Reading key

Approved, investigational, unapproved

Approval answers a different question from evidence: not 'does it work?' but 'has a regulator reviewed this product for this use?'. The three labels are often read as a quality ranking of the molecule, which is not what they are. Here is what each one actually guarantees, and where it stops.

The three labels

Approved drug

A medicines regulator has reviewed one manufacturer's product for one named indication and granted a marketing authorisation. The review weighed manufacturing quality, safety and evidence of benefit, and the licence states exactly what the product may be sold to treat.

What it means in practice: A licensed product exists: made to pharmaceutical standards, batch-tested, supplied with a patient leaflet listing known risks, and covered by a system that collects new side effects and can change or withdraw the licence.
The common misread: That the molecule is safe or effective for anything else — or that a vial of the same peptide bought online is that product. Approval attaches to a manufacturer, a formulation and a stated use, not to a molecule in general.

In this library: Semaglutide, tirzepatide, teriparatide, oxytocin and salmon calcitonin. Bremelanotide holds a US licence but not an EU one — approval is national, not global.

Investigational

The peptide is in human testing. It has passed enough of the early work to be given to volunteers and patients in trials, but no regulator has granted a licence, and the trials may still fail.

What it means in practice: It exists mainly inside studies. Outside a trial, access is narrow — sometimes a named-patient or compassionate-use programme in some countries. Most investigational candidates never reach approval; a promising phase 2 result is not a forecast of a licence.
The common misread: That being in trials predicts approval, or that material sold online is what the trial uses. Trial material is manufactured and tested specifically for that trial.

In this library: Retatrutide, cagrilintide, SS-31, kisspeptin and ARA-290 — each at a different stage, all outside any licence.

Not approved

No authorisation exists, for one of two very different reasons: the compound has never been evaluated for use in people at all, or it was evaluated and refused, withdrawn or abandoned.

What it means in practice: It is sold as a research chemical, a cosmetic ingredient or a supplement — never as a medicine for human use. Purity, dose accuracy and sterility are whatever the seller chose to test; there is no batch release, no recall route and nowhere to report a harm.
The common misread: That unapproved means dangerous, or that a 'research use only' label makes the sale legal. That sentence changes nothing about how authorities classify an injectable intended for human use.

In this library: BPC-157, TB-500, GHK-Cu and ipamorelin were never authorised. Sermorelin is the other case: it once held a licence for growth-hormone testing and lost it.

Side by side

The practical differences sit in four places: who reviewed it, how you get it, what is tested, and who is watching for harm afterwards.

Status	Review	Access	Manufacturing	Safety monitoring
approved drug	Full review of quality, safety and efficacy for a named indication.	Pharmacy or prescription, as a licensed product with a patient leaflet.	Pharmaceutical GMP; batches released and traceable.	Side effects reported to the regulator; label updated as risks emerge.
investigational	Under review through trial phases; no licence granted yet.	Clinical trials, or named-patient schemes where they exist.	Made to pharmaceutical standards for the trial, not as a commercial product.	Trial safety reporting; a serious signal can halt the programme.
not approved	None. Never submitted, or submitted and refused or withdrawn.	Sold as research chemical, cosmetic or supplement — not as a medicine.	Only what the seller tests; no independent assurance of purity or dose.	None. No pharmacovigilance, recalls or reporting route.

Why they disagree

Evidence and approval move separately

One label is about the research, the other about the paperwork and the product. They can point in different directions, and often do.

Semaglutide
Approved and strongly evidenced — for diabetes and for weight management, not for anything else it is promoted for.
Retatrutide
Investigator-favourite, phase 3, and still unlicensed: good trials in progress do not make a licensed medicine.
Sermorelin
Once licensed, then withdrawn. A former approval is not a current one, though sellers rarely mention the difference.
BPC-157
Heavily studied in animals, never authorised for human use, and sold mainly as a research chemical.

What a licence does not cover

Off-label use

Once a medicine is licensed, a doctor may prescribe it for an unstudied purpose. That is legal clinical judgement, but the evidence for that use is a separate question from the label.

Compounded copies

A pharmacy-made version of a licensed peptide is not the licensed product. It has not been through the same review, and its dose accuracy depends on the pharmacy.

Imports and personal orders

A parcel ordered from abroad does not inherit approval from the country it came from. In the EU, an unlicensed medicine brought in for personal use has no quality guarantee.

Cosmetic ingredients

GHK-Cu can appear legally in a cream sold as a cosmetic, because cosmetics make no medical claim. The same peptide in an injectable sold for healing is a different legal object entirely.

The legal layer, briefly: in the EU a substance sold for human use to treat or prevent disease needs a marketing authorisation. Injectable peptides advertised “for research only” sit outside that, and national authorities — in the Netherlands the IGJ — act against sellers who market them for human use. Imported parcels can be stopped at customs. A purity certificate does not change any of this.

Why the evidence level matters more

Approval tells you what has been reviewed. The evidence level tells you how strong the human data are — including for the many compounds that will never be submitted for a licence.

How to read evidence levels