A normal triglyceride level for an adult over the age of 20 is less than 150 milligrams per deciliter, explains WebMD. A high triglyceride level ranges between 200 and 499 milligrams per deciliter and is a risk factor for heart disease, while a very high triglyceride level is over 500.
Triglycerides are the main type of fat in the blood, according to WebMD. They form from the breakdown of fats during digestion and from carbohydrates in the body. Any surplus triglycerides in the blood are stored in different parts of the body, such as the belly and hips, and break down to provide energy when needed.