What is a lookalike audience?
A lookalike audience is a group of people an ad platform finds who resemble a seed list, such as past customers or website visitors. For hospitals the seed list is the sensitive part: uploading patient data can reveal health information, so seeds must be lawful under the DPDP Act, consented and non-clinical, and many platforms restrict health-based targeting.
Why it matters for hospitals
Lookalikes can widen reach efficiently for general services like health checks or new branch launches. They can also expose patient data if built from patient lists without consent. Platform restrictions on health targeting mean results are less predictable than in other sectors.
How to put it into practice
- Prefer non-sensitive seeds, such as people who booked a general health check or engaged with brand content.
- Never upload lists defined by diagnosis or treatment.
- Confirm consent and lawful basis with compliance before any customer list upload.
- Test lookalikes against broad targeting; platforms’ broad targeting often performs as well.
- Measure on attended appointments, not on clicks or cheap leads.
The common mistake
Uploading a list of oncology or IVF patients as a seed audience, which risks patient privacy, platform policy breaches and regulatory trouble.
An illustrative example
A hospital tested a lookalike built from consented health check customers against broad targeting for a new branch. Both performed similarly, so it chose broad targeting and avoided uploading any patient data. (Composite example, not a specific hospital.)
Related terms
Further reading
Part of the healthcare growth and digital glossary. Last reviewed 7 October 2026.