creatine-urea

In athletes who reported (retrospectively) creatine usage for up to four years, there was no significant adverse effect on healthy markers, although a nonsignificant trend to increase testosterone and decrease LDH (lactate dehydrogenase, a liver enzyme) was noted.

This retrospective study failed to find a link between creatine supplementation and any biomarker of health, suggesting no ill effects.

In subjects with cholesterol exceeding 200 mg/dL, creatine supplementation (20 g/day for 5 days followed by 5 g/day for 56 days) reduced triglycerides by 23%, total cholesterol by 5-6%, and vLDL by 22%, without much effect on LDL or HDL. Urea increased mildly (17%) in women only.

50 mg/kg/day (approximately 3.5 g, alongside 30 g of sucrose) for 6 weeks increased the circulating triglycerides and body fat percentage (+0.17%) of martial artists, but not their fat mass. Lactate and liver enzymes were lower, relative to placebo, but not to a significant extent.