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Incretin & Amylin Analogues

Semaglutide

Semaglutide is a synthetic lipidated peptide. Supplied as a lyophilised powder in a sealed vial for laboratory research. Available in 15 mg and 20 mg presentations.

In stock
Concentration
15 mg vial£50.00

£3.33 per mg

≥99% purity (HPLC) · Independent third-party testing by PeptideVerify · View report

Order before 3pm for same-day dispatch.

Cut-off 3pm, Mon–Sat

Free next-day tracked delivery on every order · Royal Mail Tracked 24

15 mg · £50.00 · £3.33/mg

Independent third-party testing by PeptideVerify

Report PV-A459AC-BBHW · issued 19 August 2026 · HPLC-PDA and LC-MS

How to read this report
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At a glance

Research area
Incretin & Amylin Analogues · Explore the research area
Presentations
15 mg and 20 mg
Form
Lyophilised powder in a sealed vial
Purity
≥99% (HPLC)
CAS number
910463-68-2
Molecular formula
C187H291N45O59
Molecular weight
4113.58 g/mol
Dispatch
Order by 3pm Mon–Sat for same-day dispatch

About Semaglutide

Semaglutide is a synthetic lipidated peptide of thirty-one amino acid residues and, by receptor class, a GLP-1 receptor agonist peptide. Two modifications distinguish it from an unmodified chain. With the residues numbered 7 to 37 by convention, position 8 is α-aminoisobutyric acid (Aib), a non-proteinogenic residue with two methyl groups on its α-carbon. The side chain of the lysine at position 26 carries an octadecanedioic (C18) diacid, attached through a γ-glutamic acid residue and two short ethylene-glycol-based spacer units. The C-terminal residue is a glycine with a free carboxylic acid.

The catalogue lists CAS number 910463-68-2, the molecular formula C187H291N45O59 and a molecular weight of 4113.58 g/mol. Identity is confirmed by electrospray mass spectrometry, deconvoluted from multiply charged ions to a neutral mass, and reversed-phase HPLC gives the chromatographic profile. Each presentation is supplied as a lyophilised powder in a sealed vial.

Further reading

Semaglutide structure and analytical profile

In one-letter code the chain is H-His-Aib-EGTFTSDVSSYLEGQAAKEFIAWLVRGRG-OH. By convention its thirty-one residues are numbered 7 to 37, so the N-terminal histidine is His7 and the C-terminal glycine Gly37. The H- and -OH mark a free N-terminal amine and a free C-terminal carboxylic acid; they are end groups, not residues.

Two positions differ from a chain of coded residues at the same places. Aib8, α-aminoisobutyric acid, carries two methyl groups on its α-carbon and has no stereocentre. Arg34 is an arginine where lysine would otherwise sit, which leaves Lys26 as the chain's single lysine and the one site for acylation. The tryptophan at position 31 and the tyrosine at position 19 give ultraviolet absorbance near 280 nm.

The ε-amine of Lys26 is acylated by two 8-amino-3,6-dioxaoctanoic acid (OEG) spacers, a γ-glutamic acid unit and octadecanedioic acid, in that order from the lysine outward. The eighteen-carbon diacid ends in a free carboxylic acid, so the side chain adds two acid groups, from γ-glutamic acid and the diacid, to the chain's own.

The molecular formula C187H291N45O59 covers chain, spacers, linker and diacid as one molecule. In reversed-phase HPLC the diacid makes semaglutide strongly retained, and a chain without it, or with an incomplete spacer, elutes at another time and shows a different mass.

With His7, Arg34 and Arg36 as the only other basic side chains, the acylated Lys26 is the single point of attachment for the side chain, and the fragment ions around residue 26 confirm it.

The monoisotopic mass is 4111.12 Da and the average molecular weight 4113.58 g/mol. The [M+H]+ ion is calculated at m/z 4112.13; electrospray shows mainly multiply charged ions, such as [M+3H]3+ near m/z 1371.38 and [M+4H]4+ near m/z 1028.79, which are deconvoluted to one neutral mass. Reversed-phase HPLC with ultraviolet detection gives purity as the main peak's share of total peak area.

Gln23 is the residue most able to deamidate, a +0.98 Da shift, and Trp31 the most able to oxidise, a +16 Da shift; both are read against the main ion in high-resolution LC-MS.

Our semaglutide is covered by PeptideVerify report PV-A459AC-BBHW, by HPLC-PDA and LC-MS, published on this page and in the COA Library. The material is a white to off-white lyophilised solid in a sealed vial. The sealed vial is stored at 2–8 °C short term, or at −20 °C and below for long-term storage, protected from light and away from repeated freeze-thaw cycles.

Buying Semaglutide in the UK

Order Semaglutide directly from British Peptide Labs, a UK-registered company, as a sealed vial in 15 mg and 20 mg presentations, from £50. Every size is listed below with its vial price and its price per mg, so the presentations compare at a glance.

Semaglutide price (UK)
PresentationPrice£/mg
Semaglutide 15 mg£50.00£3.33
Semaglutide 20 mgBest value£59.00£2.95

Choose a presentation in the buy box, add it to your basket and check out. Orders placed before 3pm Mon–Sat are packed the same working day and handed to Royal Mail Tracked 24, and your tracking number is emailed as soon as the parcel leaves us. Larger orders are welcome: add as many vials as your laboratory needs in a single basket.

For what other UK suppliers charge, see our UK price per mg data, updated every month.

Product information

CAS number
910463-68-2
Molecular formula
C187H291N45O59
Molecular weight
4113.58 g/mol
Appearance
White to off-white lyophilised powder
Purity
≥99% (HPLC)
Net content
15 mg or 20 mg per vial
Storage (sealed vial)
Store at 2–8 °C short term, or at −20 °C and below for long-term storage. Protect from light and avoid repeated freeze-thaw cycles
PubChem CID
56843331
Research use
For laboratory research use only. Not for human or veterinary use.

Semaglutide is a synthetic lipidated peptide. Supplied as a lyophilised powder in a sealed vial for laboratory research. Available in 15 mg and 20 mg presentations. Independent report by PeptideVerify (HPLC and LC-MS), published in the COA Library. Store the sealed vial at 2–8 °C for short-term storage, or at −20 °C and below for long term. Protect from light and avoid repeated freeze-thaw cycles. For research use only. Not for human or veterinary use. Sold strictly for in-vitro laboratory research; not for diagnosis or treatment.

Testing
Independent third-party testing by PeptideVerify (HPLC-PDA and LC-MS), published on this page and in the COA Library
Presentations covered
15 mg and 20 mg
Certificate of analysis
Report PV-A459AC-BBHW — issued 19 August 2026

Packing
Each sealed vial travels in protective packing.
Dispatch
Orders placed before 3pm Mon–Sat leave the same day.
Delivery
Next-day tracked delivery with Royal Mail Tracked 24.
Tracking
Your tracking number is emailed as soon as the order is dispatched.
Delivery cost
Delivery is free on every order.
Shipping details

Questions about Semaglutide

Semaglutide is a synthetic lipidated peptide. It is supplied in a sealed vial as a white to off-white lyophilised powder, in 15 mg and 20 mg presentations.

Read the Learn article

By convention the chain keeps the position numbers of the longer parent sequence it is based on, so its thirty-one residues run from His7 to Gly37. That is why the modifications are written Aib8, Lys26 and Arg34.

H-His-Aib-EGTFTSDVSSYLEGQAAKEFIAWLVRGRG-OH. His and Aib are written out at the start, H- and -OH mark the free amine and the free carboxylic acid, and the lysine at position 26 carries the fatty diacid side chain.

4111.12 Da, against an average molecular weight of 4113.58 g/mol. The [M+H]+ ion is calculated at m/z 4112.13; in electrospray LC-MS the [M+3H]3+ ion near m/z 1371.38 and the [M+4H]4+ ion near m/z 1028.79 are the ones usually read.

On the ε-amine of Lys26, the chain's only lysine. Two OEG spacers and a γ-glutamic acid unit link it to the octadecanedioic acid, whose far end is a free carboxylic acid.

910463-68-2, with the molecular formula C187H291N45O59 and a molecular weight of 4113.58 g/mol. PubChem lists the compound as CID 56843331.

In a free carboxylic acid. The C-terminal residue is Gly37 with an -OH end group, so the chain carries no C-terminal amide, and the N-terminal histidine keeps a free amine.

PeptideVerify report PV-A459AC-BBHW, by HPLC-PDA for purity and LC-MS for identity. It is published in the Independent testing section of this page and in the COA Library.

Order Semaglutide directly from British Peptide Labs, a UK-registered company. It is supplied in sealed 15 mg and 20 mg vials, from £2.95 per mg on the 20 mg vial. The 15 mg and 20 mg vials are in stock. Every vial is ≥99% purity (HPLC), with independent third-party testing by PeptideVerify. Orders placed before 3pm Mon–Sat leave the same day by Royal Mail Tracked 24 for next-day tracked delivery.

Semaglutide comes in sealed vials: 15 mg at £50.00 (£3.33 per mg) and 20 mg at £59.00 (£2.95 per mg). Delivery is free on every order.

Semaglutide is catalogued in the Incretin & Amylin Analogues research area, where compounds are grouped by molecular class. The research area page lists each of them with its identifiers.

Incretin & Amylin Analogues research area

Semaglutide has independent third-party testing by PeptideVerify: reversed-phase HPLC measures purity, at ≥99% (HPLC), and LC-MS confirms identity against the expected mass. Report PV-A459AC-BBHW, issued 19 August 2026, is published on this page and in the COA Library.

Open the COA Library