Insulin: a century-old medicine and a modern access problem

Insulin is one of the most consequential medical discoveries of the twentieth century. Before its isolation in 1921, a diagnosis of type 1 diabetes was effectively a death sentence. Today, insulin remains an irreplaceable, life-sustaining therapy for millions of people globally, relied upon to manage both type 1 and advanced type 2 diabetes. Yet, despite more than a hundred years of clinical use, insulin sits at the centre of a modern global health paradox: a medicine that is universally recognised as essential remains entirely unaffordable or inaccessible for a significant portion of the world's population.

The discovery and evolution of insulin

The journey to isolate insulin began in Toronto, where Frederick Banting and Charles Best successfully extracted the hormone from animal pancreases. In a gesture often cited in modern access debates, the original patent was famously sold for just one dollar to keep the medicine widely available. Early insulins were derived from the pancreases of cattle and pigs. While revolutionary, animal-derived insulins sometimes caused allergic reactions and were difficult to scale up as demand grew.

Over subsequent decades, scientific innovation transformed the medicine. In the 1970s and 1980s, recombinant DNA technology allowed scientists to insert the human insulin gene into bacteria and yeast, producing human insulin identical to what the body naturally makes. Later, pharmaceutical companies developed insulin analogues—slightly modified molecular versions designed to act faster or last longer in the body. While these innovations offered more options for managing blood glucose, they also introduced newer, significantly higher-priced products to the market.

Why insulin is on the WHO Essential Medicines List

Insulin has long been a core fixture on the World Health Organization’s Essential Medicines List (EML). The EML is a WHO publication detailing the minimum medicine needs for a basic health system, guiding national governments on what treatments should be prioritised for public procurement and universal health coverage. Both short-acting human insulin and intermediate-acting insulins (such as isophane insulin, commonly known as NPH) are listed.

The inclusion of insulin on the EML underscores its irreplaceable role in global healthcare. Without it, individuals with type 1 diabetes cannot survive, and many with type 2 diabetes face severe, life-threatening complications. By keeping human insulin on the EML, the WHO signals to governments and health systems that ensuring a continuous, reliable, and affordable supply of insulin is a fundamental public health priority.

Biosimilar insulins and regulatory approval

Because insulin is a large molecule produced by living cells rather than a small chemical synthesised in a lab, it is classified as a biologic medicine. Consequently, follow-on versions of insulin are known as biosimilars rather than generics. A biosimilar is highly similar to an already approved reference product, with no clinically meaningful differences in safety or efficacy.

Regulatory authorities such as the European Medicines Agency (EMA), the US Food and Drug Administration (FDA), and the South African Health Products Regulatory Authority (SAHPRA) have established strict, distinct approval pathways for biosimilar insulins. Because manufacturing biologics is highly complex, biosimilar manufacturers must demonstrate that their product matches the reference biologic through extensive analytical and clinical studies. The introduction of biosimilar insulins is generally expected to foster market competition and lower prices, though their uptake has historically been slower than that of traditional generic medicines.

Global affordability and access debates

Despite its century-old origins, insulin access remains profoundly unequal. In many high-income countries, the list price of insulin—particularly newer analogues—has risen sharply over the last two decades. This is frequently attributed to complex patent landscapes. Manufacturers have historically filed incremental patents, sometimes known as "evergreening," on minor modifications or delivery devices (like insulin pens), which can delay biosimilar competition and keep prices high.

In low- and middle-income countries, the barriers are different but equally severe. Access is often limited by weak supply chains, inadequate cold-chain infrastructure to keep insulin refrigerated, and prices that exceed what patients can afford out-of-pocket. Global health advocates and organisations frequently argue that decoupling insulin pricing from proprietary delivery devices and promoting robust biosimilar competition are essential steps to bridge the global access gap.

South African contexts and local pricing

In South Africa, all insulin products must be registered by SAHPRA to ensure they meet required standards for safety, quality, and efficacy. The pricing of registered insulin in the private sector is regulated through the Single Exit Price (SEP) mechanism, which caps the maximum price a pharmacy or dispensing doctor may charge for a medicine. Meanwhile, the public health sector primarily procures human insulin through national tender processes to secure affordable supply for state patients.

Consumers and healthcare professionals can use platforms like HealthSA to search for registered insulin products and their local pricing. Despite these regulatory and pricing mechanisms, out-of-pocket costs for uninsured patients opting for analogues, alongside the persistent need for reliable cold-chain storage at home, remain ongoing challenges.