Tirzepatide molecular mass and the charge states you would expect on ESI posts 31–41

Nausea profile: some people report tirzepatide as less nausea-prone than semaglutide, others report it as more. The trial reported gastrointestinal effects broadly comparable in character. Individual variation is the largest factor.

Helpful, and easy to find again, which is half of what a good reply is.

Post #31 is right about the mechanism and I think understates the practical bit.

Dual agonism versus dose: how much of tirzepatide's effect is the GIP component and how much is simply achieving higher receptor engagement? The honest answer is that the question is not settled. Some of the effect is surely the GIP component, but the trial design does not decompose it.

I have no interest in any supplier named above.

Coming back to post #30, because the follow-up matters more than the original answer.

On identity: the monoisotopic mass is close to 4813.5 Da and the electrospray series usually shows the 3+ and 4+ states most strongly at ordinary concentrations. A report that shows only a single charge state is worth a question.

I have deliberately not rounded that, because the rounding is where the argument starts.

SURPASS-2 compared tirzepatide with semaglutide 1.0 mg, the licensed diabetes dose at that time. It did not compare with semaglutide 2.4 mg, the highest approved dose. That is the central and legitimate criticism of the head-to-head evidence and it is worth remembering when people quote the trial.

The disagreement above is smaller than it looks once the terms are fixed.

Confirming post #35 from a second method, which matters more than confirming it from a second person.

Half-life difference: tirzepatide is about 5 days versus semaglutide's week-long. Practically, that means steady state is reached slightly faster and the post-dose swing is slightly larger. Most people do not report noticing the difference in practical terms.

Content versus purity applies here as everywhere: a lyophilised vial can be highly pure and contain less peptide than the label states, because the balance of the mass is water, counter-ion and excipient.

The arithmetic in post #37 is right; the assumption feeding it is the part to check.

Categorical response thresholds — the proportion reaching ten, fifteen or twenty per cent reduction — are more persuasive and less informative than the mean. They depend entirely on where the threshold was drawn.

A qualification I should have led with rather than closed on.

Answering the question post #38 raises rather than the one it answers.

Comparisons between the tirzepatide and semaglutide programmes across trials rather than within one are weak. Different populations, different durations, different baseline characteristics; the only fair comparison is a head-to-head one.

Post #39 put the caveat in the right place and I want to underline it.

Gastrointestinal effects were comparable in character to the GLP-1 monoagonists across the programme. Individual reports here vary in both directions, which is what you would expect from a between-person difference rather than a between-drug one.