Grapefruit vs pomelo while taking rapamycin?

Grapefruits is not a common fruit in my country. However pomelo is easily accessible.

Can I take pomelo juice instead of grapefruit juice for the bioavailability when I take 6mg rapamicin? If would be so helpful if there’s any conversion rate for grapefruit vs pomelo :nerd_face:

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Apparently you can


6 mg + GFJ or pomelo is a pretty high dose. Most people that take 6 mg one time a week do so without that.


Hi - it looks to be about the same effect as grapefruit juice. People here see anywhere from 3X to 6X increase in blood sirolimus (rapamycin) levels when they take Grapefruit (or Grapefruit juice) with rapamycin. I recommend you read up on this here: Improve Bioavailability of Rapamycin (2)

Definitely don’t start at that level. At 6mg and Pomelo you could be taking equivalent of 36mg dose, which is extremely high.

I would start slow and slowly build up slowly to see how your tolerance is. Read up here: What is the Rapamycin Dose / Dosage for Anti-Aging or Longevity?

Be careful though - if you are taking any other medications (like some statins) it could cause overdose.

Read the FAQ: Rapamycin Frequently Asked Questions (FAQ)

To clarify the mechanism of this increase in the blood level of tacrolimus, we investigated the effect of pomelo juice extract on the activities of CYP3A4 and P-glycoprotein, in comparison with that of extract of grapefruit juice (GFJ). The 10% ethyl acetate extracts of the juice of three pomelos of different origins (Banpeiyu, pomelo I; Hirado Buntan, pomelo II; and Tosa Buntan, pomelo III) and GFJ significantly inhibited 6beta-hydroxylation of testosterone in human liver microsomes by 76.4, 67.2, 37.5, and 83.9%, respectively. The extract of pomelo I was as potent as that of GFJ.

Source: Inhibitory effects of pomelo on the metabolism of tacrolimus and the activities of CYP3A4 and P-glycoprotein - PubMed


More is not better!
People need to be more careful and watch their assumptions, the VAST majority of people are deadly wrong about something they do.


Yes - while rapamycin / sirolimus by itself is not deadly, it can suppress the immune system when taking higher doses without 1 or two weeks “off” from the drug. If you run into a bad infection while you have a lowered immune function, it can be deadly.

There is one recorded instance in a rapalog (everolimus), which is basically the same drug as sirolimus, where at young 27 year old woman died from an infection she got while taking high doses (10mg/day) during a clinical trial.

Please read this before going above the 6mg, dosed once per week level which most people are taking (without grapefruit juice) .


Oh I actually only take it once a week. But you are right I should probably take 3mg with pomelo juice

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Thank you! That’s so helpful

I would recommend starting at 1mg (no pomelo), then increase by a 1mg the following week. At week 3 I would take 1mg with Pomelo…

Even 3mg rapamycin with Pomelo could be equivalent to 9mg to 18mg of rapamycin - a very high dose. I suspect you might experience diarrhea, and skin rash, by moving too quickly to high doses.


I started three months ago taking 3mg/w without juice. Then 2 months ago started 3mg with juice. Then a month ago I started taking 5mg and then finally 6mg with juice. I think I have high tolerance since I still haven’t experienced mouth sore, rashes, or diarrhea at all. Still as constipated as prior… only second day fatigue after weekly dose.

Ah - ok. I thought you were just starting rapamycin.

But - when starting with grapefruit juice or pomelo just keep in mind that you could be getting anywhere from 3X to 6X boost in the effective dose.

Let us know how it goes for you.

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For constipation I recommend 2g daily of magnesium citrate. You get your magnesium and citrate plus they act as a laxative. I use the powder with a 2 g scoop.

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I’ll give it a try thank you !

Also - you may want to review the past threads / discussions on grapefruit juice:

Here: Rapamycin and Grapefruit Juice

Here: Not all grapefruit juice is the same for the purpose of Sirolimus enchancment

Here: Grapefruit interaction with longevity meds?

Here: Grapefruit Juice x Lemon X Orange


There’s folks here and threads who have done alot more Labcorp sirulimus blood testing then I. For my body, I found that taking 6mg alone i had very low, almost zero absorbsion. Near zero from blood testing. I don’t know why.

6mg + GFJ and a stack of other nutricals from a GFJ thread here, berberine, perperine, I don’t remember if including Fisitin was rational or just kitchen sink. For me; this kitchen sink mix on empty stomach wait 2 hrs take 6 mg rapa. Wait 2 hrs run to Labcorp = around 20nm-30nm levels. Is what you’d expect on 6mg for the ave person without GFJ. I’m concerned how many folks taking rapa are like me and don’t absorb and NEED the boost from the GFJ and friends to get normal blood levels?

Just my view that every new person needs to blood test a few times to target 20nm-30 and yes this is only a guess taken off the tables. Refer to the threads on effective dose for what blood levels we should target. Only my guess in this; 20-30nm.

Call customer support off Contact Us - Life Extension ask for special order blood tests; sirolimus test. was $97. I order a few at a time.

Good luck, curt

Yesterday I went to the shop where I normally buy my Pomelo and they did not have any. Hence I have now taken 6mg of Biocon Rapacan with half a grapefruit instead. I don’t know if I will be able to tell any difference, but time will tell.

I did take 1g of mitopure this week which did seem to cause the expected sleep disruption. Urolithin A has a shorter half life (around 24 hours).