How patients actually find and access clinical trials — and why most eligible patients never enroll

A large share of clinical trials struggle to enroll enough participants, and the barriers are more structural than lack of patient interest.

Research on clinical trial enrollment barriers has consistently found that only a small fraction of eligible patients for a given trial actually enroll, and lack of interest isn't the primary driver — studies have found that a substantial share of eligible patients were simply never informed that a relevant trial existed, since trial awareness typically depends on their specific treating physician being aware of and mentioning it, which isn't systematic.

Geographic and logistical barriers compound the awareness gap — many trials, particularly for specialized conditions, are concentrated at academic medical centers, and travel burden for repeated trial visits disproportionately excludes patients without flexible work schedules, reliable transportation, or nearby lodging, which has been documented to skew trial populations away from broader representativeness.

Patient-facing trial registries (like ClinicalTrials.gov) and matching services have improved discoverability somewhat, allowing patients to search directly rather than relying entirely on their physician's awareness, but research on their actual use suggests many patients don't know these tools exist — for anyone with a serious diagnosis where standard treatment options are limited, proactively searching trial registries and asking a specialist directly about trial eligibility, rather than waiting to be offered one, meaningfully changes access odds given the documented information gap.

This article is general health information, not medical advice, and doesn’t replace evaluation by your own physician. Talk to a doctor about anything specific to your own diagnosis or treatment.

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How patients actually find and access clinical trials — and why most eligible patients never enroll

A large share of clinical trials struggle to enroll enough participants, and the barriers are more structural than lack of patient interest.

This article is general health information, not medical advice, and doesn’t replace evaluation by your own physician. Talk to a doctor about anything specific to your own diagnosis or treatment.