Amino acids are not excreted intact. Rather:
the nitrogen-containing amino group is recycled while the remainder of the molecule is excreted in the urine.
the nitrogen-containing amino group is removed and converted to urea, which is excreted in the urine.
the carboxylic acid group is removed, neutralized by the bile, and excreted in the feces.
the side-chain group is removed and excreted while the remainder of the molecule is recycled.