Development of Insulin – Timeline¹ 1921: discovery of insulin 1942: long-acting protamine/insulin zinc suspension known as Neutral Protamine Hagedorn, or NPH, insulin, with a duration of action of 12-18 hours but with a pronounced peak effect (which risks nocturnal hypoglycaemia) 1970s: mono-component insulin Unit 100 (100 U / mL) standard 1980s: recombinant (human) insulin insulin … Continue reading Insulin