Muscle creatine loading in men.
Level 3 - non-randomized controlled study
Non-randomized clinical trial comparing dosing regimens in healthy volunteers.
PubMed 8828669 · doi:10.1152/jappl.1996.81.1.232
What was done
Investigators evaluated skeletal muscle total creatine accumulation, degradation, and urinary creatinine excretion in 31 male subjects given oral creatine supplementation in varying regimens: 20 g/day for 6 days followed by 2 g/day maintenance for 30 days or cessation for 30 days, or a gradual protocol of 3 g/day for 28 days.
What was found
Muscle total creatine concentration increased by approximately 20% after 6 days of 20 g/day creatine supplementation. Continuing at 2 g/day maintained this elevated concentration for 30 days. Cessation of supplementation led to a gradual decline back to baseline levels by 30 days, accompanied by increased urinary creatinine excretion. Supplementation at 3 g/day produced a similar 20% increase in muscle total creatine over 28 days.
Why it matters
This study establishes that muscle creatine saturation can be achieved either rapidly via a 6-day loading dose of 20 g/day or gradually via 3 g/day for 28 days, and maintained with 2 g/day.
Limits
The sample size is small (31 subjects) and limited entirely to men. The abstract does not specify whether subjects were randomized, blinded, or if functional athletic performance outcomes were evaluated.
Cited by
- supports Daily supplementation of 5 grams of creatine monohydrate saturates skeletal muscle stores within 3 to 4 weeks without a loading phase.
- supports Taking 3 g of creatine daily for 1 month fully saturates muscle creatine stores.
- supports Taking 5 grams of creatine daily takes approximately 3 to 4 weeks to saturate muscle creatine stores.
- supports A daily dose of 3 grams of creatine can saturate skeletal muscle within 30 days.