The most widely studied is essential pentosuria, where a couple of grams of L-xylusol are released into a person’s system daily.[7] L-xylulose reductase, contained in red blood cells, is composed of both a major and minor isozyme.[8] For those diagnosed with essential pentosuria, the major isozyme appears to be the same as the minor one.[8] Alimentary pentosuria can be acquired through fruits high in pentose.[7] Finally, drug-induced pentosuria can be developed by those exposed to morphine, fevers, allergies, and some hormones.[7]