The following commentary comes from an independent investor or market observer as part of TheStreet's guest contributor program, which is separate from the company's news coverage.NEW YORK ( MagicDiligence.com) -- Nature's Sunshine ( NATR) is a direct selling, multi-level marketing firm. Herbal products account for about half of sales, including remedies for better circulation (Cardio Assurance), blood pressure (Blood Pressurex), and immune system function (Liquid Chlorophyll). Vitamins, minerals and supplements comprise another 43% of sales, catering to a wide variety of both general and targeted outcomes. Personal care, including skin and hair products, round out the portfolio. Nature's Sunshine is an international firm, with 45% of sales originating outside of the United States. Multi-level marketing companies are nothing new to Magic Formula® Investing, or MFI. The direct marketing model involves individuals (known as distributors) recruiting additional distributors to buy and market products, and to recruit further distributors to build out a network. Essentially, this is a low-cost way to build both an advertising and distribution network, leading to high returns on capital.