Introduction
What are peptides
A short, unadorned explanation for a first approach: what they are, why they are administered the way they are and, most importantly, how to tell the ones with real backing from the ones with only marketing.
Short chains of amino acids
A peptide is a chain of amino acids joined by peptide bonds. The difference from a protein is one of size and convention: below roughly fifty amino acids we say peptide; above that, protein. Nothing magical separates the two, only chain length.
That length matters more than it seems. It governs stability, how the molecule crosses membranes, how long it lasts in circulation and by which route it reaches the bloodstream.
Why they are not taken as tablets
The digestive tract is designed precisely to break chains of amino acids: that is how we obtain from food the ones we need. A swallowed peptide is broken down in the stomach before reaching anywhere.
Hence most are injected. And from there a counter-intuitive consequence: below roughly fifteen to twenty kilodaltons, a molecule deposited under the skin passes straight into the capillaries; above that it does not fit, and enters through the lymphatic vessels, a far slower journey. Molecular size decides how fast it acts.
They are not all the same
Very different things live under the word «peptide». Some are approved medicines with years of clinical trials and published cardiovascular outcomes. Others have only been studied in rodents. Others are sold with more enthusiasm than data.
Lumping them together is the commonest and the costliest mistake. A GLP-1 analogue and a tissue-repair peptide share neither evidence, nor regulatory status, nor safety considerations.
How to read the evidence
Every compound on this site carries its real level. It is not decoration: it completely changes what can be claimed about it.
- Clinical evidence
It has human trials and regulatory approval for specific indications. Its use is a matter for a healthcare professional.
- Under investigation
Studied in humans on markers, but without trials supporting efficacy and safety over the medium or long term. Raising a marker is not the same as a clinical benefit.
- Preclinical
The evidence comes from animal or laboratory models. There are no robust human trials. Marketed for research purposes only.
What to demand from a supplier
Three figures separate a serious supplier from the rest. All three should be published, not handed over only if you ask.
Purity
The percentage from HPLC analysis, with the method stated. «High purity» is not a figure, it is an adjective.
Net peptide content
How much actual peptide is in the vial as opposed to salts and residual water. The figure almost nobody publishes, and the one that most changes what you receive.
Batch number
Without a batch, the two figures above correspond to nothing verifiable. The three go together or they are worth nothing.
Where to go from here
The technical sheets cover, compound by compound, mechanism, evidence and considerations. And if you want the full framework, the programme develops it across eleven modules.