PrymaLab
PrymaLab Analytical · In-house laboratory
3705 Music Branch Rd, Ashland, KY 41102 · +1 (606) 465-9063 · prymalab.net
Certificate no.
PL-26-00081
Verification key
X4RKKR9H
Scan or enter both at
prymalab.net/testing/verify
Certificate of Analysis · Lot release
Retatrutide 5 mg
Lot PL-2609-081 · Lyophilized powder · Label claim 5 mg/vial
Tested in-house by PrymaLabIn-house analytical result,
not an independent third-party test
Lot / batch number
PL-2609-081
Date of analysis
2026-09-19
Retest / expiry
2028-09-18
Units in lot / sampled
500 / 3
Storage
−20 °C, desiccated, dark
Certificate type
Lot COA, 2 pages
Compound
Retatrutide
LY3437943; GIP/GLP-1/glucagon receptor triple agonist
Molecular formula
C221H342N46O68
Theoretical mass (avg.)
4731.4 Da
Sequence
H-Y-Aib-QGTFTSDYSI-[αMeLeu]-LDKK(AEEA-γGlu-C20 diacid)AQ-Aib-AFIEYLLEGGPSSGAPPPS-NH₂ (39 residues; Aib2, α-methyl-Leu13, Aib20; Lys17 acylated with eicosanedioic acid via γ-Glu and AEEA; C-terminal amide)
Purity · RP-HPLC, area %
99.33%
Specification 99.0% • main peak at 8.57 min
Identity · Observed Mass
4731.5 Da
Theoretical 4731.4 Da • +0.1 Da (21 ppm)
Overall conclusion
PASS
Meets every specification for the tests performed
| Test | Method | Specification | Result | Conclusion |
|---|
| Appearance | Visual inspection | White to off-white lyophilized powder | White lyophilized powder | PASS |
| Identity (mass) | LC-MS, ESI positive | Theoretical ± 1.0 Da | 4731.5 Da | PASS |
| Purity | RP-HPLC, UV 214 nm, area% | 99.0% | 99.33% | PASS |
| Largest impurity | RP-HPLC, area% | 1.0% | 0.21% at 7.39 min (Gln 3 /Gln 19 deamidation) | PASS |
| Water content | Karl Fischer | 5.0% | 1.4% | PASS |
| Bacterial endotoxin | LAL, kinetic | ≤ 5.0 EU/mg | 0.05 EU/mg | PASS |
| Sterility / bioburden | USP <71>, membrane filtration | No growth after 14 days | No growth; conforms | PASS |
1HPLC chromatogram
Data file: RET_PL-2609-081_20260919_01 · Column C18, 150 × 4.6 mm · UV 214 nm
Baseline uncropped; main peak and impurities labeled with retention times. Peak table on page 2.
2HPLC method · RET_PL-2609-081_20260919_01
Instrument
Waters Alliance e2695, SN E2695B742
Data System
Empower 3, Build 3471
Detection Wavelength
214 nm
Column
C18, 150 × 4.6 mm, 3.5 µm
Column Part / Serial
186003326 / USHX19800
Mobile Phase A
0.1% TFA in water
Mobile Phase B
0.1% TFA in MeCN
Sample Diluent
0.1% TFA in 30% MeCN
Sample Concentration
0.5 mg/mL
Reference Standard
In-house Retatrutide reference, lot PL-RS-RET-01, RT 8.54 min
3Gradient program
| Time (min) | % A | % B |
|---|
| 0.0 | 65 | 35 |
| 2.0 | 65 | 35 |
| 9.0 | 25 | 75 |
| 10.0 | 15 | 85 |
| 11.0 | 15 | 85 |
| 12.0 | 65 | 35 |
4Peak table
| Peak | RT (min) | Area | Area % |
|---|
| 1 | 5.96 | 6,151 | 0.13 |
| 2 (deamid.) | 7.39 | 9,936 | 0.21 |
| 3 | 8.11 | 6,624 | 0.14 |
| 4 | 8.57 | 4,699,836 | 99.33 |
| 5 | 8.93 | 8,990 | 0.19 |
| Total | | 4,731,537 | 100.00 |
Threshold 0.05% area · Blank subtracted: Y · Purity = main peak area ÷ total integrated area × 100, to two decimals; main peak shaded.
5Identity by mass spectrometry
Instrument
Waters Acquity SQD
Ionization / Mode
ESI, positive
Observed m/z (charge)
947.3 (5+ [M+5H]) · 789.6 (6+ [M+6H])
Deconvoluted Mass
4731.5 Da
Theoretical Mass
4731.4 Da
Difference
+0.1 Da (21 ppm)
Data File
RET_PL-2609-081_MS_20260919_01
Acceptance
Within ± 1.0 Da
6Additional tests
| Test | Performed by | Date | Report / file |
|---|
| Water content | PrymaLab | 2026-09-19 | RPT-KF-PL-2609-081 |
| Endotoxin | PrymaLab | 2026-09-19 | RPT-ET-PL-2609-081 |
| Sterility | PrymaLab | 2026-09-19 | RPT-ST-PL-2609-081 |
A test with no row here was not performed on this lot. Outside-laboratory reports, when used, are attached and named below.
7Review and approval
D. Reynolds
Analyst · performed the testing
Date: 2026-09-19
S. Calloway
Reviewer · checked against raw data
Date: 2026-10-02
M. Phelps
Lab Director · approved for release
Date: 2026-10-03