I have hundreds of followers on my Instagram. I don't have that many yet on my FB page, but it's steadily growing. My followers are not all reviewers either; many are just plain consumers. I have a great mixture of male and female, young and older, all races and nationalities. So there's a good chance someone is going to see your product and want to buy it! Pluse I hashtag all my reviews with your company name, product brand (if different,) and many things that will draw people to look at my review, and start following me. I also throw in other reviews (normal everyday things) as well as just regular posts, to keep my followers interested and engaged.