Clinical trial labels need to fit a great deal of information into very little space. On a vial or syringe, required regulatory text, study-specific data, and multiple languages can result in small fonts and densely packed content. For participants with dyslexia, this can make already complex information harder to read and navigate. The challenge is not only to fit the required information onto the container, but also to organize it in a way that helps participants find what they need.

The complexity of clinical trial information extends beyond the label itself. One study analyzing over 500 participant information sheets found that their average reading level corresponded to ages 15 to 16, whereas a reading age of around 11 to 12 is generally recommended (1).

Direct research specifically measuring the impact of dyslexia on clinical trial labeling is still limited. However, evidence from readability and health literacy research shows that the way information is presented can have a measurable effect on comprehension.

For example, poorly designed medication information has been associated with misunderstandings around dosing, timing, warnings, and treatment duration (2). Studies on medication labeling have also shown that applying evidence-based readability principles can significantly improve understanding, including among people with limited health literacy (3). This suggests that accessible design can reduce barriers.

Making information easier to navigate

Thoughtful label design can make information easier to navigate by creating a clear visual structure. Larger font sizes, more white space, headings, colors, and pictograms can help separate and highlight information. Multi-layer labels, booklet labels, and wrap-around solutions provide the additional space needed. With extensive booklet labels, indexes or tabs can make specific sections easier to find. The goal is not simply to create more space, but to use that space for better orientation.

QR codes and NFC technology can also connect printed labels with digital content, such as audio instructions or videos, creating an additional means of accessing information – which can be particularly useful for people who have difficulty processing written text.

Putting these approaches into practice requires collaboration between sponsors and labeling specialists. The sponsor and relevant specialist departments determine the medical and regulatory content, while labeling specialists advise on how to present it in a physical – and increasingly digital – format. This includes assessing the available space, organizing information on a particular container, and identifying technical solutions that can make it easier to access.

Accessibility should, in my view, be considered from the beginning rather than as an additional requirement at the end of label development. This means thinking not only about how the required information fits on a label, but also about how participants will access and navigate that information.

Clear structures, better navigation, and different ways of accessing information can help participants with dyslexia, but their benefits need not be limited to this group. By helping more participants understand and follow treatment instructions, accessible labeling can support adherence and make clinical trials more inclusive in practice.

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