Question: Is it true that we can’t absorb more than 1.5 grams of creatine at one time?
I don't think that's true. From what I looked at, it looked like the absorption of creatine was really, really good. I don't know if someone was arguing maybe that we don't retain more than that. But I think the retention of your muscles is going to be best with creatine if you take it post-workout and if you take it with carbohydrate to stimulate insulin. But on the whole, I think that the absorption and retention is good enough that it's more a matter of how fast will you get to peak muscular creatine than it is about where you get in the long-term.
Maybe if you follow all the best procedures to absorb and retain creatine, you'll get to the 30% increase in muscular creatine in two weeks taking 5 grams a day instead of four weeks. Maybe someone who doesn't follow any best practices takes six weeks. But ten weeks later, you're probably going to be at peak effect if you just take 5 grams of creatine at a time without paying attention to all the details around absorption.
This Q&A can also be found as part of a much longer episode, here: https://chrismasterjohnphd.com/podcast/2019/03/08/ask-anything-nutrition-feb-23-2019
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