During “the talk” about puberty in fifth grade health classes, many schools hand out sample cans of deodorant to boys. Shortly after receiving one, Lori Swedelson’s son, Eric, now a sixth grader in Mahwah, N.J., began asking for products:

“He said, ‘Can you get me Axe? I need deodorant,’ ” said Ms. Swedelson, who asked him why. “He said, ‘Ma, I got a hair under my arm!’ And I said, ‘Let me put my glasses on.’ ”

He too now steeps himself: colognes, shampoos and body washes. And he is very picky about his choices.

“I got the wrong color can of Axe,” Ms. Swedelson said. “Holy cow.”

Each bottle signifies something to tweens, who are excruciatingly aware of brand image. George Carey, head of Just Kid Inc., a market research firm, said, “More of the brands that market to kids are doing so by trying to own a human value or characteristic.”

LIKE the Sorting Hat from the Harry Potter books, the bottles and cans telegraph how a boy can sort and identify himself. Old Spice advertisements for its Swagger line featured the rap star LL Cool J as a nerd in school, then being transformed into his fabulousness by you-know-what. Anthony’s Body Essentials are available in Energy, Strength, Spirit and Courage. Abercrombie & Fitch’s popular cologne: Fierce.

Why does Jake Guttenberg, a Manhattan seventh grader, use an Axe spray? “I feel confident when I wear it,” he said.

Lyn Mikel Brown, a psychologist at Colby College and an author of a new book, “Packaging Boyhood,” said the products gave boys the mere illusion of choice. In fact, she said, they often preach an extreme, singular definition of masculinity — at a time developmentally when boys are grappling uneasily with identity.

“These are just one of many products that cultivate anxiety in boys at younger and younger ages about what it means to man up,” Ms. Brown said, “to be the kind of boy they’re told girls will want and other boys will respect. They’re playing with the failure to be that kind of guy, to be heterosexual even.”

Even when advertisements are supposed to be crudely humorous or satiric about masculinity — approaches recommended by market researchers to reach high school boys — younger boys take them more literally, Ms. Brown said.

To engage boys, marketers rely less on 30-second TV spots than on interactive Web sites, creating communities of young fans. Tag has a page on Facebook. Axe has an avatar in Pain, a PlayStation game. Swagger sponsors Xbox team competitions. Dial for Men offers advice from “sexperts.” Brands create downloadable apps, have lengthy “advergames” on their Web sites, and urge fans to text friends with coy messages about the products. They make commercials just for YouTube, which is, in turn, filled with commercials made by boys themselves — some of whom are self-anointed reviewers.

“Girl repellent!” said one boy, holding up a spray can in front of a camera.

Parents, generally, are clueless.

“Axe has commercials?” Ms. Swedelson asked.

What further drives the boys’ rush to the products are girls themselves. Marshal Cohen, chief industry analyst for the market research firm NPD Group, said that in a recent survey, 41 percent of boys ages 8 to 18 said that one of their best friends was a girl.

“They shop with girls, and girls influence them,” Mr. Cohen said, much as the girls in the hit Nickelodeon tween show “iCarly” hold sway over Freddie, their hapless male buddy.

“Boys are paying attention to personal brands more than ever because it’s too easy to be criticized virally by a girl,” said Pat Fiore, a market consultant for body image products in Morristown, N.J. “The peer pressure is starting from the girls, who are discussing how much someone smells or what they look like, and it’s being recorded in real time by e-mail and texting.”

These girls are also becoming sexualized at earlier ages, applying lip gloss and wearing racier clothes. Boys, a bewildered developmental step or three behind, feel additional pressure to catch up.

Ms. Wiseman, who also wrote “Queen Bees & Wannabes,” a nonfiction book about the social pecking order of tween girls, speaks with students around the country. Even in rural North Dakota, she said, 12-year-old boys were highlighting their hair, a focus on appearance that was almost nonexistent five years ago.

“We consistently look at boys in a position of privilege and power,” she said. “But if you ask a 12-year-old boy if they’re in a position of power, they feel out of control of themselves, their bodies.” She added: “I defy anyone to tell me that an eighth-grade girl doesn’t look like she has more power and control than a boy.”

SO while men’s colognes have been marketed since at least the last century for their irresistibility to women — even Joey Bishop was swarmed when he wore Hai Karate aftershave in a 1960s commercial — Axe’s similar approach offers a jokey safe haven to a tween boy: you can have power over those frightening, provocative creatures, those girls. Small wonder that a boy would love to believe those magic powers promised by a pheromone-infused product are real.

Kristen Gilbert, an assistant principal at Waterville Junior High School, in Waterville, Me., who has impounded her share of spray cans, wrote in an e-mail message that when she asked a young student why he wore the product, he replied, “I have to have it, Ms. G., because I don’t have the money to dress the right way. This is all I can afford.”

The boy added that the body spray was his “best chance to get a girl.”

With consumer researchers pumping out reports on strategies to attract tween boys — make them feel accepted by peers, yet make them feel like cool individuals — and the success, over all, of the expanding, multibillion dollar male grooming products industry, the market is hardly saturated.

A shopper browsing the aisles of a Perfumania, a discount fragrance chain, can find products that allow boys to start brand attachments and grooming habits even sooner than the tweens.

SpongeBob SquarePants Eau de Toilette Spray for Boys, anyone?