What causes my bruises to heal so ridiculously slowly?

The more blood capillaries and veins broken the longer and the lack of protein, build up of lactic acid, or if you don’t have much muscle.

My guess is poor circulation.

Are you diabetic?
Or perhaps it’s a dietary issue.
B-12 or iron deficiency is another possible reason.

lack of iron and vitamin c could be it too

lack of iron. Lack of iron. Lack of iron.

Taking vitamins may help. Other remedies for bruises are things that improve the circulation like ginger or foods containing capacin (chili peppers).

Arnica is also an effective topical cream that will help remove the discoloration of bruises quickly. It is found in health food stores.