Diabetes patients may soon be able to take a pill to control their condition instead of repeated injections.
Some patients need daily injections of insulin
UK company Diabetology, with experts at Cardiff University, says it has solved a crucial problem with oral insulin.
The capsule's special coating protects the drug from acids in the stomach, allowing it to pass into the small intestine where it is absorbed.
The researchers will present their early trial results in 16 patients to the American Diabetes Association.
The details of Dr Steve Luzio's presentation cannot be released until he has made it, but are expected to show that oral doses achieve the necessary changes in the body's blood sugar handling to treat diabetes.
The trial is expected to show that the oral dose, taken twice daily before breakfast and dinner, controls glucose levels successfully, at least in patients with type 2 diabetes.
Other scientists have also been looking at ways to deliver insulin by mouth without it being degraded in the stomach. Taiwanese investigators are using a chemical found in shrimp shells to protect the drug.
And inhaled insulin is already available to those diabetics with a proven needle phobia or people who have severe trouble injecting.
Diabetes UK welcomed the new research but said the findings were very early and should be treated with caution.
Dr Iain Frame, research manager at Diabetes UK, said: "There are currently 700,000 people in the UK who take insulin injections, sometimes up to four times a day, so being able to take their insulin orally would have a great impact on their quality of life.
"This research, however, is still in its early stages. We would like to see further results."
People with type 1 diabetes rely on insulin injections.
Often, type 2 diabetes can be controlled by diet alone or other oral diabetes drugs. It is only as the disease progresses that insulin may be needed.
Type 2 diabetes is far more common than type 1.