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Placebo in Clinical Trials: What You Need to Know

Published 02 Oct 20263 min read
Written by
Łukasz Izbicki
Placebo in Clinical Trials: What You Need to Know
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What is a Placebo?

A placebo is a substance designed to look like the real treatment but it has no therapeutic effect. Placebos help researchers compare outcomes between the actual treatment and "no treatment" to determine if the new therapy is effective.

The Placebo Effect: Why Some Patients Feel Better

The placebo effect is an improvement in symptoms that occurs simply because patients believe they are receiving treatment, even if it’s just a placebo. The power of this effect highlights the mind-body connection and can be influenced by factors like the appearance of the placebo and the patient’s expectations.

Summary: The placebo effect demonstrates how belief in treatment alone can sometimes improve symptoms.

Active Treatment vs. Placebo: What’s the Difference?

Comparison of Active Treatment and Placebo

The Role of Placebo-Controlled Trials

Placebo-controlled trials are key for understanding whether a treatment truly benefits patients. By comparing the active treatment group with the placebo group, researchers can identify any real improvements due to the treatment itself. However, not all trials use placebos; some compare new treatments with existing therapies, especially if withholding treatment could be risky.

Types of Placebo-Controlled Trials

  • Single-blind trials: Only participants do not know whether they receive the treatment or placebo.
  • Double-blind trials: Both participants and researchers are unaware of who receives the treatment or placebo. This method reduces bias and helps ensure accurate results.
  • Open-label placebo trials: Patients are informed they are receiving a placebo. Surprisingly, even knowing this, some patients still experience symptom improvement, as the act of taking "treatment" and the attention from healthcare providers can contribute to feeling better.

Summary: Placebo-controlled trials help determine if a treatment offers real benefits, though not all trials include placebos, particularly when it might be unsafe to withhold treatment.

Non-Placebo Studies: Why They Matter

In non-placebo studies, all participants receive active treatment. This approach is preferred by patients who want immediate access to a new therapy. On our platform, these trials are marked with an extra star for easy identification, as they provide greater certainty that participants will receive active treatment, not a placebo.

Summary: Non-placebo studies guarantee that all participants receive active treatment, and these trials are highlighted on our platform for patient convenience.

How We Rate Clinical Trials on Our Platform

To help you find the right trials, our platform highlights placebo-free trials with an extra star. This allows you to quickly spot studies where you’re guaranteed active treatment if that’s your preference.

If you are interested in further understanding how we evaluate and score the trials listed on our platform, we invite you to read our detailed article.

Key Takeaways

  • Placebos are inactive substances used in trials to measure a new treatment’s effectiveness.
  • Placebo-controlled trials help establish if a treatment has a real impact.
  • Some trials do not use placebos, which we highlight for easy identification on our platform.
  • Knowing if a trial involves a placebo can help you make informed choices about participating.
Share this articleEmailLast updated 02 Oct 2026

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On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).