(Capcom's primary storyline)
β Hetero Nonserotonin is a hormone secreted from the human pituitary gland during the later stages of puberty (16-20). It has been linked to the secretion of noradrenaline in the locus coeruleus when the individual is in a state of extreme stress or panic.
Its properties makes it a prime candidate for use in increasing the effectiveness of a B.O.W. (Bio Organic Weapon) by directly stimulating its level of brutality and ferocity. It was applied to the further development of the Tyrant series developed by the Umbrella Corporation, though has only been directly connected to the Hypnos-T Type prototype.
β Hetero Nonserotonin can only be successfully extracted from active brain cells; it cannot be obtained from the deceased or surgery patients declared braindead. As a result of this, the Tyrant Plant on Sheena Island resorted to the unethical practice of vivisecting kidnapped youths. Because anasthesia risked diluting the extracted hormone, the vivisected were ordered to be conscious at the time. A healthy brain is also considered essential: One of Umbrella's detainees was considered worthless for extraction when a tumour was found in his cerebellum.