The world of medicine is full of planned discoveries, but quite a few of the biggest breakthroughs were actually born by chance. Sometimes a drug that was developed for one purpose completely failed in its original designation, and only a surprising side effect or a random discovery led it to become one of the most important treatments in the world.
The most well-known example today is the family of GLP-1 receptor agonists medications, including Ozempic, Zepbound and Trulicity. What is less known is that the basis for their discovery actually began in research on the anglerfish, a deep-sea fish with a threatening appearance.
In the 1980s, Dr. Joel Habener from Massachusetts General Hospital identified the precursor to the GLP-1 hormone during genetic research on the fish’s pancreas. That hormone, which increases insulin secretion and suppresses glucagon after meals, later became one of the most important tools in the treatment of diabetes and obesity.
Today, research around these drugs is expanding far beyond blood sugar balance and weight loss, with possible evidence of benefits also in sleep apnea, chronic kidney disease, and even alcohol addiction.
But Ozempic is far from the only one.
Viagra: From angina to erection
In the late 1980s, the company Pfizer developed sildenafil, now known as Viagra, as a treatment for angina and high blood pressure. The trial did not provide the hoped-for results in the cardiac field, but participants reported one side effect that could not be ignored: A significant improvement in erection.
Thus, in 1998, the small blue pill became a groundbreaking treatment for erectile dysfunction, and later was also found to be effective in improving blood flow to the lungs.
Minoxidil: From the stomach to the scalp
Minoxidil was originally developed in the 1950s as a treatment for stomach ulcers, but did not prove effective. Later it was approved as a medication for high blood pressure, and then doctors noticed an interesting phenomenon: Increased hair growth among patients.
The result was a rebranding of the drug as a topical treatment for baldness under the name Rogaine, one of the most well-known products in the field of hair loss.
Botox: From strabismus to wrinkle smoothing
Before it became a star of the aesthetics world, Botox was approved in 1989 for the treatment of strabismus, eyelid spasms, and neurological disorders in the face.
Only later was it discovered that the substance, OnabotulinumtoxinA, is also effective in reducing wrinkles. Since then, its use has also expanded to chronic migraines, excessive sweating, and even an overactive bladder.
AZT: A chemotherapeutic failure that saved lives
Zidovudine was developed in the 1960s as a chemotherapy drug, but failed in trials against tumors in mice. In the 1980s, with the outbreak of the AIDS epidemic, it returned to the picture and became AZT, the first antiviral drug approved for HIV.
This is one of the most dramatic stories of drug repurposing that saved millions of lives.
Thalidomide: From tragedy to rehabilitation
Thalidomide is considered one of the most painful affairs in the history of medicine. In the 1950s it was given to pregnant women to treat nausea and insomnia, but was linked to severe birth defects in thousands of babies and was removed from the shelves.
However, despite the difficult history, it was later found to have renewed use in the treatment of complications of leprosy, multiple myeloma, and even lupus.
Metformin: From a malaria drug to an anti-aging star
Metformin, one of the most common medications in the world for type 2 diabetes, was once used at all as a treatment for malaria and influenza.
Today, beyond treating diabetes, it is also widely studied in the contexts of slowing aging, metabolic improvement, and reducing the risk of chronic diseases.
These stories remind us how much medicine advances not only thanks to planning, but also thanks to curiosity, attention to unexpected effects, and sometimes also luck. Medications that initially seemed like a complete failure became over time breakthroughs that changed the lives of millions.