By Patrina Pellett & Sarah Snyder

What Is a Medical Science Liaison (MSL)? The 2025 Career Guide

(Updated annually to keep you ahead in the field)

You’ve probably heard the title before: Medical Science Liaison.

Sometimes it’s whispered like it’s a secret club in pharma. Other times, it’s confused with sales. And if you’ve tried explaining the role to friends or family, you may have gotten the polite nod and the look that says, “I have no idea what you do.”

If that’s you, you’re not alone.

The truth is, the MSL role is one of the most unique and misunderstood careers in the life sciences industry. It’s a job that blends deep science with strategic influence, and when done right, it changes how medicine is practiced.

Whether you’re curious about breaking in, new to the role, or leading a team, this guide will give you the clearest, most current picture of what an MSL is in 2025 and how their impact goes far beyond delivering data. In this 2025 career guide to what is a Medical Science Liaison, we’ll break down the role, how it fits within the bigger picture of Medical Affairs, and why MSLs are one of the most in-demand, high-impact careers in pharma and biotech today.

What Is a Medical Science Liaison (MSL)?

A Medical Science Liaison (MSL) is a field-based medical affairs professional who connects pharmaceutical, biotech, or medical device companies with the healthcare community. Not to sell products, but to share and exchange medical and scientific information that can influence patient care.

MSLs are trusted partners to the top experts in their field, known as Key Opinion Leaders (KOLs), and they play a strategic role in shaping how data, clinical trials, and real-world evidence are understood and applied.

Today, the role reaches far beyond academic KOLs. MSLs now engage across the full healthcare continuum, from leading researchers and community specialists to advanced practice providers (APPs) such as nurse practitioners (NPs) and physician assistants (PAs). These clinicians often guide treatment decisions and shape how therapies are used in real-world practice.

Because each stakeholder group has its own priorities, challenges, and preferred ways of engaging, building access requires tailored strategies. MSLs adapt their approach for each, whether preparing a deep scientific discussion for a researcher or a practical, patient-focused exchange for an APP managing a high patient load. We cover this in depth in our KOL and HCP Access training program for teams. The same principles apply whether you’re earning the trust of a top-tier academic or a high-volume community provider.

💡 Related reading: If you want to understand why companies invest so heavily in these roles, check out our post The $200,000 Question: Why Do MSLs Get Paid So Much?

The MSL Elevator Pitch

An elevator pitch isn’t just for interviews, it’s how you explain your role to anyone, anywhere, in a way that clicks. The words you choose will shift depending on who’s asking, but the essence stays the same: you’re a scientific expert who builds trusted relationships to improve patient care. Every MSL should be able to explain their role in 15 seconds and tailor it to their audience. Here are 4 field-tested versions:

MSL Elevator Pitch For Your Family and Friends

“You know those medicine commercials you see on TV? I’m the person who talks to doctors and other healthcare professionals behind the scenes, helping them understand which treatments are right for which patients. I answer questions about complex medications and share the latest scientific data so patients can benefit from the best possible care.”

MSL Elevator Pitch For Internal Colleagues (Medical Affairs, Market Access, Sales)

“I’m a field-based scientific expert who meets with healthcare decision-makers to exchange insights and support our medical strategy. I bring back real-world perspectives that help us refine our data communication, anticipate market needs, and ensure our work delivers measurable value, all while staying compliant.”

MSL Elevator Pitch For KOLs and HCPs

“I’m part of the medical team for [company/product/therapeutic area]. My role is to provide you with up-to-date, balanced scientific information and learn from your clinical experience. That way, we can make sure new evidence is applied in ways that truly support your practice and benefit your patients.”

MSL Elevator Pitch For Networking or Industry Events

“I’m a Medical Science Liaison, a field-based medical professional who connects our company’s science with the healthcare community. I focus on building relationships with the experts shaping clinical practice so we can share evidence, exchange insights, and work toward better patient outcomes.”

Build Your Own MSL Elevator Pitch

A strong MSL elevator pitch should answer 3 things quickly:

• Who you are (your role and credibility)
• What you do (in plain language)
• Why it matters to them (the value you bring to their world)

Think: Role → Action → Impact

The 3-Step Formula
“I’m a [role/credibility statement] who [what you do] so that [value to them].”

Pro tip: Practice these until they feel natural. You’ll use them more than you think.

What Does a Medical Science Liaison Do?

At its core, the MSL role is about connecting the science to the people who use it and bringing back what those people know to shape company strategy.

MSLs are scientific relationship-builders. They meet with healthcare decision-makers to share meaningful, unbiased medical information and gather real-world insights — all in service of improving patient care.

Think of the MSL role as part scientist, part strategist, and 3 parts connector. Typical responsibilities include:

• Engaging KOLs and HCPs — Building trust through scientific exchange, not promotion.
• Presenting clinical and real-world data — Tailored to the audience’s expertise and interests (storytelling and not data dumping is key here!).
• Gathering field insights — Capturing and communicating what’s happening in clinical practice back to the company.
• Supporting clinical trials — From site identification to investigator engagement.
• Collaborating cross-functionally — Working with medical affairs, market access, and yes, sales, in a compliant way, to align on strategy.

These aren’t one-off tasks. They’re ongoing, relationship-based activities that can have long-term impact on how therapies are adopted and used.

💡 Related reading: If you want to see how MSLs turn strategy into action, read Why a KOL List Isn’t a Territory Plan and how the top performers run their territories like CEOs.

Where Do MSLs Work?

If you picture an MSL in a white coat sitting in a lab all day, think again.

MSLs are field-based medical professionals, meaning they spend most of their time out in the real world meeting with healthcare providers where they work, rather than in a corporate office.

That could mean:

• Academic medical centers
• Community hospitals and clinics
• Private practices
• Integrated health systems
• Conference centers and medical congresses

The “field” is wherever their stakeholders are. For some MSLs, that’s a single city or region. For others, it’s a multi-state territory or even international travel. Your therapeutic area shapes your day-to-day from the size of your territory to the type of KOLs you engage.

Office? What Office?

While MSLs are part of a corporate team, most don’t have a traditional office routine. Their “office” might be a sweet home office setup, multiple monitors, coffee within reach, maybe even a sleeping dog in the background, but their schedule is built around:

• Face-to-face meetings with KOLs and other HCPs
• Virtual scientific exchanges
• Travel to medical conferences
• Collaborating with internal teams remotely

It also means travel is part of the job. Some territories require just a few overnights a month, while others may have you on the road 50–75% of the time (especially for large territories).

Field work is rewarding, but it also comes with unique lifestyle considerations — from travel routines to balancing family life. If you’re curious about what that really looks like, check out these posts from our MSL Mastery community.

💡 Related Reading

• 8 Work Travel Tips for Medical Science Liaisons — Whether you’re clocking a few overnights a month or practically living in airports, these pro tips from experienced MSLs will help you travel smarter, stay organized, and show up ready for every meeting.
• Is the MSL Role Compatible with Being a Parent? — Hear from MSLs and parents on how they balance travel, field time, and family life and the strategies that make it possible.

How Is the MSL Role Different from Sales?

One of the most common misconceptions about the MSL role is that it’s just another form of sales. It’s not and that’s an important distinction for both compliance and how you approach the job.

Sales teams are responsible for promoting approved products and driving revenue. Their success is measured in prescriptions written or units sold.

Medical Science Liaisons, on the other hand, operate within Medical Affairs and are non-promotional. The role is to exchange scientific and clinical information, gather insights from the field, and ensure that healthcare providers have the latest, most relevant data to inform patient care.

That doesn’t mean MSLs work in isolation. In fact, the best MSLs partner closely with sales teams compliantly, aligning on strategic priorities, understanding market needs, and ensuring consistent, evidence-based messaging. Done right, this collaboration benefits patients, strengthens relationships, and helps the organization move faster and smarter.

Think of it this way:

• Sales opens doors and drives adoption.
• MSLs deepen understanding and help make the science stick.

When both roles respect each other’s boundaries and strengths, everyone wins, especially the patients we ultimately serve.

💡 Related reading: If you want to go deeper on building trust and opening doors, read What Sales Reps Understand That MSLs Often Miss and see how top MSLs adapt proven strategies from the best sales reps.

More to Come

This is just the start of the 2025 Career Guide to What Is a Medical Science Liaison.

In the next update, we’ll cover:

• A day in the life of an MSL

• The key skills every MSL needs to stand out

• Career paths, salaries, and breaking into the role

Got thoughts on what else we should include? We’d love to hear from you. Contact us here or send us a message on LinkedIn; your input might shape the next update of this guide.