 Now, you might be wondering, what about vitamin F and G and H and I and J to Z, right? Well, originally scientists actually used all these letters as they were discovering these vital amines, these bioactive compounds. But the more we learned about the human body and these compounds and vitamins, some of them either fell off the list or got reclassified. For example, vitamin F was originally essential fatty acids. Vitamin G eventually became known as vitamin B2 or riboflavin. Vitamin H was reclassified as vitamin B7 and became part of the B complex. Vitamins J and P, for example, we eventually discovered that these nutrients were beneficial for rats but didn't really help human health very much.