normal charge. I took them up on it. It might be illegal to share the podcast that is members-only, not sure.

@vegasallen1: The enteric capsules I used are just the ones from Amazon; I’m waiting to hear of other’s results doing this (or a similar) test. I have some of those that @MAC used (bought before I read of his experiment which soured me on them & I subsequently got the ones claiming to be enteric). I’ll try the same test with those as well.

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I performed this same test with the delayed release capsules (from Amazon) twice, and both times the coffee was spilled in under 55 minutes. In this instance, it’s more like the capsule itself dissolves; quite different from the behavior (described in an earlier post) with the enteric capsules.