# What are peptides?

Canonical: https://europeanpeptideshop.com/blog/what-are-peptides/

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Compound research · 8 November 2026 · 4 min read · By [European Peptide Shop](https://europeanpeptideshop.com/about/)

### On this page

A peptide is a short chain of amino acids joined by peptide bonds. Amino acids are also the building blocks of proteins. The word describes a type of molecule; it does not tell you what a particular product does, how well it has been studied or whether it is suitable for personal use. [National Human Genome Research Institute: peptide definition](https://www.genome.gov/genetics-glossary/Peptide).

Peptides appear in conversations about medicines, skincare and laboratory work. Those settings can involve different compounds and finished products. The most useful first question is therefore not simply “Are peptides good?” It is “Which peptide, in which product, and supported by what evidence?”

## Why does the same word appear on such different products?

A molecule’s name and a product’s purpose answer different questions. A prescription medicine has a particular formulation and prescribing information. A cosmetic is a finished product intended for a stated cosmetic purpose. A research material is supplied for laboratory work. Similar ingredient names do not make these products interchangeable.

Setting | What to identify | What not to assume

Prescription medicine | The exact approved product, formulation and prescribing information. | That a similarly named research vial has the same approval.

Skincare | The finished formulation, ingredients and label claims. | That a raw powder shares the finished product’s evidence or instructions.

Research material | The compound, labelled amount, batch and available lab report. | That purity or a vial label establishes suitability for personal administration.

FDA explains that a product’s intended use and claims help determine whether it is a cosmetic, a drug or both. A skincare claim therefore needs to be assessed in the context of the actual product. [FDA cosmetics labelling guide](https://www.fda.gov/cosmetics/cosmetics-labeling-regulations/cosmetics-labeling-guide).

## Are retatrutide, tirzepatide and semaglutide the same?

No. They are different compounds, with different receptor targets and product/development histories. The [three-compound comparison](https://europeanpeptideshop.com/blog/retatrutide-vs-tirzepatide-vs-semaglutide/) explains those distinctions without turning percentages from different trials into a ranking.

The cited FDA guidance states that retatrutide is not a component of an FDA-approved drug. The agency also warns about unapproved GLP-1 products marketed to consumers under research labels. A research label does not turn a product into an approved medicine. [FDA’s current GLP-1 information](https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss).

## What does 10mg or 50mg on a vial mean?

It states the labelled amount of material. It does not independently verify that amount, specify a treatment duration or tell you the concentration of a solution. A concentration such as mg/mL also needs a volume. The [vial-label guide](https://europeanpeptideshop.com/blog/peptide-vials-vs-pens/) explains the difference.

For a blend, a total such as 80mg includes multiple components. It is not 80mg of every ingredient. The [GLOW and KLOW comparison](https://europeanpeptideshop.com/blog/glow-vs-klow-peptide-blends/) shows why a component list and its amounts matter.

## Does 99% purity tell me everything I need to know?

No. Purity, identity and amount are different measurements. An HPLC purity result describes the laboratory measurement under that method; it is not automatically a milligram count or a sterility result. Bachem’s analytical FAQ distinguishes chromatographic purity, gross material weight and net peptide content. [Bachem’s peptide-analysis definitions](https://www.bachem.com/knowledge-center/faq-frequently-asked-questions/).

Use the [plain-English HPLC guide](https://europeanpeptideshop.com/blog/what-hplc-purity-means/) to understand those numbers. If a result is not reported, keep it marked unknown rather than filling in an assumed value.

## What is a CoA?

CoA stands for certificate of analysis: a report of tests performed on a described sample. Check the lab, report number, date, batch and results. A genuine report can still concern another sample or vial size, so authenticity and relevance are separate checks. Follow the [CoA checklist](https://europeanpeptideshop.com/blog/how-to-read-peptide-coa/) for a practical example.

## Are NAD+, 5-Amino-1MQ and SLU-PP-332 peptides too?

No. They appear in some of the same discussions and catalogues, but their names refer to different kinds of material. NAD+ is a coenzyme; 5-Amino-1MQ and SLU-PP-332 are small molecules. Read the [NAD+ explanation](https://europeanpeptideshop.com/blog/nad-plus-research/) or the [5-Amino-1MQ and SLU-PP-332 comparison](https://europeanpeptideshop.com/blog/5-amino-1mq-vs-slu-pp-332-nnmt-err-research/) before carrying claims across from one to another.

## What should a useful product page tell me?

Look for the exact identity, labelled amount, ingredient breakdown where relevant, current availability and applicable report. Price per labelled mg can help compare the same material in different sizes; it cannot rank different compounds by benefit. The [supplier-comparison checklist](https://europeanpeptideshop.com/blog/peptide-supplier-checklist/) brings these checks together.

## EPS documentation

Use the [research catalogue](https://europeanpeptideshop.com/shop/) to check the exact name, labelled amount and format. The [COA library](https://europeanpeptideshop.com/coa/) publishes the original Janoshik reports selected for EPS, retaining the original report client name and any missing batch fields. Literature findings and another supplier's analytical results are not evidence about an EPS batch.

## Laboratory research only

Materials listed on this site are supplied for in-vitro laboratory research and are not for use in or on humans or animals. They are not medicines. This article summarises published work and gives no dosing, administration, treatment or in-vivo guidance. Findings from a study apply to the material and conditions of that study, and they say nothing about any product listed here.

## References

- [National Human Genome Research Institute: peptide definition](https://www.genome.gov/genetics-glossary/Peptide)

- [FDA cosmetics labelling guide](https://www.fda.gov/cosmetics/cosmetics-labeling-regulations/cosmetics-labeling-guide)

- [FDA’s current GLP-1 information](https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss)

- [Bachem’s peptide-analysis definitions](https://www.bachem.com/knowledge-center/faq-frequently-asked-questions/)

## More articles

Compound research · 4 min read

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A plain-English guide to BPC-157: what the studies measured, what a 10mg vial label means, and how to distinguish evidence from unsupported claims.

8 November 2026

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## [Five research peptides compared](https://europeanpeptideshop.com/blog/kpv-mots-c-tb-500-semax-epitalon-explained/)

HHS named six peptides in a US draft policy. What KPV, MOTS-c, TB-500, Semax, Epitalon and BPC-157 are as molecules, and what HHS said about the evidence.

8 November 2026