Double bonds in cis are approximately 5x more accessible to the membrane surface than the equivalent trans double bonds, which makes it easier for peripheral membrane proteins (such as Cti) to act on them. Cis fatty acids are thus more responsive to processing and metabolism than trans fatty acidswhich could underly the mechanism for why trans fats are such a risk factor in human health, and are so hard to remove biologically. Beyond the mechanical effect of trans lipids to stiffen the membrane, their low availability to enzymatic action compared to cis fatty acids would decrease their chances of getting metabolized, thereby lingering longer in membranes.