Established vs Investigational Use
What "established" and "investigational" mean for health products and procedures, how a medicine moves from testing to approval in the United States, and what a trial listing does not prove.
Content last updated . This page has not been medically reviewed.
The words, kept apart
"Established" and "investigational" are plain-language labels used across this library. Regulators use their own terms (approved, cleared, authorized, investigational), so the table shows how we use ours.| Label | What it means here | A question to ask |
|---|---|---|
| Established | Tested in people for a named use, with consistent results; often approved by a regulator for that use | Approved for what use, in which people? |
| Investigational | Being tested; benefit and safety are not yet settled | Is it in a registered trial, and who oversees it? |
| Commercially speculative | Sold or promoted without matching approval or evidence | Who is paid if I say yes? |
What "investigational" means in the United States
The U.S. Food and Drug Administration (FDA) describes investigational medical products as drugs, biologics or devices "being tested to see whether they are safe and effective." [1]Federal law requires a drug to have an approved marketing application before it is shipped across state lines. A sponsor (usually the company) gets an exemption for testing through an Investigational New Drug (IND) application. [2] After an IND is submitted, the sponsor must wait 30 calendar days before starting any clinical trial. [2] An IND lets testing begin. It is not a finding that the product works.
For devices, the FDA says clinical trials of a device in development fall under the Investigational Device Exemption rules. [3]
How a medicine moves from testing to approval
FDA's patient pages describe clinical research in phases. These are the descriptions and rough percentages as that page stated them (page current as of January 2018).| Phase | Who takes part | Main aim |
|---|---|---|
| Phase 1 | Healthy volunteers or people with the condition | Safety and dosage; "approximately 70%" of drugs move on [4] |
| Phase 2 | Up to a few hundred people with the condition | Efficacy and side effects; these studies are not large enough to show whether the drug will be beneficial; "approximately 33%" move on [4] |
| Phase 3 | 300 to 3,000 people with the condition | Show whether the product offers a treatment benefit for a specific population; "approximately 25-30%" move on [4] |
| Phase 4 | After approval | Ongoing safety and effectiveness monitoring [4] |
Before filing a marketing application, a developer must have adequate data from two large, controlled clinical trials, according to the same page. [4] A New Drug Application is meant to show that a drug is safe and effective for its intended use in the population studied. [5] Once an application is complete, the FDA review team has 6 to 10 months to decide whether to approve the drug. [5]
"Safe" here does not mean free of side effects. It means the FDA decided the benefits of the drug for a particular use outweigh the risks. [6] That is why approval belongs to a use, not just a product. See Approved Product vs Approved Indication.
Devices use different words
A device can reach the U.S. market without the same kind of testing as a drug. A 510(k) submission asks the FDA to find a device substantially equivalent to a legally marketed device, and the device may not be marketed until the submitter receives that letter. [3] Premarket approval (PMA) is the most stringent device application. [7] "Cleared" and "approved" are therefore not the same thing, and neither proves that every marketing claim about a device is true.What does not make something established
- A registered trial. The FDA warns that a product's listing in the clinicaltrials.gov database, or a firm's registration with the FDA, does not mean the product is legally marketed. [8] A registry entry says a study was planned or run, not that the treatment works. See Registered Trials vs Published Results.
- A small early study. Phase 2-sized studies are not large enough to show whether a drug is beneficial. [4]
- A laboratory mechanism. A plausible biological pathway is a reason to test, not a result. See Mechanism vs Demonstrated Benefit.
- A clinic offering it. Availability at a clinic does not establish approval.
Using this in practice
Ask three plain questions: approved or cleared by which regulator, for what exact use, and in whom? If the answer is "it is being studied," the FDA says an investigational product should, whenever possible, be used as part of a clinical trial. [1] Some serious conditions have a separate regulated route, described in Expanded Access. For the steps of testing, read Clinical-Trial Phases Explained, and for how this library words evidence, see How We Label Evidence in Specialty Topics. Talk with your own clinician before relying on any of this for a decision.Frequently asked questions
Is "investigational" the same as "experimental"?
In everyday speech, yes: both mean the product is still being tested. The FDA says investigational products have not yet been approved or cleared and have not been found safe and effective for their specific use. [1]
Does an IND mean the FDA thinks a treatment works?
No. An IND is the route a sponsor uses to obtain an exemption so that testing in people can start. [2] Approval comes later, from a marketing application backed by trial data. [5]
Can a product be established for one use and investigational for another?
Yes. A drug can be approved for one condition and studied for another, and a physician may even run a study of an approved product for a new indication. [2] Each use is judged on its own evidence.
If a clinic lists a trial, is the treatment approved?
No. The FDA says appearing in clinicaltrials.gov, or registering with the FDA, does not mean a product is legally marketed. [8]
Does "established" mean risk-free?
No. Even approved uses have side effects; approval means the benefits outweighed the risks for that use. [6]
References
- U.S. FDA, Expanded Access: Information for Patients (page current as of 10/22/2026). Read 2026-10-22.
- U.S. FDA, Investigational New Drug (IND) Application. Read 2026-10-22.
- U.S. FDA, Premarket Notification 510(k). Read 2026-10-22.
- U.S. FDA, The Drug Development Process, Step 3: Clinical Research (page current as of 01/04/2018). Read 2026-10-22.
- U.S. FDA, The Drug Development Process, Step 4: FDA Drug Review (page current as of 01/04/2018). Read 2026-10-22.
- U.S. Food and Drug Administration (FDA), Understanding Unapproved Use of Approved Drugs "Off Label" (page current as of 02/05/2018). Read 2026-10-22.
- U.S. FDA, Premarket Approval (PMA). Read 2026-10-22.
- U.S. FDA, Important Patient and Consumer Information About Regenerative Medicine Therapies (posted June 3, 2021; page current as of 04/08/2024). Read 2026-10-22.