Post-Baccalaureate Programs
These are programs designed for people who completed their bachelor's degrees but who may not have complete prerequisites. While researching programs, be aware of the following.
Financial Aid
Most of these programs may not offer financial aid and will need to be paid in full or with scholarships. Alternatively, some students employed by universities use their "tuition remission" to cover the cost of attendance. There are some post-baccs which also fall under the category of pipeline programs. Some are paid fellowships but have certain restrictions. The NIH for example has a paid fellowship program, and this one extends to affiliate institutions who receive NIH funding for research.
Degree
Most of these programs do not provide degrees after completion. This is part of the reason financial aid is not offered.
Time
Depending on the number of courses a student needs to complete, and their status as a part-time or full-time student will dictate whether the program will take one, two, or more years to finish. Because some students will still be completing requirements, they may not apply until after the end of the program. This means there would be at least yet another year (as opposed to one summer as a traditional applicant) between finishing the program and starting medical school.
Linkage Programs
These are great programs that have affiliations with specific institutions. Those who are successful may receive an admissions offer to one of the program's affiliate schools. Unlike the situation described under "Timing," these students would begin medical school immediately after completing the program if "matched" or "linked."
Eligibility
Some programs only accept students who have yet to complete most or all of their premed requirements. Some programs are specifically for individuals who have completed their prerequisites and want to enhance their academic background. Be sure to check application requirements before investing too much time looking at certain programs.
Advising and Community
One great aspect of these programs is that they are specifically created for and tailored to premed students. They will be able to provide mentorship and resources. All will vary, but a well-structured program will have MCAT prep, premed advising, application support (during and beyond the program), and access to research and clinical experiences. You will also be surrounded by people with similar goals and pursuits. Not all programs are the same, so if these details are important to you, be sure to ask.
DIY Post-bacc
A formal program may be appealing for many reasons, but it may not always be affordable or appropriate considering the student's situation. Creating your own schedule and curriculum may sound intimidating, but it's possible! Even if it's been years since you have been out of school, the pre-med advisor at your undergraduate institution is a great place to start. If you do not have a pre-med counselor, checkout the National Association of Advisors for the Health Professions. Schools without formal programs may also provide an advisor to help navigate the process.
Recommendations
Students considering a post-bacc program should seriously note the financial burden and time commitment required. If finances are not an issue, think about what you need in your application and what the program will offer. Ask to speak directly with current students, and with alumni if possible. If you are considering a linkage program, it would be best to speak with a student who did not "link." When searching for programs, use databases but do not be confined by them. Use google to find other options at local schools or at institutions that are of interest for medical school.
One place to start: AAMC Post-Bacc database