Why Asparagus Makes Your Urine Smell Funny

When you eat asparagus, your urine will smell funny. However, not everyones noses can detect the odor of asparagus pee. The chemical that produces the effect is called asparagusic acid. Asparagusic acid is not volatile, so if you sniff a spear of aparagus, you wont smell anything noteworthy. However, when your body digests asparagus, aspargusic acid is broken down into simpler compounds, which are volatile, so they transfer from urine into the air, where they make their way to your nose so  you can smell them. These compounds  include dimethyl sulfide, dimethyl disulfide, dimethyl sulfone, and  dimethyl sulfoxide. The sulfurous compounds or mercaptans are related to the chemicals that make  skunk spray and rotten eggs  so odious. Asparagus Doesnt Make Everyones Pee Stink While it is believed everyone excretes these compounds in their urine after eating asparagus, somewhere between 22% and 50% of the population lack  the chemoreceptors to detect the funky smell. Also, some people may metabolize asparagusic acid in a way that produces lower quantities of the distinctive-smelling molecules. Whether or not you can smell the distinctive funky odor of asparagus pee depends on your genetics. Inability to smell the chemical results from a single base pair genetic mutation, which is passed on in families.  While you might not consider yourself fortunate if you can smell it, the upside is youre more likely able to smell other sulfurous molecules, which might protect you from toxic chemicals. Learn More What Is the Worst Smelling Chemical?How To Color UrineChemical Composition of Urine