For nearly 100 years, candy companies have made gummy treats — those chewy, gelatin-based, fruit-flavored bears, worms and fish that kids love to eat.

But now the gummy bear has grown up.

A number of supposedly “good-for-you” gummies for adults have been introduced in the vitamin and supplement market. Among the many choices: Vitafusion sells Power C Gummy Vitamins for Adults, which promise “great tasting gummies with natural orange flavor.” Caltrate Gummy Bites pack calcium and vitamin D in black cherry, orange or strawberry gummy candies.

“They taste good — like candy,” said Susan Drexler, 53, a Manhattan real estate agent and gummy vitamin lover. “I take them much more consistently.”

Ms. Drexler got into gummies through her 10-year-old daughter, Alana. Ms. Drexler has a “bear of a time swallowing large pills or capsules,” she said. A few years ago, she tried some of her daughter’s gummy vitamins, and from then on she was hooked. “Her kid gummies were my ‘gateway drug,’” said Ms. Drexler. “Now I buy the adult ones, and we share those.”

Millions of people are hooked on gummies as a health supplement. Gummy multivitamins accounted for 7.5 percent of the $6 billion multivitamin market in the United States in 2016, according to estimates from the Nutrition Business Journal and projections from IBISWorld, a research company. And gummy products over all now account for $1 billion of the $41 billion supplement market in the United States, a more than 25 percent jump in sales since 2015, according to IBISWorld.

“We’ve seen a really nice increase in demand for gummy supplements over the past three to four years,” Doug Jones, the chief merchandise officer at Vitamin Shoppe, which carries a broad assortment of gummy vitamins and supplements, said in an email.

Gummy vitamins and supplements originally targeted children, and were offered as a fun way to get kids to take their vitamins. But in 2012, Perrigo, a supplement maker with headquarters in Ireland, began marketing gummy products to adults. Last year, the company announced that it was partnering with Ferrara Candy Company, maker of Trolli Sour Brite Crawlers, to develop multivitamins for adults over 30.

One reason gummy vitamins are so popular with adults these days is “pill fatigue.” A 2005 AARP study found that, on average, adults 45 and older said they take four prescription medications daily. But some people say that switching to a gummy version of a vitamin or supplement makes them feel as if they aren’t taking so many pills. Gummies also appeal to people who, like Ms. Drexler, have difficulty swallowing pills.

The flavorings in gummy candy can also hide the taste. “Vitamins can be nasty,” said Paul Breslin, a professor of nutritional sciences at Rutgers University, and a researcher at the Monell Chemical Senses Center in Philadelphia. “Some taste bad. Some can be astringent. A lot of others have foul odors. Gummies are a pleasant way to mask the aversiveness.”

But beyond the sweet flavor, humans enjoy chewing, said Mr. Breslin.

“Let’s face it, these are dynamic experiences of moving your mouth,” he said. “People love to chew; it’s in our genes. We buy chewing gum.”

But the pleasures of chewing come at a cost. Consumers can take one Nature Made Vitamin C 1,000 milligram pill costing about 10 cents (a 300-tablet bottle costs about $30). To get the same amount of vitamin C from a Nature Made gummy vitamin, consumers would need to take eight gummies, at a cost of about 70 cents (a bottle of 80 125 milligram gummies costs $7)

And gummy vitamins typically contain one to two grams of sugar each — a 1,000 milligram dose of Nature Made Gummy Vitamin C contains 8 grams of sugar. Some companies have begun offering sugar-free versions of gummy vitamins for consumers who prefer a sugar substitute.

One issue with the sweet taste of gummy vitamins and supplements is that people might eat too many. “The only concern I might have is if people are tempted to eat these like candy and end up overdosing on vitamins,” especially “those that are fat soluble,” which can cause a range of problems if ingested over long periods, said Kim Larson, a registered dietitian and spokeswoman for the Academy of Nutrition and Dietetics.

Hallie Rich, the president of Alternavites, steered clear of gummies when coming up with her own line of vitamins. “With the fillers and additives there’s only so much space for active nutrients,” she said. “You’re missing ingredients or they aren’t there in enough quality to make a difference. They are a glorified candy.”

Susan Pica agrees. Ms. Pica, 40, the vice president of national sales for an executive transportation company, in Stamford, Conn., saw a gummy vitamin C display at CVS, along with a coupon to “buy one get one free.” She had fond memories of the Flintstones chewables she took as a child, so she thought she’d try them.

“I felt like I was eating Sour Patch Kids,” she said. “’How can these be good for you? My teeth actually hurt from eating them.” After seeing sugar sprinkled on the vitamins and settled at the bottom of the bottle, she checked the ingredients on the label. The bottle listed sugar, corn syrup and sodium citrate among the ingredients.

“I decided to use the gummy vitamins as a treat, like candy,” she said. “Because that’s what they are — candy.”