Triglycerides: Normal Range, What High & Low Levels Mean

A triglycerides blood test measures the concentration of triglycerides — the most common type of fat in your body — circulating in your bloodstream at the time of your blood draw. Triglycerides come from two main sources: dietary fat you consume and excess calories, especially from sugars, that your liver converts into fat. The result is expressed in milligrams per deciliter (mg/dL) and gives your doctor a snapshot of how much fat energy is currently moving through your blood. Elevated levels are associated with an increased risk for heart disease and pancreatitis. Talk to your healthcare provider about what your specific reading means for you.

According to the National Heart, Lung, and Blood Institute, a normal triglyceride level for adults is below 150 mg/dL. Results between 150 and 199 mg/dL are considered borderline high, meaning they deserve attention even though they haven't crossed into the high category yet. A level from 200 to 499 mg/dL is classified as high, and anything at 500 mg/dL or above is very high. These categories help your doctor understand your cardiovascular risk and decide whether any action is needed. Keep in mind that reference ranges can vary slightly between laboratories, so always review your result alongside your lab's own reference values and discuss what yours means with your healthcare provider.

Several factors can push your triglyceride level above the normal range. Dietary habits play a big role — a diet high in refined carbohydrates, sugar, and alcohol is a common driver. Obesity, particularly excess abdominal fat, and conditions like type 2 diabetes and insulin resistance can raise levels significantly. Underlying health issues such as hypothyroidism, kidney disease (nephrotic syndrome), and liver disease are also known contributors. Genetics matter too — a condition called familial hypertriglyceridemia can cause inherited elevation. Certain medications, including beta-blockers, corticosteroids, estrogen, retinoids, and some antipsychotics, may also raise levels, as can pregnancy. Your healthcare provider can help identify what is driving your specific result.

Low triglyceride levels are less commonly discussed, but they can occur for several reasons. A very low-fat diet naturally keeps levels down, which is generally not a concern. However, lower-than-expected readings can also point to hyperthyroidism (an overactive thyroid), malnutrition, or conditions that affect how your body absorbs nutrients (malabsorption). Certain medications — including fibrates, fish oil supplements, and niacin — are sometimes prescribed specifically to lower triglycerides, so a low result may simply reflect treatment working as intended. In rare cases, a genetic condition called abetalipoproteinemia can cause very low levels. Low triglycerides typically cause no symptoms on their own. Discuss your result with your healthcare provider to understand what it means in your situation.

For most people, mildly to moderately elevated triglycerides cause no noticeable symptoms at all — which is exactly why routine blood testing matters. The situation changes when levels reach 500 mg/dL or above. At that very high threshold, triglycerides can trigger acute pancreatitis, a serious inflammation of the pancreas that causes severe abdominal pain, nausea, and vomiting requiring prompt medical attention. Extremely high levels can also produce eruptive xanthomas — small yellow-white fat deposits that appear on the skin — and a condition called lipemia retinalis, where the blood vessels at the back of the eye take on a milky appearance. Because symptoms are often absent until levels are dangerously high, speak with your healthcare provider about your result without delay.

Whether and how often you should retest depends on your individual risk profile, your current result, and any lifestyle or medication changes you may have made. A one-time reading can be influenced by a recent meal, illness, stress, or even a poor night's sleep, so your doctor may want a follow-up test to confirm a result that looks unexpectedly high or low. If you have been working on diet changes or started a new medication, retesting after a few months helps show whether those efforts are having an effect. Triglycerides are typically checked as part of a lipid panel, which your provider will recommend at an interval suited to your health history. Ask your healthcare provider what retesting schedule makes the most sense for you.