Does magnesium tell me anything about hepatic fat on liraglutide?

Stated plainly: magnesium · liraglutide.

This is one of those things that everyone repeats and nobody derives.

This matters practically, not just academically, because it changes what I would do next.

Why does this happen, and what would falsify the usual explanation?

Start with the pattern. A hepatocellular pattern with alanine aminotransferase above aspartate aminotransferase points one way; a cholestatic pattern with alkaline phosphatase and gamma-glutamyl transferase points another.

Reference upper limits around forty units per litre for ALT are conventional rather than physiological; several groups have argued for limits closer to thirty for men and twenty-five for women.

Gamma-glutamyl transferase is sensitive and unspecific: it rises with alcohol, with several medications and with fatty liver, and an isolated elevation rarely changes anything on its own.

Laboratory-specific reference intervals for transaminases vary enough that cross-laboratory comparison of borderline values is unreliable.

New training, alcohol and over-the-counter products first. Then the interesting hypotheses.

Answering this needs the magnitude in multiples of the upper reference limit, because the thresholds that matter clinically are defined that way and not in absolute units.

Hy's law describes the combination that matters: transaminases above three times the upper limit together with bilirubin above twice the upper limit and no cholestatic explanation. That combination is a signal; isolated mild transaminase elevation is not.

More usefully, an isolated result three weeks after starting anything is difficult to interpret. A baseline taken before starting makes the same result trivially interpretable, which is the argument for baselines.

Hy's law and its variants are the standard framework for identifying drug-induced liver injury in trials and are why bilirubin is measured alongside transaminases rather than instead.

Nothing here is medical advice. An abnormal result needs somebody who can take a history and examine you.

Get a baseline before you start anything, because it converts an uninterpretable result into an interpretable one for the cost of one blood draw.

edited 7 Apr 2025 by Dr_Bram_Verhoeven — reworded for clarity after a comment

Reference intervals for alanine aminotransferase differ between laboratories and have been revised downward over time, so the same value can be normal on one report and elevated on another.

Creatine kinase, alkaline phosphatase and bilirubin together tell you which compartment the abnormality is in, and ordering the transaminases alone throws that information away.

Put another way, very rapid weight loss can transiently worsen liver biochemistry, which is one of several arguments against pursuing the steepest possible trajectory.

Research-use material of unknown content is an unquantifiable variable in any such attribution.

Transaminases plus bilirubin plus alkaline phosphatase, or you have not measured enough to conclude anything.