1. In-vitro evidence
Findings come from cells, tissues or biochemical systems studied outside a living organism. Such findings describe what a compound can do in a controlled system, not what it does in a person.
Peptide research, clearly explained.
Independent educational information on peptide science, laboratory standards and the current research landscape.
Starting points
What this site is for
A peptide is a short chain of amino acids joined by peptide bonds. The definition is structural: it describes how a molecule is built, not what it does. Peptides are studied because they sit between small molecules and proteins — straightforward enough to synthesise and modify systematically, specific enough to probe how proteins interact with one another.
That breadth is also why peptide literature is difficult to read well. Almost any peptide can be connected to a plausible-sounding mechanism, and plausibility is cheap. What separates a mechanism from a result is whether an effect was measured in a living organism, whether that organism was human, whether the study was controlled, and whether anyone independent has reproduced it.
Most published findings about peptides come from cells and animals. Comparatively few come from adequately powered human trials. An experimental finding is a reason to keep looking, not a conclusion about people, and treating the two as interchangeable is the single most common error in how this field is summarised.
Everything here is written to keep that distinction visible. Each compound profile reports evidence level by level and states plainly where a level is empty. Each regulatory statement links to the body that made it. Where something has not been verified, the page says so rather than leaving a reader to assume it has.
Evidence framework
Four levels, kept separate
This framework is applied consistently across the research library. A finding is described at the level it was actually obtained, and never promoted to a level it has not reached.
2. Animal evidence
Findings come from studies in living non-human animals. Species differences in physiology, metabolism and dosing mean animal results frequently do not carry over to humans.
3. Early human evidence
Findings come from small, early-phase or observational human studies. These are typically short, sparsely replicated, and designed to examine tolerability or signal rather than to establish effect.
4. Established clinical evidence
Findings come from adequately powered, replicated controlled trials in humans, generally supported by regulatory assessment or systematic review.
A fifth state, “evidence not yet assessed”, applies to records whose literature no editor has reviewed. It is a statement about our review process, not about the compound.
Research library
How a research profile reads
The library currently contains worked examples built on fictional compounds. They exist so the structure of a profile can be examined without publishing claims about a regulated substance before it has been reviewed.
Peptide
Illustrative Compound ALPHA-1
Also known as ALPHA-1, Teaching example A
A fictional research peptide used to demonstrate how Terminus Peptides presents a compound overview. ALPHA-1 does not exist.
In vitro — evidence level 1 of 4: In-vitro evidenceNot a medicine — UK regulatory status: Not classified as a medicinal product
Read the research profile
Peptide analogue
Illustrative Compound BETA-2
Also known as BETA-2, Teaching example B
A fictional peptide analogue used to demonstrate how a profile reads when the underlying evidence is limited to animal work. BETA-2 does not exist.
Animal — evidence level 2 of 4: Animal evidenceNot a medicine — UK regulatory status: Not classified as a medicinal product
Read the research profile
Educational topics
Where readers usually start
- Understanding peptide purityWhat a purity percentage measures, and the three structural reasons it is narrower than it sounds.
- What a certificate of analysis actually showsA certificate records specific tests on a specific batch. Most questions people bring to one are not questions it answers.
- Research evidence versus clinical evidenceFour evidence levels, what each can support, and how to read the gaps between them.
- How peptide stability is studiedReal-time, accelerated and forced-degradation designs, and why a method has to be shown capable of detecting change.
- UK regulation of medicinal productsHow medicines are classified in the UK, what advertising restrictions apply, and where the authoritative sources are.
Articles
Longer explanations
Terminology · Biochemistry
What is a peptide?
A peptide is a short chain of amino acids. That simple definition hides most of what actually matters — where the boundary with proteins sits, why sequence is not the whole story, and why two vials labelled with the same name are not necessarily the same substance.
6 minute read · reviewed 17 August 2026
Evidence · Study design
Research evidence versus clinical evidence
Most published findings about peptides come from cells and animals. Very few come from adequately powered human trials. The distance between those two positions is not a detail — it is the single most useful thing to hold in mind when reading about any compound.
7 minute read · reviewed 17 August 2026
Laboratory standards · Quality
What a certificate of analysis actually shows
A certificate of analysis records what specific tests found in a specific batch on a specific date. It is a useful document and a frequently misread one. Most of the questions people bring to a certificate are not questions it answers.
6 minute read · reviewed 17 August 2026
Research updates
Hear when something new is published
Occasional emails when a research profile clears review, when an article goes up, or when a regulatory position we have written about changes. Nothing else.