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

For Sirolimus users enhancing their absorption with grapefruit juice, be advised that differences were found between canned and frozen. This study found frozen magnified the effect at a rate of 3.5–meaning 2 pills = 7 when downed the juice made from the frozen concentrate form. in the absence of a particular brand endorsement, I prefer to make my own from fresh grapefruits.

https://www.uchicagomedicine.org/forefront/news/grapefruit-juice-lets-patients-take-lower-dose-of-cancer-drug

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Yes - Also - some additional reading if you are considering grapefruit juice with rapamycin:

Here: Improve Bioavailability of Rapamycin (2)

Here: Rapamycin and Grapefruit Juice

Here: Grapefruit interaction with longevity meds?

Here: Rapamycin Interactions with Other Food, Drinks, Supplements and Drugs

Here: Ketoconazole timing for enhanced Rapamycin absorption

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By dumb luck - I found and use the Red Grapefruit I get at Walmart - costs about a buck each.

I cut it into quarters and hand squeeze (literally) into a glass using a strainer. I get about 5 fluid ounces and that alone downed with my rapamycin dose gives me a 6-7x’s increase. I use Labcorp and it seems consistent with fresh Red Grapefruit. Plus it doesn’t taste too bad - I am not a GFJ fan. . Will do my next test in April.

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Does anyone know of advantages to squeezing the juice, rather than simply eating the whole of the fruit?

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FWIW

I eat the entire fruit, 45 minutes to 1 hours before.

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I was doing 6 mg with GFJ. Now I think that’s a bit much as I went to my dermatologist last evening and she said the rash on my neck appeared to be autoimmune related. She asked if I was taking any chemicals that may have caused this… Also, the sebaceous hyperplasia has been linked to transplant patients taking tacrolimus. So I may have shutdown too much of my MTOR systems.

So, I’m going back to 3 mg + GFJ weekly and forgoing the hair tonic for now. I’ll re-evaluate later.

Also, the beta-alanine was making things worse and I should cut it out. Itching and rashes are signs of inflammation and probably not healthy.

Too much of a good thing… At least now I know my limits and that I shouldn’t go beyond 6 mg + GFJ bi-weekly.

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Why does it seem that no one uses quercetin, a potent competitive inhibitor of CYP3A4, for enhanced bioavailability? GFJ seems a bit random by comparison.

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Please post any good research papers you have seen on this

Effects of quercetin on the bioavailability of doxorubicin in rats: Role of CYP3A4 and P-gp inhibition by quercetin

From paper

“Quercetin inhibited CYP3A4 enzyme activity in a concentration-dependent manner with a 50% inhibition concentration (IC(50)) of 1.97 μM. In addition, quercetin significantly enhanced the intracellular accumulation of rhodamine-123 in MCF-7/ADR cells overexpressing P-gp.”

Would you want to post this as a separate thread?

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I read it here:

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I am using Naringin

I know that it is supposedly only one of the flavonoids in GFJ but the dose is the same each time, and I just take 1 capsule an hour before Sirolimus

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Yes - I like the standardized dosing as you mention. Do we have any idea on the actual effect on blood sirolimus levels? Have you done any testing after dosing?

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I have no clue, I have the desire to learn, but lack the motivation to actually follow through. :grinning:

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I read somewhere that white GFJ is preferable (in terms of efficacy) to ruby red. Has anyone heard this?

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Yes, I looked up the Florida citrus report, and the white more bitter Grapefruit has more of the essential flavonoids

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I’m not sure - here is one study suggesting similar outcomes with both:

and another article/paper:

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Interesting, white grapefruit is yucky anyway

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Yep. I get 6xs to 7xs increase of my rapamycin dose on Red Grapefruit. Goes down smooth-ish.

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Red/pink or yellow - Duncan (yellow) apparently has the highest levels of most of the four furocoumarins .
Variation of bioactive furocoumarins and flavonoids in different varieties of grapefruits and pummelo | SpringerLink

Full Paper / PDF Below:

s00217-007-0654-4.pdf (483.1 KB)

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Forget that grapefruit juice deal - crap ! Do ketoconazole instead as it is more effective and u know what u are getting.

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