Courtesy of Dr. Bill: I know of no reason why to limit grapefruit juice from use with any Hammer Nutrition supplements.
Here is why: Grapefruit juice increases the absorption, bioavailability, and potency of nutrients due to the bergamottin content of grapefruit temporarily blocking some types of Cytochrome P-450 enzymes (especially CYP3A4 enzyme) in the gastrointestinal tract. Like all Cytochrome P-450 enzymes, CYP3A4 is responsible for the (phase I) detoxification of various substances in the intestines and liver. This inhibitory effect of Grapefruit juice may last for up to 48 hours after ingestion. Conclusion: In my opinion, the effect of grapefruit or grapefruit juice is positive, favoring nutrient potency effects in human metabolism.
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