Whether an SMP is going to be for your depends on your situation:
If you have a large number of hours at a low cumulative uGPA, just taking a few science courses is not likely to raise that cGPA very much. This becomes problematic if you apply to a school that screens by uGPA (not all schools do this).Things like upward trend are helpful but SMPs are a good application enhancer if you have significant ground to cover in terms of getting your uGPA into a competitive range.
The downside of SMPs are that you need an outstanding performance in this type of program. You have to be ready to give your studies priority as these programs are expensive and demanding. This is why they are great for showing that you would be able to navigate a demanding medical school curriculum.
If you don't do well in an SMP and you have a low uGPA, you could run the risk of "tanking" your chances. In short, an SMP is a "last-ditch" and a "second-chance" for those who have some uGPA "damage-control" to accomplish. Again, be ready to make your studies a priority.
Some SMPs will have you taking the same courses as medical students but with different performance criteria. This too can be problematic in that you as an SMP would be expected to perform at a higher level in order to "prove" yourself whereas the medical student just has to pass. Again, be prepared for this situation if you happen to enroll in one of these types of programs.
There are also certificate programs for people who need grade enhancement for medical school application. Virginia Commonwealth University has one of these types of programs. Again, you need a strong performance but you are likely not competing against medical students. These type of programs can also provide you with counseling and extra-curricular activity assistance.
Also be aware that some SMPs will want either a GRE or MCAT score. If you haven't taken those classes(non-science majors), then you would need to take the pre-med prerecs before you sit for the MCAT and before you could enter an SMP. There are specific post bacc programs out there for non-science majors so investigate these too.
Bottom line: Go to the AAMC website and search for post-bacc programs. You will find a listing of all types of these programs both at the undergraduate and graduate level. Investigate thoroughly and pick the ones that will allow you to get yourself competitive in the shortest amount of time with the least amount of expense.
