Two Vendors, Two Strategies
Ascension Peptides and EZ Peptides currently sit at the top of our vendor rankings — EZ at #1 for catalog breadth and COA convenience, Ascension at #2 for raw value after its 50% discount. If you're buying peptides in 2026 and want to stick to vendors with verified third-party testing and strong reputations, these are the two names that come up in every conversation.
But they aren't interchangeable. They have different pricing strategies, different catalog depths, and different COA systems. Pick the wrong one and you're either overpaying by 30% or missing a peptide you needed.
This is the head-to-head breakdown — live pricing, catalog gaps, COA methodology, shipping, and a verdict by use case.
Quick Verdict
For pure price after discount: Ascension Peptides. The 50% sitewide discount is the biggest verified discount in the space and beats EZ's 10% on nearly every overlapping SKU on a per-mg basis.
For catalog breadth: EZ Peptides. Its catalog runs wider — EZ carries semaglutide, Epitalon, Follistatin-344, IGF-1 LR3, MGF, and GHRP-2/6, which Ascension doesn't stock.
For COA convenience: EZ Peptides. QR-linked per-product COAs that you scan with your phone. Ascension's third-party COAs are legitimate but less user-friendly to access.
For GLP-1 research (semaglutide specifically): EZ Peptides. Ascension doesn't carry semaglutide at all.
For a BPC-157 / retatrutide / tirzepatide stack: Ascension Peptides. Post-discount pricing wins decisively on these compounds.
For "one vendor for everything": EZ Peptides. The broader catalog means fewer split orders.
Price Comparison
Base prices are roughly comparable between the two vendors. The discount is where the math diverges.
Prices below link directly to the vendor's product page. Pulled live from our database — — means the vendor doesn't currently carry that peptide. Ascension's 50% discount applies automatically through the affiliate link; EZ's 10% requires code .
| Peptide | Vial | Ascension | EZ Peptides | Winner |
|---|---|---|---|---|
| BPC-157 | 10mg | $49.00 | $44.00 | Ascension (-31% after 50%) |
| TB-500 | 5mg vs 10mg | $54.00 | $48.00 | EZ on $/mg |
| Retatrutide | 10mg vs 12mg | $100.00 | $37.00 | Ascension (-33%) |
| Tirzepatide | 10mg | $90.00 | $28.00 | Ascension (-29%) |
| Semaglutide | 5mg | $38.00 | $27.00 | EZ (only option) |
| CJC-1295 | 5mg | $45.00 | $38.00 | Ascension (-34%) |
| Ipamorelin | 5mg | $50.00 | $44.00 | Ascension (-31%) |
Two things worth flagging:
Vial size differences matter. Ascension sells TB-500 in 5mg vials while EZ ships 10mg. Retatrutide is 10mg at Ascension, 12mg at EZ. Don't compare sticker prices — compare price per mg.
Discount mechanics differ. Ascension's 50% is applied automatically via the affiliate link (no code to enter). EZ requires the code at checkout. Both apply to the entire cart with no minimum.
For live pricing across both vendors plus all others we track: Ascension Peptides live pricing and EZ Peptides live pricing.
Catalog & Category Focus
The two vendors position their catalogs differently, and that difference is more useful to think about than a raw count — inventory turns over constantly, so any specific list goes stale fast.
EZ Peptides leans broad and mainstream. Its catalog is built to be a one-stop shop across the most-searched research categories, including the GLP-1 analogues that drive most current demand and the standard growth-hormone-axis and healing compounds. If you want to run most of a stack from a single vendor and minimize split orders, breadth is EZ's core strength.
Ascension Peptides leans toward depth in longevity and niche research compounds. Its focus skews to the mitochondrial, longevity, and specialty research side alongside the core healing and GH-axis staples. Researchers whose work sits in that territory tend to find more of what they need in one place.
Both keep the high-demand overlap — the popular healing, GH-axis, and metabolic compounds most buyers come for — well covered. The practical takeaway isn't "who has more," it's category fit: pick EZ if you want the widest mainstream lineup from one cart, and Ascension if your research skews longevity/niche and you want the deepest discount on the compounds both carry. Because catalogs change, confirm current availability on each vendor's live listing before you buy.
Verdict: EZ wins on mainstream breadth and single-cart convenience. Ascension wins on longevity-stack depth and post-discount value. Match the vendor to what you're actually researching.
COA / Quality Testing
Both vendors use independent third-party testing. The difference is in how that testing is delivered.
EZ Peptides — QR-linked per-product COAs:
- Every product ships with a unique QR code on the vial
- Scanning with any phone camera opens the COA for that specific vial
- Testing covers purity (HPLC), identity (mass spec), and sterility
- Per-product system is harder to fake than a static PDF archive
Ascension Peptides — Independent third-party COAs:
- Third-party lab testing including CLIA-certified facilities
- HPLC purity confirmation + mass spectrometry identity verification
- COA documentation includes underlying chromatographic data (not just a purity number)
- Delivered via website/email rather than QR-on-vial
Both exceed the industry floor. Vendors that ship with no COA at all, or rely on a single "batch PDF" that might be 6 months old, are a different tier entirely — neither Ascension nor EZ is in that group.
Verdict: EZ wins on convenience (scan-to-verify beats searching a website). Ascension wins on data depth (chromatographic data is meaningful for researchers who know how to read it). Both are legitimate. Pick based on how you actually interact with COA documents.
Shipping + Customer Service
Shipping speed:
- EZ Peptides: 1-2 business days to ship, domestic tracked shipping
- Ascension Peptides: 1-3 business days to ship, domestic tracked shipping
Both are US-based operations with similar fulfillment windows. Real-world delivery times vary based on USPS/UPS rather than vendor.
Customer service reputation:
- EZ Peptides — 4.7/5 Trustpilot. Support is generally responsive via email, but some customers reported slower response times during the post-Peptide-Sciences-shutdown volume spike in late 2025.
- Ascension Peptides — 4.8/5 Trustpilot across 88+ reviews. Multiple reviewers specifically mention that shipping issues were resolved immediately without pushback.
Returns:
- EZ Peptides — 30-day money-back guarantee on damaged or mismatched COA products
- Ascension Peptides — case-by-case on damaged or incorrect orders (confirm terms directly before purchase)
Discreet packaging: Both use plain outer packaging with proper cold-chain considerations.
Verdict: Ascension edges out on Trustpilot rating and on consistent service reports. EZ is close, but the scaling issues during peak demand are a real data point. Neither vendor has serious service red flags.
Coupons + Discounts
This is the single most important section for most buyers.
Ascension Peptides — 50% off sitewide. No code required. The discount applies automatically when you visit through the affiliate link. No minimum order, no product restrictions. This is the largest verified discount in the research peptide space — bigger than Ion Peptide's 15%, bigger than every other vendor we track.
EZ Peptides — 10% off with code . Applies at checkout to the entire cart, no minimum. Works on all products including semaglutide, retatrutide, BPC-157, and their full catalog.
Stacking with sales: Both discounts apply on top of base prices, not on top of additional promotional sales. Neither stacks with itself or other codes.
Durability: EZ's 10% has been stable for 12+ months. Ascension's 50% has been active since their affiliate partnership launched roughly 18 months ago. Neither is guaranteed forever — vendor discounts can change without notice — but both are well-established.
