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L-Leucine by Biotest - Serving Questions

Why does the company warn consumers not to consume more than 20 grams of L-Leucine a day? [from the supplement]

Well, if you read that literature, they mention that spiking blood levels is what is beneficial, not the actual amount.

Therefore, if you are spiking with 5g every 4th hour:

Hour 0: 5g
Hour 4: 10g (5g plus previous 5g)
Hour 8: 15g
Hour 12: 20g

And most people either sleep the remainder of the day or get in enough protein to where that extra window of time (another 4 hour slot) isn’t really worth it to take another 5 grams.

My understanding, anyway.

Personally, I think even 3x a day is fine:

Upon rising, with a shake or breakfast

If it’s a lifting day:

PWO solid meal

I get 5g before, during and after my workouts…and I’m liking it.

At some point a company just needs to cover themselves. It’s probably more to stop people from taking a whole bottle in a day and wonder why they ‘feel funny’. Or they have figured it’s a waste of money to go beyond a certain amount.

because you’d get so damn huge that everyone else would suffer in comparison.


I take 5g with every one of my 6 meals, and this stuff is excellent. Definitely notice I’m more lean and my muscles look “harder” IF you will. I’ve also gone up 3 pounds in 20 days with a decrease in fat. (no increase in cals)