Independent vendor review · 2026

Nextday Peptides Review

Scored 3.27/10 on the published Peptide Source Review formula: lab credibility, shipping, pricing, operating history, and transparency.

COAs on file
9

COAs on file

Confirmed at the lab
6

Confirmed at the lab

Products
27

Products

Labs
4

Labs

Testing gate applies (limit 6.00); this score is already below it

Third-party testing not established. The gate records that testing could not be verified; it is not a finding of a quality or safety problem.

Is Nextday Peptides legit?

Nextday Peptides scores 3.27 out of 10 (Poor, #88 of 100) as of November 6, 2026 and does not meet our testing gate: 9 of the 27 products we score carry a certificate, 6 confirmed with the issuing lab (labs we grade A to B+). Its strongest area is transparency (4.5/10); its weakest is operating history (1.9/10), with about eleven months of records. We also record that most of its certificates were issued to another business.

On lab evidence, the heaviest-weighted factor, Nextday Peptides has no third-party testing we could independently verify, with COA work on record from Freedom Diagnostics Testing, Krause Analytical LLC, Harrens Lab, Janoshik Analytical. The testing gate applies because that testing could not be independently verified (Third-party testing not established); its limit for Nextday Peptides is 6.00, and this score is already below it. Its lowest price per milligram in our data is on AHK-Cu (see the table below).

How this score was calculated

Every point below follows the published tables in our methodology, with the policy wording we scored and a link to where we read it. Evidence last checked October 22, 2026. Lab credibility is worked product by product from the certificates on file.

Lab credibility3.1/10

Each carried product (lab supplies excluded) is scored from the certificate on file for it, on the published lab rubric: 3 for a published certificate, then points for the laboratory, the verification key, the tests on the certificate and its purity, held to 0 to 10. A certificate that is self-issued, names no laboratory, or comes from a laboratory whose independence is not established scores a flat 2.0; a product with no certificate, a certificate the laboratory’s own record fails, or a posted copy that differs materially from the laboratory’s copy scores 0. Calculated on , the day this page was built; the date each certificate was tested is shown on its row.

  • Certificate from Harrens Lab, tier B- · tested 2026-09-23

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier B- (Harrens Lab)
    • +1.5Verification key printed
    • +0.5Purity 99.9% (99.7% or higher)
  • Certificate from Freedom Diagnostics Testing, tier A · tested 2026-07-31

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier A (Freedom Diagnostics Testing)
    • +1.5Verification key printed
    • +1.5Key confirmed at the laboratory's own site
    • 0.0Purity 99.54% (99.0% up to but not including 99.7%)
  • Certificate from Krause Analytical LLC, tier B- · tested 2026-06-02

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier B- (Krause Analytical LLC)
    • +1.5Verification key printed
    • +0.5Endotoxin test
    • +0.5Purity 99.9% (99.7% or higher)
  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • Certificate from Freedom Diagnostics Testing, tier A · tested 2026-09-02

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier A (Freedom Diagnostics Testing)
    • +1.5Verification key printed
    • +1.5Key confirmed at the laboratory's own site
    • +0.5Endotoxin test
    • 0.0Purity 99.61% (99.0% up to but not including 99.7%)
  • No certificate on file for this product: scores 0, counted fully because it is one of the core products.

  • No certificate on file for this product: scores 0, counted fully because it is one of the core products.

  • No certificate on file for this product: scores 0, counted fully because it is one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted fully because it is one of the core products.

  • Certificate from Janoshik Analytical, tier B+ · tested 2026-10-13

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier B+ (Janoshik Analytical)
    • +1.5Verification key printed
    • +1.5Key confirmed at the laboratory's own site
    • +0.5Purity 99.753% (99.7% or higher)
  • Certificate from Krause Analytical LLC, tier B- · tested 2026-05-20

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier B- (Krause Analytical LLC)
    • +1.5Verification key printed
    • +0.5Endotoxin test
    • +0.5Purity 99.9% (99.7% or higher)
  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted fully because it is one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • No certificate on file for this product: scores 0, counted at 0.5 weight because it is not one of the core products.

  • Certificate from Freedom Diagnostics Testing, tier A · tested 2026-09-02

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier A (Freedom Diagnostics Testing)
    • +1.5Verification key printed
    • +1.5Key confirmed at the laboratory's own site
    • +0.5Endotoxin test
    • 0.0Purity 99.55% (99.0% up to but not including 99.7%)
  • Certificate from Freedom Diagnostics Testing, tier A · tested 2026-09-02

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier A (Freedom Diagnostics Testing)
    • +1.5Verification key printed
    • +1.5Key confirmed at the laboratory's own site
    • +0.5Endotoxin test
    • +0.5Purity 99.72% (99.7% or higher)
  • GLOW8.5

    Certificate from Freedom Diagnostics Testing, tier A · tested 2026-08-05

    • 3.0Certificate published (base)
    • +2.0Laboratory in our directory at tier A (Freedom Diagnostics Testing)
    • +1.5Verification key printed
    • +1.5Key confirmed at the laboratory's own site
    • +0.5Purity 99.75% (99.7% or higher)

Weighted mean of 27 products (13 non-core products without a certificate counted at half weight): 73.0 ÷ 20.5 = 3.561.

  • −0.50SUPPLIER Certificates ordered by a supplier or another client (cap −0.5): none of the 21 certificates in the vendor's library names Next Day Peptides: 15 are Finnrick records whose own data list the vials as from Shanghai ERP Peptide Biotechnology (13) and Shanghai Wibson (2), and 5 Freedom certificates show client 'G'

3.561 − 0.500 = 3.061, rounded to 0.1: 3.1/10.

Testing gate: 6 of 27 products have a certificate from a directory laboratory (not tier D, not self-issued) with the key confirmed at the laboratory. That is fewer than half, so the testing cap applies (see the methodology).

Shipping and refunds3.5/10

Total +3.5: 3.5/10.

Pricing3.6/10

We compared Nextday Peptides’s current single-vial prices on 24 products, each matched to the same product and milligrams per vial, with the median price of the other vendors. Its typical price (the median ratio across those products) is 48% above the market median (ratio 1.48), which the published scale maps to 3.6/10. checked

Operating history1.9/10

Counted from November 12, 2025, the earliest dated evidence of this business operating: 11.3 months as of October 22, 2026, which the published table maps to 1.9/10.

Start is the registration of nextdaypeptides.com on 2025-11-12; Wayback has no capture between registration and the first store capture (2026-04-10), so it was never shown parked (the blank 2025-07/08 captures belong to an earlier registration). The named operator Nextday Sciences LLC is Florida L26000231807, filed 2026-04-24 at the site's St. Petersburg address, which is later.

Transparency4.5/10

Total +4.5: 4.5/10.

Third-party tested: NoLabs: Freedom Diagnostics Testing, Krause Analytical LLC, Harrens Lab, Janoshik AnalyticalProducts tracked: 27

Shop Nextday Peptides

  • Rated 3.27/10 · Poor
  • 6 COAs confirmed at the issuing lab
  • Best value: AHK-Cu at $0.11/mg
Visit Nextday Peptides → (opens in new tab)

Audit history and why the rating changed

We re-audit vendors against their live COAs and site. Here is what most recently moved this rating, and why.

See the full score history and chart

  1. Most recent audit · 3.21to3.27

    Lab evidence recomputed under the published rule on 6 November 2026: the list of the 15 products carried by the most vendors changed when new vendors were added (KLOW replaced sermorelin), which changes the weight of a missing certificate under rule A1b. Lab evidence 3.0 to 3.1.

  2. Audit · 3.20to3.21

    Market medians updated on 3 November 2026 after the Prime Peptides re-check added priced listings: pricing 3.5 to 3.6.

  3. Audit · 3.14to3.20

    Core products recomputed on 29 October 2026 (rule A1b): listings added for newly reviewed vendors made NAD+ a core product in place of CJC-1295, so a missing certificate for each now counts at its new weight: lab 2.9 to 3.0.

Earlier audits (16)
  1. Audit · 3.16to3.14

    Pricing recomputed on 25 October 2026: listings added for a newly reviewed vendor (Pexo Labs) moved the market median for the same products: pricing 3.6 to 3.5.

  2. Audit · 3.13to3.16

    Prices re-computed on 24 October 2026 after products were added for Spartan Peptides, Next Day Peptides and Honest Peptide, which moved the market medians: pricing 3.4 to 3.6.

  3. Audit · 2.63to3.13

    Three products added on 24 October 2026: MOTS-c, SS-31 and GLOW, sold on the vendor's site and covered by Freedom Diagnostics certificates confirmed at the laboratory. Their client field reads 'G', which the existing SUPPLIER adjustment already covers. Lab 2.0 to 2.9.

  4. Audit · 2.65to2.63

    Pricing recomputed on 24 October 2026 after Bionova Peptides' first-review prices were recorded; other vendors move only through the market medians: pricing 3.5 to 3.4.

  5. Audit · 2.63to2.65

    Prices re-checked on 23 October 2026 under rule E (standing prices only): prices taken from a time-limited sale were replaced with the vendor's standing price, current prices were re-read, and other vendors' price changes moved the market medians pricing 3.4 to 3.5.

  6. Audit · 2.69to2.63

    Laboratory grades re-checked on 22 October 2026 under the published laboratory rulebook (checks L1 to L6 on How We Rate). Harrens Lab's A2LA accreditation covers cannabis, hemp and food microbiology testing but not peptides, so its certificate no longer earns the accreditation point (check L6); it also offers no public way to look up a report (check L3), which grades it B-. This affects one Nextday Peptides certificate (BPC-157). Lab 2.1 to 2.0.

  7. Audit · 2.36to2.69

    Lab score recalculated on 22 October 2026 under the published core-product rule (A1b): a missing certificate on one of the 15 most widely carried products still counts fully, while on any other product it now counts at half weight, so a broad catalogue is not penalised as much for its breadth. Lab 1.5 to 2.1.

  8. Audit · 2.30to2.36

    Claim deductions re-checked on 22 October 2026 under the published rule that a claim deduction applies only where a site claim is contradicted by what its certificates show, never for products merely lacking a certificate. Lab 1.4 to 1.5.

  9. Audit · 2.50to2.30

    Re-scored on 22 October 2026 under the published rulebook, which now gives one rule for each judgement call and applies it to every vendor: shipping and refunds 4.5 to 3.5.

  10. Audit · Verified, no change

    Re-scored on 22 October 2026 under version 2 of our published rules. No score change. The testing gate is now computed from the certificates instead of set by hand: 3 of 24 products have a certificate from a directory laboratory with the key confirmed at the laboratory, fewer than the half required, so the testing cap applies; the cap sits above the weighted score, so it does not lower it.

  11. Audit · 2.45to2.50

    MDx BioAnalytical Laboratory confirmed accredited in PJLA's register on 22 October 2026 (certificate L26-502, scope includes peptides and endotoxins), so its certificates now receive the accreditation credit under our published lab rule. Lab 1.3 to 1.4.

  12. Audit · 4.16to2.45

    Re-scored on 22 October 2026 under our published rubric for shipping, pricing, operating history and transparency, applied to every vendor the same day: prices re-read from the vendor's site and matched by milligrams per vial, operating history from the earliest dated evidence of the business, and policies scored item by item. shipping and refunds 9.5 to 4.5, pricing 7.2 to 3.4, operating history 2.0 to 1.9, transparency 7.3 to 4.5.

  13. Audit · 4.27to4.16

    Lab score recalculated on 22 October 2026 under the uniform published rubric applied to every vendor: every listed product was rescored on the same fixed certificate points, with fixed deductions for certificates ordered by a supplier or issued to another business and site statements about testing that the certificates do not bear out. Lab 1.5 to 1.3.

  14. Audit · 7.30to4.27

    Lab evidence re-checked on 20 October 2026 under our coverage rule, which counts a listed product with no published certificate as zero in the lab average. Certificates cover 6 of the 24 products we list that the vendor offers for sale. Lab 7.0 to 1.5.

  15. Audit · 7.28to7.30

    Lab roster corrected to the five independent laboratories actually appearing (PharmLabs, the sixth name on the certificates, is excluded from the roster); TrustPointe Analytics is gone from the site and was removed. Harrens Lab added to the tier table at A after reading one of its certificates in full. Transparency raised because the vendor states plainly that the certificates are its suppliers' and that it does not test lots itself. Lab held at 7.0: six laboratories across 27 supplier certificates covering 10 of 24 products is breadth, not depth.

  16. Audit · 7.23to7.28

    Re-audited from live COAs. Read 25 Janoshik reports in the vendor's certificate library and credited current transparency. Noted two mislabeled COA links and that only 28 of 59 products publish a COA.

Editor’s notes

Nextday Sciences LLC, doing business as Nextday Peptides, lists a registered-agent mailbox address in St. Petersburg, Florida, names no individuals, and states Florida governing law. Its domain was registered in late 2025. When we checked on 2026-10-08, its certificate library held 27 certificates covering 10 compounds from six laboratories (Krause Analytical, BT Labs, Freedom Diagnostics, Janoshik, PharmLabs, Harrens Lab); TrustPointe Analytics no longer appeared. The site says the certificates come from manufacturing vendors or their contracted laboratories. When we re-checked on 2026-10-20, 6 of the 24 products we list had a published certificate, while product pages state that a COA is available. On 24 October 2026 we added MOTS-c, SS-31 and GLOW, which the site sells, with Freedom Diagnostics certificates we confirmed at the laboratory; like the vendor's other Freedom certificates, they name the client 'G', so 9 of the 27 products we list now have a published certificate. Library cards label lots with internal numbers that differ from the lot numbers printed on the documents. On 22 October 2026 the shipping policy stated that order processing takes 24 to 48 hours, with economy, standard, express and overnight options, and that risk of loss passes to the buyer once the order is with the carrier, and the site stated that it does not accept credit or debit cards. Transparency is the strongest part of its score; the lab score is low because most listed products have no certificate.

Nextday Peptides COAs and lab test results

One row per product: the certificate on file and how the lab rule reads it, the laboratory that issued it and its tier, the date it was tested, the purity it reports, and the lowest price per milligram we recorded (per IU or mL where a product is sold that way).

Harrens LabTier B-tested

Purity
99.9%
Price per mg
$6.38$127.50 / 20mgbest of 2 sizes

Freedom Diagnostics TestingTier Atested

Purity
99.54%
Price per mg
$11.00$110.00 / 10mg

Krause Analytical LLCTier B-tested

Purity
99.9%
Price per mg
$1.10$110.00 / 100mgbest of 2 sizes
CJC-1295No public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$22.00$110.00 / 5mg

Freedom Diagnostics TestingTier Atested

Purity
99.61%
Price per mg
$12.75$127.50 / 10mg
SemaxNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$7.50$75.00 / 10mg
SelankNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$7.50$75.00 / 10mgbest of 2 sizes
Melanotan-2No public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$5.75$57.50 / 10mg
SermorelinNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$12.75$127.50 / 10mgbest of 2 sizes
TesamorelinNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$10.75$215.00 / 20mgbest of 3 sizes

Janoshik AnalyticalTier B+tested

Purity
99.753%
Price per mg
$4.17$250.00 / 60mgbest of 7 sizes

Krause Analytical LLCTier B-tested

Purity
99.9%
Price per mg
$3.88$232.50 / 60mgbest of 5 sizes
SemaglutideNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$4.25$127.50 / 30mgbest of 3 sizes
AOD-9604No public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$12.75$127.50 / 10mgbest of 2 sizes
5-Amino-1MQNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$3.60$180.00 / 50mgbest of 2 sizes
GHRP-6No public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
—
HexarelinNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
—
CagrilintideNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$16.25$162.50 / 10mgbest of 2 sizes
CJC-1295 + IpamorelinNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$9.00$180.00 / 20mgbest of 2 sizes
AHK-CuNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$0.11$215.00 / 2000mgbest of 2 sizes
ARA-290No public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$11.00$110.00 / 10mg
BPC-157 + TB-500No public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$8.13$162.50 / 20mgbest of 2 sizes
SLU-PP-332No public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
$22.00$110.00 / 5mg
PEG-MGFNo public COANo third-party COA was publicly available at audit time
Purity
—
Price per mg
—

Freedom Diagnostics TestingTier Atested

Purity
99.55%
Price per mg
$4.50$180.00 / 40mgbest of 4 sizes

Freedom Diagnostics TestingTier Atested

Purity
99.72%
Price per mg
$3.95$197.50 / 50mgbest of 3 sizes

Freedom Diagnostics TestingTier Atested

Purity
99.75%
Price per mg
$1.82$127.50 / 70mg

Learn more about what Nextday Peptides carries

Rated higher than Nextday Peptides, with a reader code

Nextday Peptides is not one of our affiliate partners, so we have no code for it. These partners score above it under the same published rules, pass our testing gate, and give readers a discount.

Affiliate links: we may earn a commission if you buy. It never changes a score or rank.

Honest Peptide

7.42/10 · Strong · carries 19 of the same products

Arctic Lab Supply

6.98/10 · Fair · carries 19 of the same products

NextGen Peps

5.95/10 · Fair · carries 25 of the same products

Nextday Peptides: Frequently Asked Questions

Is Nextday Peptides legit?

Nextday Peptides scores 3.27 out of 10 (Poor, #88 of 100) as of November 6, 2026 and does not meet our testing gate: 9 of the 27 products we score carry a certificate, 6 confirmed with the issuing lab (labs we grade A to B+). Its strongest area is transparency (4.5/10); its weakest is operating history (1.9/10), with about eleven months of records. We also record that most of its certificates were issued to another business.

Is there a Nextday Peptides promo code, coupon code, or discount code?

We do not have a verified Nextday Peptides promo code or coupon code right now. When Nextday Peptides runs a sale or issues a discount code, we post it here and on our promos page, so bookmark this page for the latest Nextday Peptides discount.

Does Nextday Peptides use third-party lab testing?

Not to our verification standard. Fewer than half of this vendor's scored products have a certificate from an independent laboratory in our directory (not tier D) whose verification key we confirmed at that laboratory, so the testing gate applies. This records what we could verify; it is not a finding of a quality or safety problem. Laboratories on the certificates we hold: Freedom Diagnostics Testing, Krause Analytical LLC, Harrens Lab, Janoshik Analytical.

Where can I see Nextday Peptides' COAs?

In the "Nextday Peptides COAs and lab test results" table on this page. We hold 9 certificates for Nextday Peptides, covering 9 of the 27 products we track, issued by 4 laboratories (Freedom Diagnostics Testing, Krause Analytical LLC, Harrens Lab, Janoshik Analytical). 6 products' certificates were confirmed at the issuing laboratory itself. Each row links the certificate, its lab, its test date and the purity it reports.

What peptides does Nextday Peptides carry?

Nextday Peptides carries BPC-157, TB-500, GHK-Cu, CJC-1295, Ipamorelin, Semax, Selank, Melanotan-2, and 19 more. Current per-milligram pricing, COA links, and verification keys for each are in the comparison table on this page.

Is the Nextday Peptides review on Peptide Source Review affected by affiliate status?

No. All affiliate relationships are publicly disclosed and never change a vendor's score, rank, or gate status. Our scoring formula is published in full and applied identically to every vendor.

Want to understand how this score was built?

Read the full methodology or the editorial integrity policy.

Visit Nextday Peptides → (opens in new tab)

Nextday Peptides3.27Poor

6 confirmed at the lab

Visit Nextday Peptides (opens in new tab)

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