I have a pre-workout that contains 300mg of grape seed extract. Is this likely to interfere with my Indigo?
If it doesn’t contain quercetin, then as opinion it’s unlikely it would reduce effect. The various advice to avoid unproven combinations has been from not knowing for certain that performance would be equally good, rather than evidence of losing anything or specific reason to really expect it, other than quercetin for which there is evidence that absorption could be decreased.
Analyses of grape seed extract typically report no quercetin but in at least one instance 8% was reported. How often that’s the case, I don’t know. If often, then there could be a significant chance of interference.
Thank Bill, much appreciated.