Liver steatosis (fatty infiltration) is the accumulation of fat in hepatocytes, when it occupies more than 5% of liver cells. It is the earliest and, as a rule, reversible stage of NAFLD and alcoholic liver disease; steatosis itself is usually asymptomatic and is found on ultrasound or blood tests.
As long as it is "pure" steatosis without inflammation, the outlook is favorable. The danger is that in some people it progresses to steatohepatitis with inflammation and fibrosis.
Why it appears
Most often steatosis is metabolic: it is linked to excess weight, insulin resistance, type 2 diabetes and lipid disorders — that is, to metabolic syndrome. In 2023 this form was renamed MASLD (metabolic dysfunction-associated steatotic liver disease).
The second major cause is alcohol. Less often steatosis is caused by certain medications, rapid weight loss, fasting and inherited metabolic disorders.
Why it is dangerous and its link to aging
Steatosis is not just "fat in the liver". It is closely linked to cardiovascular risk, diabetes and an overall acceleration of metabolic aging. The main cause of death in people with a fatty liver is not the liver but cardiovascular events.
In roughly one in four or five people steatosis progresses over time to inflammation and scarring, so it is important to assess not only the presence of fat but also the risk of fibrosis.
What to do
There is no approved drug for simple steatosis specifically — the basis of treatment is lifestyle. Losing 7–10% of body weight can significantly reduce or clear fat from the liver.
A Mediterranean-style diet, regular physical activity, control of blood sugar and lipids, and limiting alcohol and sugary drinks all work. It is useful to assess the risk of fibrosis with calculated indices.
Reference ranges
The degree of steatosis is graded by the share of fat-laden hepatocytes (biopsy) or by the CAP parameter on elastography.
| S0 — no steatosis | < 5% of hepatocytes; CAP < 248 dB/m |
| S1 — mild | 5–33%; CAP ≈ 248–267 dB/m |
| S2 — moderate | 34–66%; CAP ≈ 268–279 dB/m |
| S3 — marked | > 66%; CAP ≥ 280 dB/m |
Calculate using this marker
Calculators where Steatosis is used directly:
Frequently asked questions
Is liver steatosis dangerous?
"Pure" steatosis without inflammation carries a low risk by itself, but it is an important marker of metabolic problems and a signal of increased cardiovascular risk. The danger appears if it progresses to steatohepatitis and fibrosis.
Can steatosis be reversed?
Yes, at this stage fat in the liver is reversible. Losing 7–10% of body weight, a Mediterranean-style diet, physical activity and giving up alcohol often clear the steatosis.
Related terms
Sources
- StatPearls (NCBI) — Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)
- AASLD — New MASLD Nomenclature
- MedlinePlus — Fatty Liver Disease