Tirzepatide storage and stability: what is published versus what is assumed — does this still hold?

Research-use-only tirzepatide is not approved for human use and is not made to pharmaceutical standards. Anyone discussing it here is describing what they did, not recommending it.

I would rather be precise about what I do not know than vague about what I do.

Post #3 is right about the mechanism and I think understates the practical bit.

Heart rate rises modestly across this class, tirzepatide included. It is consistent, small, and worth knowing about rather than worth alarm — and it is one of the reasons the trials monitored it explicitly.

One of those cases where knowing the mechanism does not help the decision.

The five maintenance doses in the tirzepatide programme give a genuine dose-response curve, which is unusual. Most trials in this space compare one or two doses against placebo and cannot say anything about the shape of the relationship.

I would treat that as a working assumption and revisit it.

Where I part company with post #10, and it is a narrow parting.

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.

Nothing above should be read as advice about what anyone else should do.

I had written a reply contradicting post #14 and deleted it. Here is what survived.

Mass and charge states: tirzepatide is about 4813.5 Da and on an electrospray instrument you would expect to see charge states mostly in the 2+ to 4+ range, the same as semaglutide. A doubly charged species would appear at about (4813.5 + 2 × 1.008) / 2 ≈ 2408.

I am confident about the direction and much less about the magnitude.