How to choose the best lab for endotoxin testing: what 21 peptide labs report

How to choose a lab for endotoxin testing

Choose the lab whose report you can use. That means endotoxin as a number in EU per mg and EU per vial, or in EU/mL with the volume and dilution that let you convert it. The report should also name the technique, give the limit of quantitation (LOQ) and show that the spike recovery passed. A plain “pass” says only that the result was under someone’s limit. The units are explained in endotoxin testing for peptides.

Ask each lab five questions before you send a vial:

1. Which technique? Gel-clot, kinetic turbidimetric, kinetic chromogenic, or a recombinant reagent (rFC). The photometric methods read a number from a standard curve. The gel-clot limit test gives a yes or no at one level.
2. Which unit? EU per mg and EU per vial describe the product. EU/mL describes the solution in the instrument.
3. What is the LOQ? A result below it should read “less than” a stated number.
4. Is spike recovery on the report? For the photometric methods, the harmonised pharmacopoeia accepts a result only when 50% to 200% of the added endotoxin is recovered.
5. Whose limit? Research peptides have no official endotoxin limit, so someone chose any limit printed on the report.

Then ask for a sample endotoxin report, not only a purity report, and read it with our guide to reading a COA.

Endotoxin testing labs compared: what 21 labs report

The table shows what each lab’s own pages say, and what an endotoxin report we read showed, where we found one. We checked on 23–24 September 2026. “Not stated” means we found nothing published, not that the lab does not do it. The table does not say whether any number is right.

Lab	Technique named	What the lab states	What a report we read showed
Janoshik	LAL	EU per vial; “measurement up to 10 EU/vial”; separate vial preferred	0.212 EU per vial, with a photo of the test plate; no method or limit printed
Freedom Diagnostics	LAL (USP <85>)	Unit not stated	Two replicates, each “Pass”; sensitivity ≤0.05 EU/mL; no EU value
Vanguard Laboratory	Not stated	Alone or in its Gold panel	“Pass”, against a limit written per human dose
Krause Analytical	LAL (USP <85>)	An add-on to its peptide tests	No endotoxin result read
MZ Biolabs	USP <85>	For injection vials and certain raw materials	No endotoxin result read
Chromate	Kinetic chromogenic LAL	Result in endotoxin units (EU)	Less than 0.5 EU per vial, against a printed spec of less than 80 EU per vial
TrustPointe Analytics	USP <85>, Charles River LAL cartridges	Unit not stated	No endotoxin result read
ILS Laboratories	Kinetic chromogenic LAL (USP <85>)	EU per mg	Example report: kinetic turbidimetric, in EU/mL
BioRegen	Kinetic chromogenic LAL, Endosafe nexgen-PTS	EU/mL (range 0.05–5.0), spec, pass or fail, spike recovery and suitability, cartridge lot	No endotoxin result read
Bioviridian	LAL and rFC, Charles River Endosafe	Unit not stated	EU/mL, with no volume to convert it
Ethos Analytics	Gel-clot LAL (USP <85>), on reports	Unit not stated	Less than 1.25 EU/mL at a 1:10 dilution; spec less than 5 EU/mL
Accumark Labs	LAL	An add-on	“Pass”, with no value
ACS Peptide Testing Labs	Kinetic chromogenic LAL (USP <85>), Endosafe nexgen-PTS	EU/mL; sensitivity 0.005 EU/mL	No endotoxin result read
PharmLabs	Not stated	Needs 100 mg of sample	No client endotoxin result read
MDx BioAnalytical	Gel-clot and kinetic turbidimetric LAL	Unit not stated	“PASS”, with no value
Horizon Analytical	LAL	Unit not stated	A result with no method and no per-mg or per-vial basis
SideChain Analytics	Kinetic chromogenic LAL/TAL (USP <85>)	EU/mL against a limit	Lab’s demo report: 0.05 EU/mL against a 1 EU/mL limit
Ozcanium Analytics	Kinetic chromogenic LAL, Endosafe nexgen-PTS, on reports	Method not named on its site	Less than 15.0 EU per vial at 1:100; instrument, cartridge, curve and “less than” rule printed; no spike recovery
Testides Analytical	Kinetic LAL (USP <85>)	USP <85> listed	Public record: less than 0.125 EU/mL at a 1:16 dilution, from a vial reconstituted in 3.0 mL
PeptideVerify	Kinetic turbidimetric LAL	Quantitative EU/mL; sensitivity 0.005 EU/mL; listed as paused for calibration in September 2026	Demo report: control table with replicate CV and curve; spike recovery marked N/A
Uzorak	Chromogenic LAL	EU per vial in a chosen range (1–100, 10–1,000 or 100–10,000); outside it, “over” or “under limit”	No endotoxin result read

What the table shows

Four ways a result appears

• A number per vial: Janoshik, Chromate, Ozcanium and Uzorak. A buyer can compare batches in this form without more arithmetic.
• A number per mL: BioRegen, ACS, SideChain, PeptideVerify, Ethos, Bioviridian, the Testides record and the ILS example report. Comparing vials also needs the volume and the dilution.
• A number per mg: ILS states EU per mg on its site, although the example report we read gave EU/mL from a kinetic turbidimetric run. Ask any lab which unit your report will show.
• A pass with no value: the reports we read from Freedom Diagnostics, Vanguard, Accumark and MDx.

On the main certificates in our September 2026 review of public reports from 25 labs and one rating site, none showed a passed spike-recovery result. Some labs state on their sites that they run one.

What individual labs do well

• BioRegen: spike recovery on every run; assay range, suitability and cartridge lot listed among the report contents.
• Ozcanium: instrument, cartridge, dilution and curve printed, plus the rule behind its “less than” value (the cartridge’s lowest point times the dilution).
• Testides: dilution and reconstitution volume in the public record, so the result can be converted.
• Ethos: dilution and lysate sensitivity printed, so the “less than” figure can be checked.
• Freedom Diagnostics: two replicates and the assay sensitivity on the report.
• Uzorak: its three measuring ranges published before you order.
• Janoshik: a photo of the test plate on its verify page.
• PeptideVerify: its demo report states that it is not a sterility result, and gives no EU per mg without a verified peptide mass.

How to convert EU/mL into EU per vial

To turn EU/mL into EU per vial you need the volume the vial was dissolved in, and whether the result already allows for the dilution. Testides’ record shows the idea. If its “less than 0.125 EU/mL” refers to the vial’s 3.0 mL solution, the vial held less than 0.375 EU (0.125 × 3.0).

Ethos’s gel-clot result shows where a “less than” number comes from. The lysate sensitivity (0.125 EU/mL) times the dilution (10) gives 1.25 EU/mL, the lowest level that run could detect. EU per mg needs one more number: the mg of peptide per mL of the solution. If a report gives neither the volume nor the concentration, ask the lab for both.

Who sets the endotoxin limit

These limits came from different places and are not interchangeable:

• Chromate’s report printed a spec of less than 80 EU per vial.
• Ethos’s report printed a spec of less than 5 EU/mL.
• SideChain’s demo report used a limit of 1 EU/mL.
• A Vanguard report framed its limit per human dose.
• Finnrick’s members-only Accuracy Focus standard fails a sample whose lab report shows more than 40 EU per sample. It is the only Finnrick standard that grades endotoxin, and it applies only when an endotoxin result exists.

For licensed injectable medicines, the pharmacopoeia sets the limit per product from its largest dose per kg of body mass. Research peptides have no labelled dose, so no official limit exists for them. A lab result tells you how much endotoxin was in the vial tested. It cannot tell you whether that level is safe for any use.

Accreditation and endotoxin

ISO/IEC 17025 accreditation covers the tests listed on a lab’s scope, not the whole lab. Vanguard Laboratory’s A2LA scope, as published, does not list endotoxin testing of peptides. PharmLabs’ PJLA scope lists HPLC potency and purity for ten named peptides; endotoxin and sterility are not on it. Both scopes are public, so a buyer can check. If a lab shows an accreditation mark, ask for its scope and check that endotoxin is on it. We do not hold ISO/IEC 17025 accreditation. More in ISO/IEC 17025 and peptide testing.

Sample needs, cost and sterility

Endotoxin usually needs its own material. Janoshik prefers a separate vial, PharmLabs asks for 100 mg, and ACS lists 5–10 mg on top of its other tests. BioRegen also tests bacteriostatic water and reconstitution solutions. Plan your vials with how many vials to send. Published prices are in endotoxin and sterility test cost.

Endotoxin cannot show whether live microbes are present. For that, see which labs run a 14-day sterility test.

What HK Analytical reports

Our endotoxin test uses LAL and reports EU per mg and EU per vial, with the limit of quantitation, replicates and spike recovery. Below the LOQ we print “less than” the LOQ as a number. Every number comes with its raw data, and the report is a signed record you can check on hkanalytical.com/verify. Each report carries our own photo of the vial as received and states how the client is related to HK Analytical. Results within days of receipt. Sterility (USP <71>, 14 days) is the one test that takes 14 days, because the method incubates for 14 days. The example report shows the format, and you can request a quote.