DENVER -- The mass health and beauty care business here is quite vibrant. At supermarket chains alone, HBC sales were up 3.9% to $274 million for the 52 weeks ended March 31, 1996, according to A.C. Nielsen, Schaumburg, Ill. In a breakdown of four categories -- headache remedies, liquid foundation, face powder and toothpaste -- A.C. Nielsen looked at how Denver sales compared with national sales at grocery chains for the 52 weeks ended May 5, 1996. It found headache remedy sales in Denver up 0.2% to $20.6 million, the same percentage growth as national sales. As for cosmetics, liquid foundation sales fell 0.5% to $791,000, compared with national growth of 4%. However, face powder did much better, with sales up 8.6%, above the national increase of 4.6%. Toothpaste sales at Denver food chains also did better than national sales. They were up 4.2% to $14 million, compared with national growth of 2.3%. Aiding HBC sales in Denver are a strong economy and a younger, educated, active and health-oriented consumer base. "It's a very active environment and lifestyle for all age groups here," said one source, who did not want to be identified. "The economy is good. There has been a lot of migration out of Texas. There is a high percentage of people with a college degree in the work force," said another source. According to Statistical Market Area data, the median age in Denver is 34. The population of just under half a million is mostly white, 80.3%; educated, with 83% having a high school diploma, and white collar, 63%. The percentage of mothers who work is high at 71%. The median household income of $37,000 also is healthy. With this growth has also come what one source described as an "overstored" marketplace. Like most markets, there is a lot of competition in mass retailing in Denver. The food chains are dominant, but they are getting hit by the mass merchandisers and their supercenters. Alfalfa's and Wild Oats appear to have found a niche. There are also the two drug chains, Walgreens and Pay Less Drug Stores, which are attempting to find a niche. Price and Sam's Club stores are popular in the market. There also is a Biggs hypermart.