High cholesterol means there is too much cholesterol — a waxy fat the body needs in small amounts — circulating in the blood, chiefly carried by low-density lipoprotein (LDL) particles that can build up in artery walls. Over years this narrows and hardens arteries (atherosclerosis), raising the risk of heart attack and stroke. It is very common and, crucially, almost always silent: it causes no symptoms until it has already damaged blood vessels, which is why it is found — and confirmed — by a simple blood test called a lipid panel rather than by how you feel.
Who is at risk
Cholesterol reflects both how you live and the genes you inherit. Risk rises with a diet high in saturated and trans fats, low physical activity, excess weight (especially around the middle), smoking and heavy alcohol use, and it climbs with age and after menopause. Type 2 diabetes and metabolic syndrome shift the pattern toward high triglycerides and low HDL. Inherited forms matter: familial hypercholesterolemia, a common genetic condition, drives very high LDL from birth and greatly raises the risk of early heart disease, and a high lipoprotein(a) — also inherited — adds risk on top of ordinary cholesterol. An underactive thyroid, kidney disease and some medications can also push levels up.
Symptoms
For most people high cholesterol produces no symptoms whatsoever — the reason screening is recommended even when you feel completely well. Visible signs appear only with very high or inherited levels: fatty deposits called xanthomas over tendons such as the knuckles or Achilles, yellowish xanthelasma patches around the eyelids, and a grey-white ring around the cornea (corneal arcus) at a young age. By the time cholesterol produces felt symptoms, it is usually because arteries have already narrowed: chest pain or tightness on exertion (angina), calf pain when walking (claudication), or the sudden symptoms of a heart attack or stroke. Very high triglycerides can additionally cause abdominal pain and inflammation of the pancreas. Because these overlap with many conditions, the symptoms hub can help you connect a complaint to the right tests — but cholesterol itself is confirmed on the panel below, not by symptoms.
Which lab tests confirm it
A lipid panel measures the core four; two add-on tests refine risk. Where units differ between reports, a unit converter helps you match your numbers to the thresholds.
- Total cholesterol — the headline number: desirable below 200 mg/dL (5.2 mmol/L), borderline 200–239, and high at 240 mg/dL (6.2 mmol/L) or above. It is a starting point, not the full story.
- LDL cholesterol — the main treatment target and the most atherogenic fraction. Optimal is below 100 mg/dL (2.6 mmol/L); 160 mg/dL (4.1 mmol/L) is high and 190 mg/dL (4.9 mmol/L) or above is very high and suggests familial hypercholesterolemia.
- HDL cholesterol — the protective fraction, so here low is the problem: below 40 mg/dL (1.0 mmol/L) raises risk, while 60 mg/dL (1.55 mmol/L) or above is protective.
- Triglycerides — normal below 150 mg/dL (1.7 mmol/L), high from 200, and very high at 500 mg/dL (5.6 mmol/L) or above, where pancreatitis becomes a concern.
Two further tests sharpen the assessment:
- ApoB — counts the actual number of atherogenic particles, so it can expose risk that LDL underestimates, particularly when triglycerides are high; a level of 130 mg/dL or more is a recognised risk-enhancing factor.
- Lipoprotein(a) — a largely genetic, extra-atherogenic particle. 50 mg/dL (or 125 nmol/L) or above enhances risk, and because it is inherited and stable, it is measured once in a lifetime.
Doctors also read non-HDL cholesterol (total minus HDL), a robust summary of all the harmful fractions.
How to read the results together
The panel is interpreted as a pattern set against your overall cardiovascular risk, not one value in isolation.
- Classic high cholesterol: a high total and high LDL with normal triglycerides. When LDL reaches 190 mg/dL or more — especially with tendon xanthomas or a family history of early heart attacks — familial hypercholesterolemia is likely and warrants early, thorough assessment.
- The metabolic pattern: high triglycerides with low HDL and a deceptively “normal” LDL, common in metabolic syndrome. Here ApoB or non-HDL cholesterol reveals the true particle burden that LDL alone hides.
- Hidden genetic risk: an acceptable-looking panel but a high lipoprotein(a), or a strong family history of premature cardiovascular disease, points to inherited risk that standard numbers miss — the case for measuring Lp(a) at least once.
What happens next
Management starts with lifestyle and is guided by your total risk, not a single number. Cutting saturated and trans fats, eating more fibre and oily fish, moving regularly, losing excess weight and stopping smoking can meaningfully lower LDL and raise HDL, and are the foundation for everyone. Whether medication such as a statin is added depends on your calculated cardiovascular risk, LDL level and any inherited condition — a decision your doctor makes with you, not from one result. Lipids are typically rechecked after lifestyle changes or starting treatment, often around 6–12 weeks at first, then periodically. Any inherited pattern usually prompts screening of close relatives.
When to see a doctor
Most cholesterol issues are handled at a routine appointment, where the panel is placed in the context of your blood pressure, blood sugar, weight and family history. Arrange assessment sooner if you have tendon lumps, an eyelid patch, a corneal ring at a young age, or a family history of heart attacks before 55 in men or 65 in women. Treat as an emergency any chest pain or pressure, breathlessness, one-sided weakness, slurred speech or sudden vision loss — signs that atherosclerosis may have caused a heart attack or stroke — and call emergency services at once.
