Choline and inositol are naturally occurring nutrients that have attracted interest for their potential role in managing fatty liver disease, also known as non-alcoholic fatty liver disease (NAFLD) or metabolic dysfunction-associated steatotic liver disease (MASLD). Whilst both nutrients are involved in lipid metabolism and liver function, there is currently no established therapeutic dosage for fatty liver, and they are not licensed medicines for this indication in the UK. NICE guidance does not recommend choline or inositol supplementation as part of standard NAFLD management, which focuses on evidence-based lifestyle interventions including weight loss, increased physical activity, and dietary modification. This article examines the available evidence, typical dosing ranges used in research, safety considerations, and when to seek medical advice.

What Are Choline and Inositol?

Choline and inositol are naturally occurring nutrients that play important roles in cellular metabolism and liver function. Choline is an essential nutrient, meaning the body cannot produce sufficient quantities independently and must obtain it through diet or supplementation. It is a precursor to phosphatidylcholine, a major component of cell membranes, and is crucial for the synthesis of acetylcholine, a neurotransmitter involved in memory and muscle control. Dietary sources of choline include eggs, liver, fish, poultry, and certain legumes.

Inositol, whilst not classified as a vitamin, is often grouped with B-complex vitamins due to its similar functions. It exists in several forms (isomers), with myo-inositol being the most abundant in the human body. Inositol participates in cell signalling pathways and lipid metabolism, and is found naturally in fruits, beans, grains, and nuts. Both nutrients have been investigated for their potential role in managing non-alcoholic fatty liver disease (NAFLD)—also increasingly referred to as metabolic dysfunction-associated steatotic liver disease (MASLD)—a condition characterised by excessive fat accumulation in liver cells in individuals who consume little to no alcohol.

The theoretical basis for using choline and inositol in fatty liver relates to their involvement in lipid transport and metabolism. Choline is required for the formation of very-low-density lipoproteins (VLDL), which transport triglycerides out of the liver. Deficiency in choline can impair this process, potentially contributing to hepatic fat accumulation. Inositol may support insulin sensitivity and lipid metabolism through its role in cellular signalling. However, it is important to note that whilst these mechanisms are biologically plausible, clinical evidence supporting their use specifically for fatty liver remains limited. NICE guidance (NG49) does not recommend choline or inositol supplementation as part of standard NAFLD management, which focuses on evidence-based lifestyle interventions.

Recommended Dosage for Fatty Liver

There is no officially established dosage of choline and inositol specifically for the treatment of fatty liver disease, as these supplements are not licensed medicines for this indication in the UK. Choline and inositol are generally regulated as food supplements under UK food law, unless medicinal claims are made. Consequently, dosing recommendations vary considerably between products and are not standardised.

In research settings, studies investigating choline supplementation have used doses ranging from 500 mg to 3,000 mg daily, whilst inositol studies have employed doses between 2,000 mg and 4,000 mg daily. However, these research doses should not be interpreted as clinical recommendations, as the evidence base remains insufficient to establish therapeutic efficacy for NAFLD.

Adequate Intake (AI) levels for choline have been established by the European Food Safety Authority (EFSA): 400 mg daily for adults, 480 mg daily during pregnancy, and 520 mg daily during lactation. These represent nutritional requirements rather than therapeutic doses. For individuals with confirmed or suspected fatty liver disease, dietary optimisation to meet these baseline requirements through food sources should be the primary approach.

Some sources reference a tolerable upper intake level (UL) for choline of 3,500 mg daily; this figure is derived from the US Institute of Medicine and should not be assumed to apply in the UK or EU, where EFSA has not established a UL for choline. High doses should not be taken without clinical supervision.

It is crucial to emphasise that lifestyle modification remains the cornerstone of NAFLD management according to NICE guidance (NG49). This includes achieving gradual weight loss (typically 7–10% of body weight for those who are overweight), increasing physical activity, and adopting a Mediterranean-style diet. Any consideration of choline or inositol supplementation should occur only after discussion with a healthcare professional and should complement, not replace, evidence-based lifestyle interventions. Self-prescribing high-dose supplements without medical supervision is not advisable.

Safety Considerations and Potential Side Effects

Choline and inositol are generally considered safe when consumed at nutritional doses through diet or standard supplementation. However, as with any supplement, there are important safety considerations, particularly when taken at higher doses or in specific populations.

Common side effects associated with choline supplementation, particularly at doses exceeding 3,000 mg daily, include gastrointestinal disturbances such as nausea, diarrhoea, and abdominal discomfort. A characteristic fishy body odour may develop due to the bacterial conversion of choline to trimethylamine, which is then absorbed and excreted. The US Institute of Medicine has set a tolerable upper intake level of 3,500 mg daily for choline, above which adverse effects become more likely; however, EFSA has not established a UL for choline in the UK or EU. Excessive choline intake has also been associated with hypotension, increased salivation, and sweating in some individuals. Avoid high doses without clinical supervision.

Inositol supplementation is typically well-tolerated, with mild gastrointestinal effects being the most commonly reported adverse reactions. These may include nausea, flatulence, and loose stools, particularly when initiating supplementation or at higher doses. Such effects often diminish with continued use or dose reduction.

Drug interactions warrant consideration. Inositol may influence blood glucose levels and insulin sensitivity; individuals with diabetes, particularly those taking insulin or sulfonylureas, should monitor blood glucose closely and consult their diabetes care team before starting inositol, due to the potential risk of hypoglycaemia.

Special populations require additional consideration. Pregnant and breastfeeding women should aim to meet the EFSA Adequate Intake levels (480 mg daily during pregnancy and 520 mg daily during lactation) through diet and should not exceed these amounts through supplementation without medical advice. Individuals with liver disease, kidney disease, or trimethylaminuria (a genetic condition affecting choline metabolism) should consult healthcare professionals before supplementation. Quality and purity of supplements can vary significantly between manufacturers; choose products from reputable manufacturers that comply with UK food supplement regulations.

If you experience any suspected side effects from choline or inositol supplements, you can report them via the MHRA Yellow Card Scheme at yellowcard.mhra.gov.uk.

When to Seek Medical Advice

Individuals concerned about fatty liver disease or considering choline and inositol supplementation should consult their GP or healthcare provider before commencing any supplement regimen. Self-diagnosis and self-treatment of liver conditions can be potentially harmful, as fatty liver may progress to more serious conditions including non-alcoholic steatohepatitis (NASH), fibrosis, and cirrhosis if not properly managed.

Seek prompt medical attention if you experience symptoms that may indicate liver dysfunction, including:

• Persistent fatigue or weakness

• Unexplained weight loss

• Loss of appetite

• Abdominal pain or discomfort, particularly in the upper right quadrant

• Jaundice (yellowing of the skin or eyes)

• Dark urine or pale stools

• Easy bruising or bleeding

• Swelling of the abdomen or legs

These symptoms may indicate progression of liver disease and require urgent medical assessment. For jaundice, marked abdominal swelling, confusion, or signs of bleeding, arrange same-day assessment with your GP or urgent care service. Contact NHS 111 for urgent advice if your GP is unavailable. Call 999 or attend A&E immediately if symptoms are severe or rapidly worsening.

Additionally, if you are already taking choline or inositol supplements and develop new or worsening symptoms such as severe gastrointestinal disturbance, allergic reactions, or any concerning changes in health status, discontinue the supplements and contact your GP.

For individuals with diagnosed NAFLD, regular monitoring through your GP or hepatology service is essential. In primary care, initial assessment typically includes fibrosis risk stratification using tools such as the FIB-4 score (with age-appropriate thresholds), followed by second-line testing (such as the Enhanced Liver Fibrosis [ELF] blood test or transient elastography) if indicated. Referral to hepatology is recommended if advanced fibrosis is suspected, in line with NICE and British Society of Gastroenterology guidance. Monitoring typically includes periodic blood tests to assess liver function (liver enzymes, bilirubin) and metabolic parameters (glucose, lipids), and potentially imaging studies. Any proposed changes to your management plan, including the addition of supplements, should be discussed during these reviews.

It is particularly important to seek medical advice if you have co-existing medical conditions such as diabetes, cardiovascular disease, or metabolic syndrome, as these frequently accompany fatty liver disease and require integrated management. Your healthcare team can provide personalised advice on evidence-based interventions, including dietary modification, physical activity programmes, and when appropriate, pharmacological treatments that have demonstrated efficacy in clinical trials. Remember that whilst supplements may seem harmless, they can interact with prescribed medications and may not be appropriate for everyone.

Frequently Asked Questions