Nagai Nagayoshi was a chemist and pharmacologist, known as the first man to synthesize methamphetamine.
Originally from Tokushima, he later became a professor at the College of Sciences at Tokyo Imperial University, where he played a significant role in building the foundation for the teaching and research of modern medicines. He was also a founding member of the Pharmaceutical Society of Japan.
In his own research, Nagai devoted much efforts to attempts to isolate the efficacious compounds in traditional Chinese medicinal herbs and treatments. It was in that vein that he isolated in 1885 the stimulant ephedrine from the plant Ephedra sinica, one year after Sigmund Freud published a paper on the wonders of cocaine, the synthesis of which was also recently discovered at that time. In 1893, Nagai found a way to use this ephedrine to produce methamphetamine. In 1919, one of his students, Ogata Akira, produced a crystalline form of the substance, inventing crystal meth.
A prominent member of Japan's scientific community, Nagai is also known to have hosted Albert Einstein, who visited Japan in 1923, six years before Nagai's death.