Checkup. Match. Pen page. Checkout. Certificate.

Overview

Peptide Checkup stocks 24 pre-filled AERVYN peptide pens. It also answers one question before you buy: given your goal, your history and your medicines, which pen — if any — is worth discussing with a clinician? Four parts do the work.

1. A database of 32 compounds, each written to the same standard from regulator labels and peer-reviewed trials: mechanism, evidence for each goal, regulatory status in 5 jurisdictions, published dosing studies, contraindications, interactions and pregnancy guidance. Every compound in the range has a record; blends have one per component.
2. A structured assessment — the Peptide Checkup — of 10 short sections that asks in categories: conditions, medicine classes, yes/no safety checks. Categories are what rules can evaluate reliably.
3. A deterministic rules engine and matcher that maps your answers onto the database, produces a report, and then scores the 24 pens against it. The same answers always give the same report and the same pen, and every label can be traced to a field a clinician can inspect.
4. The range: Tesamorelin, MOTS-C, GHK-Cu, NAD+, Wolverine, Klow, Glow, KPV, Retatrutide (R3T), BPC-157, CagriSema, CJC-1295 (no DAC), Epitalon, FOXO4-DRI, Gonadorelin, Ipamorelin, Liraglutide, LL-37, PT-141, Semaglutide, Sermorelin, TB-500, Thymosin Alpha-1 and Tirzepatide. One format, every lot tested by an independent laboratory before it is listed, the certificate published against the lot number. Tesamorelin, Semaglutide, Gonadorelin, Liraglutide, PT-141 (bremelanotide) and Tirzepatide are authorised medicines in other countries; the pens are research products of the same compounds, not those medicines.

If you arrived from an advert, your goal and the problem you came with are pre-selected from the landing page and recorded so the report can address them. You can change both in the first section.

One focused screen per question group. Single-choice questions advance automatically; the 3 optional sections can be skipped, and the report says what it could not assess as a result.

Details that are easy to miss: the conditions grid extends itself with any condition a compound in the range lists as a contraindication; the safety screen shows compound-specific hints; you can record an amount you are considering and the report compares it with published study exposures; and anyone under 18 is shown a full stop rather than a report.

02 · Rules engine

A fixed set of checks — no language model, no free text. For each compound in the range it evaluates:

• Goal alignment — whether the compound has human evidence for your goal, and at what grade on the five-point scale.
• Contraindications — your medical history against the compound’s documented absolute and caution-level contraindications.
• Interactions — the classes of medicine you take against the compound’s documented interactions, graded major, moderate or minor.
• Pregnancy, breastfeeding and age — with an immediate notice where relevant.
• Amount comparison — if you entered an amount, how it compares with exposures used in published human studies. Where there are no human data, it says so.
• Regulatory and anti-doping status for your country and, where relevant, your sport. Several compounds in the range are on the WADA Prohibited List; a tested athlete is never matched to them.
• Expectations, source and previous experience — unrealistic timeframes and previous adverse reactions become flags.
• Blend analysis — for Wolverine, Klow, Glow and CagriSema: combination evidence, overlapping mechanisms and an uncertainty rating. No blend in the range has been studied in people as the combination sold here.

The result per compound is one of three labels — Potentially relevant, Higher concern or Insufficient information — with the rationale and every flag that contributed. The label is not a clinical determination; it describes whether your answers identified factors that warrant professional review. The methodology explains the grading and the matcher in detail.

03 · Your match

The matcher takes the report and scores every pen in the range on five things: your goal, the specific problem you picked, the compound’s evidence grade for that goal, format and experience fit, and the safety verdict from the rules engine. It returns one of three verdicts per pen — not a ranking of how “good” a pen is, and never influenced by price, margin or stock.

The report also lists the compounds researched for your goal that the matcher did not land on, drawn from the same database, so the result is never a single unexplained answer. Completing the Checkup unlocks the code CHECKUP10 (10% off).

04 · Checkout

The cart is standard: pen count, a promo field and totals in GBP with UK VAT at 20% included. Two things are not standard.

• Research-use acknowledgement. Every pen in the range is a research-channel product, so you must confirm you are 18 or over and that the product is for research use, not human consumption. The label is printed on the pen page, in the cart, at checkout and on the carton — with a further line where the compound is an authorised medicine elsewhere or still investigational.
• Nothing is added for you. The match panel offers; you add. A pen the Checkup marked not recommended cannot be added from the result at all.

Card details are handled by the payment provider and never touch this site. Orders are confirmed by email. Standard chilled courier is £5.95 (1–2 working days) and free on UK orders of £300 or more; orders placed before 2 pm UK time on a working day are dispatched the same day, chilled, in insulated packaging. The shipping page has every option — next-day, EU and international — and the returns policy.

05 · In the box

• The pen: 3 mL of solution in a pre-filled multi-dose pen with a numbered dial window, capped and sealed.
• The lot-numbered carton, printed with the compound, the amount, the lot number and the research-use statement.
• The certificate of analysis for that lot: purity by HPLC, identity by LC-MS, endotoxin by LAL — per component for blends — with the laboratory and the test date. The same certificate is published online against the lot number.
• A pen-needle compatibility note. The pens take standard pen needles; needles are not included unless the listing says so.

Put the pen in the fridge (2–8 °C, never frozen) as soon as the parcel arrives and check that the lot number on the carton matches the certificate. If it does not, or anything about the package looks wrong, email hello@comparepeptide.co.uk before you use it. The lab-testing page explains how to read each figure.

The report is rendered directly from the engine’s output and nothing else. Sections appear in this order; the stack section appears for the blends and whenever more than one compound is in play.

Every report ends with questions to ask a clinician, the monitoring a clinician would typically consider, an appendix of your answers, the full disclaimer, and the option to print or save.

Time and saving progress

Most people finish in about 7 minutes. It takes longer if you enter a long list of medicines, and each of the 3 optional sections adds a minute or two — the report and the match are better when you complete them.

Progress is saved in your browser as you go. Choose Save & exit at any point and a resume card appears on the assessment page when you return on the same device and browser. Before the report is generated you see a review screen where you can change any answer.

After the report

• Take it to an appointment. The questions section is specific to the pen, the compounds inside it and the flags in your report.
• Add the pen, or don’t. The match carries the current lot and price. Nothing is added until you choose to add it.
• Read the record. Every compound page lists its sources, and the compare tool puts evidence, regulatory status and dosing studies side by side — including for the components of a blend.