On July 21st 2025, the Chemical Probes Portal celebrates its 10th anniversary—marking a decade since its launch was announced through the online publication of the seminal Nature Chemical Biology paper by Arrowsmith and colleagues.

Authored by leading chemical biologists and drug discovery scientists, and titled “The promise and peril of chemical probes” this foundational paper drew attention to the power of chemical tools to determine the function of proteins in complex biological systems – and at the same time highlighting the continued widespread use of nonselective or poorly characterized small molecule reagents and also the uncritical usage of chemical tools.

The impact of the paper is shown by its garnering >920 citations in the ten years since its publication.

In addition to providing advice and consensus guidelines, this call-to-action paper envisaged the need for a community-driven resource to help ensure the informed and responsible use of chemical probes – a vision that gave birth to the Portal.

Great progress has been made over the last decade, but there is still much to do, as discussed in a recent Portal publication by Müller et al in Cancer Cell. This article focuses on applications to cancer research, but the messages are generic across biological and medical fields.

An early highlight was the inclusion on the Portal of (+)-JQ1, a potent and selective BET bromodomain inhibitor, which quickly became among the Portal’s most highly referenced probes. The availability of JQ1 and related probes empowered researchers to explore chromatin biology, oncology, and beyond.

Fulfilling its mission to offer free, user-friendly access to expert-reviewed data on high-quality chemical probes, the Portal has grown into a critical repository for biomedical research. It connects researchers with meticulously validated probes, precise guidance, and best-practice protocols, empowering studies that rely on on-target activity and the need for careful controls.

Over the last decade, the Chemical Probes Portal has expanded beyond a trusted expert-curated probe list to become an educational hub, providing guidance on probe selection, best practice usage, and misuse avoidance. Especially now that chemical probes are moving beyond simple inhibitors to encompass increasingly more complex and sophisticated mechanisms of action – such as covalently-acting reagents, PROTAC degraders and molecular glues – the availability of expert guidance is ever more vital.

Now entering its second decade, the Portal continues to serve as an indispensable resource, supporting scientific discovery with robust, well-characterized tools and topical advice. The Portal also organizes Hackathons to train early career researchers in the assessment of chemical probes.

Cheryl Arrowsmith, co-author of the 2015 paper that catalysed the Portal, said:

“We noticed that many biologists, not trained in chemistry or chemical biology, often used chemical reagents without critical assessment of their on-target and off-target activities and properties. We realized that a resource was needed to help guide the non-specialist scientists to choose the best chemical tool for their experiments.”

Paul Workman, also a co-author and current Executive Director of the Portal, added:

“From the initial grand vision and small beginnings, I’m proud to see the tremendous growth of the Portal – which now hosts 1163 compounds, covering 614 protein targets, and features a total of 1623 probe assessments provided by our amazing panel of over 250 Scientific Expert Reviewers. In addition, our Portal web site (www.chemicalprobes.org) provides a wealth of information on selecting and using chemical probes in biomedical research.

“But we still have a long way to go to expand our protein coverage, incorporate new chemical modalities, and also reach out further to experimental biologists who are commonly not aware either of the challenges we face with chemical probes or the solutions we offer on the Portal”.

A Decade of Advancing Chemical Biology: The Chemical Probes Portal Celebrates Ten Years