HDL, or high-density lipoprotein, is the “good” cholesterol. It earns that label because it pulls excess cholesterol out of your bloodstream and artery walls, then ferries it back to your liver, where your body flushes it out. For most adults, an HDL level of 60 mg/dL or higher is considered ideal.
What HDL Actually Does in Your Body
Cholesterol doesn’t float through your blood on its own. It travels on protein carriers called lipoproteins. HDL particles are small and dense, and their job is essentially cleanup: they absorb cholesterol from places it shouldn’t accumulate, particularly the walls of your arteries, and carry it to the liver. The liver then breaks it down and sends it out through bile into your digestive tract, where it leaves your body in stool. This entire loop is called reverse cholesterol transport.
The process starts at the cellular level. Special transporters on the surface of cells push cholesterol outward onto waiting HDL particles. As HDL collects more cholesterol, it matures into a larger particle that eventually docks at the liver. Some of the cholesterol HDL picks up also gets transferred to other lipoproteins that the liver can absorb. Either way, the net result is less cholesterol sitting in your artery walls, which means less plaque buildup and a lower risk of heart attack and stroke.
How HDL Differs From LDL
LDL, or low-density lipoprotein, is the “bad” cholesterol, and it makes up most of the cholesterol in your blood. LDL’s job is to deliver cholesterol to your tissues, but when you have too much of it, the excess starts building up inside artery walls. That buildup hardens into plaque over time, narrowing your arteries and raising your risk of heart disease and stroke.
HDL works in the opposite direction. Instead of depositing cholesterol, it removes it. Think of LDL as delivery trucks dropping off packages and HDL as the trucks picking up the excess and hauling it away. Your heart disease risk depends heavily on the balance between the two. A high LDL number with a low HDL number is one of the more dangerous combinations for cardiovascular health.
What Your HDL Number Should Be
For both men and women over 20, an HDL level of 60 mg/dL or higher is considered best. The threshold for “low” differs by sex: below 40 mg/dL is low for men, while below 50 mg/dL is low for women. These cutoffs reflect the fact that women naturally tend to have slightly higher HDL levels than men, partly due to estrogen’s effects on cholesterol metabolism.
Your doctor may also look at your cholesterol ratio, which is your total cholesterol divided by your HDL. If your total cholesterol is 200 mg/dL and your HDL is 50 mg/dL, your ratio is 4 to 1. A higher ratio signals higher risk. Many clinicians now consider this ratio, or a related measure called non-HDL cholesterol (your total cholesterol minus HDL), to be a better predictor of heart disease than looking at any single number alone.
When “Good” Cholesterol Gets Too High
More HDL is generally better, but research has revealed an important exception. The relationship between HDL and mortality follows a U-shaped curve: both very low and very high levels are linked to increased risk. A large Korean study found that men with HDL above 80 mg/dL had a 32% higher mortality risk compared to men in the normal range, even after adjusting for other health factors. Among men under 60, very high HDL (above 80 mg/dL) carried a 76% higher mortality risk in some models, comparable to the elevated risk seen in men with very low HDL (below 40 mg/dL).
The reasons aren’t fully understood, but extremely high HDL may reflect dysfunctional particles that are less effective at removing cholesterol, or it may signal underlying conditions that independently raise mortality. For most people, this isn’t a practical concern since very few people naturally reach these extreme levels. But it does mean that aggressively trying to push HDL as high as possible through supplements isn’t necessarily a good strategy.
How to Raise HDL Naturally
Exercise
Regular aerobic exercise is one of the most reliable ways to boost HDL. Research shows that as little as two hours of moderate-intensity exercise per week can produce a meaningful increase. Both men and women in studies showed higher HDL levels with regular activity, and even people who fell short of the standard 150-minute weekly recommendation still saw benefits. Walking, cycling, swimming, and jogging all count. The key is consistency over weeks and months rather than intensity on any single day.
Diet
The type of fat you eat matters more than the total amount. Replacing saturated fats (full-fat dairy, fatty meats, butter, lard) and trans fats (some margarines, fried foods, processed baked goods) with unsaturated fats tends to improve your HDL profile. Good sources of unsaturated fats include avocados, olive oil, nuts, and fatty fish. Limiting refined carbohydrates and sugar also helps. Fiber-rich foods like oatmeal and beans support better cholesterol numbers overall.
Quitting Smoking
Smoking suppresses HDL, and quitting produces a noticeable rebound. A review of 94 estimates of HDL changes after smoking cessation found an average increase of about 4 mg/dL in the short term, with the biggest gains appearing within the first three to six months. One study found that significantly more people who quit smoking crossed from below 40 mg/dL to above it compared to people who kept smoking. The HDL benefit appears quickly and is one of many cardiovascular improvements that follow quitting.
Do Supplements Work?
Niacin (vitamin B3) can raise HDL by more than 30% and lower triglycerides by about 25%. Those numbers sound impressive, but clinical trials have consistently shown that boosting HDL through niacin doesn’t actually translate into fewer heart attacks, strokes, or deaths. People already taking a statin see almost no additional benefit from adding niacin. The Mayo Clinic notes that niacin may still help a narrow group of people who can’t tolerate statins and have both high triglycerides and low HDL, but for most people, it’s not recommended as a strategy to improve cardiovascular outcomes.
This finding is part of a broader lesson from cholesterol research: the number on your lab report matters less than how your HDL particles are actually functioning. HDL that efficiently pulls cholesterol from artery walls and delivers it to the liver is protective. Simply inflating the HDL number with a supplement, without improving that transport function, doesn’t reduce risk. That’s why lifestyle changes like exercise, diet, and not smoking remain the most effective approaches. They don’t just raise HDL levels; they appear to improve how well those particles do their job.