What this is, what it is not, and when to stop reading.

Not medical advice

The Peptide Checkup provides educational information and a structured summary of published research and regulatory status. It is not medical advice, does not diagnose or treat any condition, and does not replace a consultation with a qualified healthcare professional.

Nothing on this site — compound pages, pen pages, comparisons, landing pages, your report or your match — tells you to take, stop or combine anything. Suitability labels describe whether your responses identified factors that warrant professional review; they are not a diagnosis, a prescription or a clinical determination. A match describes a fit to the record, not an outcome. Dosing information is a summary of published research and is not a recommendation. Pen pages state what is in the pen, not what to do with it.

Research-use labelling

Sold for research use only. Not a medicine and not authorised for human consumption. Purchasers must be 18+ and confirm intended use at checkout.

None of the 24 pens in the AERVYN range is supplied as an authorised medicine. They are laboratory reagents under research-use labelling, which means exactly what it says: not a medicine, not for human consumption, not manufactured or licensed for use in people. We ask you to confirm that you are 18 or over and that you understand the intended use at checkout, and the statement is printed on the pen page, in the cart and on the carton. Lot testing does not change any of this.

Some of the compounds inside the pens — Tesamorelin, Semaglutide, Gonadorelin, Liraglutide, PT-141 (bremelanotide) and Tirzepatide — are authorised medicines in other countries, as branded prescription products made under GMP. The pens are research products of the same compounds, not those medicines, and are not supplied as treatment; the pen page says so under the research-use label. Retatrutide and Cagrilintide are investigational: in late-stage trials and not authorised anywhere.

We sell no prescription-only medicines and offer no consultation service. Where the Checkup points you to a clinician, that is advice to see one — not an introduction to one.

Pens and the cold chain

Every product in the range is a pre-filled 3 mL multi-dose pen with a numbered dial window; the dial sets the volume delivered per actuation. The solution is temperature-sensitive.

The pen page for each product repeats its storage line and its box contents. Nothing on this site describes how to use a pen on a person, because the products are not supplied for that.

Tested is not licensed

Products sold online labelled “for research use” are usually not tested at all: nobody checks what is in them, how much, or what else is present. The pens we stock are tested by an independent laboratory every lot — per component for the four blends — and the certificate is published against the lot number. It is worth being precise about what that does and does not tell you.

• It does tell you the identity of each compound (LC-MS), its purity as a percentage of the main peak (HPLC) and the endotoxin level (LAL) for that lot, on the date tested, at the laboratory named.
• It does not tell you that the compound is safe or effective in people, that the pen is sterile at the point of use, or that it is legal to hold where you live. It does not make an unlicensed compound a medicine.
• The evidence grade is separate. A lot can be 99% pure and the compound can still have no human evidence for your goal. The compound page says which, and so does the match.

If you need help now

If you are worried about a symptom that is not an emergency, contact your doctor, pharmacist or a national health advice line. If you are having thoughts of harming yourself, contact your local crisis line or emergency services now.

Pens sold elsewhere

Pre-filled pens are sold through social media, messaging apps and unregistered websites with no lot number, no certificate and no way to check what is inside. Regulators in several countries have issued warnings about falsified pens, some containing no active compound and some containing a different one altogether.

• An AERVYN pen carries a lot number on the carton and a certificate for that lot in the box and online. If either is missing, it is not ours.
• Be suspicious of sellers with no published testing, no labelling, and no willingness to say what a product is not for.
• If you think you have received a falsified product, do not use it; report it to your national medicines regulator.

Tested athletes

Tesamorelin, MOTS-C, Wolverine, Klow, Glow, BPC-157, CJC-1295 (no DAC), Gonadorelin, Ipamorelin, Sermorelin, TB-500 contain compounds named on the World Anti-Doping Code Prohibited List — as recorded in the compound records — and several licensed medicines are listed too. Every record carries its anti-doping status, and if you say you compete in tested sport the Checkup will not land on a listed compound: the verdict is not recommended and nothing is added to your cart. That status is a summary for information only. If you compete, check the current Prohibited List and consult your national anti-doping organisation before using anything, including supplements — strict liability means you are responsible for what is found in your sample.

Pregnancy and breastfeeding

Every compound record includes a pregnancy field — contraindicated, not recommended, insufficient data, or not applicable — drawn from the label where one exists. For most compounds in the range the honest answer is that there are no adequate human data. If you are pregnant, trying to conceive or breastfeeding, the Checkup shows an immediate notice, the report flags every compound accordingly and no pen is matched. Discuss anything you are considering with your midwife, obstetrician or doctor first.

Under 18

The Checkup and the store are for adults. If you enter an age under 18 the assessment stops and does not generate a report or a match; checkout requires confirmation that you are 18 or over. Compound pages remain readable as educational information; none of it is aimed at, or appropriate for, decisions about children or adolescents without specialist medical care.

Reporting side effects

If you experience a suspected side effect from any medicine or product, tell a healthcare professional and report it to your national pharmacovigilance scheme — in the UK, the MHRA Yellow Card scheme; elsewhere MedWatch (US), the EMA's national reporting systems, or the equivalent where you live. Reporting helps regulators identify problems, including with unregulated and falsified products.

The disclaimer in every report

This report is generated by a deterministic, clinician-reviewable rules engine from the information you provided and our maintained compound, evidence and regulatory database. It does not recommend that you take any compound. Suitability labels describe whether your responses identified factors that warrant professional review — they are not a clinical determination. Always consult a qualified healthcare professional before starting, stopping or combining any medicine, peptide or supplement.

Questions about any of this? Email hello@comparepeptide.co.uk, or read the methodology and terms.