What I have: creatinine · cagrilintide.
The empirical answer seems settled. The explanation does not.
If the honest answer is that nobody knows, I would rather hear that than a plausible story.
Is the standard explanation correct, and if so, what is the evidence for it?
To be exact about it, 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.
Very rapid weight loss can transiently worsen liver biochemistry, which is one of several arguments against pursuing the steepest possible trajectory.
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.
Nothing here is medical advice. An abnormal result needs somebody who can take a history and examine you.
Read the pattern before the magnitude, and the magnitude in multiples of the upper limit.
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Browse resultsThe short version: enzymes in this class usually fall as weight falls, and a rise is a reason to look for a cause rather than to assume a drug effect.
Alanine aminotransferase is relatively liver-specific; aspartate aminotransferase is also present in muscle, heart and red cells. A raised AST with a normal ALT after heavy resistance training is usually muscle, and creatine kinase settles the question.
Creatine kinase, alkaline phosphatase and bilirubin together tell you which compartment the abnormality is in, and ordering the transaminases alone throws that information away.
The caveat is direct: rising liver enzymes with jaundice, dark urine or right-upper-quadrant pain is a same-day clinical problem, not a forum question.
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.
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.
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.
Trials in this class have generally reported improvement rather than deterioration in liver biochemistry, consistent with the weight-mediated mechanism.
Transaminases plus bilirubin plus alkaline phosphatase, or you have not measured enough to conclude anything.
edited 18 Dec 2024 by rhian_prydderch — added a caveat about sampling
Before attributing anything to a compound, account for alcohol, muscle injury from new training, and any over-the-counter product being taken alongside.
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.
Population data show a substantial fraction of adults with mild transaminase elevation attributable to hepatic steatosis, which sets the base rate against which any new finding should be read.
Research-use material of unknown content is an unquantifiable variable in any such attribution.
Get a baseline before you start anything, because it converts an uninterpretable result into an interpretable one for the cost of one blood draw.
In practice, this is one of the areas where the trend across several measurements is far more informative than any single result.
Weight loss of ten per cent or more typically reduces transaminases substantially in people whose elevation was driven by hepatic fat, which is the majority of mild elevations in this population.
Laboratory-specific reference intervals for transaminases vary enough that cross-laboratory comparison of borderline values is unreliable.
Isolated mild elevation is common and usually improves with weight loss.
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