Julia Coney, 36, can still remember her first chemical burn. She was a teenager and she had been getting her hair straightened since she was 8. In the early days, her mother used to take her to a hairdresser, who would gently spread a relaxer on her thick hair to tame its tight coils. The sodium-hydroxide-based paste was a creamy white color and had a harsh smell, but it left Coney with fine, silky, straight hair that was easy to manage.

The burns came later, when Coney went to sloppy hair stylists or disobeyed the cardinal rules of relaxing, which include not scratching the scalp or washing the hair too soon before the application. During those teenage years, when vanity often trumped safety, Coney once got a burn so bad that it left the area behind her right ear raw. "I was like, ‘Why am I doing this?'" she recalled.

With a pH of about 12, similar to that of household ammonia or soap, chemical relaxers are among the most caustic cosmetic products on the market, according to the Environmental Working Group, a nonprofit environmental organization. Along with hair dyes, hair straighteners are the source of more complaints to the Food and Drug Administration's Office of Cosmetics and Colors than almost any other product.

Though millions of black women have used relaxers, often for many years, there is a growing push among consumer advocates and some consumers for gentler products that are no less effective.

Coney at times has wondered about the broad health effects of hair relaxers. But most of all she worried about the health of her hair, which became dry and brittle and began to fall out -- the result, she suspected, of years of relaxing and creating adventurous hair styles, including short, spiky dos and an asymmetrical bob. At 25, she stopped relaxing her hair and wore it closely cropped for about 10 years. When Coney, who now runs a beauty blog called All About the Pretty, recently decided to grow and straighten her hair again, she was wary of the harsh relaxers and happy to find a shelf full of straightening products being marketed as gentler, plant-based or organic.

In recent years, some manufacturers, including Colomer USA, the maker of Creme of Nature, have been listing at least one "certified organic ingredient" in their products, including their sodium-based relaxers. The French company Phyto markets its PhytoSpecific line as a "non chemical relaxing system" and charges about $60 for a tub of its straightener, more than triple the price of a traditional relaxer. According to the company, the Phyto relaxer uses a substance called guanidine carbonate derived from mushroom salts as its straightening agent.

"I think it's great for black women. Now there are so many choices," Coney said.

Coney, who applies her own relaxer, said she is aware that all products labeled "natural" or "organic" are not necessarily much gentler than other ones. Even the hair relaxers that incorporate plant products, such as Phyto's guanidine carbonate, contain naturally occurring chemicals strong enough to break her hair's tightly coiled bond and make it straight. But she said she has noticed with the Phyto relaxer "a difference in the smell, which isn't as chemical-ly."

"I'm sure some of the chemicals aren't the best for your body, but I think there are so many things that we do that are not good for us," Coney said. "I know that watching TV is probably killing my brain cells, but I still do it. There are things that aren't good for you in the hair products, but there are also things in the drinking water.... You can't worry about everything."

The emphasis on natural ingredients in hair products is growing. But there are no regulatory standards for labeling a personal-care product "organic" or "natural," a term that is even more ambiguous.

"It's a trend that's been under way for a number of years, to be more natural and green and sustainable and all the things that seem to be popular now, and the move is mostly driven by consumer demand," said John Bailey, the chief scientist at the Personal Care Products Council, a trade group. "The cosmetics industry has always been good at responding to what consumers want."

Cosmetics are not required to undergo the same sort of approval process as drugs before going on the market, and the FDA takes action only after safety or mislabeling issues surface or are reported by consumers. Nonetheless, Bailey pointed out that "the products on the market are required by the FDA to be safe, whether they be more in the natural ingredient line or more traditional. I don't see why consumers should be alarmed based on whether it is natural or traditional."

Hair relaxers generally fall into two categories: lye and no-lye. Lye relaxers contain sodium hydroxide, which is also used to make soap and strip paint. Most no-lye relaxers contain calcium hydroxide, which is also used to treat water and sewage, and guanidine carbonate, which is also used for hair removal.

When researchers at the Black Women's Health Study, based at Boston University, were looking to understand why black women younger than 45 have a higher incidence of breast cancer than white women, they looked to use of chemical hair relaxers for a possible explanation. But they found no evidence to support that.

The researchers found that between 1997 and 2003, 574 women of the more than 48,000 in the study developed breast cancer, but there was no correlation between relaxer use and the illness. Women who had never used the products were found to have the same breast-cancer risk as those who did.

Even as the ingredient lists change for some of the straighteners and other hair and body products, and manufacturers emphasize the words "organic" and "natural," consumers should beware, said Stacy Malkan of the Campaign for Safe Cosmetics.

"We have seen companies reformulating products as natural products, but it is very confusing because there are no legal standards as far as using the words "organic' or "natural' in marketing hair and body products," Malkan said. "You have to do your own research."

Toya Smith Marshall, 30, who used chemical relaxers for 18 years, said she has learned that lesson. She no longer chemically straightens her hair; since she began styling it herself, she has begun reading labels closely to find out exactly what she is putting onto her scalp.

"I don't fall prey to the labeling, because in order to straighten your hair, (the product) has to break your hair down," she said. "That's why it stings and burns. There's no way to make that healthy for you."