I have started taking one Naringin 600mg, which is reportedly the extract of Grapefruit. I’ve known about Grapefruit as an inhibitor of the cytochrome P450 (CYP) 3A4 enzyme and transporters for quite some time. I hope Naringin will have a similar effect to grapefruit and effectively enhance my 6 mg of rapamycin weekly. Does anyone have knowledge of Naringin? I know I won’t buy a grapefruit every week, so that’s why I chose this route.
If you are an MD with easy access to rapamycin just increase the dose, that’s much more reliable
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Right now, I pay 128.00 from Amazon Pharmacy for 30 pills; I am trying to save money because when you add all my supplements up, it starts to get expensive.
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Even if you take Rapamycin without grapefruit juice (GFJ), everyone has a different level of absorption. So if you take 3 mg without GFJ, you may have more or less rapamycin in your system than someone else who takes 3 mg without GFJ or another who takes 1 mg with GFJ.
If Rapamycin is too difficult to get or too expensive, GFJ is a good solution.
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I am also looking for the substitutes for grapefruit juice, because the grapefruit season is between October to November, and it’s not a popular fruit, so it’s very hard to buy/find grapefruit in spring and summer.
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I personally choice packaged non fresh grapefruit juice, at least that will be consistent
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"The results showed that the inhibition of quinine 3-hydroxylation (CYP3A4 activity) by bergapten (67%), and quercetin (55%) was greater than naringenin (39%) and naringin (6%), at the same inhibitor concentration of 100 M. "
Are you taking it with a meal containing fat? Seems that it’s hydrophobic (quercetin is also).
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This would suggest that more than naringin participate in the process, maybe the juice or fruit itself in theory could be better choice. I will try to learn more about my supplement.
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The supplement would have the advantage of being consistent. Grapefruits being a natural product, they will vary in their content of these natural products by variety, season, and weather. You would get a more consistent effect on the enzyme with a standard dose of one defined active.
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If I recall, most of the CYP450 inhibition with grapefruit comes from various furanocoumarins, so pure naringin will have a smaller effect, likely not clinically relevant if my quick internet search is any guide.
Frozen grapefruit juice is probably the most consistent alternative if you want to go that route. Be careful – 6mg with juice could be a very large dose.
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I’m not sure that is accurate… from reading the study and articles about the study it sounded like there is a lot of variation in all the different ways of taking GFJ… I think they only got the “right” version of frozen GFJ when they got a special version of frozen GFJ supplied by the Florida dept. of citrus. I have no idea if you can generalize to frozen GFJ more broadly… do you have some added information I’m missing?
Original Study here: Phase 1 Studies of Sirolimus Alone or in Combination with Pharmacokinetic Modulators in Advanced Cancer Patients - PMC
More discussion on this topic: Improve Bioavailability of Rapamycin (2)
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I don’t think you’re missing anything. I figure fresh grapefruit is out, because of variations in fruit size, origin, and cultivar. Heat processed (I assume this includes the “canned” referenced in the first link) are out because it destroys the actives. Frozen, from a single supplier, partially mitigates both problems, but it’s still not great.
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