Compounds having the formula (I), ##STR00001## G is a novel side chain selected from C.sub.2-6alkenyl, A.sub.3-aryl, --OR.sub.18, heteroaryl, A.sub.1-cyano, A.sub.2--OR.sub.17, A.sub.1--C(.dbd.O)R.sub.18, A.sub.1--CO.sub.2R.sub.18, A.sub.1--C(.dbd.O)NR.sub.18R.sub.19, A.sub.1--OC(.dbd.O)R.sub.18, A.sub.1--NR.sub.18C(.dbd.O)R.sub.19, A.sub.1--OC(.dbd.O)NR.sub.18R.sub.19, A.sub.1--NR.sub.18CO.sub.2R.sub.19, A.sub.1--NR.sub.18SO.sub.2R.sub.17, A.sub.1--SO.sub.2R.sub.17, A.sub.1--NR.sub.20C(.dbd.O)NR.sub.18R.sub.19, and A.sub.1--SR.sub.18; or when y is 0 or when W is not NHR.sub.22, G may be A.sub.1-heterocyclo, wherein A.sub.1 is a bond, C.sub.1-6alkylene or C.sub.2-alkenylene, A.sub.2 is C.sub.1-6alkylene or C.sub.2-6alkenylene, and A.sub.3 is C.sub.2-6alkenylene; W is selected from --NR.sub.21R.sub.22, --OR.sub.23, --NR.sub.21C(.dbd.O)R.sub.24, --NR.sub.21CO.sub.2R.sub.24, amidino, guanidino, or a heteroaryl, heterocyclo or C.sub.3-7cycloalkyl as defined in the specification, and X and R.sub.1 through R.sub.24 are as defined in the specification, are effective as modulators of melanocortin-receptors, particularly MC-1R and MC-4R.