Although faculty are preferred as evaluators by admissions committees, if you have had graduate teaching assistants in some laboratory or discussion sections, you may ask one of them for a letter and have the instructor in charge of the course endorse the letter in the space provided. Do this for at most one recommendation. In large university classes this procedure is fairly common. Junior college and other transfer students may wish to ask for letters from at most one or two professors at the schools in which they were previously enrolled. Applicants at the University of Florida typically submit 3-5 letters of evaluation, depending on to which schools they apply.
Most applicants also request one or two personal letters of recommendation.
These may come from employers, a volunteer coordinator, a physician that you shadowed, a research supervisor etc. These personal letters are to be written on letterhead, but they may be included in your file. It is best if they come from those who can impartially evaluate your qualities, not indiscriminately praise you. Employers, research supervisors, and faculty advisors to organizations you have been involved with can be helpful because they have had the opportunity to assess characteristics such as your ability to work with others cooperatively better than a family friend. Political letters are not looked upon favorably by most medical schools.