Liver & protein

ALT test (alanine aminotransferase)

ALT is a liver enzyme that leaks into your blood when liver cells are under stress.

Included in every $199 draw

Key benefits of ALT testing

Can flag fatty liver, which often has no symptoms.
Shows how alcohol, weight, medications and supplements affect your liver.
Adds an early signal for insulin resistance.
Tracks whether diet, exercise or cutting alcohol is helping.
Reads best with AST, GGT and bilirubin, which Insyght includes.

What is ALT?

ALT is an enzyme found mostly inside liver cells, where it helps turn food into energy. When liver cells are irritated or damaged, ALT spills into your blood and the level rises.

Why ALT matters

Fatty liver now affects about one in three adults and is closely tied to insulin resistance, belly fat and high triglycerides. A mildly high ALT is often the first sign. Caught early, it’s usually reversible.

What your ALT results mean

Low: usually not a concern.
In range: no sign of liver cell stress.
Mildly high: most often fatty liver, alcohol or a medication or supplement. Retest and review with a physician.
Very high: can point to hepatitis or other liver injury. Needs prompt physician review.
Context matters: hard or new strength training in the past week can raise ALT and AST, since muscle also contains them.

Standard vs. optimal range

	Range
Standard lab range	Varies by lab; many flag above about 30 U/L for women and 45 to 55 U/L for men
Insyght optimal range	Set by the Insyght medical team

LowHigh

Lab reference rangeYour optimal range

A value can read normal on a standard panel and still sit outside optimal. Insyght flags it.

Do I need an ALT test?

Carry extra weight around your middle, drink most days, or take regular pain relievers or supplements? Your liver rarely complains until late. ALT checks in early.

Check your liver before it tells you

Insyght tests ALT with AST, GGT, bilirubin, albumin and the metabolic markers that drive fatty liver, reviewed by a physician. $199 a year.

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Similar biomarkers

ASTGGTAlkaline phosphataseTriglycerides Fasting insulin

Frequently asked questions

What is the difference between ALT and AST?

Both are liver enzymes. ALT is more specific to the liver, while AST is also found in muscle and the heart.

Can exercise raise ALT?

Yes. Intense or new training, especially weightlifting, can raise ALT and AST for up to a week. Avoid new or very hard workouts in the week before your draw.

How can I lower my ALT?

Losing weight if needed, cutting alcohol and added sugar and moving more are the most proven steps. Review medications and supplements with your physician.

Medically reviewed by Dr. Rishi Panchal, DO, FACC, Board-certified cardiologist, Fellow of the American College of Cardiology. Last updated October 21, 2026.