The Science Behind Hangovers: What Actually Causes Them?

When alcohol reaches our liver to metabolize, it produces the highly toxic chemical acetaldehyde. Our bodies combat this with acetaldehyde dehydrogenase, a naturally ocurring enzyme. But drinking too much can overwhelm these enzymes, leading to a build up of acetaldehyde. This may result in a hangover, nausea, fatigue and even loss of intelligence.