LDL cholesterol rises when your liver either produces too much of it or can’t clear it from your bloodstream fast enough. The causes range from what you eat and how much you move to your genetics, hormones, body composition, and even certain medications. Understanding which factors apply to you is the first step toward managing your levels effectively.
How LDL Cholesterol Works in Your Body
Your liver produces cholesterol and packages it into particles called LDL (low-density lipoprotein) that travel through your blood delivering cholesterol to cells. When your cells have enough, they display fewer receptors on their surface to grab LDL from the bloodstream. The leftover LDL keeps circulating, and if levels stay high long enough, it can build up inside artery walls.
The two basic ways LDL goes up: your liver pumps out more cholesterol-carrying particles than your body needs, or the cleanup system (those receptors on liver and other cells) slows down and stops pulling LDL out of circulation efficiently. Nearly every cause of high LDL traces back to one or both of these mechanisms.
Diet: Cholesterol and Saturated Fat
Dietary cholesterol has the stronger direct effect on LDL levels. When you eat cholesterol-rich foods (egg yolks, organ meats, shellfish), your liver senses the incoming supply and dials down its LDL receptors, meaning less LDL gets pulled out of your blood. Saturated fat plays a supporting role: palmitic acid, the most common saturated fat in Western diets, can further suppress receptor activity, but primarily when dietary cholesterol intake is already high.
Primate research shows that saturated fat has a negligible effect on LDL clearance when dietary cholesterol is low and polyunsaturated fat intake is adequate (around 5 to 10 percent of daily calories). In other words, saturated fat matters most when it’s layered on top of a diet already high in cholesterol. Trans fats, found in partially hydrogenated oils, are a separate problem: they both raise LDL and lower HDL (the protective type), making them uniquely harmful.
Genetics and Familial Hypercholesterolemia
Some people inherit genes that keep their LDL high regardless of diet. Familial hypercholesterolemia (FH) is the most common inherited cardiovascular condition, affecting roughly 1 in 200 to 1 in 250 people worldwide. Most people with FH have no idea they carry it.
FH involves mutations in genes that control how your body handles LDL. The most common mutation affects the LDL receptor gene itself, meaning the liver has fewer working receptors to pull LDL out of the blood. Other mutations affect the protein on LDL particles that docks with those receptors, or a protein called PCSK9 that controls how many receptors the liver keeps active. People who inherit one copy of the mutation (heterozygous FH) typically have LDL levels two to three times higher than normal from birth. Those who inherit two copies face extremely high levels and serious heart disease risk even in childhood.
If your LDL has been stubbornly high despite a healthy diet and exercise, or if heart attacks run in your family before age 55, genetic testing for FH is worth discussing with your doctor.
Visceral Fat and Liver Overproduction
Where you carry your body fat matters more than how much you weigh. Fat stored deep in your abdomen, surrounding your organs (visceral fat), has a direct pipeline to your liver through the portal vein. As visceral fat increases, it releases more free fatty acids into that pipeline. The liver takes up a large proportion of these fatty acids, and when the supply is abnormally high, it responds by ramping up production of VLDL particles, which are the precursors to LDL.
This is why two people at the same body weight can have very different cholesterol profiles. Someone who carries fat around the midsection will typically produce more LDL than someone who carries it in the hips and thighs. The proportion of fatty acids delivered to the liver from visceral fat increases as visceral fat mass grows, and this relationship is even more pronounced in women than men. Waist circumference is a rough but useful proxy: above 40 inches in men or 35 inches in women signals higher visceral fat and increased metabolic risk.
Menopause and Hormonal Shifts
Estrogen helps keep LDL levels in check by maintaining active LDL receptors on liver cells. When estrogen drops during menopause, the liver clears LDL less efficiently. Women commonly see a noticeable jump in LDL cholesterol in the years surrounding menopause, even with no changes in diet or activity. This shift is one reason heart disease risk in women rises sharply after midlife, eventually matching or exceeding that of men.
Thyroid hormones also regulate LDL receptors. An underactive thyroid (hypothyroidism) slows receptor activity and raises LDL. This is common enough that doctors often check thyroid function when cholesterol levels climb unexpectedly.
Medications That Raise LDL
Several widely prescribed drugs can push LDL higher as a side effect. This doesn’t necessarily mean you should stop taking them, but it’s worth knowing the connection so you and your doctor can monitor your levels.
- High-dose thiazide diuretics (used for blood pressure): can raise LDL by about 10 percent at doses of 50 mg per day or more.
- Corticosteroids (prescribed for inflammation, autoimmune conditions): high doses tend to increase LDL along with triglycerides.
- Anabolic steroids: studies of bodybuilders and weight lifters show LDL increases of roughly 20 percent.
- Protease inhibitors (used in HIV treatment): associated with LDL increases of 15 to 30 percent.
- Immunosuppressants like cyclosporine: can raise LDL anywhere from 0 to 50 percent depending on the dose and individual.
- Certain anticonvulsants, particularly carbamazepine, have shown consistent LDL increases in children and adolescents with epilepsy.
- Amiodarone (a heart rhythm medication): raises LDL by directly reducing the expression of LDL receptor genes in the liver.
If you’ve started a new medication and your next blood test shows higher LDL, the drug could be a contributing factor.
Exercise Changes LDL Particle Quality
Regular aerobic exercise doesn’t always drop your total LDL number dramatically, but it shifts the type of LDL particles in your blood in a favorable direction. A meta-analysis of 10 exercise interventions found that regular exercise decreases the concentration of small, dense LDL particles (the type most likely to penetrate artery walls) while increasing larger LDL particles, which are less harmful. It also increases large HDL particles and shrinks the most dangerous type of triglyceride-rich particles.
These improvements occurred across diverse exercise programs and, notably, happened with very little weight loss (participants lost an average of less than 3 percent of body weight). The mechanism involves better processing of triglyceride-rich particles, which leaves fewer raw materials for the liver to convert into small, dense LDL. So even if your LDL number on a standard blood test doesn’t budge much with exercise, the composition of your LDL is likely improving.
LDL Levels and What They Mean
Standard cholesterol panels report LDL in milligrams per deciliter (mg/dL). For adults, the current clinical approach focuses less on universal “normal” ranges and more on your personal cardiovascular risk. If you have existing heart disease, diabetes, or multiple risk factors, your target LDL will be lower (often below 70 or even 55 mg/dL) than someone with no risk factors, for whom staying below 100 mg/dL is a common benchmark.
For children and adolescents, the 2026 guidelines from the American College of Cardiology and American Heart Association define LDL below 110 mg/dL as acceptable, 110 to 129 as borderline, and 130 or above as abnormally high. Catching elevated levels early is especially important for families with a history of high cholesterol, since FH begins affecting arteries from birth.
LDL isn’t the only number that matters. Your ratio of total cholesterol to HDL, your triglyceride levels, and newer markers like particle count and size all contribute to a more complete picture of your cardiovascular risk. A single LDL reading is a starting point, not the full story.