Peptide basics
Four things in this peptide directory are not peptides
On this page
A peptide is a chain of amino acids joined by peptide bonds. It is a structural definition, not a marketing one.
Four compounds tracked here do not meet it: MK-677, enclomiphene, orforglipron and tesofensine.
They are small molecules — enclomiphene contains chlorine, tesofensine contains two chlorine atoms, and none has an amino-acid backbone.
They are here because people search for them alongside peptides, and their pages say what they actually are.
This page explains which compounds in this directory are not chemically peptides and why they are included anyway. It makes no claim about any of them and contains no dose, schedule or route.
What makes something a peptide
A peptide is a chain of amino acids linked by peptide bonds. That is a structural fact you can read off a formula and a structure, and it has nothing to do with what a compound is used for.1
The international naming system encodes it: generic names ending in -tide mark peptides, which is why semaglutide, tirzepatide, liraglutide and pramlintide all share the ending. None of the four compounds below does.2
The four
- MK-677, or ibutamoren: C27H36N4O5S. A non-peptide compound acting at the ghrelin receptor, which is why it appears beside growth hormone peptides.
- Enclomiphene: C26H28ClNO. A selective oestrogen receptor modulator, the same family as tamoxifen.
- Orforglipron: C48H48F2N10O5. A non-peptide GLP-1 receptor agonist, taken orally, with an FDA-approved product.
- Tesofensine: C17H23Cl2NO. A monoamine reuptake inhibitor developed for weight reduction.13
The chlorine atoms in enclomiphene and tesofensine are the quickest tell. Amino acids contain carbon, hydrogen, nitrogen, oxygen and sometimes sulfur. A chlorine in the formula means you are not looking at a peptide.1
Why orforglipron is the interesting one
It acts on the same receptor as semaglutide and produces the same class of effect, and it is not a peptide. It is a small molecule that can be swallowed, with an FDA-approved product and 33 verified trials enrolling 29,343 people.13
That directly undercuts the idea that peptide names a mechanism or a kind of effect. It names a structure, and two molecules with completely different structures can act on the same target.1
Why they are in this directory
Because people look them up here. They are sold in the same channels, listed on the same product pages, and discussed in the same forums as the peptides. Excluding them would leave a gap exactly where readers arrive.3
The obligation that comes with including them is to say plainly what they are, which their individual pages do.1
Common questions
Is a non-peptide worse or better?
Neither. Small molecules are often easier to take orally and cheaper to make. Structure is not a quality ranking.
Is cerebrolysin a peptide?
It is a tissue-derived preparation containing a mixture of peptides and amino acids, rather than a single defined peptide. That is why it has no molecular formula on this site.
How can I check this myself?
Look at the molecular formula on any compound page. Halogens like chlorine or fluorine, or an absence of the repeating nitrogen pattern, indicate you are not looking at a peptide.
Sources
- RegulatoryPubChem PUG REST — compound property serviceNational Center for Biotechnology Information, 2026pubchem.ncbi.nlm.nih.gov/docs/pug-rest ↗↩ Back to text
- RegulatoryWHO — International Nonproprietary Names (INN) programmeWorld Health Organization, 2025www.who.int/teams/health-product-and-policy-standards/inn ↗↩ Back to text
- RegulatoryDrugs@FDA — approved drug products databaseU.S. Food and Drug Administration, 2026www.accessdata.fda.gov/scripts/cder/daf/ ↗↩ Back to text