Liver Health: The Complete Guide

How your liver works, why liver disease is usually silent until late, and what protects it, from fatty liver disease, alcohol and hepatitis testing to acetaminophen safety, supplements and cirrhosis care. For anyone who wants to understand their liver, and especially for people with diabetes, excess weight, regular drinking or abnormal liver tests.

Key numbers at a glance

What your liver does

Your liver is the largest solid organ in your body, weighing about 3 pounds (1.4 kg), and sits under your ribs on the upper right side of your abdomen. Almost all the blood leaving your stomach and intestines passes through it before reaching the rest of the body, which puts it in charge of processing what you absorb. It stores sugar as glycogen and releases it between meals, handles fats and cholesterol, and makes most of the proteins in your blood, including albumin and the clotting factors that stop bleeding.

The liver also breaks down medicines, alcohol and many other substances so they can be removed, and it makes bile, a fluid stored in the gallbladder that helps you digest fat and carries waste products, including bilirubin, out of the body. When the liver cannot clear bilirubin, it builds up and turns the skin and eyes yellow, which is called jaundice.

The liver has a remarkable ability to repair itself. Injured liver cells can be replaced, and early damage from fat, alcohol or inflammation can often reverse if the cause is removed. But repeated or ongoing injury leads to scarring, called fibrosis. Advanced scarring, called cirrhosis, distorts the structure of the liver and does not reverse, though its progression can be halted. Much of liver care is about finding damage while it can still heal.

Why liver disease often goes unnoticed

The liver has no pain-sensing nerves inside it and a great deal of spare capacity, so it keeps working well even while it is being damaged. Fatty liver disease, hepatitis C and early alcohol-related liver disease usually cause no symptoms for years. When symptoms do appear, such as tiredness, itching, swelling of the abdomen or legs, easy bruising, jaundice or confusion, the disease is often advanced.

Blood tests do not always help as much as people expect. Standard liver function tests can be normal even when significant scarring is present, and they can be mildly abnormal for harmless reasons. That is why doctors increasingly use risk-based testing: checking people with known risk factors, and using fibrosis scores and specialized scans rather than relying on a single panel of results.

The encouraging side of this is that the main causes of liver disease in the US are largely preventable or treatable. Fatty liver disease responds to weight loss and activity, alcohol-related damage stops progressing when drinking stops, hepatitis C can be cured, and hepatitis B can be prevented by vaccination and controlled with treatment. The practical lesson is to act on risk rather than on symptoms: if you have a risk factor, ask to be checked now, while any damage is still likely to be reversible or at least stoppable.

Who is at higher risk

Your risk of liver disease depends mostly on a handful of factors, several of which are common. Metabolic conditions are now the biggest driver in the US: excess weight, particularly around the waist, type 2 diabetes, high blood pressure and high triglycerides all make fat build up in the liver. Alcohol remains a major cause, and the amount that harms the liver is lower than many people assume, especially in people who already have fatty liver or are overweight.

Viral hepatitis is the third main cause. Many people with hepatitis B or C were infected years ago and do not know it. Some medicines and supplements can injure the liver, and a smaller number of conditions, such as hemochromatosis (iron overload), Wilson disease and autoimmune hepatitis, run in families or arise from the immune system. A family history of cirrhosis or liver cancer is worth mentioning to your doctor.

• Excess weight, especially around the waist
• Type 2 diabetes or prediabetes
• High blood pressure, high triglycerides or low HDL cholesterol
• Drinking above the Dietary Guidelines limits, or binge drinking
• Ever having injected drugs, even once or long ago
• A blood transfusion or organ transplant before July 1992
• Being born in a region where hepatitis B is common
• Regular use of herbal, bodybuilding or weight-loss supplements
• A family history of liver disease or liver cancer

Fatty liver disease

Fatty liver disease is now called metabolic dysfunction-associated steatotic liver disease (MASLD), replacing the older name nonalcoholic fatty liver disease (NAFLD). The new name reflects what drives it: the same metabolic problems that cause type 2 diabetes and heart disease. It is one of the most common liver conditions in the US, and it is usually found by chance on a blood test or a scan done for another reason.

In most people, MASLD stays as simple fat in the liver and never causes serious harm. In a minority, the fat triggers inflammation and liver cell injury, called metabolic dysfunction-associated steatohepatitis (MASH). Over years, MASH can lead to fibrosis and then cirrhosis. The amount of scarring, rather than the amount of fat, predicts what happens next, which is why doctors focus on assessing fibrosis. Many people with MASLD will in fact die of heart disease rather than liver disease, so managing heart risk is part of treating it.

Weight loss is the most effective treatment. Losing around 7 to 10 percent of your body weight is linked to less liver inflammation, and even smaller losses reduce liver fat. Gradual loss is better than crash dieting, which can worsen inflammation. Physical activity helps independently of weight loss, so it is worth doing even if the scale does not move. Managing diabetes, blood pressure and cholesterol slows progression, and avoiding alcohol removes a second source of injury.

For people with MASH and moderate to advanced scarring, the FDA has in recent years approved the first medicines specifically for this condition, and some diabetes and weight-loss medicines may also help the liver. These are prescribed by a liver doctor alongside lifestyle changes, not instead of them. They are not suitable for everyone, and they work best when combined with weight loss and activity. Ask your doctor whether your fibrosis assessment suggests you might benefit, and whether a referral to a hepatologist, a doctor who treats liver disease, makes sense for you.

Eating and moving for a healthier liver

No single food protects the liver, but an overall eating pattern does. The Dietary Guidelines for Americans recommend building meals around vegetables, fruits, whole grains, beans, lean proteins, nuts and healthy oils, and keeping added sugars below 10 percent of daily calories. That matters for the liver because sugary drinks and large amounts of refined carbohydrates are turned into fat there. Swapping soda and sweetened coffee drinks for water is one of the simplest changes with a real effect.

For activity, aim for at least 150 minutes of moderate activity a week, such as brisk walking, plus muscle-strengthening activity on 2 days. Both aerobic exercise and resistance training reduce liver fat, even before any weight is lost. If you are starting from very little, short walks after meals are a good beginning, and any increase helps. Sitting less through the day also counts.

Alcohol and the liver

The liver processes almost all the alcohol you drink, and when it is busy with alcohol it stores more fat. Sustained drinking leads first to fatty liver, which is largely reversible if you stop. Continued heavy drinking can cause alcohol-related hepatitis, a serious inflammation that can come on suddenly with jaundice and can be life-threatening, and then cirrhosis. Early stages cause no symptoms, so people often have advanced damage by the time they feel unwell.

The Dietary Guidelines for Americans 2020–2025 advise that adults who drink should limit themselves to 2 drinks or fewer a day for men and 1 or fewer for women, and that drinking less is better for health than drinking more. A US standard drink contains 14 g of pure alcohol: 12 fl oz of regular beer, 5 fl oz of wine, or 1.5 fl oz of 80-proof distilled spirits. Many restaurant pours and craft beers contain more than one standard drink. If you have any liver disease, the safest amount of alcohol is none.

If you drink heavily every day, do not stop suddenly on your own. Alcohol withdrawal can cause seizures and can be life-threatening, so talk to your doctor first about a safe plan. Effective treatments exist, including medicines that reduce craving and behavioral support. The SAMHSA National Helpline, 1-800-662-4357, is free, confidential and open 24/7, and can help you find treatment near you.

Binge and heavy drinking

Daily averages are not the whole story. Binge drinking, which typically means 5 or more drinks on one occasion for men or 4 or more for women, stresses the liver and the rest of the body even if you drink little the rest of the week. Saving up drinks for the weekend does not make them safer. It can help to track what you drink for a few weeks, using standard drink sizes rather than glasses, because people often underestimate their intake.

If cutting down is harder than you expected, that is common and not a personal failing. Your doctor can talk through options without judgment, including medicines approved by the FDA to treat alcohol use disorder and referral to counseling or support programs. The NIAAA Rethinking Drinking site offers practical tools for checking your pattern and planning changes. Support from family and friends, and from mutual-help groups, also makes a difference, and many people need more than one attempt before a change sticks. Each drink you cut lowers the load on your liver.

Hepatitis B and C

Hepatitis B and C are viruses that infect the liver and can persist for decades without symptoms while slowly causing scarring and raising the risk of liver cancer. Both spread through blood, including shared needles and other drug-use equipment and, in the past, transfusions before modern screening. Hepatitis B also spreads through sex and from a mother to her baby at birth. Many people with either infection do not know they have it.

Hepatitis C is now curable in the great majority of people with a short course of pills called direct-acting antivirals, usually taken for 8 to 12 weeks. The CDC recommends that all adults 18 and older be tested for hepatitis C at least once, and that pregnant people be tested during every pregnancy. People with ongoing risk, such as current injection drug use, should be tested regularly. Being cured does not make you immune, so you can be reinfected if exposed again.

Hepatitis B can be prevented with a safe and effective vaccine, and long-term infection can be controlled with antiviral medicines that lower the risk of cirrhosis and liver cancer. The CDC recommends that all adults 18 and older be tested for hepatitis B at least once. If you have hepatitis B, tell household and sexual partners so they can be tested and vaccinated. Hepatitis A, which spreads through contaminated food and water, is usually short-lived but can be severe in people who already have liver disease; a vaccine is available for it too.

Medicines, acetaminophen and supplements

Because the liver breaks down most medicines, it is exposed to anything you take. Acetaminophen (Tylenol) is safe at recommended doses, but it is a leading cause of acute liver failure in the US, usually through accidental overdose. For adults, the maximum is 4,000 mg in 24 hours unless your doctor tells you otherwise, and some product labels set a lower limit. The danger comes from doubling up: acetaminophen is in hundreds of prescription and over-the-counter products, including cold and flu remedies and some prescription pain medicines.

Check the active ingredients of every product, take only one product containing acetaminophen at a time, and ask your pharmacist about a lower limit if you drink regularly, are underweight, or have liver disease. An overdose may cause no symptoms for the first day, so call Poison Control at 1-800-222-1222 straight away if you think you have taken too much, even if you feel completely well. Treatment works best when it starts early.

Herbal and dietary supplements are a recognized and growing cause of liver injury. The FDA does not approve supplements for safety or effectiveness before they are sold, and products vary in what they actually contain. Bodybuilding products, weight-loss supplements and concentrated green tea extract are among those linked to liver damage. "Detox" and "liver cleanse" products have no good evidence of benefit; the liver already does that work. The NIH LiverTox database lets you look up the liver risks of specific medicines and supplements.

How liver health is checked

Liver function tests are a panel of blood tests. ALT and AST rise when liver cells are injured. ALP and GGT rise mainly when the bile ducts are involved. Bilirubin rises in jaundice. Albumin and clotting tests, such as the INR, are the closest blood measures of how well the liver is actually working, and they usually change only when disease is advanced. Mildly abnormal results are common and often repeated before any further tests, while normal results do not rule out scarring.

If you have risk factors such as type 2 diabetes, excess weight or regular drinking, ask your doctor about assessing liver scarring directly. The FIB-4 score is calculated from routine blood results and your age, and helps sort people into low, uncertain and higher risk. If it is not clearly low, a specialized ultrasound called elastography, which measures liver stiffness, can give a clearer picture without a biopsy. A liver biopsy is now needed only in a minority of cases.

Your doctor will also look for the cause. That can include hepatitis B and C tests, iron studies, autoimmune markers and an ultrasound of the liver and bile ducts. Be honest about how much alcohol you drink and list every medicine and supplement you take, because these details often explain an abnormal result. Strenuous exercise in the days before a blood test can also raise AST and ALT temporarily, so mention it if it applies. Ask for your actual numbers and how they compare with earlier results; the trend is often more informative than a single reading.

Cirrhosis, its complications and liver cancer

Cirrhosis means advanced scarring that has distorted the liver's structure. In the US, the main causes are alcohol, fatty liver disease and viral hepatitis. Many people have compensated cirrhosis, meaning the liver still copes and there are few or no symptoms, sometimes for many years. Treating the underlying cause, such as stopping alcohol completely, curing hepatitis C or losing weight, can stop progression and lower the risk of complications.

Decompensation is when the liver can no longer keep up. Fluid can collect in the abdomen (ascites), toxins can affect the brain and cause confusion or drowsiness (hepatic encephalopathy), and pressure in the veins leading to the liver can create swollen veins in the esophagus, called varices, that can bleed heavily. People with cirrhosis are usually checked for varices by endoscopy, and some take beta blockers to lower the bleeding risk. Infections, including of abdominal fluid, are more dangerous and can show up only as fever or confusion.

Cirrhosis from any cause is the main risk factor for primary liver cancer. Guidelines recommend surveillance with an ultrasound about every 6 months, sometimes with a blood test, because finding a cancer early makes curative treatment far more likely. Keeping these appointments when you feel well is one of the most valuable things you can do. People with chronic hepatitis B may need surveillance even without cirrhosis. For people whose liver fails, a liver transplant can be life-saving, and a referral is worth discussing early.

• Stop drinking alcohol completely
• Keep every 6-monthly surveillance scan
• Ask about vaccines for hepatitis A and B, flu, COVID-19 and pneumococcal disease
• Avoid NSAIDs such as ibuprofen and naproxen, which raise bleeding and kidney risk
• Avoid raw or undercooked shellfish, which can cause severe infection
• Check every new medicine and supplement with your pharmacist

Jaundice, gallstones and other warning signs

Jaundice, yellowing of the skin and the whites of the eyes, always needs assessment in an adult. Dark urine with pale stools suggests a blocked bile duct, often from a gallstone, while painless jaundice with weight loss needs prompt investigation for cancer of the pancreas or bile ducts. A common and harmless cause is Gilbert syndrome, in which mild jaundice comes and goes, often during illness or fasting. Your doctor can tell these apart with blood tests and an ultrasound.

Gallstones are very common and most never cause symptoms or need treatment. When a stone blocks the gallbladder outlet, it causes a gallbladder attack: sudden pain in the upper right or center of the abdomen, often after a meal, sometimes spreading to the back or right shoulder blade. Attacks tend to recur, and the usual treatment is laparoscopic removal of the gallbladder. Pain lasting several hours, pain with fever, jaundice or persistent vomiting can mean infection, a blocked bile duct or pancreatitis and needs urgent care. Very rapid weight loss raises gallstone risk.

• Yellowing of the skin or eyes
• Dark, tea-colored urine or pale, clay-colored stools
• Swelling of the abdomen or legs
• Persistent itching without a rash
• Easy bruising or bleeding
• Confusion, drowsiness or personality change
• Vomiting blood or black, tarry stools, which are emergencies

Pregnancy, children, older adults and costs

Liver care differs across life stages, and in the US it also depends on what your coverage pays for. The notes below cover the groups who need particular attention, starting with pregnancy, and explain how to get recommended tests and vaccines at low or no cost where possible. If you are not sure which applies to you, your primary care provider or pharmacist is a good first stop.

Hepatitis C and B testing during pregnancy matters because both can pass to the baby, and babies of mothers with hepatitis B need treatment at birth to prevent infection. Severe itching in late pregnancy, especially of the palms and soles, can be a liver condition called intrahepatic cholestasis of pregnancy and should be reported promptly. Some antiviral treatments are not used in pregnancy, so plan treatment with your doctor. Pregnant people should also avoid alcohol entirely, and check any medicine or supplement with their obstetric provider before taking it.

Babies and children

Jaundice is common in newborns and usually harmless, but jaundice in the first 24 hours of life always needs same-day medical care, and jaundice lasting beyond the first couple of weeks, or with pale stools or dark urine, needs prompt assessment for conditions such as biliary atresia, where early surgery matters. Fatty liver disease is increasingly found in children and teens with obesity. Ask your child's doctor about hepatitis A and B vaccines.

Older adults

Older adults are more likely to take several medicines, which increases the chance of drug-related liver injury and of doubling up on acetaminophen. A yearly medicine review with a doctor or pharmacist is worthwhile. Liver disease can show up subtly, for example as confusion or falls, so new changes deserve a check rather than being put down to age. Alcohol also affects older adults more strongly, because the body holds less water and many common medicines interact with it, so the same number of drinks can do more harm than it did at a younger age.

Costs and coverage

Under the Affordable Care Act, most private plans, Medicaid expansion plans and Medicare cover recommended screenings such as hepatitis C and hepatitis B testing, and recommended adult vaccines, without a copay when you use an in-network provider. Hepatitis C medicines are expensive, but insurance, Medicaid and Medicare drug plans generally cover them, and manufacturer assistance programs exist; ask your doctor's office or pharmacist for help with prior authorization if it is needed.

Myths, talking to your doctor and a practical plan

A few persistent myths lead people to worry about the wrong things or to miss the right ones. Normal liver tests do not guarantee a healthy liver, and abnormal ones do not always mean disease. "Natural" does not mean safe for the liver, and no supplement or cleanse has been shown to protect it. Only drinking spirits is not what matters; the total amount of alcohol is. And thin people can have fatty liver disease too, particularly if they carry weight around the waist or have diabetes.

When you see your doctor, ask what exactly was abnormal on your blood tests, whether your FIB-4 score has been calculated, and whether you need an elastography scan. Ask if you have been tested for hepatitis B and C, and whether you are protected against hepatitis A and B. Bring a list of every medicine and supplement, and give an honest estimate of how many standard drinks you have in a typical week. Liver health improves with steady habits, so the plan below is designed to be kept up, not completed once.

• Week 1: Count your standard drinks for a typical week and compare them with the Dietary Guidelines limits.
• Week 2: Check every medicine and supplement for acetaminophen and for liver risks, using the label and the NIH LiverTox database.
• Week 3: Book a checkup and ask about hepatitis B and C testing, vaccines, and a FIB-4 score if you have diabetes or excess weight.
• Week 4: Build toward 150 minutes of moderate activity a week, and set a realistic, gradual weight-loss goal if you need one.
• Every year: Review your liver results and medicines with your doctor; if you have cirrhosis, keep a scan every 6 months.

Every guide in this topic

• What the Guidance Really Says About Fatty Liver Disease
• Alcohol-Related Liver Disease: What Published Guidance Supports
• The Evidence on Liver Function Tests, Without the Hype
• Hepatitis B and C: What the Evidence Actually Says
• What the Guidance Really Says About Cirrhosis
• The Evidence on Jaundice, Without the Hype
• Gallstones: Sorting the Evidence From the Noise
• Acetaminophen Safety: What the Evidence Actually Says
• What the Guidance Really Says About Supplements and the Liver
• The Evidence on Liver Cancer Risk, Without the Hype

Frequently asked questions

Can the liver repair itself?

Yes, to a large extent. Liver cells can regenerate, and early damage from fat, alcohol or inflammation can often reverse when the cause is removed. Ongoing injury, though, leads to scarring. Mild to moderate scarring can improve over time, but cirrhosis, the most advanced stage, does not reverse. Its progression can still be halted, which is why treating the cause matters at every stage.

Is fatty liver disease serious?

For most people, simple fatty liver does not cause serious liver harm, but it is a signal of metabolic risk, including heart disease and type 2 diabetes. In a minority, it progresses to inflammation, scarring and cirrhosis. A FIB-4 score and, if needed, an elastography scan help show where you stand. Gradual weight loss and regular activity can reduce liver fat and inflammation.

Do normal liver blood tests mean my liver is healthy?

Not necessarily. Standard liver function tests can be normal even when significant scarring is present, especially in fatty liver disease and hepatitis C. If you have risk factors such as type 2 diabetes, excess weight, regular drinking or possible hepatitis exposure, ask your doctor about a fibrosis score such as FIB-4, and about hepatitis B and C testing, rather than relying on the panel alone.

How much alcohol is safe for the liver?

There is no level that is risk-free. The Dietary Guidelines for Americans 2020–2025 advise that adults who drink limit themselves to 2 drinks or fewer a day for men and 1 or fewer for women. If you already have liver disease of any kind, including fatty liver, hepatitis or cirrhosis, the safest choice is not to drink at all.

Is acetaminophen (Tylenol) safe for my liver?

At recommended doses, acetaminophen is safe for most people and is often preferred to NSAIDs in people with liver disease. The risk comes from taking more than the label allows, often by accident through combination cold or pain products. Adults should not exceed 4,000 mg in 24 hours unless directed. If you drink regularly or have liver disease, ask your doctor or pharmacist about a lower limit.

Should I get tested for hepatitis C even if I feel fine?

Yes. The CDC recommends that all adults 18 and older be tested at least once, and that pregnant people be tested in every pregnancy. Most people with hepatitis C feel well for years while the virus damages the liver. Testing is a simple blood test, and treatment with 8 to 12 weeks of pills cures the great majority of people.

Do liver detox or cleanse products work?

There is no good evidence that they do. Your liver already removes waste and toxins on its own, and no product has been shown to improve that. Some supplements sold for liver health or weight loss have instead been linked to liver injury, and the FDA does not approve supplements before they are sold. Cutting alcohol, staying active and managing weight are what actually help.

What are the early signs of liver disease?

Often there are none. Most liver disease is found on blood tests or scans before it causes symptoms. When symptoms appear, they can include tiredness, itching, discomfort in the upper right abdomen, swelling of the legs or abdomen, easy bruising, dark urine, and yellowing of the skin or eyes. Any of these deserve a visit to your doctor.

Can thin people get fatty liver disease?

Yes. Although fatty liver disease is strongly linked to excess weight, people of normal weight can develop it, especially if they carry fat around the waist, have type 2 diabetes or prediabetes, or have high triglycerides. If you have these risk factors, ask your doctor whether your liver should be assessed, even if your weight is in the healthy range.

Is there a vaccine for hepatitis?

There are safe and effective vaccines for hepatitis A and hepatitis B, but not for hepatitis C. Hepatitis B vaccination also lowers the risk of liver cancer. Vaccination is especially important if you already have liver disease, because another infection can cause serious harm. Ask your doctor whether you are protected; most insurance plans cover recommended vaccines without a copay.

When to speak to a doctor

See your doctor for persistent tiredness, itching, discomfort in the upper right abdomen, abnormal liver test results, or recurrent abdominal pain after meals. Seek same-day medical care for yellowing of the skin or eyes, dark urine with pale stools, new swelling of the abdomen, any fever if you have cirrhosis, or jaundice in a newborn in the first 24 hours of life. Call Poison Control at 1-800-222-1222 straight away if you have taken too much acetaminophen, even if you feel well. Call 911 for vomiting blood, black tarry stools, confusion or extreme drowsiness, severe abdominal pain with fever, or a seizure, including during alcohol withdrawal.

Where this comes from

• National Institute of Diabetes and Digestive and Kidney Diseases — Nonalcoholic Fatty Liver Disease & NASH
• American Liver Foundation — Nonalcoholic Fatty Liver Disease (NAFLD)
• Dietary Guidelines for Americans — Dietary Guidelines for Americans, 2020-2025
• National Institute on Alcohol Abuse and Alcoholism — Rethinking Drinking
• CDC — CDC Recommendations for Hepatitis C Screening Among Adults — United States, 2020
• CDC — Screening and Testing for Hepatitis B Virus Infection: CDC Recommendations — United States, 2023
• FDA — Don't Double Up on Acetaminophen
• National Institute of Diabetes and Digestive and Kidney Diseases — LiverTox: Clinical and Research Information on Drug-Induced Liver Injury
• National Institute of Diabetes and Digestive and Kidney Diseases — Cirrhosis
• National Cancer Institute — Liver (Hepatocellular) Cancer Prevention (PDQ)

How this page was put together

Every figure, recommendation and warning above is taken from the guidance named in Where this comes from. Nothing on this page is inferred, summarized or generalized beyond what those bodies publish: where they give a number, it is their number, and where they are silent, so are we. Pages are rebuilt whenever the underlying record changes. Sign-off by a named clinician, where it has happened, is shown at the top of the page along with the date.

Medical disclaimer

This article is general information, not medical advice. It cannot account for your own history, medication or circumstances. Always speak to your doctor, pharmacist or another qualified health professional before making changes that affect your treatment, and never delay seeking medical advice because of something you have read here. In an emergency, call 911.