As 2013 draws to a close and many resolve to lose weight in the new year, weight management will require a year-round commitment. Evidence of this is the successful launch of the Nu Skin Enterprises (NUS 0.87%) weight-loss product ageLOC TR90, which has sold briskly since its launch in September 2013. There are high expectations that the product's success will continue into 2014. Shares of Nu Skin have risen approximately 43% since the product's launch and 229% since the beginning of 2013 .

Nu Skin, which directly sells its products in 53 international markets across the globe, generated more than $2.17 billion in revenue during 2012. For its third fiscal quarter of 2013, the company reported a 76% increase in revenue over last year to $927.6 million. Earnings per share improved by 107% year-over-year to $1.80. Nu Skin noted a 3% negative impact due to foreign currency volatility. The company reported growth in all of its market segments, especially China and the South Asia/Pacific region .

What does the future hold?
Consumers in Asia have responded well to the company's ageLOC TR90 weight management system. During the quarter, the company generated $205 million in sales during a limited-time sales promotion. The global offer is expected to positively affect other regions during the fourth quarter. The full-year 2013 revenue guidance was increased and the company estimates that revenue will range between $3.18 billion-$3.21 billion. Full-year 2013 EPS was estimated to be $5.77- $5.82, though foreign exchange rates are expected to negatively impact earnings by 4% .

According to Research and Markets, the principal markets for weight loss management products and services are North America, Europe, and Asia. China is expected to experience the most growth over the next five years in its demand for weight loss products . These trends fare well for Nu Skin and its TR90 weight management product. The company's investments in the anti-aging market should also generate positive returns, as this market is expected to be valued at $1 trillion by 2025.

For 2014, Nu Skin expects revenue to reach about $3.9 billion for an estimated growth rate of 25%. EPS, expected to grow between 25% and 30%, should range between $7.25-$7.50. The company's focus for the next few years will be on personalized skin care and nutrition, next generation nutrition and home-use devices, and the creation of products that serve local markets .

How will other direct sellers impact Nu Skin?
Nu Skin's TR90 product competes directly with Herbalife's (HLF 1.65%) popular Formula One shakes. While Nu Skin has seen a strong response in Asia, Herbalife gets more sales in North America, the global market leader for weight loss. The company also provides its customers with social support through nutrition clubs, fit camps, and weight loss challenges. This has increased the number of customers and the daily use of Herbalife products. In the first six months of 2013, 150,000 new U.S. members joined Herbalife, and more than 75,000 joined in the third quarter alone .

Herbalife's net sales for the third quarter rose 19% from the prior year to $1.2 billion. Adjusted EPS grew 44% from last year to $1.41. Operating cash flows also grew to more than $220 million . Despite the negative publicity the company has received, a recent reaudit of its financial statements for fiscal years 2010, 2011, and 2012 found no material issues . The company is currently working on new products for the sports nutrition and personal care segments.

Another direct seller, Avon Products (AVP), competes with Nu Skin's skin care line. On its website, Avon markets itself as a "company for women," though it does have fragrances and personal care products for men. The company sells mostly personal and beauty care products, along with some fashion and home items. Unlike Herbalife and Nu Skin, Avon does not sell weight loss products. Avon has more than 6 million sales reps who are located in over 100 countries .

Avon's fiscal 2013 third quarter revenue decreased 7% to $2.3 billion. Diluted EPS decreased to ($0.01) versus $0.07 reported in 2012's third quarter. The North American market continues to drag down results for Avon, as the company works on reaching its three-year financial goals.

In December, the company announced a major cost-cutting initiative expected to deliver $400 million in expense reduction by 2016. The changes expected include the elimination of about 650 positions and a halt to the roll-out of the company's service model transformation, or SMT, project. The SMT project included a new and improved order management system that did not deliver the desired results .

My Foolish conclusion
Nu Skin Enterprises is operating in two business segments that have high growth expectations over the long term -- anti-aging and weight loss. Unless macroeconomic forces create headwinds for the company, it's reasonable to expect healthy demand for Nu Skin's products over the long term. Transparency Market Research expects the weight management industry to reach $650 billion by 2015 , so it will be interesting to see if Nu Skin can gain market share as its TR90 product rolls out into the U.S market in 2014, where rival Herbalife has had good results.