Does vasoconstriction cause ed?

Not likely . . . We/i think of vasoconstriction as temporary, rather than somewhat permanent. Erectile dysfunction is due to inadequate blood flow into the penis which can be due to plaque buildup from excess cholesterol as you've noted. Studies show that successful efforts at lowering heart disease risk also improve ed. Ps once blood gets into penis, you need vasoconstriction of venous return to stay erect.