Is there any published stability data for semaglutide at 4 °C?

Question

Concretely: semaglutide · 4 °C. I want to know whether there is evidence behind this or only repetition. I have checked the obvious registries and monographs without success. Has anyone verified this independently?

Dr_Colm_Fitzhenry · Accepted Answer

Probably not at 4 °C specifically, because that is not where stability programmes take their readings. Accelerated work is conventionally run at 25 °C and 40 °C, with the refrigerated condition as the control, so 4 °C sits between or beyond the published points and what you will find is bracketing rather than a measurement. 4 °C is the condition the rule of thumb is anchored to, so it is the baseline rather than a multiplier: everything else in this thread is quoted relative to it. Whatever you find, check what was measured before you use it: a paper reporting purity at 4 °C has not measured content, and the two fail at different rates for different reasons. The honest answer is that most reported "degradation" is adsorption and dilution error rather than chemistry. Oxidation targets methionine, cysteine and tryptophan, adding sixteen daltons per oxygen. It is catalysed by trace metals and promoted by dissolved oxygen and by light. Reported and extrapolated stability by condition State Condition Usable window Basis Lyophilised solid −20 °C, sealed, dry 24–36 months Supplier guidance Lyophilised solid 2–8 °C, sealed 12–24 months Supplier guidance Lyophilised solid 25 °C, sealed 4–8 weeks Extrapolated (Arrhenius) Lyophilised solid 40 °C, sealed 1–2 weeks Extrapolated Solution, preserved 2–8 °C 28 days USP microbiological convention Solution, preserved 25 °C 3–7 days Extrapolated Solution, unpreserved 2–8 °C 24 hours USP microbiological convention Windows for the solid state are chemical; windows for solution are microbiological and usually shorter than the chemical limit. Mechanically, adsorption onto glass and plastic is significant at low concentrations — micrograms per millilitre — and negligible at milligrams per millilitre. It is the usual explanation for an apparent loss in a dilute preparation. Metal-catalysed oxidation of methionine is documented across peptide and protein formulations and is why chelators appear in some formulations. Nothing here is medical advice, and research-use compounds are not approved for human use. A mass spectrum names the pathway. Plus one, plus sixteen, minus eighteen.

meniscus_film · Answer

The relevant point is that a mass shift of plus one dalton is deamidation and plus sixteen is oxidation, so degradation is often visible in a mass spectrum if anyone looks.

Aggregation is physical: peptides unfold at air-liquid interfaces and associate. Shaking maximises that interface, which is why swirling and shaking produce visibly different outcomes on the same vial.

Freeze-thaw cycling drives aggregation through concentration at the ice interface and pH shifts as buffer components crystallise out at different rates. Each cycle costs something.

Sequence determines which pathways apply, so general statements are general.

Sequence decides which pathways are even available. Check the residues.

edited 19 Jan 2026 by meniscus_film — added a caveat about sampling

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answeredmeniscus_film32k2726 Dec 2025

Dr_Ilse_Vandenberg · Answer

Answer first: the degradation pathways worth knowing are hydrolysis, deamidation, oxidation, aggregation and adsorption, and each has a different trigger and a different mitigation.

Hydrolysis cleaves the backbone, most readily at aspartate-proline and aspartate-glycine sequences, and is acid-catalysed. In a dry solid it barely proceeds at all.

A mass spectrum resolves most of this: minus eighteen is dehydration or succinimide, plus one is deamidation, plus sixteen is oxidation, and an unchanged mass with a shifted retention time is an isomer.

Deamidation via the succinimide intermediate is well characterised, with sequence-dependent rates highest for asparagine-glycine motifs.

Swirl, never shake. Aggregation is a handling problem more than a time problem.

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answeredDr_Ilse_Vandenberg113k2484 Dec 2025

5Aliquoting before the first freeze is the advice I wish I had read two years ago. – Dr_Fatima_Belkacem 9 months ago

4I would add a sentence about light, since tryptophan-containing sequences care. – plunger_stop 7 months ago

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deamidation_watch · Answer

This is answerable from the chemistry rather than from anecdote, which is unusual and welcome.

Light exposure matters for tryptophan-containing sequences and for anything with a chromophore. Amber vials and a closed box are free mitigations.

Apparent loss in a dilute preparation is usually adsorption rather than degradation and is worth ruling out first.

At dilute concentrations, suspect adsorption before you suspect chemistry.

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answereddeamidation_watch45k5815 Dec 2025

halvard_ness · Answer

Asparagine and glutamine are the deamidation risk, and methionine is the oxidation risk. Deamidation converts asparagine or glutamine to the corresponding acid via a succinimide intermediate, adding one dalton. It is base-catalysed, accelerates above neutral pH and is the dominant aqueous pathway for many peptides. Cold, dry, dark, still. Those four words cover most of the mitigation.

Is there any published stability data for semaglutide at 4 °C?

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Reported and extrapolated stability by condition

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State	Condition	Usable window	Basis
Lyophilised solid	−20 °C, sealed, dry	24–36 months	Supplier guidance
Lyophilised solid	2–8 °C, sealed	12–24 months	Supplier guidance
Lyophilised solid	25 °C, sealed	4–8 weeks	Extrapolated (Arrhenius)
Lyophilised solid	40 °C, sealed	1–2 weeks	Extrapolated
Solution, preserved	2–8 °C	28 days	USP microbiological convention
Solution, preserved	25 °C	3–7 days	Extrapolated
Solution, unpreserved	2–8 °C	24 hours	USP microbiological convention