Funny because I'm not sure I quite notice it immediately when I stop taking it, presumably since the body retains a certain amount of it. But I definitely notice a difference when taking it the first day after not having had it a little while, especially when taking 20+ grams a day. It gives me so much mental energy and alertness that I won't get a whole lot of sleep, but the next day I end up feeling just fine. If I remember correctly, there have been at least 2 studies that suggested high doses of creatine reduce the side effects of suboptimal sleep, and that definitely seems to be the case in my experience.
Isn't 20+ grams a day a lot for the kidneys? genuine question
Elevated creatinine levels (in absence of supplementation) is a sign of kidney issues. There are many studies showing no reverse link i.e. supplementing creatine damaging kidneys
https://link.springer.com/content/pdf/10.1186/s12882-025-045...
Okay but logically kidney issues leading to high creatine does suggest that creatine is not all that good for the body, no? else why would the kidney keep it under control?
No, elevated creatinine levels is only a sign of kidney disease if all else remains equal. Consuming more creatine will naturally increase production of creatinine because creatinine is a byproduct of the kidneys processing creatine.
In other words, it's not a very reliable signal for kidney disease. There is a more reliable blood test called a "Cystatin C" test.
Not the parent, but someone else commented on this: https://news.ycombinator.com/item?id=48347735