HDL (high-density lipoprotein) is what people usually call the “good” cholesterol. These particles pick up excess cholesterol from tissues and artery walls and carry it back to the liver, where it is disposed of. This process is called reverse cholesterol transport.
The more efficiently this mechanism works, the less cholesterol is deposited in the vessel wall. That is why low HDL is regarded as an independent cardiovascular risk factor — regardless of a person’s LDL level.
Reference ranges
Reference values depend on sex: HDL is on average higher in women because of the effect of estrogen.
| Men — normal | above 1.0 mmol/L |
| Women — normal | above 1.2 mmol/L |
| Optimal (protective) level | 1.5 mmol/L and above |
| Low — a risk factor | below 1.0 (men) / below 1.2 (women) |
What an elevated level means
High HDL has traditionally been read as a favorable sign. But there is an important nuance here that is rarely mentioned.
Studies from recent years have shown that very high HDL (above 2.3–2.5 mmol/L) provides no additional protection, and in a number of papers it has even been associated with higher mortality — the relationship turns out to be U-shaped. The reason is that what matters is not the number of particles but their functionality: “poorly working” HDL fails to perform its transport role.
So the rule “the higher, the better” is an oversimplification. A sensible goal is not to “maximize” HDL but to avoid a low level.
What a low level means
Low HDL is one of the five criteria of metabolic syndrome and an independent risk factor for atherosclerosis, heart attack and stroke.
It almost always comes paired with high triglycerides — a combination known as “atherogenic dyslipidemia”, a typical companion of insulin resistance and visceral obesity.
Common causes: excess weight (especially visceral fat), a sedentary lifestyle, smoking, a diet high in refined carbohydrates, type 2 diabetes, certain medications (beta-blockers, anabolic steroids), and heredity.
How the test is done
HDL is part of the lipid panel (lipid profile), together with total cholesterol, LDL and triglycerides.
Blood is drawn strictly on an empty stomach — at least 12 hours without food (water is allowed). For the preceding day it is worth avoiding alcohol and heavy physical exertion. Acute illness, a recent heart attack and pregnancy distort the result — the test is best postponed or interpreted with that in mind.
What affects the value
- Regular aerobic exercise — one of the few factors that reliably raises HDL.
- Quitting smoking — smoking lowers HDL, quitting raises it.
- Reducing visceral fat — directly improves the lipid profile.
- The quality of dietary fats — mono- and polyunsaturated fats instead of trans fats.
- Insulin resistance and high triglycerides drag HDL down.
- Alcohol raises HDL, but that is no reason to recommend it — the overall harm outweighs the benefit.
Calculate using this marker
Calculators where HDL is used directly:
Frequently asked questions
Is low HDL dangerous?
Low HDL by itself is not a disease, but it is an independent cardiovascular risk factor and one of the criteria for metabolic syndrome. It should be assessed not in isolation but together with triglycerides, glucose, blood pressure and waist circumference.
How do you raise HDL?
The most evidence-based measures are regular aerobic exercise, quitting smoking and reducing visceral fat. An important fact: drugs designed specifically to raise HDL did not reduce the number of cardiovascular events in clinical trials. So the modern goal of treatment is not to “raise HDL” but to lower LDL and address the causes of low HDL.
Why is the normal range higher for women than for men?
Estrogen raises HDL, so in women of reproductive age it is on average higher. After menopause the difference narrows and the risk evens out.
Related terms
Sources
- 2019 ESC/EAS Guidelines for the management of dyslipidaemias. European Heart Journal
- American Heart Association — HDL, LDL cholesterol and triglycerides
- MedlinePlus (NIH) — HDL: the “good” cholesterol