胍基乙酸 (英语：Glycocyamine)是一种甘氨酸的代谢中间产物，其氨基被胍基取代。

胍基乙酸是肌酸生物合成的直接前体（如下图）。 但这一反应会造成高半胱氨酸水平的升高，导致一些心血管问题。

医学导航：遗传代谢缺陷

代谢、k,c/g/r/p/y/i,f/h/s/l/o/e,a/u,n,m

k,cgrp/y/i,f/h/s/l/o/e,au,n,m,人名体征

药物(A16/C10)、中间产物(k,c/g/r/p/y/i,f/h/s/o/e,a/u,n,m)

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.