What do high triglycerides mean?

The thresholds differ in name more than in substance [6]:

• 150 to 199 mg/dL (1.7 to 2.2 mmol/L)1.7 to 2.2 mmol/L (150 to 199 mg/dL): borderline high in AHA and NLA guidance.
• 200 to 499 mg/dL (2.3 to 5.6 mmol/L)2.3 to 5.6 mmol/L (200 to 499 mg/dL): high. The 2019 European guideline considers drug treatment in high-risk patients above 200 mg/dL (2.3 mmol/L)2.3 mmol/L (200 mg/dL) once secondary causes are excluded [1].
• 500 mg/dL (5.6 mmol/L)5.6 mmol/L (500 mg/dL) or more: very high or severe. The 2026 US guideline shifts the main goal toward preventing pancreatitis here, most urgently at 1,000 mg/dL (11.3 mmol/L)11.3 mmol/L (1,000 mg/dL) or more [2].

The 2018 US guideline also treats persistent levels of 175 mg/dL (1.97 mmol/L)1.97 mmol/L (175 mg/dL) or more as a factor that can favor a statin [7]. For a nonfasting sample, European labs flag 175 mg/dL (2 mmol/L)2 mmol/L (175 mg/dL) or more [8]. Every guideline category is on the triglycerides hub.

The 2026 US guideline review lists the reversible causes to check first: poor blood sugar control, alcohol excess, obesity, an underactive thyroid, kidney disease, refined-carbohydrate intake, pregnancy and triglyceride-raising medicines [2].

Mechanism matters. With borderline to moderately raised triglycerides, overproduction by the liver is usually the main problem. With severe elevations, reduced clearance by lipoprotein lipase dominates [1]. Insulin resistance feeds both: it sends more fatty acids to the liver, increases fat made in the liver and raises apoC-III, which slows clearance [1]. That is why high triglycerides so often come with raised fasting insulin, a rising HbA1c and liver fat.

Genes set the background. Rare variants that impair lipoprotein lipase raise triglycerides even when output is normal, and a complete lack of the enzyme causes extreme levels [1].

Sugar has a measurable effect on its own: in trials, higher sugar intakes raised triglycerides by about 10 mg/dL (0.11 mmol/L)0.11 mmol/L (about 10 mg/dL) regardless of weight change [9].

Between 150 and 499 mg/dL, triglycerides do their damage silently, through the arteries over years. You will not feel them.

At very high levels the picture changes. Hypertriglyceridemia is the third most common cause of acute pancreatitis after alcohol and gallstones, behind up to 4% of cases [6]. The inherited form, familial chylomicronemia syndrome, causes persistent chylomicronemia, recurrent abdominal pain and a high pancreatitis risk [2].

Because triglycerides fall quickly in the first days of pancreatitis, hospitals are advised to measure them on admission so the cause is not missed [6]. Sudden severe abdominal pain is a reason to seek urgent care, whatever your last lipid result.

In one retrospective study, 20% of patients with triglycerides above 1,000 mg/dL had at least one attack of acute pancreatitis [6]. Chylomicrons at these levels are too large to enter the artery wall, so the main threat is to the pancreas rather than the arteries [1].

What guidelines describe at this level [2]:

• Fix reversible contributors quickly: uncontrolled diabetes, alcohol, pregnancy, an underactive thyroid, kidney disease, obesity and triglyceride-raising medicines.
• A very low-fat diet to cut chylomicron production, with specialist dietary support and no alcohol or added sugar. NLA guidance limits fat to 10 to 15% of calories [6].
• Fenofibrate and prescription omega-3 as add-ons, aimed at pancreatitis rather than heart risk.
• Suspect familial chylomicronemia syndrome when levels stay above 1,000 mg/dL after secondary causes are fixed. The 2026 guideline recommends olezarsen for confirmed cases.

The newest evidence comes from drugs that block apoC-III. In two trials of 1,061 people with severe hypertriglyceridemia, olezarsen lowered triglycerides by 49 to 72 percentage points more than placebo and cut acute pancreatitis (rate ratio 0.15) [4]. In persistent chylomicronemia with a median level of 2,044 mg/dL, plozasiran lowered triglycerides by 78 to 80% versus 17% with placebo [5].

Across 29 studies, people in the top third of triglycerides had 1.72 times the coronary risk of those in the bottom third [10]. Genetically higher remnant cholesterol, the cholesterol inside triglyceride-rich particles, carried a 2.8-fold causal risk per 39 mg/dL (1 mmol/L)1 mmol/L (39 mg/dL) [11].

The benefit of lowering triglyceride-rich particles appears proportional to the drop in ApoB [12]. That explains why pemafibrate lowered triglycerides by 26.2% without reducing events: ApoB went up by 4.8% [13]. For heart risk, the 2026 US guideline keeps LDL and non-HDL cholesterol as treatment targets and uses statins as the foundation [2]. See the ApoB guide and the LDL cholesterol guide.

Useful questions to take to an appointment:

• Was the sample fasting? If a nonfasting value was above 440 mg/dL (5 mmol/L)5 mmol/L (440 mg/dL), a fasting repeat is reasonable [8].
• Have blood sugar, thyroid, kidney function and medicines been reviewed as causes [2]? HbA1c and TSH are the usual first tests.
• What do ApoB and non-HDL cholesterol show? With high triglycerides, LDL cholesterol alone can understate the particle count.
• Is my level in the range where pancreatitis prevention comes first?

The how to lower triglycerides page ranks the lifestyle and medical options by how much they lower the number.