{"id":6086,"date":"2026-05-13T22:03:56","date_gmt":"2026-05-13T22:03:56","guid":{"rendered":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/?p=6086"},"modified":"2026-05-13T22:08:49","modified_gmt":"2026-05-13T22:08:49","slug":"the-development-of-insulin","status":"publish","type":"post","link":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/blog\/2026\/05\/13\/the-development-of-insulin\/","title":{"rendered":"The Development of Insulin"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">The 1920s are often remembered as a decade of scientific progress, changing culture, and major medical discoveries. Radios became more common in homes, movies became more popular, and doctors made important advances in medicine. One of the greatest medical breakthroughs of the decade was the discovery and development of insulin.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Before insulin existed, diabetes was one of the deadliest diseases in the world. Many children diagnosed with type 1 diabetes died only months or years after learning they had the disease. Doctors understood that diabetes affected blood sugar levels, but they had no reliable way to treat it. Instead, patients were placed on extremely strict diets that often left them weak and starving.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article&nbsp;<em>History of Insulin<\/em>&nbsp;explains, \u201cBefore the availability of insulin, the life expectancy of children with diabetes mellitus was short and the prognosis for the adult onset diabetes was very poor.\u201d Because doctors had no effective treatment, \u201cphysicians Allen and Joslin endorsed fasting and calorie restricted diets for diabetes.\u201d These starvation diets sometimes delayed death, but they could not cure the disease. Patients often became dangerously thin because they were forced to eat very little food in order to survive longer.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Scientists knew that the pancreas played an important role in diabetes, but they struggled to isolate the substance responsible for controlling blood sugar. According to the&nbsp;<em>Diabetes UK<\/em>&nbsp;article, \u201cAttempts had been made to extract insulin from ground up pancreas cells, but they\u2019d all proved unsuccessful.\u201d The problem was that other tissues inside the pancreas destroyed the insulin before it could be used.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">During the early 1920s, however, a small group of researchers in Canada changed medical history forever. Frederick Banting, Charles Best, John Macleod, and James Collip worked together to isolate insulin and develop it into a treatment that could save human lives. Their discovery quickly became one of the most important medical breakthroughs of the twentieth century.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Diabetes Before Insulin<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Before insulin was discovered, diabetes was extremely difficult to treat. Patients with severe diabetes often experienced constant thirst, rapid weight loss, weakness, and exhaustion. Children diagnosed with type 1 diabetes almost always died because their bodies could no longer produce insulin naturally.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Doctors understood some parts of the disease, but they did not know how to stop it. Most treatments focused only on reducing symptoms instead of curing the condition. Starvation diets became one of the main methods used by doctors because reducing food intake sometimes lowered blood sugar levels temporarily.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>History of Insulin<\/em>&nbsp;article explains that these treatments \u201cresulted in some improvement of glucosuria and acidosis, decreased coma, and delayed death among children with diabetes.\u201d Even so, patients still suffered greatly, and most eventually died from the disease.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Scientists continued studying the pancreas because they believed it released a substance that controlled blood sugar. The article explains, \u201cLong before the discovery of insulin, it was hypothesized that the pancreas secreted a substance that controlled carbohydrate metabolism.\u201d Researchers spent years attempting to isolate this substance, but impurities and toxic materials inside pancreatic extracts caused experiments to fail repeatedly.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Frederick Banting and the Beginning of Research<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The breakthrough finally began in 1920 when Frederick Banting developed a new theory about how insulin could be isolated safely. Banting was a Canadian surgeon rather than an experienced scientist, but he became interested in diabetes research after reading medical articles about the pancreas.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>Diabetes UK<\/em>&nbsp;article explains that Banting read research suggesting \u201cinsulin producing cells in the pancreas are slower to deteriorate than other pancreas tissue.\u201d Banting realized that this discovery might allow scientists to destroy harmful pancreatic tissue while preserving the cells that produced insulin.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article explains, \u201cBanting realised that this might allow for the removal of insulin by breaking down the pancreas in a way that would leave just the cells that produce insulin intact.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Although Banting believed strongly in his idea, he knew he needed scientific support to test it. On November 7, 1920, he met with John Macleod, a professor at the University of Toronto who specialized in diabetes research. Macleod agreed to provide laboratory space, experimental dogs, and a student assistant named Charles Best.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>History of Insulin<\/em>&nbsp;article explains that Macleod \u201cgranted him laboratory space, ten dogs for his experiments, a student research assistant (Charles Best), and provided supervision and guidance.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This partnership became the beginning of one of the most important scientific discoveries in modern medicine.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Early Experiments and Insulin<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The insulin experiments officially began in May 1921. According to the&nbsp;<em>Diabetes UK<\/em>&nbsp;article, \u201cOn 17 May 1921 Banting, Best and Macleod first got together to begin their research.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The researchers worked mainly with dogs. They tied off pancreatic ducts to destroy parts of the pancreas while keeping the insulin producing cells alive. Afterward, they created pancreatic extracts and tested them on diabetic dogs whose pancreases had been removed.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>History of Insulin<\/em>&nbsp;article explains that \u201cthe experiments began on May 17, 1921.\u201d By September, the experiments began showing successful results. The article explains that \u201cintravenous injection with their pancreatic extract, which they named isletin, lowered the blood glucose.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">These results were extremely important because they proved that pancreatic extracts could lower blood sugar levels in diabetic animals. For the first time, researchers had strong evidence that insulin could become a treatment for diabetes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The experiments were difficult and time consuming. Many failed completely, but Banting and Best continued working every day in the laboratory. According to the&nbsp;<em>Diabetes UK<\/em>&nbsp;article, \u201cProgress was initially slow.\u201d Still, the researchers noticed regular improvements in blood sugar levels during successful experiments.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article explains that \u201cBy November, they\u2019d successfully treated a dog with diabetes with their insulin extract for 70 days.\u201d This achievement demonstrated that insulin could keep diabetic animals alive much longer than before.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">James Collip and Purifying Insulin<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Although the experiments on dogs were successful, another major problem still existed. The insulin extract was not pure enough for use in humans. Impurities inside the extract caused dangerous side effects and made the treatment unreliable.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To solve this problem, biochemist James Collip joined the research team in December 1921. The&nbsp;<em>Diabetes UK<\/em>&nbsp;article explains, \u201cJames Collip, a biochemist, joined the group to work on purifying insulin so it would be safe enough to be tested in humans.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Collip worked constantly to improve the insulin extract. His goal was to remove impurities while keeping the insulin effective. According to the article, \u201cWith his help, a more concentrated and pure form of insulin was developed.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This purification process became one of the most important parts of the entire discovery because insulin could not be safely tested on humans without it.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Leonard Thompson and the First Human Injection<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">In January 1922, the researchers attempted one of the most important medical experiments in history. A fourteen year old boy named Leonard Thompson became the first human patient to receive insulin treatment.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>Diabetes UK<\/em>&nbsp;article explains, \u201cIn January 1922, Leonard Thompson, a 14 year old boy dying from type 1 diabetes, became the first person to receive an injection of insulin.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Leonard was extremely sick and close to death because of diabetes. Doctors hoped the insulin extract might save his life.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The first injection showed both promise and problems. According to the&nbsp;<em>History of Insulin<\/em>&nbsp;article, \u201cThe first injection of the pancreatic extract to a 14 year old boy by Banting and Best on January 11, 1922, caused a sterile abscess.\u201d The injection lowered blood sugar somewhat, but the extract still contained impurities that caused complications.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Collip immediately continued purifying the insulin. He worked day and night to improve the extract before another injection was attempted.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Later in January, Leonard received a second injection. This time the results were historic. The&nbsp;<em>Diabetes UK<\/em>&nbsp;article explains, \u201cThis time it was a complete success and Leonard\u2019s blood sugar levels become near normal, with no obvious side effects.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article then states, \u201cFor the first time in history, type 1 diabetes was not a death sentence.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The successful treatment of Leonard Thompson changed medicine forever. Doctors now had a treatment capable of saving patients who otherwise would have died.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The International Announcement of Insulin<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">After the successful human treatments, news about insulin spread quickly throughout the medical world. Researchers and doctors recognized immediately that the discovery could transform diabetes treatment permanently.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>Diabetes UK<\/em>&nbsp;article explains, \u201cOn 3 May 1922, Macleod announced the discovery of insulin to the international medical community.\u201d Macleod presented the research at a meeting of the Association of American Physicians in Washington.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article also explains that this was \u201cthe first time the team used the word \u2018insulin\u2019.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Doctors and scientists responded with excitement because the treatment offered hope to diabetic patients around the world.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Insulin Belongs to the World<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">As insulin became more successful, questions arose about patents and ownership. Banting and the other researchers believed insulin should remain available to everyone who needed it instead of becoming a private source of profit.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>Diabetes UK<\/em>&nbsp;article explains, \u201cOn 23 January 1923, Banting, Collip and Best were awarded U.S. patents on insulin and the method used to make it.\u201d However, instead of keeping the patents for themselves, the researchers sold them to the University of Toronto for only one dollar each.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The article explains, \u201cBanting famously said, \u2018Insulin does not belong to me, it belongs to the world.\u2019\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">This decision helped insulin become widely available much more quickly.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Mass Production and Worldwide Expansion<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">As reports of insulin\u2019s success spread, demand increased rapidly. Pharmaceutical companies began working with the researchers to produce insulin on a much larger scale.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">According to the&nbsp;<em>Diabetes UK<\/em>&nbsp;article, \u201cEli Lilly become the first manufacturer to mass produce insulin.\u201d In October 1923, the company began shipping commercial insulin supplies.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>History of Insulin<\/em>&nbsp;article explains that early insulin production still faced challenges. \u201cEli Lilly began producing insulin from animal pancreas but fell short of the demand, and the potency varied up to 25% per lot.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Scientists continued improving insulin production methods to make the medicine more reliable and more widely available. The article explains, \u201cThe development of an isoelectric precipitation method led to a purer and more potent animal insulin.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Insulin also spread internationally during 1923. The&nbsp;<em>History of Insulin<\/em>&nbsp;article explains, \u201cIn 1923, August Krogh, from the University of Copenhagen, met with Banting and Macleod to learn more about insulin because his wife had diabetes mellitus.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Krogh later helped establish insulin production in Scandinavia, allowing the treatment to reach even more patients.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The Nobel Prize<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The discovery of insulin quickly became recognized as one of the greatest medical achievements in history. In 1923, Frederick Banting and John Macleod received the Nobel Prize in Physiology or Medicine.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>Diabetes UK<\/em>&nbsp;article explains, \u201cIn recognition of their life saving discovery, Banting and Macleod were jointly awarded the 1923 Nobel Prize in Physiology or Medicine.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The Nobel Prize helped make the insulin researchers internationally famous. Banting shared part of his prize money with Charles Best, while Macleod shared his portion with James Collip. This reflected the teamwork involved in the discovery.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">The Significance of Insulin<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">The discovery and development of insulin during the 1920s completely transformed medicine. Before insulin, severe diabetes almost always led to death. After insulin became available, millions of people gained the chance to survive and live much longer lives.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The&nbsp;<em>History of Insulin<\/em>&nbsp;article explains, \u201cThe discovery of insulin in 1922 marked a major breakthrough in medicine and therapy in patients with diabetes.\u201d&nbsp;<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The development of insulin also demonstrated the importance of scientific cooperation. Banting, Best, Macleod, and Collip all contributed different skills to the project. Without their combined efforts, insulin might not have been discovered when it was.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">The success of insulin encouraged future medical research as well. Scientists realized that diseases once considered hopeless could potentially be treated through careful experimentation and teamwork.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Today, historians continue studying the discovery of insulin because it remains one of the most important medical breakthroughs in modern history. Millions of people around the world still rely on insulin every day, and the events of the 1920s permanently changed diabetes treatment forever.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Timeline of Events<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">1918 \u2013 Doctors mainly use starvation diets to treat diabetes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">7 November 1920 \u2013 Frederick Banting meets John Macleod to discuss insulin research.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">17 May 1921 \u2013 Banting, Best, and Macleod officially begin insulin experiments.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">September 1921 \u2013 Researchers discover insulin extracts lower blood sugar in dogs.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">10 November 1921 \u2013 Scientists successfully treat a diabetic dog for 70 days.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">12 December 1921 \u2013 James Collip joins the research team to purify insulin.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">11 January 1922 \u2013 Leonard Thompson receives the first insulin injection.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">23 January 1922 \u2013 Purified insulin successfully treats Leonard Thompson.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">3 May 1922 \u2013 Insulin is officially announced to the medical community.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">23 January 1923 \u2013 Banting, Best, and Collip sell insulin patents to the University of Toronto for $1 each.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">15 October 1923 \u2013 Eli Lilly begins mass production of insulin.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">25 October 1923 \u2013 Banting and Macleod receive the Nobel Prize.<\/p>\n\n\n\n<p class=\"has-medium-font-size wp-block-paragraph\"><strong>Works Cited<\/strong><\/p>\n\n\n\n<p class=\"wp-block-paragraph\">DIABETES UK. 2024. \u201c100 Years of Insulin.\u201d Diabetes UK. 2024. https:\/\/www.diabetes.org.uk\/our-research\/about-our-research\/our-impact\/discovery-of-insulin.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">Quianzon, Celeste C, and Issam Cheikh. \u201cHistory of insulin.\u201d\u00a0<em>Journal of community hospital internal medicine perspectives<\/em>\u00a0vol. 2,2 10.3402\/jchimp.v2i2.18701. 16 Jul. 2012, doi:10.3402\/jchimp.v2i2.18701<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The 1920s are often remembered as a decade of scientific progress, changing culture, and major medical discoveries. Radios became more common in homes, movies became more popular, and doctors made&hellip;<\/p>\n","protected":false},"author":51,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2],"tags":[63,110,56],"class_list":["post-6086","post","type-post","status-publish","format-standard","hentry","category-2","tag-1920s","tag-documents","tag-essays"],"_links":{"self":[{"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/posts\/6086","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/users\/51"}],"replies":[{"embeddable":true,"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/comments?post=6086"}],"version-history":[{"count":0,"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/posts\/6086\/revisions"}],"wp:attachment":[{"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/media?parent=6086"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/categories?post=6086"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/dh-wordpress.ramapo.edu\/discovering1920s\/wp-json\/wp\/v2\/tags?post=6086"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}