Question: is it true that the colour of your blood is blue before its hits oxygen?

John Short answered on 22 Jun 2012:

Blood is red because it is full of red blood cells, which are red. The RBCs are red because they contain a red pigment called hemoglobin. When hemoglobin binds to oxygen, it changes the shape of the molecule. that affects its color somewhat, but it’s not so drastic as to change it from blue to red. Instead, it’s more like dark red in our veins (not blue) to bright (or blood) red in our arteries upon contact with oxygen.