Penguin Peptides reviews
Penguin Peptides review: our rating is F (9/100), from 9 independently tested vials across 2 peptides; 7 of 9 were the labelled peptide and 5 met our pass mark. Newest test: Aug 6, 2026. Peptide Vendor Reviews publishes each of these 9 results with its certificate.
Grades describe the samples tested; some links earn us a commission, but never change a vendor's grade. How we grade
Is Penguin Peptides legit? Evidence assessment
Evidence assessment
Grade F
Our rating · 9/100
In the reviewed independent records, 2 of 9 vials were the wrong peptide, and 6 of 7 were within 10% of the labelled dose. Fewer than 10 independently tested vials contribute to this assessment. These results describe the tested samples, not all products or future batches.
See alternatives- Capped at F: test results graded F.
Test results
What was actually in the vials?
Failing · 31/100
Results often failed: wrong peptide, low purity or far-off doses.
- 2 of 9 vials were not the peptide on the label.
- 6 of 7 held within 10% of the labelled dose.
- Purity 98.9–99.95% (good).
- 4 of 9 failed our basic check: identity not confirmed (2), dose more than 35% off the label (1), purity under 99.5% (1).
Strength of evidence
How much can you rely on these results?
Moderate · 68/100
The evidence meets our C-band thresholds for sample count, recency and sourcing.
- 9 vials tested by independent labs. We like to see 10 or more.
- All 9 were sent in anonymously by buyers. We can't confirm who bought each anonymous vial.
- 2 of 9 can be traced to a batch.
- 3 of 9 were checked for contamination.
Shop reputation
Is the shop itself trustworthy?
Not reviewed yet
We haven't researched this shop's business record or customer complaints yet.
- Not part of this grade until we've checked it.
Products
Penguin Peptides lab test results by peptide
- C
$2.47/mg
Estimated price · as of May 7, 2026
- Vials tested
- 6
- Right peptide
- All
- Purity
- 98.9–99.95%
- Labelled quantity
- 5 of 6 within 10%
Higher-rated vendor
AGuangzhou Jeep Biotechnology JEEP
16 Tirzepatide vials tested · last Aug 4, 2026
$0.42/mg · 83% cheaper than Penguin Peptides
Estimated price · as of Aug 22, 2026
Retatrutide
Weak assessmentListed on the shop's site · last tested Jul 20, 2026
$4.79/mg · cheapest: 100 mg vial
F$4.79/mg
cheapest: 100 mg vial
- Vials tested
- 3
- Right peptide
- 2 wrong
- Purity
- 99.6%
- Labelled quantity
- 1 of 1 within 10%
Higher-rated vendor
APeptide Partners
32 Retatrutide vials tested · last Oct 14, 2026
$4.79/mg · about the same price as Penguin Peptides
Estimated price · as of Sep 6, 2026
- N/A
$1.74/mg
cheapest: 50 mg vial
No lab has tested this shop's 5-Amino-1MQ, so we can't say what's in the vial.
Graded vendor
BRetalux
3 5-Amino-1MQ vials tested · last Jun 16, 2026
$0.39/mg · 77% cheaper than Penguin Peptides
Estimated price · as of May 30, 2026
- N/A
$7.40/mg
cheapest: 10 mg vial
No lab has tested this shop's Adamax, so we can't say what's in the vial.
Compare all Adamax vendorsNo other Adamax vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$0.74/mg
cheapest: 100 mg vial
No lab has tested this shop's AHK-Cu, so we can't say what's in the vial.
Compare all AHK-Cu vendorsNo other AHK-Cu vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$8.40/mg
cheapest: 5 mg vial
No lab has tested this shop's AOD-9604, so we can't say what's in the vial.
Compare all AOD-9604 vendorsNo other AOD-9604 vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$6.20/mg
cheapest: 10 mg vial
No lab has tested this shop's ARA-290, so we can't say what's in the vial.
Compare all ARA-290 vendorsNo other ARA-290 vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$6.20/mg
cheapest: 10 mg vial
No lab has tested this shop's BPC-157, so we can't say what's in the vial.
Graded vendor
BHK Peptides
22 BPC-157 vials tested · last Sep 9, 2026
$0.82/mg · 87% cheaper than Penguin Peptides
Estimated price · as of Aug 14, 2026
- N/A
$11.00/mg
cheapest: 5 mg vial
No lab has tested this shop's CJC-1295, so we can't say what's in the vial.
Graded vendor
BQing Li Peptide
19 CJC-1295 vials tested · last Aug 12, 2026
$1.40/mg · 87% cheaper than Penguin Peptides
Estimated price · as of Jul 21, 2026
- N/A
$8.00/mg
cheapest: 5 mg vial
No lab has tested this shop's DSIP, so we can't say what's in the vial.
- N/A
$5.20/mg
cheapest: 10 mg vial
No lab has tested this shop's Epithalon, so we can't say what's in the vial.
Compare all Epithalon vendorsNo other Epithalon vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$0.74/mg
cheapest: 100 mg vial
No lab has tested this shop's GHK-Cu, so we can't say what's in the vial.
Graded vendor
AReta-Peptide
28 GHK-Cu vials tested · last Sep 15, 2026
$0.06/mg · 92% cheaper than Penguin Peptides
Estimated price · as of Jul 1, 2026
- N/A
$0.05/mg
cheapest: 1500 mg vial
No lab has tested this shop's Glutathione, so we can't say what's in the vial.
Compare all Glutathione vendorsNo other Glutathione vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$0.02/mg
cheapest: 5000 mg vial
No lab has tested this shop's HCG, so we can't say what's in the vial.
Compare all HCG vendorsNo other HCG vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$15.20/mg
cheapest: 5 mg vial
No lab has tested this shop's Hexarelin, so we can't say what's in the vial.
Compare all Hexarelin vendorsNo other Hexarelin vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$67.00/mg
cheapest: 1 mg vial
No lab has tested this shop's IGF-1 LR3, so we can't say what's in the vial.
Compare all IGF-1 LR3 vendorsNo other IGF-1 LR3 vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$6.00/mg
cheapest: 10 mg vial
No lab has tested this shop's Ipamorelin, so we can't say what's in the vial.
Graded vendor
AReta-Peptide
16 Ipamorelin vials tested · last Jul 20, 2026
$0.75/mg · 87% cheaper than Penguin Peptides
cheapest: 10 × 10 mg pack
- N/A
$7.20/mg
cheapest: 10 mg vial
No lab has tested this shop's Kisspeptin, so we can't say what's in the vial.
Compare all Kisspeptin vendorsNo other Kisspeptin vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$1.68/mg
cheapest: 80 mg vial
No lab has tested this shop's KLOW, so we can't say what's in the vial.
Graded vendor
BHeman Peptide HM
3 KLOW vials tested · last Sep 21, 2026
$0.29/mg · 83% cheaper than Penguin Peptides
Estimated price · as of Sep 16, 2026
- N/A
$6.90/mg
cheapest: 10 mg vial
No lab has tested this shop's KPV, so we can't say what's in the vial.
Graded vendor
BHomopeptide
3 KPV vials tested · last Sep 4, 2026
$0.56/mg · 92% cheaper than Penguin Peptides
Estimated price · as of Jul 13, 2026
- N/A
$18.40/mg
cheapest: 5 mg vial
No lab has tested this shop's LL-37, so we can't say what's in the vial.
Compare all LL-37 vendorsNo other LL-37 vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$5.20/mg
cheapest: 10 mg vial
No lab has tested this shop's Melanotan II, so we can't say what's in the vial.
Graded vendor
BHK Peptides
12 Melanotan II vials tested · last Jul 9, 2026
$0.41/mg · 92% cheaper than Penguin Peptides
Estimated price · as of Feb 1, 2026
- N/A
$4.92/mg
cheapest: 40 mg vial
No lab has tested this shop's MOTS-c, so we can't say what's in the vial.
Graded vendor
BReta-Peptide
9 MOTS-c vials tested · last Oct 12, 2026
$0.65/mg · 87% cheaper than Penguin Peptides
cheapest: 10 × 10 mg pack
- N/A
$0.12/mg
cheapest: 1000 mg vial
No lab has tested this shop's NAD+, so we can't say what's in the vial.
Compare all NAD+ vendorsNo other NAD+ vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$21.00/mg
cheapest: 2 mg vial
No lab has tested this shop's Oxytocin, so we can't say what's in the vial.
Compare all Oxytocin vendorsNo other Oxytocin vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$5.50/mg
cheapest: 10 mg vial
No lab has tested this shop's PT-141, so we can't say what's in the vial.
- N/A
$8.50/mg
cheapest: 10 mg vial
No lab has tested this shop's Selank, so we can't say what's in the vial.
Compare all Selank vendorsNo other Selank vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$8.50/mg
cheapest: 10 mg vial
No lab has tested this shop's Semax, so we can't say what's in the vial.
Compare all Semax vendorsNo other Semax vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$6.70/mg
cheapest: 10 mg vial
No lab has tested this shop's Sermorelin, so we can't say what's in the vial.
Compare all Sermorelin vendorsNo other Sermorelin vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$4.00/mg
cheapest: 10 mg vial
No lab has tested this shop's SNAP-8, so we can't say what's in the vial.
Compare all SNAP-8 vendorsNo other SNAP-8 vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$7.00/mg
cheapest: 10 mg vial
No lab has tested this shop's TB-500, so we can't say what's in the vial.
Graded vendor
BPeptide Partners
11 TB-500 vials tested · last Aug 5, 2026
$4.90/mg · 30% cheaper than Penguin Peptides
cheapest: 10 × 10 mg pack
- N/A
$6.25/mg
cheapest: 20 mg vial
No lab has tested this shop's Tesamorelin, so we can't say what's in the vial.
Graded vendor
BShanghai ERP peptide Biotechnology
13 Tesamorelin vials tested · last Oct 12, 2026
$1.45/mg · 77% cheaper than Penguin Peptides
cheapest: 10 × 20 mg pack
- N/A
$4.50/mg
cheapest: 10 mg vial
No lab has tested this shop's Thymalin, so we can't say what's in the vial.
Compare all Thymalin vendorsNo other Thymalin vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$9.70/mg
cheapest: 10 mg vial
No lab has tested this shop's Thymosin Alpha-1, so we can't say what's in the vial.
Compare all Thymosin Alpha-1 vendorsNo other Thymosin Alpha-1 vendor met our quality score, sample-count, and recent-testing requirements.
- N/A
$10.00/mg
cheapest: 10 mg vial
No lab has tested this shop's VIP, so we can't say what's in the vial.
Compare all VIP vendorsNo other VIP vendor met our quality score, sample-count, and recent-testing requirements.
Vendors shown must meet our published grading criteria for that peptide and follow the shared quality ranking. Partner status never changes the order. We earn a commission on purchases through partner links. Shops can't pay for a grade, and inclusion is not an endorsement.
Quick facts
Penguin Peptides reviews: key findings
From 9 vials tested by independent labs. These results describe the tested vials, not every vial the shop sells. Tap i for test definitions and thresholds.
What was in the vials
Right peptide?
2 wrong
2 of 9 vials were not the peptide on the label
Amount matches label?
6 of 7 vials
Within 10% of the labelled amount
Peptide purity
98.9–99.95%
Purity across 7 tested vials
Failed our quality check
4 of 9 vials
Wrong peptide; Purity below 99.5%; Amount more than 35% off label
Testing coverage and limitations
Vials tested for contaminants
3 of 9 vials
Checked for bacterial toxins
Vials with a batch number
2 of 9 vials
Tested vials linked to a production run
Bought anonymously?
Unknown
Who bought the tested vials is unknown
Most recent lab test
Aug 2026
3 months ago
Test results
What the lab found
How close each vial was to the dose on its label
0% means exactly the amount on the label. Green band: within 10%, which is good. Dashed lines: 35% over or under, where a vial fails our basic check.
What looks good
- 6/7
Close to the labelled dose
6 of 7 vials held within 10% of the dose on the label.
- Clean
No bacterial toxin problems
3 vials were checked for bacterial toxins (endotoxins); none tested positive.
What to watch
- 2/9
Wrong peptide in the vial
2 vials turned out not to be the peptide on the label.
- +103%
Doses off the label
1 of 7 vials were more than 10% off the labelled dose, including Tirzepatide 20 mg (batch 09/03/2027) at +103%.
- 9
Few vials tested
Only 9 vials have been tested, too few to describe the whole shop.
- 33
Products never tested
33 products on sale have never been independently tested, including 5-Amino-1MQ, Adamax, AHK-Cu.
Compare recorded results
Reta-Peptide has sample grade A; Penguin Peptides has sample grade F. Neither grade establishes safety or suitability.
Strength of evidence
What supports these results?
Moderate evidence
Few batch numbers and just 3 checked for contamination. The evidence meets our C-band thresholds for sample count, recency and sourcing.
- How many vials were tested9 vials. We like to see 10 or more.Fair
- Who bought themall sent in anonymously by buyers.Good
- Batch numbers2 of 9 vials.Poor
- How recentLatest test 96 days before our check.Good
- Lab reports9 of 9 link to the lab report; none confirmed with the lab yet.Good
- Checked for contamination3 of 9 vials.Poor
- Different labs2 labs.Good
What this review can't tell you (3)
- 2 records have no purity figure.
- 2 records have no quantity measurement.
- Lab results describe the vials that were tested, not future batches or other products, and say nothing about whether a peptide is safe or suitable for you.
Shop reputation
Penguin Peptides store status, shipping and payment
Not reviewed yet
We haven't checked this shop's storefront, registration, news or complaint records yet, so this part isn't graded and doesn't count toward the verdict. Know something we should look at? Tell us.
All tests
Every Penguin Peptides vial tested
- Quantity
- 20 mg → 40.6 mg
- Right peptide?
- Yes
- Batch
- 09/03/2027
- Contamination tests
- None
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
- Quantity
- 5 mg → Not measured
- Right peptide?
- No
- Batch
- Not given
- Contamination tests
- Bacterial toxins: Low
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
- Quantity
- 10 mg → Not measured
- Right peptide?
- No
- Batch
- Ryre48a
- Contamination tests
- None
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
- Quantity
- 5 mg → 4.78 mg
- Right peptide?
- Yes
- Batch
- Not given
- Contamination tests
- Bacterial toxins: Below LOQ
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
- Quantity
- 60 mg → 59.6 mg
- Right peptide?
- Yes
- Batch
- Not given
- Contamination tests
- Bacterial toxins: Below LOQ
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
- Quantity
- 5 mg → 5.2 mg
- Right peptide?
- Yes
- Batch
- Not given
- Contamination tests
- None
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
- Quantity
- 5 mg → 4.96 mg
- Right peptide?
- Yes
- Batch
- Not given
- Contamination tests
- None
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
- Quantity
- 5 mg → 5.09 mg
- Right peptide?
- Yes
- Batch
- Not given
- Contamination tests
- None
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
- Quantity
- 50 mg → 53.6 mg
- Right peptide?
- Yes
- Batch
- Not given
- Contamination tests
- None
- Sent by
- Sent in anonymouslySent in anonymously by a member of the public; who bought it, and any tie to the shop, is not published
- Checked
- Copied from the published lab record
Comparison
Penguin Peptides vs other peptide vendors
Tirzepatide
Aug 6, 2025 – Aug 6, 2026 · 240 shops tested
Penguin Peptides
6 vials · typical error 3.1%
Passed67%4/6Quantity within 10%83%5/63.1%
104 vials · typical error 7.5%
Passed85%87/102Quantity within 10%60%59/997.5%
86 vials · typical error 7%
Passed85%73/86Quantity within 10%64%54/857%
52 vials · typical error 9.9%
Passed88%46/52Quantity within 10%56%29/529.9%
48 vials · typical error 8%
Passed81%39/48Quantity within 10%55%26/478%
Market average across all 240 shops: 81% passed, 61% within 10% of the label.
The 4 open shops with the most Tirzepatide records in the same window, chosen by record count only.
Methodology
How we grade
Lab results45%
How pure each vial was and how close it came to the labelled dose. Recent tests count more; a wrong peptide scores zero.
Strength of evidence25%
How many vials were tested, whether they were bought anonymously, and whether the reports can be checked.
Shop reputation30%
Starts at 100 and loses points for each problem we can source. Customer reviews never change a lab result.
Grade scale
- A90+
- B80+
- C70+
- D60+
- F<60
Evidence uses lower cut-offs, because anonymous purchases are rare across the market.
Limits on the overall grade
- Never higher than the lab-results grade.
- D at most if the shop can't be ordered from, has a critical problem or fails its lab tests.
- C at most if the evidence is very weak.
- No lab results means no grade.
Full scoring rulesPoints, caps and cut-offs behind each score
Lab results
- Each vial scores out of 100: half for purity, half for how close it was to the labelled dose.
- A wrong peptide scores zero, and costs the shop 1.5 more points for every 1% of vials affected.
- A vial that tests positive for bacterial toxins can score no more than 30.
- Recent vials count more than old ones. Reports the shop published itself count 50%.
- With only a few vials, we hold back: one perfect vial can't earn an A.
Strength of evidence
- How many vials were tested (up to 35 points).
- Whether they were bought anonymously, like a customer would (up to 20).
- Batch numbers, how recent the tests are, a lab report you can check, contamination tests and more than one lab (the remaining 45).
- Cut-offs: A 80+ · B 70+ · C 60+ · D 50+ · F 0+.
Shop reputation
- Starts at 100. Each problem we can source costs points: critical 35, major 20, minor 7.
- "Not reviewed yet" until we've checked, and then it doesn't count toward the overall grade.
- Customer reviews inform this score only; they never change a lab result.
What the lab grade means. A: Vials were the right peptide, very pure and close to the labelled dose. C: Results were mixed: some measurements missed the mark. F: Results often failed: wrong peptide, low purity or far-off doses.
Where the data comes from, and what we didn't doSources, the basic check, missing data, authorship
Lab data. Results come from independent lab records, each published with its lab report. We copy the measurements, link the report, and grade them ourselves; nobody else's rating is used. The data is refreshed at most hourly.
The basic check. A vial passes if it's the right peptide, at least 99.5% pure, and within 35% of the labelled dose. A vial missing purity or dose is marked "not enough data", never a pass.
Missing data and look-alikes. Missing values are shown as "not measured" or "not checked". Shops with similar names aren't combined unless a connection is documented.
What we didn't do. Unless a vial says otherwise, we didn't buy or test it ourselves, didn't confirm reports with the labs, and didn't contact the shop.
Authorship. This page is compiled automatically from lab data and hasn't been reviewed by an editor yet. We have no affiliate relationship with Penguin Peptides and earn nothing from it.
Have evidence we should see? Lab reports with a batch number, order records or corrections can be sent through our contact page or to editorial@peptidevendorreviews.org.
The same rubric applies to every shop, and commercial relationships never change ratings, grades, rankings, or the selection of alternatives. Partner links are labelled. A grade describes the evidence on the date shown. It isn't advice to buy or avoid a shop, or a judgement on whether any peptide is safe or right for you. Rubric grading-v2 (2026-10-24).
Elsewhere
Where Penguin Peptides is discussed
FAQ
Penguin Peptides reviews: common questions
Is Penguin Peptides legit?
The reviewed evidence receives grade F under our published rubric. Independent labs have tested 9 of its vials across 2 peptides; 7 were the right peptide and 5 passed our basic check. Failed: Tirzepatide 20 mg (batch 09/03/2027) (failed: the dose was +103% from the label, beyond the 35% limit); Retatrutide 5 mg (failed: it wasn't the peptide on the label); Retatrutide 10 mg (batch Ryre48a) (failed: it wasn't the peptide on the label); Tirzepatide 5 mg (failed: purity was 98.9%, below 99.5%). We grade lab evidence and published facts; grades are not endorsements and do not determine whether a business acts lawfully.
Visit Reta-Peptide, graded AWhat do Penguin Peptides' lab results show?
9 vials tested between Oct 23, 2025 and Aug 6, 2026: Tirzepatide (6) and Retatrutide (3). 7 of 9 were the right peptide, purity was measured on 7, and 5 of 7 were within 5% of the labelled dose. 4 failed our basic check (right peptide, at least 99.5% pure, within 35% of the labelled dose).
Who sent Penguin Peptides' vials for testing?
sent in anonymously (9). Krause Analytical (6) and BTLabs (3) ran the tests. Anonymous submissions come from buyers, but we can't confirm who bought each vial.
What do Penguin Peptides reviews say?
We hold 200 reviews from Penguin Peptides' Trustpilot profile for penguinpeptides.com, dated Nov 9, 2025 to Nov 27, 2025: 184 five-star and 6 one-star. Review titles and text are not republished. Ratings do not establish product contents, safety or efficacy, and we have not checked that any reviewer bought from the shop.
Does Penguin Peptides have a discount code?
We haven't verified a discount code for Penguin Peptides. We only list codes we have seen on the shop's site or confirmed at checkout.
Compare recorded results
Reta-Peptide has sample grade A; Penguin Peptides has sample grade F. Neither grade establishes safety or suitability.
Sources
Sources, updates and corrections
- Independent lab test records, one linked per vial in the test list · Test data: Finnrick Analytics · read Nov 10, 2026
For this shop
Show Penguin Peptides's grade on your site
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