Structure of cholesterol: What it is, function, and types Health ConditionsHealth ConditionsAlzheimer's & DementiaAnxietyArthritisAsthma & AllergiesBreast CancerCancerCardiovascular HealthCOVID-19Dermatology & SkincareDiabetesEnvironment & SustainabilityExercise & FitnessEye HealthHeadache & MigraineHealth EquityHIV & AIDSHuman BiologyInflammatory Bowel DiseaseLeukemiaLGBTQIA+Men's HealthMental HealthMultiple Sclerosis (MS)NutritionParkinson's DiseasePsoriasisSexual HealthWomen's HealthDiscoverNewsLatest NewsOriginal SeriesMedical MythsHonest NutritionThrough My EyesNew Normal HealthPodcastsHow to understand chronic painWhat is behind vaccine hesitancy?The amazing story of hepatitis C, from discovery to cureNew directions in dementia researchCan psychedelics rewire a depressed, anxious brain?Why climate change matters for human healthToolsGeneral HealthDrugs A-ZHealth HubsHealth ToolsBMI Calculators and ChartsBlood Pressure Chart: Ranges and GuideBreast Cancer: Self-Examination GuideSleep CalculatorHealth ProductsAffordable Therapy OptionsBlood Pressure MonitorsDiabetic SuppliesFitness TrackersHome GymsGreen Cleaning ProductsHow to Shop for CBDQuizzesRA Myths vs FactsType 2 Diabetes: Managing Blood SugarAnkylosing Spondylitis Pain: Fact or FictionConnectAbout Medical News TodayWho We AreOur Editorial ProcessContent IntegrityConscious LanguageNewslettersSign UpFollow UsMedical News TodayHealth ConditionsDiscoverToolsConnectSubscribe What is the chemical structure of cholesterol Medically reviewed by Megan Soliman, MD — By Mary West on July 28, 2022Cholesterol comprises carbon, hydrogen, and oxygen. It is a waxy, fatty substance that is solid and white or light yellow. The nature of atoms means that cholesterol cannot mix well with water, meaning it cannot travel through the bloodstream unless it combines with proteins. The combination of proteins with cholesterol is called lipoproteins. Cholesterol has several functions. It is an important component of the cell membrane, and the body uses it to make bile salts, vitamin D, and hormones, such as estrogen and testosterone. Read more to learn more about the structure of cholesterol, its types, and its function. What is cholesterol Share on PinterestGetty ImagesCholesterol is a waxy, fat-like substance that:is white or faint yellowis almost odorlesshas a solid rather than liquid consistency The body needs cholesterol to maintain a person’s health, but only in limited amounts. Although the liver makes its own cholesterol, people can also consume it through animal foods such as meat, poultry, fish, eggs, and dairy. The body makes all the cholesterol it needs, so health experts recommend eating as little dietary cholesterol as possible. Research links diets with less cholesterol to a lower risk of cardiovascular disease. Cholesterol s chemical structure The chemical formula of cholesterol is C27H46O. This means it consists of 27 atoms of carbon, 46 atoms of hydrogen, and one atom of oxygen. Cholesterol’s structure consists of:a central sterol nucleus of four hydrocarbon rings, which are hydrogen and carbon atoms with a circular arrangementa hydrocarbon tail, a chain of hydrogen and carbon atoms at the end of a moleculea hydroxyl group, which is one hydrogen atom bonded to one oxygen atom The four hydrocarbon rings join together in the middle of the compound. The hydrocarbon tail attaches to one end, and the hydroxyl group attaches to the other. Both the sterol nucleus and hydrocarbon tail do not mix with water, so this structure cannot travel through the bloodstream alone. For this reason, cholesterol combines with proteins to create lipoproteins, which can travel through the blood to reach cells that need them. Function Although people generally believe cholesterol is harmful, it has several important roles, including:A cell membrane component: Cholesterol is an important part of the cell membrane structure. It changes the fluid in the membrane, which can affect the internal cell environment. It also fosters transportation within the cell.A digestive aid: Cholesterol is a component of bile salt. The digestive system uses this to absorb fat-soluble vitamins A, D, E, and K.A precursor for important bodily substances: The body uses cholesterol to make:vitamin D, which plays a role in bone healthsteroid hormones, such as cortisol, which help the body respond to stressreproductive system hormones such as estrogen and testosterone Cholesterol also plays a role in the immune system and brain synapses. These are points of contact between nerve cells in the brain. Types of cholesterol There are two primary types of cholesterol: low-density lipoprotein (LDL) and high-density lipoprotein (HDL). While people often refer to LDL as “bad” cholesterol, HDL is known as “good” cholesterol. Most of the body’s cholesterol is LDL. High levels of LDL can cause fatty deposits called plaque to accumulate in the walls of blood vessels. Over time, this can cause the narrowing of the arteries, blocking blood flow and increasing a person’s risk of heart attack and stroke. High LDL may stem from a combination of genetic factors and lifestyle habits. Conversely, HDL reduces the buildup of plaque in blood vessels. It absorbs cholesterol and brings it to the liver, which removes it from the body. Having high levels of HDL can reduce a person’s risk of a heart attack and stroke. Summary The structure of cholesterol consists of a central portion of four hydrocarbon rings that join together with a hydrocarbon tail on one end and a hydroxy group on the other. Because the structure does not mix well with water, proteins combine with cholesterol to form lipoproteins, allowing them to travel through the bloodstream. While cholesterol serves essential functions, the body makes all that it needs. Therefore, experts recommend consuming as little dietary cholesterol as possible. Last medically reviewed on July 28, 2022CholesterolBiology / BiochemistryBlood / Hematology 5 sourcescollapsedMedical News Today has strict sourcing guidelines and draws only from peer-reviewed studies, academic research institutions, and medical journals and associations. We avoid using tertiary references. We link primary sources — including studies, scientific references, and statistics — within each article and also list them in the resources section at the bottom of our articles. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.Cholesterol. (2022).https://www.cdc.gov/cholesterol/index.htmCholesterol. (2022).https://pubchem.ncbi.nlm.nih.gov/compound/CholesterolCraig, M., et al. (2021). Biochemistry, cholesterol.https://www.ncbi.nlm.nih.gov/books/NBK513326/Huff, T., et al. (2022). Physiology, cholesterol.https://www.ncbi.nlm.nih.gov/books/NBK470561/What is blood cholesterol? (2022).https://www.nhlbi.nih.gov/health/blood-cholesterolFEEDBACK:Medically reviewed by Megan Soliman, MD — By Mary West on July 28, 2022 Latest newsWhat sets 'SuperAgers' apart? Their unusually large neuronsOmega-3 may provide a brain boost for people in midlifeSeasonal affective disorder (SAD): How to beat it this fall and winterCDC: Monkeypox in the US 'unlikely to be eliminated in the near future'Why are more women prone to Alzheimer's? New clues arise Related CoverageWhat causes high cholesterol?Medically reviewed by Daniel Murrell, MD High cholesterol is a risk factor for heart attacks and coronary heart disease, because it builds up in the arteries, narrowing them. It does not…READ MOREFoods high in cholesterol: What to know Eating a healthy diet is one way to keep cholesterol levels in check. Learn which foods to avoid and which to prioritize to maintain healthy…READ MOREWhat's the link between erectile dysfunction and high cholesterol?Medically reviewed by Matt Coward, MD, FACS High cholesterol is a risk factor for many conditions, including erectile dysfunction (ED). Learn more about the link between high cholesterol and ED…READ MORE