Submitted by Epidemic

PharmaLinea Clinical Research Recruitment with Influencer Marketing

Epidemic recruited participants for PharmaLinea's clinical research on iron in the blood through Instagram story links from health and sport influencers, generating 1256 applications.

11%average conversion rate
1256completed applications
30%time to goal vs allocated

Case in 60 seconds

PharmaLinea needed applications for clinical research on iron in the body, but ethics advertising rules restricted paid platforms such as Google and Meta, and out-of-home advertising failed to generate enough applications from the desired audience.

The campaign appears to turn on the recognition that recruitment depended on trust rather than reach, because a stranger will only volunteer for a clinical trial once the research reads as safe and personally useful for a symptom such as fatigue.

Rather than advertise the trial, Epidemic had influencers whose own lives intersected with iron deficiency explain the condition and their experience of it, making the research an answer to a problem the audience already recognised.

Sport-related and health-focused influencers, along with a few doctors, posted Instagram stories combining facts about iron in the body with personal accounts of iron-related health issues, linking directly to the application form, with UTM links tracking clicks, sessions and completed forms.

Epidemic reports that 1256 applications were received through influencer links posted on their stories, at an average conversion rate of 11%, with a peak of 25%, and that the goal was reached in less than 30% of the time allocated.

Strategy Breakdown

The primary strategy-learning section — interpretation, not a press-release summary.

People aged 18 to 50 who met the criteria for clinical research on iron in the blood, including athletes and women at higher risk through menstruation, and excluding pregnant people.
Clinical research asks for a commitment strangers rarely give, and the page describes the campaign having to counter that by conveying that participation was safe and gave people information about their own health conditions.
Ethics advertising rules restrict how clinical trials can be promoted on Google and Meta, so a category with a genuine recruitment need was left with limited scope for reaching its audience through paid channels.
PharmaLinea positioned itself as a company that invests time, knowledge and resources into research, and the page reports the campaign enhanced that image while filling a contact database for future work.
Fatigue is a symptom people already notice in themselves without attributing a cause, so content that named insufficient iron as a possible explanation gave viewers a reason to act on something they were already carrying.

Creative & Execution System

Assets & channels

  • Instagram
  • Instagram stories

Partners

  • Epidemic (lead_agency)

Participation mechanic

  • Followers tapped the link an influencer added to an Instagram story and completed a research application form on the website in one click.

Creator role

  • a few doctors
  • health-focused influencers
  • sport-related influencers

Results & Evidence

MetricValueResult type
average conversion rateThe average conversion rate for the campaign was 11%, with a peak of 25% achieved through the selection of the right influencers and optimisation.performance
completed applications1256 applications were received through influencer links posted on their stories.content_pieces
time to goal vs allocatedThe goal of the campaign was achieved in less than 30% of the time allocated for the campaign.performance

Why Epidemic's strategy worked

  1. 1

    Where regulation closes paid social to a category, creator audiences remain reachable, because the message travels as an influencer's own account of a health issue rather than as an ad unit subject to platform ethics rules.

  2. 2

    Screening influencers on follower composition, here an age range of 18 to 50 and the exclusion of pregnant followers, does recruitment work upstream, because unqualified applications cost the client screening time without advancing the trial.

  3. 3

    The gap between an 11% average and a 25% peak suggests that conversion on recruitment campaigns is set by fit between influencer and criteria rather than by volume, so reallocating towards the best performing accounts is the main lever available mid-campaign.

  4. 4

    Pairing factual explanation with personal testimony gives an audience both a reason to care and a way to self-diagnose, which converts passive interest into an application because the viewer recognises their own symptoms in the story.

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