Pre-med requirements include a set of science and non-science courses, the MCAT exam, clinical experience, and letters of recommendation. There is no single universal checklist: each medical school sets its own prerequisites. But the overlap across schools is significant enough that you can map out a clear path. Here’s what most MD and DO programs expect.
Required Science Courses
The core science prerequisites have been remarkably consistent for decades, though schools have added to the list in recent years. At most programs, you’ll need all of the following:
- Biology: Two semesters (8 credit hours) with lab. This usually means introductory biology covering cell biology, genetics, evolution, and ecology.
- General Chemistry: Two semesters (8 credit hours) with lab. Covers atomic structure, chemical bonding, reactions, thermodynamics, and equilibrium.
- Organic Chemistry: Two semesters (8 credit hours) with lab. Focuses on carbon-based molecules, reaction mechanisms, and functional groups. Some schools count this as part of your overall chemistry requirement of 8 to 16 credit hours.
- Physics: Two semesters (8 credit hours) with lab. Introductory physics covering mechanics, electricity, magnetism, waves, and optics.
- Biochemistry: One semester (3 to 4 credit hours), increasingly required as a standalone course rather than just recommended. Some schools, such as those in the University of California system, require up to 8 credit hours of biochemistry.
Labs matter. Many schools specify that laboratory components must be completed in person, so online-only lab courses may not satisfy the requirement. If you took virtual labs during the COVID-19 pandemic, most schools made exceptions for that period, but the expectation has generally returned to hands-on work.
Required Non-Science Courses
Medical schools want evidence that you can write clearly, think critically, and understand human behavior. The most common non-science prerequisites are:
- English or Writing: Two semesters (6 credit hours) of English, composition, rhetoric, or writing-intensive literature courses.
- Mathematics or Statistics: One to two semesters (3 to 6 credit hours). Some schools want calculus, others want statistics or biostatistics, and many accept either. Statistics is arguably more useful for interpreting medical research, and it appears on the MCAT.
- Psychology and Sociology: One semester each (3 to 6 credit hours total). These behavioral and social science courses are now tested heavily on the MCAT, making them effectively required even at schools that list them as “recommended.”
A handful of schools add less common requirements. One program requires 6 credit hours of anthropology. Others ask for specific ethics or humanities coursework. Since requirements vary, check the AAMC’s Medical School Admission Requirements (MSAR) database, which lists prerequisites for every accredited MD program. It costs a small fee but saves you from missing a course that a target school requires.
Choosing a Major
You do not need to major in biology or any science. Medical schools accept applicants from every undergraduate major, including English, history, engineering, and music, as long as you complete the prerequisite courses. About half of medical school matriculants majored in biological sciences, but that reflects self-selection more than admissions preference. What matters is your GPA in the prerequisite courses and your overall GPA, not the name of your major.
If you choose a non-science major, you’ll simply layer the required science courses on top of your degree requirements. This typically works out to about 30 to 40 credit hours of science prerequisites, which fits comfortably into a four-year plan if you start early.
The MCAT Exam
The Medical College Admission Test is a standardized, computer-based exam required by virtually all MD and DO programs. It has four multiple-choice sections, each scored separately:
- Chemical and Physical Foundations of Biological Systems: 59 questions in 95 minutes. Tests general chemistry, organic chemistry, physics, and biochemistry in biological contexts.
- Critical Analysis and Reasoning Skills: 53 questions in 90 minutes. Passage-based reading comprehension that requires no specific content knowledge, similar to the reading sections of other standardized tests.
- Biological and Biochemical Foundations of Living Systems: 59 questions in 95 minutes. Tests biology, biochemistry, and organic chemistry.
- Psychological, Social, and Biological Foundations of Behavior: 59 questions in 95 minutes. Tests psychology, sociology, and biology as they relate to human behavior and health.
Each section is scored from 118 to 132, for a total score range of 472 to 528. The median score is 500. Competitive applicants to mid-tier MD programs typically score around 510 to 515, while the most selective programs often see median scores above 520.
The MCAT draws from the same disciplines you’ll cover in your prerequisite courses. The AAMC describes the science sections as organized around ten “foundational concepts” that pull from year-long introductory courses in general chemistry, organic chemistry, physics, biology, biochemistry, psychology, and sociology. Most students take the MCAT in the spring or summer after completing their prerequisites, typically at the end of junior year.
GPA Expectations
Medical schools evaluate two GPAs: your cumulative GPA and your science GPA (which includes all biology, chemistry, physics, and math courses). Both are recalculated by the centralized application services regardless of what appears on your transcript. A science GPA of 3.5 or above makes you competitive at many programs, while top-tier schools typically enroll students with science GPAs closer to 3.7 or higher. Below a 3.0 science GPA, your chances drop significantly at most allopathic (MD) programs, though some osteopathic (DO) programs may be more flexible.
Grade trends matter too. An upward trend, where your later semesters are stronger than your first year, works in your favor. A downward trend raises red flags even if your cumulative number looks fine.
Clinical Experience and Shadowing
Prerequisite courses and test scores get your application past initial screens, but clinical experience is what convinces admissions committees you understand what a medical career actually looks like. Most programs expect two types of exposure:
Physician shadowing means observing a doctor during patient encounters. There’s no universal hour requirement. The AAMC suggests arranging something that fits both the doctor’s schedule and your interest level, whether that’s a single day, a few hours per week over several months, or a full-time week during a break. Most pre-med advisors recommend accumulating at least 40 to 100 hours across multiple specialties so you can speak knowledgeably about different practice settings. That said, in a 2016 AAMC survey, 87% of admissions officers indicated they accept an alternate activity in place of clinical shadowing, so it’s not always a strict gatekeeper.
Direct patient contact carries more weight than passive observation. Working as an EMT, medical scribe, certified nursing assistant, or hospital volunteer where you interact directly with patients demonstrates that you’re comfortable in clinical settings. Many successful applicants log several hundred hours of direct patient care by the time they apply.
Research Experience
Research is not a formal prerequisite at most schools, but it has become a de facto expectation, especially at research-intensive programs. Admissions committees want to see that you can think scientifically, ask good questions, and work on a problem over time. A meaningful experience typically means at least one to two semesters in a lab or research project, ideally resulting in a poster presentation, publication, or thesis. Clinical research, bench science, public health studies, and social science research all count.
Extracurriculars and Community Service
Medical schools look for sustained commitment over scattered participation. Admissions committees generally value depth in a few activities over a long list of brief involvements. Community service, leadership roles, teaching or tutoring, and work with underserved populations all demonstrate the interpersonal qualities schools want. The common thread is showing that you’ve engaged meaningfully with other people, especially people from different backgrounds than your own.
Letters of Recommendation
Most medical schools require three to four letters of recommendation, and who writes them matters. The typical expectation includes at least one letter from a science faculty member who taught you in a prerequisite course, one from a non-science faculty member or professional supervisor, and one from a physician or clinical supervisor who observed your work with patients. Some schools cap the number of letters at three, while others accept up to six or more.
Requirements vary by school. One program might require at least one letter from a life sciences or physical sciences professor. Another might want three academic or professional letters plus a fourth non-academic letter from a mentor. A pre-health committee letter, if your college offers one, can sometimes substitute for multiple individual letters. Start building relationships with potential recommenders early, ideally by your sophomore year, so they have enough interaction with you to write something specific.
Situational Judgment Tests
A growing number of medical schools now require a situational judgment test as part of the application. These are online assessments that present hypothetical scenarios and ask you to evaluate possible responses, measuring interpersonal skills, ethical reasoning, and professionalism. The two most common tests are the AAMC PREview exam and Acuity Insights’ CASPer. Each school specifies which test it accepts. For the 2027 application cycle, the AAMC lists participating schools that require a situational judgment test, with the PREview score satisfying that requirement. You can submit your application before completing the test, but schools may not consider your file complete until they receive a score.
Timeline for Completing Requirements
Most students apply to medical school during the summer between junior and senior year of college, which means you need to finish nearly all prerequisites before that point. A typical schedule looks like this:
- Freshman year: General chemistry (both semesters with lab), introductory biology (both semesters with lab), English or writing courses.
- Sophomore year: Organic chemistry (both semesters with lab), math or statistics, psychology, sociology. Begin clinical volunteering or shadowing.
- Junior year: Physics (both semesters with lab), biochemistry, upper-level electives. Take the MCAT in spring or early summer. Continue research and clinical hours.
- Senior year: Complete remaining coursework, submit secondary applications, interview.
If you decide on medical school later in college or after graduating, you can complete prerequisites as a post-baccalaureate student through formal post-bacc programs or by enrolling in individual courses. This path typically adds one to two years before you’re ready to apply.