Glycocyamine (or guanidinoacetate) is a metabolite of glycine in which the amino group has been converted into a guanidine. Glycocyamine is a direct precursor of creatine and is used as a supplement. However the metabolism of creatine from glycocyamine in the liver causes a depletion of methyl groups. This causes homocysteine levels to rise, which has been shown to produce cardiovascular and skeletal problems.