Published August 20, 2026 Liver Health

Fatty Liver Disease Symptoms: What to Look For, and What to Test Instead

Most people with fatty liver disease have no symptoms at all. Here is what the condition actually feels like, why normal liver enzymes do not rule it out, and the specific blood tests that catch it early.

Medically reviewed by Rhonda Collins, FNP-C | Mito Health on August 20, 2026.

Here is the honest answer to the question you searched: fatty liver disease usually has no symptoms. Not vague symptoms, not subtle ones. None. The liver has no pain receptors in its tissue, and it keeps performing its several hundred jobs while fat accumulates inside its cells. Most people who have it find out from a blood test, an incidental ultrasound, or not at all.

That matters more than it sounds, because the condition is common. Steatotic liver disease affects roughly one in four adults worldwide, and around 24% of adults in the United States [1][2]. It is also one of the more reversible things on that list, particularly in its early stages. The problem is almost entirely a detection problem: by the time it produces symptoms you can feel, it has often progressed to a stage where reversal is harder.

So the useful version of this article is not a symptom checklist. It is what to measure.

The naming changed, and it tells you what the disease actually is

If you have read about this before, you probably saw the term NAFLD, for non-alcoholic fatty liver disease. In 2023, a multi-society international consensus retired that name [3]. The current terms:

• SLD (steatotic liver disease) is the umbrella for any excess fat in the liver.
• MASLD (metabolic dysfunction-associated steatotic liver disease) replaces NAFLD.
• MASH (metabolic dysfunction-associated steatohepatitis) replaces NASH, the inflammatory form where liver cells are actively being damaged.
• MetALD is a new category for people who have metabolic dysfunction and drink moderately, which was previously a diagnostic no-man’s-land.

The rename was not cosmetic. The old name defined the disease by what it was not, which is alcohol. The new one defines it by what it is, which is a metabolic condition. A MASLD diagnosis now requires liver fat plus at least one cardiometabolic criterion: elevated waist circumference or BMI, elevated fasting glucose or existing type 2 diabetes, elevated blood pressure, elevated triglycerides, or low HDL cholesterol [3].

Read that list again. Every one of those is a blood test or a tape measure. This is a metabolic disease that happens to show up in the liver, which is exactly why the same lab panel that tracks your metabolic health is the one that catches it.

The symptoms people do report

When symptoms exist, they are non-specific enough to be attributed to almost anything:

• Fatigue. The most commonly reported symptom, and the least useful diagnostically. It overlaps with iron deficiency, thyroid dysfunction, poor sleep, and dozens of other causes. If you are chasing this one, our guide on why you might always be tired works through the differential.
• A dull ache or fullness in the upper right abdomen. Caused by stretching of the capsule around an enlarged liver, not by the fat itself.
• Unexplained malaise or brain fog. Reported often, poorly characterised in the literature.

Signs that suggest the disease has already advanced to cirrhosis are different and more specific: yellowing of the eyes or skin, swelling in the legs or abdomen, easy bruising, dark urine, and confusion. These are reasons to see a doctor promptly, not reasons to order a test and wait.

The asymmetry here is the whole point. The early stage, which is the treatable one, is silent. The stage with clear symptoms is the one you did not want to reach.

Why a normal ALT does not rule it out

This is the single most useful thing to know, and it is where most general health content stops short.

ALT (alanine aminotransferase) is the liver enzyme most people have on a routine panel, and a normal result feels reassuring. It should not be, entirely. A meaningful proportion of people with biopsy-confirmed fatty liver disease, including some with advanced fibrosis, have ALT values inside the standard reference range [4]. The reference range itself is part of the problem: it was derived from populations that included people with undiagnosed liver disease, so the upper bound is arguably too generous.

Two practical consequences:

1. A single in-range ALT is weak evidence of a healthy liver. Direction and trend over time carry more information than one value against a wide range.
2. ALT should be read alongside AST, GGT, and your platelet count rather than alone. Our breakdown of ALT, AST, ALP and GGT covers what each one adds, and ALT versus AST covers why the ratio between them matters.

What to test, in order

You do not need a comprehensive panel to start. The first tier is two ordinary tests, and together they give you something better than either alone.

Start here: the two tests that produce a fibrosis score

1. A hepatic function panel. This is the direct read on the liver: ALT, AST, alkaline phosphatase, bilirubin, and albumin. It tells you whether liver cells are being damaged and whether the liver’s synthetic function is intact.

2. A complete blood count with platelets. This looks unrelated, and it is the reason the pairing is worth understanding. Platelet count falls as liver scarring progresses, because a fibrotic liver produces less thrombopoietin and an enlarged spleen sequesters more platelets. A falling platelet count is one of the earlier quiet signals of fibrosis.

Order those two and you have all four inputs to the FIB-4 index: your age, AST, ALT, and platelet count. FIB-4 is the non-invasive score that major guidelines recommend as the first step for assessing whether someone with suspected fatty liver has advanced fibrosis [5][6]. It is the difference between knowing you have some liver fat and knowing whether it has started to scar. Mito calculates and reports it automatically when those inputs are present, and our FIB-4 reference page explains the score in isolation.

Then: the metabolic context

Because MASLD is defined by metabolic dysfunction, the liver markers only make sense next to the metabolic ones. The high-value additions are triglycerides, HDL cholesterol, HbA1c, and fasting insulin. Insulin resistance is arguably the engine of the whole process, and it shows up in insulin before it shows up in glucose. Our article on insulin resistance covers that lag in detail.

If you want the whole picture at once

The individual tests above answer the specific question. What they cannot easily do is show you how the liver markers, the lipids, the glucose markers, and inflammation move together over time, which is where the actual pattern lives. Liver fat rarely appears in isolation. It travels with rising triglycerides, rising fasting insulin, a falling HDL, and often a creeping hs-CRP.

That is what Mito Core is for. It includes the liver enzymes, the platelet count, FIB-4, the full lipid panel, HbA1c, insulin, and inflammatory markers in one draw, with clinician review and tracking across retests. If you are testing once to answer a specific worry, start with the hepatic function panel. If you want to see the metabolic pattern the liver is reporting on, and watch it change, the panel is the better instrument.

Reading a FIB-4 result

The thresholds used in current MASLD guideline pathways [6][10]. Note these are not the score’s original cutoffs: FIB-4 was developed in HIV/HCV coinfection with cutoffs of 1.45 and 3.25 [5], and the values below were derived and validated specifically for fatty liver disease:

Two limitations worth holding onto. First, FIB-4 is a risk-stratification tool, not a diagnosis. It sorts people into “probably fine” and “needs a closer look,” and the middle band is genuinely uninformative.

Second, the score is age-sensitive at both ends. In people over roughly 65, a threshold of 1.3 produces a high rate of false positives, and a cutoff around 2.0 has been proposed for that group [7]. Under about 35 it is also less reliable, and guidance suggests going straight to an alternative assessment such as elastography rather than leaning on the score [6][10]. If your result sits near a boundary, that context matters, and it is worth discussing your specific number with your doctor rather than acting on the band alone.

What actually reverses it

Early fatty liver is genuinely reversible, and the evidence base points at weight loss more strongly than at anything else.

The most-cited prospective data comes from a 52-week study of 293 people with biopsy-confirmed MASH, with paired biopsies before and after [8]. It found a clear dose-response: the more weight participants lost, the greater the improvement in MASH features, with the strongest results in those reaching 10% or more. The limitation matters as much as the finding. Fewer than half the participants hit even the 7 to 10% range, so the result describes what happens if you get there, not how likely you are to.

Beyond weight:

• Alcohol. Under the new framework, alcohol is no longer an exclusion criterion but an additive one. If you have metabolic risk factors, alcohol compounds them rather than sitting in a separate category. Our piece on alcohol and recovery covers the mechanism.
• Exercise, independent of weight loss. Both aerobic and resistance training reduce liver fat even when body weight does not change much.
• Diet composition. Reducing added sugar, and fructose in particular, has a specific effect here, because the liver metabolises fructose directly into fat. Our guide to foods that damage your liver and to lowering liver enzymes naturally go into practical detail.
• Visceral fat specifically. Waist circumference tracks liver fat better than BMI does. See visceral fat.

Two drugs now carry an FDA approval for this condition, both for noncirrhotic MASH with moderate to advanced fibrosis, and both under accelerated approval alongside diet and exercise. Resmetirom (Rezdiffra), a thyroid hormone receptor-beta agonist, was approved in March 2024 [9]. Semaglutide (Wegovy) followed in August 2025 on the strength of the ESSENCE trial, which randomised 1,197 adults with biopsy-confirmed MASH and reported MASH resolution in about 63% on treatment against 34% on placebo at 72 weeks [11]. Accelerated approval means confirmatory evidence of long-term benefit is still outstanding for both.

These are prescribing decisions for your doctor, and neither replaces the metabolic work above. Our GLP-1 monitoring guide covers what to track if you are already on one.

The risk most people miss

If you take one thing from this beyond the testing: the most likely thing to harm someone with fatty liver disease is not their liver. It is their heart. Cardiovascular disease, not liver failure, is the leading cause of death in this population [1][6].

This reframes what a fatty liver finding means. It is not only a liver problem to monitor. It is a signal that the metabolic and cardiovascular system around it deserves attention, which means ApoB, Lp(a), and blood pressure belong in the same conversation as ALT. A liver panel that comes back mildly abnormal and gets filed away as “watch that” misses the larger point.

Where to start

If you have metabolic risk factors and have never had your liver markers checked, or you have had a borderline ALT that nobody followed up, order a hepatic function panel and a CBC with platelets. That pair costs little, needs no referral, and produces a FIB-4 score that tells you whether this is something to act on now or track over time.

If your metabolic picture is the actual question, and the liver is one part of it, test it as a system with Mito Core instead of assembling it one marker at a time.

References

1. Younossi ZM, et al. Global epidemiology of nonalcoholic fatty liver disease: meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology. 2016;64(1):73-84.
2. National Institute of Diabetes and Digestive and Kidney Diseases. Definition and Facts of NAFLD and NASH.
3. Rinella ME, et al. A multisociety Delphi consensus statement on new fatty liver disease nomenclature. Hepatology. 2023;78(6):1966-1986. Co-published in Journal of Hepatology. 2023;79(6):1542-1556.
4. Mofrad P, et al. Clinical and histologic spectrum of nonalcoholic fatty liver disease associated with normal ALT values. Hepatology. 2003;37(6):1286-1292. PMID 12774006.
5. Sterling RK, et al. Development of a simple noninvasive index to predict significant fibrosis in patients with HIV/HCV coinfection. Hepatology. 2006;43(6):1317-1325. PMID 16729309. The paper that introduced FIB-4, using cutoffs of 1.45 and 3.25 in that population.
6. Rinella ME, et al. AASLD Practice Guidance on the clinical assessment and management of metabolic dysfunction-associated steatotic liver disease. Hepatology. 2023.
7. McPherson S, et al. Age as a confounding factor for the accurate non-invasive diagnosis of advanced NAFLD fibrosis. American Journal of Gastroenterology. 2017;112(5):740-751.
8. Vilar-Gomez E, et al. Weight loss through lifestyle modification significantly reduces features of nonalcoholic steatohepatitis. Gastroenterology. 2015;149(2):367-378.e5. PMID 25865049.
9. U.S. Food and Drug Administration. Accelerated approval of resmetirom (Rezdiffra) for noncirrhotic NASH with moderate to advanced liver fibrosis, March 14, 2024.
10. Kanwal F, et al. AGA Clinical Practice Update on the role of noninvasive biomarkers in the evaluation and management of nonalcoholic fatty liver disease. Gastroenterology. 2023.
11. U.S. Food and Drug Administration. Accelerated approval of semaglutide (Wegovy) for noncirrhotic MASH with moderate to advanced liver fibrosis, August 2025. Pivotal trial: Sanyal AJ, et al. ESSENCE. New England Journal of Medicine. 2025.