Approved vs Off-Label vs Investigational Use

Four situations that get mixed up

When a clinic or website says a peptide is "available", it can mean very different things. This page defines the terms using United States FDA pages read on 2026-10-22. Unless another country is named, the statements describe the United States. Rules differ elsewhere, and this is not legal or medical advice. It does not tell anyone to start, stop or change a medicine.

Off-label use

FDA says an unapproved use of an approved drug is often called "off-label." It can mean the drug is used for a disease it is not approved to treat, given in a different way, or given in a different dose. [1] From FDA's perspective, once a drug is approved, health care providers generally may prescribe it for an unapproved use when they judge that it is medically appropriate for their patient. FDA adds that it has not determined that the drug is safe and effective for the unapproved use. [1]

The reasons FDA gives for off-label prescribing include that no approved drug exists for a condition, or that approved treatments have not helped. [1] FDA suggests asking what the drug is approved for, what scientific studies support the proposed use, what the benefits and risks are, and whether a clinical trial is available. [1]

Off-label use depends on an approved drug existing. It is not a pathway for a molecule that has no approved product. Example: tesamorelin has an approved US product, so a prescriber using it for a different purpose would be an off-label question; a product sold online under a similar name is a different question altogether, because FDA has described such products as unapproved new drugs. [5] See tesamorelin.

Investigational use

Once a sponsor wants to test a new molecule in people in the US, it becomes a new drug under the law and the sponsor uses an IND application to obtain the exemption that allows studies to begin. [2] The sponsor must provide nonclinical data on whether the product is reasonably safe for initial testing in humans and must wait 30 calendar days before starting trials. [2] Clinical trials move through phases that look first at safety and dosage, then at efficacy and side effects, then at larger-scale efficacy and adverse reactions. [6] See clinical trials for peptides.

An investigational compound has not been shown to work. Preclinical work answers whether a drug might cause serious harm, and is not a substitute for studies in people. [7][6]

Expanded access

FDA describes expanded access (sometimes called "compassionate use") as a potential pathway for a patient with a serious or immediately life-threatening disease to gain access to an investigational product outside clinical trials when no comparable or satisfactory alternative exists and trial enrollment is not possible. FDA states these products have not been found safe and effective for their specific use. [8] It is a regulated process involving the patient's physician and FDA, not a reason to buy a product from a website.

Compounded products are a separate category

Compounded drugs are not FDA-approved, and a compounded version of a drug is not the approved version. [9] FDA also notes that compounders may not use a bulk substance unless it meets conditions in the law, such as being a component of an FDA-approved drug or appearing on FDA's list. [10] Read compounded medicines for the full picture.

Questions to take to a clinician

• What is this product approved for, and by which regulator?
• If the use is off-label or investigational, what studies in people support it, and what do they show?
• Is the product made by an approved manufacturer, a compounder, or an unknown source?

See talking with a health professional and what medicine approval means.