Having high cholesterol means there’s more cholesterol circulating in your blood than your body can use, and the excess gradually builds up inside your artery walls. For most adults, “high” starts at a total cholesterol above 200 mg/dL or an LDL (often called “bad” cholesterol) above 100 mg/dL. The condition itself causes no symptoms in the vast majority of people, which is why it’s detected through a blood test and why it often goes unnoticed for years.
What Cholesterol Actually Does in Your Body
Cholesterol is a waxy, fat-like substance your liver produces because your body genuinely needs it. It helps build cell membranes, produce hormones, and make vitamin D. Your liver manufactures enough cholesterol on its own to handle all of these jobs. The problem starts when extra cholesterol from your diet or from your body’s own overproduction accumulates in the bloodstream with nowhere useful to go.
There are two main types you’ll see on a lab report. LDL (low-density lipoprotein) carries cholesterol into your arteries and is the primary driver of plaque buildup. HDL (high-density lipoprotein) works in the opposite direction, picking up excess cholesterol and ferrying it back to the liver for disposal. When people talk about “high cholesterol,” they’re usually talking about too much LDL, too little HDL, or both.
The Numbers That Matter
For adults 20 and older, healthy cholesterol levels look like this:
- Total cholesterol: below 200 mg/dL
- LDL cholesterol: below 100 mg/dL
- HDL cholesterol: 60 mg/dL or higher is ideal. Below 40 mg/dL for men or below 50 mg/dL for women is considered low and increases risk.
For children and teens (19 and younger), the thresholds are slightly different: total cholesterol should be below 170 mg/dL and LDL below 110 mg/dL. These numbers matter because the process of artery damage can begin surprisingly early in life, even though the consequences don’t show up for decades.
How High Cholesterol Damages Your Arteries
When LDL levels stay elevated, the excess particles seep into the inner lining of your artery walls. Once trapped there, they undergo chemical changes, becoming oxidized and clumping together. Your immune system recognizes these altered particles as threats and sends white blood cells to consume them. Those white blood cells swell with cholesterol and become what researchers call “foam cells,” forming the fatty core of a plaque.
Over time, the plaque hardens as calcium deposits form within it. Smooth muscle cells in the artery wall multiply and lay down scar-like tissue around the fatty core, narrowing the artery. This entire process, called atherosclerosis, can take decades. If a plaque eventually ruptures, a blood clot forms at the site and can block blood flow entirely. When that happens in an artery feeding the heart, it causes a heart attack. In an artery supplying the brain, it causes a stroke. In the legs, it leads to peripheral artery disease, which can cause pain, poor wound healing, and in severe cases, tissue loss.
Why You Won’t Feel It
High cholesterol produces no pain, no fatigue, no obvious warning signs. Your arteries can narrow significantly before you notice anything wrong, and the first symptom is sometimes a heart attack or stroke itself. This is the core reason routine blood testing matters.
There is one exception. People with extremely high cholesterol, particularly a genetic form called familial hypercholesterolemia, can develop visible physical signs. These include yellowish, waxy deposits around the tendons of the hands, elbows, or Achilles tendon (called tendon xanthomas), and a white or gray ring around the colored part of the eye (corneal arcus). In someone under 45, these findings are highly suggestive of a genetic cholesterol disorder. But these signs appear only at very high levels and in a small subset of people.
What Causes It
For most people, high cholesterol results from a combination of diet, activity level, and body weight. Diets high in saturated fat and trans fat raise LDL. Carrying excess weight, particularly around the midsection, tends to lower HDL and raise triglycerides. Smoking damages blood vessel walls and also lowers HDL. Physical inactivity contributes to all of the above.
Genetics play a larger role than many people realize. Familial hypercholesterolemia affects roughly 1 in 220 people worldwide, making it one of the most common genetic disorders. People with this condition have LDL levels that are significantly elevated from birth, often above 190 mg/dL in adults or above 160 mg/dL in children, regardless of how well they eat or how much they exercise. Because the condition is inherited in a dominant pattern, it only takes one copy of the gene from one parent to cause it. Most people with familial hypercholesterolemia don’t know they have it.
Age and sex also matter. Cholesterol levels tend to rise with age. Before menopause, women generally have lower LDL levels than men of the same age. After menopause, LDL often climbs.
How Cholesterol Testing Works
A standard lipid panel measures total cholesterol, LDL, HDL, and triglycerides from a simple blood draw. Traditionally, doctors required you to fast for 9 to 12 hours before the test, but that recommendation has shifted. Multiple medical societies now endorse non-fasting lipid panels, and the differences between fasting and non-fasting results are clinically minor. On average, eating before a test raises triglycerides by about 26 mg/dL and lowers LDL by about 8 mg/dL. Those shifts rarely change what your doctor would recommend.
Non-fasting testing is actually more convenient for both patients and labs, and some experts argue it gives a more realistic picture of your cholesterol levels throughout a normal day, since most of your waking hours are spent in a non-fasting state. Your doctor may still request a fasting test if your triglycerides come back very high on a non-fasting draw, but for most people, fasting is no longer necessary.
Beyond Standard LDL Testing
A newer test that’s gaining traction measures a protein called ApoB (apolipoprotein B), which sits on the surface of every LDL particle. The American Heart Association uses a helpful analogy: a standard lipid panel counts the number of passengers (cholesterol) on the road, while ApoB counts the number of cars (particles). Two people can have the same LDL cholesterol level but a very different number of particles carrying that cholesterol. The person with more particles faces higher risk, even if their LDL number looks fine.
ApoB testing is particularly useful if you have high triglycerides, metabolic syndrome, or diabetes, because these conditions can increase particle count without obviously raising LDL on a standard panel. If your doctor suspects your standard numbers aren’t telling the full story, an ApoB test can clarify things.
How High Cholesterol Is Managed
Treatment depends on how high your numbers are and your overall risk of developing cardiovascular disease in the next 10 years. Doctors now calculate that risk using a set of equations that factor in age, blood pressure, cholesterol levels, diabetes status, kidney function, and other variables.
For people at low risk (below 3% chance of a cardiovascular event in the next 10 years), lifestyle changes are the first and often only recommendation. That means shifting toward a diet lower in saturated fat, increasing physical activity, losing excess weight, and quitting smoking. These changes can meaningfully lower LDL, though the exact degree varies from person to person.
For people at intermediate risk (5% to 10% over 10 years), statin therapy is typically recommended alongside lifestyle changes. Statins work by blocking the liver’s production of cholesterol, forcing it to pull more LDL out of the bloodstream. At moderate intensity, statins reduce LDL by 30% to 49%. High-intensity statin therapy can lower LDL by 50% or more. For people with diabetes between ages 40 and 75, moderate-intensity statin therapy is recommended regardless of their calculated risk score.
For people with severely elevated LDL (190 mg/dL or higher), which often points to a genetic cause, the most aggressive statin therapy tolerable is the standard first step. Some of these patients will need additional medications to reach safe levels. The goal at every stage is to reduce the number of LDL particles depositing cholesterol into artery walls, slowing or stopping the progression of plaque.
What You Can Control
Even when genetics are part of the picture, lifestyle still matters. Replacing saturated fats (found in red meat, full-fat dairy, and many processed foods) with unsaturated fats (olive oil, nuts, avocados, fatty fish) lowers LDL. Soluble fiber, found in oats, beans, and certain fruits, binds cholesterol in the gut and helps remove it. Regular aerobic exercise raises HDL and improves the overall ratio of good to bad cholesterol. Losing even a modest amount of weight, around 5% to 10% of body weight, can improve lipid numbers noticeably.
These changes won’t override a strong genetic predisposition on their own, but they reduce the total burden on your cardiovascular system and make medications more effective when they’re needed. The earlier you know your numbers and start managing them, the less plaque accumulates over a lifetime, and that accumulated damage is what ultimately determines your risk.