Your pancreas has two major jobs: it produces enzymes that break down the food you eat, and it releases hormones that control your blood sugar. It’s a small organ, roughly 15 to 22 centimeters long and weighing between 50 and 125 grams, tucked behind your stomach and in front of your spine. Despite its size, it plays a central role in both digestion and metabolism.
Where the Pancreas Sits
The pancreas stretches horizontally across your upper abdomen. Its wider end, called the head, sits on the right side of your body, nestled into the curve of the duodenum (the very first section of your small intestine, where food goes after leaving your stomach). The thinner end, called the tail, extends to the left toward your spleen. Your gallbladder, liver, and spleen all surround it.
This positioning matters because it allows the pancreas to deliver digestive juices directly into the small intestine right where partially digested food arrives from the stomach.
How It Helps You Digest Food
About 95% of the pancreas is devoted to its digestive role. It produces a cocktail of enzymes, each targeting a different type of nutrient in your food. Lipases break down fats. Proteases break down proteins. Amylases break down starches. These enzymes flow through a duct into your duodenum, where they go to work on the food your stomach has already started processing.
The pancreas also produces a bicarbonate-rich fluid that neutralizes stomach acid as it enters the small intestine. Your stomach is highly acidic, which is great for initial digestion but would damage the delicate lining of the small intestine if left unchecked. The bicarbonate solution the pancreas releases can reach concentrations of up to 140 millimoles per liter, enough to shift the environment from acidic to slightly alkaline. This also creates the right conditions for the digestive enzymes to function, since they work best in a non-acidic environment.
How It Controls Blood Sugar
Scattered throughout the pancreas are small clusters of hormone-producing cells called islets. These contain two key cell types that work in opposition to keep your blood sugar stable throughout the day.
Beta cells release insulin when blood sugar rises, such as after a meal. That burst of insulin after eating drives glucose out of the bloodstream and into muscle, fat, and liver cells, where it’s stored as glycogen for later use. High insulin levels paired with suppressed glucagon signal the liver to store glucose rather than produce it.
Alpha cells release glucagon when blood sugar drops, such as overnight or between meals. Glucagon tells the liver to break down its glycogen stores back into glucose (a process called glycogenolysis) and release it into the bloodstream. The liver can also manufacture new glucose from amino acids and fat byproducts when stores run low.
This back-and-forth between insulin and glucagon is constant. After a meal, insulin dominates and glucagon falls. During a fast or while you sleep, glucagon rises and insulin drops, allowing the body to tap into its stored energy. The balance between these two hormones is what keeps blood sugar within a narrow, healthy range.
Its Lesser-Known Hormonal Role
The pancreas also produces somatostatin, a hormone that acts as a kind of off switch. Its primary function is to prevent overproduction of other hormones and digestive secretions when the body doesn’t need them. Within the pancreas itself, somatostatin inhibits the release of both insulin and glucagon, keeping the system from overshooting in either direction. It also slows gastric secretion in the digestive tract and influences neurotransmission and memory formation in the brain.
What Happens When the Pancreas Fails
Because the pancreas handles both digestion and blood sugar, problems with this organ tend to show up in one of two ways.
Pancreatitis
Pancreatitis is inflammation of the pancreas, and it comes in two forms. Acute pancreatitis strikes suddenly and typically causes upper belly pain that may radiate to the back, along with nausea, vomiting, fever, and a fast heartbeat. The most common triggers are gallstones blocking the bile duct and heavy alcohol use. Chronic pancreatitis develops over time, often from repeated bouts of acute inflammation, heavy drinking, or smoking. Its hallmarks are constant upper belly pain, unintentional weight loss, diarrhea, and oily or foul-smelling stools. Over time, chronic pancreatitis can damage enough of the organ to impair both digestion and blood sugar control.
Exocrine Pancreatic Insufficiency
When the pancreas can no longer produce enough digestive enzymes, a condition called exocrine pancreatic insufficiency (EPI) develops. Without adequate enzymes, your body can’t properly absorb fats, proteins, and certain vitamins. The most telling signs are weight loss, malnutrition, and greasy stools. Doctors most commonly diagnose it by measuring levels of a specific enzyme (elastase) in a stool sample. Low levels suggest the pancreas isn’t keeping up with digestive demands.
Diabetes
When beta cells are destroyed or stop working properly, insulin production drops and blood sugar rises. In type 1 diabetes, the immune system attacks the beta cells directly. In type 2, the cells gradually lose their ability to produce enough insulin to overcome the body’s increasing resistance to it. Either way, the result is the same: glucose builds up in the blood instead of entering cells.
Pancreatic Cancer
Pancreatic cancer is particularly dangerous because it rarely causes symptoms in its early stages. By the time people notice warning signs, including belly pain that spreads to the back, unexplained weight loss, jaundice (yellowing of the skin and eyes), light-colored stools, dark urine, or a new diabetes diagnosis that’s difficult to control, the cancer has often already spread. A blood marker called CA 19-9 can sometimes be elevated, but no reliable early screening test exists for the general population.