Understanding the Role of a Medical Science Liaison (MSL)

Updated: 2 days ago

Introduction: What Does a Medical Science Liaison Really Do?

The Medical Science Liaison (MSL) role is well-established in the pharmaceutical industry. However, it remains misunderstood—even by some in the field. Job descriptions may mention “scientific engagement” or “stakeholder mapping,” but the actual responsibilities of MSLs go far deeper than these buzzwords.

In this blog, we will break down the full job description of an MSL. This includes what MSLs do, why their work matters, how they interact with internal and external stakeholders, and why this role is critical in today’s pharmaceutical ecosystem.

Core Purpose of the MSL Role: Scientific Engagement, Not Sales

At its core, the MSL serves as a field-based scientific expert. They are the bridge between the pharmaceutical company and the external medical community. The primary objective is a peer-to-peer scientific exchange, not product promotion.

MSLs engage with Key Opinion Leaders (KOLs)—healthcare professionals and influential physicians—on high-level clinical and scientific topics. Their value lies in their credibility, not their sales skills. This is what sets MSLs apart: they are not commercial representatives. Their success hinges on the quality of their scientific conversations and the trust they build with thought leaders in their therapeutic areas.

What Scientific Engagement Looks Like in Practice

Scientific engagement involves more than delivering slide decks. MSLs must:

Understand clinical data in detail, including mechanisms of action, safety profiles, and statistical rigor.
Respond to complex scientific questions from KOLs. For example, “Is there any emerging real-world evidence comparing Drug A and Drug B in diabetic patients with renal impairment?”
Bring back insights from the field. This includes data on patient adherence, treatment gaps, and unmet needs. These insights can inform strategy development, publication plans, and even protocol changes in ongoing trials.

These insights aren’t just informational; they are strategic inputs that shape medical plans and market access strategies.

Stakeholder Mapping and Tailored Engagement Plans

MSLs do not work randomly. One of their most strategic responsibilities is stakeholder mapping, which includes:

Identifying the most influential experts at a regional or national level.
Segmenting these experts based on their academic contributions, research interests, and collaboration potential.
Creating tailored engagement plans for each stakeholder.

For instance, during a lung cancer product launch, MSLs might engage academic oncologists involved in clinical trials differently from community physicians who need scientific updates and patient case support.

MSLs and Internal Collaboration: Working Within Medical Affairs

Though field-based, MSLs maintain strong connections with internal cross-functional teams. They:

Support advisory boards, participate in scientific strategy meetings, and assist with training initiatives.
Capture and report essential field insights to facilitate internal knowledge sharing.
Collaborate on developing educational content, speaker programs, or post-congress summaries.

Importantly, all of these activities adhere to a strict compliance framework. MSLs do not promote products or engage in commercial discussions.

Medical Insight Generation: One of the Most Impactful Contributions

After engaging with KOLs, MSLs capture insights through structured platforms. These insights are crucial as they:

Help identify treatment trends and unmet clinical needs.
Guide medical strategies and publication plans.
Inform amendments to protocols or Health Economics and Outcomes Research (HEOR) modeling.

Well-documented insights are invaluable; they transform anecdotal feedback into actionable knowledge that benefits the entire organization.

Scientific Congresses, Symposia, and Continuous Learning

MSLs regularly attend medical congresses to stay current with emerging data. They engage with investigators and experts. Their responsibilities can include:

Hosting scientific booths.
Supporting scientific symposia.
Delivering post-congress summaries within their organizations.

MSLs contribute to speaker training as well, helping experts prepare presentations, anticipate difficult questions, and relay data with scientific accuracy. Lifelong learning is vital. Beyond formal training, the best MSLs follow journals, attend webinars, and monitor global guidelines in their spare time.

Compliance: The Backbone of the MSL Role

Compliance is critical in the MSL role. MSLs must adhere to strict ethical standards, including:

No off-label discussions.
No pricing or reimbursement information.
Accurate documentation of all engagements.
Full adherence to the company’s Code of Conduct and legal requirements.

These regulations protect the role's credibility and ensure trust within the medical community remains intact.

How MSLs Are Measured: Beyond the Number of Visits

Currently, performance metrics are evolving toward a focus on quality rather than quantity. Key Performance Indicators (KPIs) now include:

Quality of scientific engagement.
Generation of strategic insights.
Coverage and segmentation of stakeholders.
Contributions to training.
Feedback from KOLs regarding value and relevance.
Participation in collaborative projects.

This holistic approach guarantees that MSLs receive recognition for their impact, not merely their activity.

Conclusion: The MSL as a Strategic Partner in Pharma

The Medical Science Liaison is no longer an obscure role. MSLs serve as strategic partners in medical affairs. They translate complex science into meaningful conversations that inform strategies and ultimately enhance patient care.

If you enjoy science, thrive on expert dialogue, and want to work at the intersection of research and real-world application, this role might be your calling.