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Although there are billions of people in the world, it’s always tempting to believe your existence is unprecedented in some way. For me it’s my hair, which I’ve long suspected poses an uncanny challenge to the world of follicular maintenance. It’s curly yet fine, frizzy yet flat, oily at the roots yet dry as kindling at the ends. Everything I do to it only makes it worse, including bleaching the ends, wearing it in a topknot most of the time, and flat-ironing it half to death.

Maybe the problem is me. But maybe, I sometimes imagine, the problem is simply that hair products aren’t equipped to deal with the paradox atop my head. Every high-quality shampoo and conditioner I’ve ever used has been some version of fine: My hair ends up looking clean and smooth enough, but it still feels like there’s some yet unseen level of beauty I could be achieving. I let myself believe that the only thing standing between me and perfect hair are the whims of cosmetic chemistry.

A few months ago, Prose, a start-up that offers personalized, custom-blended hair-care products based on customers’ responses to a lengthy survey, wore me down with an alluring marketing tactic: beautiful Instagram ads indulging the idea that what’s going on on my head might be too unique for whatever Sephora has to offer. If I told the company my long list of petty hair complaints, perhaps I’d never again have to stand in front of a wall of indistinguishable products, trying to guess which one might be my holy grail.

What did I have to lose except money, which history suggests I am almost always willing to lose? I ordered a shampoo, a conditioner, and a mask that promised to “balance” my roots. The package arrived with a full-color card-stock brochure of the ingredients that would fix my hair and maybe my life. It was the beauty enthusiast’s answer to a baseball fan’s advanced stats: In the “diagnostic” section, I learned about the causes of my bad-hair days, such as “sebum” and “damage.” On the next page, little illustrations of things like plant collagen and silk proteins promised a better tomorrow.

The personalized shampoo, conditioner, and hair mask came in simple containers that evinced a distinctly Millennial sense of understated luxury. Each had my name on the label. I wasn’t just going to wash my hair, I told myself. I was going to outsmart it.

For 40 years, Burger King has been offering customers the opportunity to “have it your way.” But technological limitations have long prevented personalization from moving beyond food service and into the consumer-product market. If you go to the drugstore to buy face wash, picking up a version blended just for you would require it to be made on-site, just like your Whopper. Shopping for one-of-a-kind things has been the province of the wealthy—those who could afford bespoke suits and customized cars while the rest of America bought off the rack.

Now, aided by advances in manufacturing and the direct-to-consumer nature of online shopping, personalization has become the hot new thing at much more accessible prices. That’s especially true in the wellness industry, where Prose is one of a slew of new companies offering everything from custom-blended face creams to individualized vitamin cocktails. Together, these brands have attracted millions of shoppers (and millions of dollars in venture-capital funding) by tapping into something powerful: the idea that we’re all fancy and special enough to have something made just for us.

Before starting Prose, Arnaud Plas, the company’s CEO and co-founder, spent 10 years in the beauty industry, including six at the behemoth L’Oréal, where the demand for constant novelty wasn’t fueled by any particular consumer need. “Retailers [were] asking for more and more new products just to fill the shelves,” Plas says. Meanwhile, he got the feeling that consumers wanted the opposite: more simplicity and clearer choices.

Because everyone’s hair has different needs, however, making a one-shampoo-to-rule-them-all company wouldn’t work in the same way it has for Millennial-friendly brands of mattresses or suitcases, which distill broad, confusing product categories down to a single product they promise is the best. That’s where personalization comes in. “It’s simplicity for customers, because we’re only pushing one option,” Plas says. In addition to a bespoke product, personalized beauty brands offer something maybe even more beguiling for overstimulated shoppers: freedom from choice.

To make that happen, Prose uses a method preferred by many personalization start-ups, including Care/of, which doles out nutritional supplements, and Curology, which mixes custom creams: an internet survey. I love talking about myself, so taking a lengthy quiz that would assure me of my hair’s snowflake status wasn’t exactly a tough sell. Plas says the brand now gets more than a million survey submissions a month.

Even so, asking people to describe their hair—or their skin, or their eating habits—has limitations. “It’s very important not only to ask the questions, but how you ask the questions,” Plas cautions. “We’re realizing that some people don’t really know how to answer.”

According to Holly Maguire, the creative director at the cosmetic-development company Freelance Formulations, people have a difficult time situating themselves on a continuum when they don’t have much experience with other people’s skin or hair. “I think everyone’s perception of themselves and their skin and hair and how they look varies,” she says. “What constitutes oily hair? How do you tell if you do actually have oily hair, and what level is it?”

In reality, my paradoxical hair isn’t as special as I’d like to believe. Lots of people bleach and heat-style, leave their hair in a ponytail holder for a day or two, or go a little overboard with the dry shampoo. I simply believe my hair is special because it’s my problem. While taking my own survey on Prose’s website, my potential to be an unreliable hair narrator (hairrator?) became clear. Prose asks about texture and moisture, but also about your environment, your activity level, and how much time you spend outside. I live in New York City and walk a lot, but I don’t exercise outside—unless exercise includes walking a lot? Prose also wants to know how you eat, which means I had to divine the practical difference between a diet that is “balanced” and one that is “unrestricted.”

To get the most out of personalization via algorithm, not only do you have to know the ins and outs of your own needs, but you have to think about what a brand might be trying to learn by asking a particular question, and how that information might impact your results. It’s the e-commerce version of swiping your hand under an automatic faucet, trying to determine what kind of motion the machine wants in order to get your hands wet. These services can only go as far as the partnership between user and technology allows, which means that if you do a half-assed job answering the survey, you could end up with a multivitamin or skin-care routine no better than what you would have bought at a store.

That doesn’t mean personalization programs can’t have upsides for both consumers and brands. Maguire sees advantages to using personalized products, even though her company creates things for the mass market. “When you’re talking about skin sensitivities or allergies, I definitely think that a custom product could be needed,” she says. Personalized beauty-product brands frequently let customers opt out of fragrances or ingredients derived from animals, which gives shoppers with sensitivities or ethical preferences more options than they would have otherwise. In addition to the lengthy up-front explanation of which ingredients are in each product, Prose follows up with buyers after three weeks to tweak their formulas as needed.

This is the internet, though, so acquiring a personalized life isn’t a simple exchange of money for goods and services. Brands like Prose don’t just collect revenue—they collect data. Exhaustive surveys provide useful context when formulating a bespoke product, but they also give companies a level of granular information about their consumers that most traditional brands could never hope to acquire. L’Oreal will never know anything about my exercise habits, but Prose already does.

Ronald Goldsmith, a consumer psychologist and a professor emeritus at Florida State University, says that data collection has always been a lucrative by-product of any customization program. “Companies will frequently collect that information, mesh it with what other information they can get from other sources, and sell the information back and forth” to other companies, he says. Prose’s privacy policy allows it to sell your data to other companies at will, as do the policies of most similar brands. (Prose shares data with partner companies like payment processors, but Pras says that Prose does not sell data to third parties.)

Even with the privacy issues that are rampant in much of modern shopping, Goldsmith thinks personalized products are an easy sell to many consumers, who tend to love them. In spite of the indignities of admitting that an Instagram ad worked on me (and in spite of the healthy amount of journalistic skepticism with which I approached my Prose shampoo order), I’m now part of that group. My curls are shiny and bouncy, even though most curl-friendly products weigh down my hair. The products smell amazing (and so does my hair), and my one-of-a-kind shampoo and conditioner were a couple of bucks less expensive per bottle than the high-end stuff I normally buy.

I also didn’t have to flip between product listings, trying to divine the secrets of several near-identical varieties of hair goop. The correct choice showed up in my apartment with my name right there on the label. “Choice overwhelms people, and studies have shown that people don’t respond well to too much choice,” Goldsmith explains. Personalization is a way out of that.

Nevertheless, Goldsmith says, the current crop of companies offering personalization might end up too successful for their own good: “The problem is that when it works, competitors do it.” It’s not hard to imagine a near future in which upstarts and big brands alike will let you have it your way with a custom cocktail of nutrients or a special face serum all your own, as long as you’re willing to tell them everything about yourself.

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