CNN  — 

What does summer smell like? If you were a teen girl at any point over the last 50 years, there’s a good chance that, among the coconut tanning oil and leather car seats, your memory detects something else.

A whiff of peroxide, perhaps. A top note of lemon.

Summer is the season of Sun-In, a hair lightening spray that’s been birthing beach blondes (and beach oranges) for decades. Some may be surprised to know it’s still on shelves at all. So much has changed, and yet the lemon-peroxide elixir captures the timeless allure of DIY beauty treatments – and the endless, sunny optimism that keeps us trying them again and again.

A brief history of hair lightening

The desire for lighter, brighter hair has plagued virtually every culture in history at some point. Ancient Roman and Egyptians used everything from wine to bird droppings to gild their tresses. Women in Medieval Europe turned to eggs or even animal organs. (Those who could afford it, and who didn’t want to go through the trouble of smearing offal on their scalps, just donned wigs instead.) In the golden age of Hollywood, starlets sometimes risked becoming high school science experiments by heaping ammonia and bleach on their heads.

In fact, precursors to modern bleaching processes didn’t come on the scene until the turn of the 20th century, leaving our foremothers and forefathers plenty of time to get creative with their blonde pursuits. Lemon and peroxide, the two lightening ingredients in Sun-In, are more natural, less combustible options that have their own long histories in the annals of beauty.

“Ingredients like lemon juice and peroxide work together by stripping individual hair strands of their natural pigment,” says Brandi Jacobs, a hair stylist and cosmetologist in Atlanta. “The problem is, once that initial pigment is gone, darker hair has to go through several phases of orange and yellow tints before it is stripped enough to appear blonde. It’s a very unreliable process that’s different for everyone, especially if you’re using ingredients that aren’t specifically formulated for the hair.”

How Sun-In became a summer staple

Sun-In first became popular in the 1970s, capturing the imagination with bright ads featuring effortlessly sunkissed models cavorting on the beach or standing, just so, in a flattering ray of sunshine. As with all effectively marketed beauty products, Sun-In didn’t just promise lighter hair: It promised a perfect summer.

“Just spray Sun-In under the sun, and see what happens,” a 1971 ad from Glamour Magazine reads. “To your hair, maybe even your life.”

By the late ’80s, Sun-In was a summer go-to. (“Put sun in your hair!” a 1989 ad croons.) Other hair lightening sprays have come and gone, like Clairol’s Lemon Go Lightly, but Sun-In occupies a singular place in people’s hair memories. It’s still on shelves today, manufactured by an unassuming company called Chattem, Inc. that makes other drugstore icons like IcyHot, Gold Bond and Selsun Blue. Though the design of that bright yellow bottle has changed over the years, the wave of nostalgia it triggers still feels the same.

“Oh, Sun-In brings back so many memories,” says Kerry Hardaway, a server in Baltimore. “Like most young teens in the late ’90s I wasn’t allowed to dye my hair, but I thought, ‘Hey, I can buy something similar for a few dollars!’ Even my mom knew what it was.”

As seen in the intoxicating Sun-In ads of yore, Hardaway says it wasn’t just the promise of beachy locks that drew in her young self.

“Everyone wanted to make a big summer transformation,” she says. “Of course, we didn’t know what we were doing but it was fun.”

Fun, cheap, easy: It might as well be the trifecta of DIY beauty. But many who have fond memories of Sun-In summers also have less fond memories of dry, orangey strands that fell far short of the golden ideal.

“I honestly don’t know what we were thinking,” says Chelsea Locke, a 40-something mom from Alpharetta, Georgia. “It turned my brown hair nearly red, but I still kept using it, convinced it would eventually go blonde. I remember smelling it on the headrests of my mom’s car.”

Such are the pitfalls of doing things yourself (one has to think our ancient ancestors, with their guano hair masks, could relate).

Sun-In and similar products are still going strong

“I’ve been a hairdresser for almost 20 years, and I’ve seen almost everything people can put in their hair,” says Jacobs. “Yes, it’s true that stuff like Sun-In is the bane of our existence, but people still do it, and we’ll gladly help them correct it later.”

Even decades of trial and error hasn’t stopped Sun-In from trending every summer, and in recent years similar hair lightening products have hit the market, dressed up in chic pastel bottles and promising luxe results. Such alternatives pepper social media feeds, drawing in a new generation of young people to run the acrid gauntlet of blonde ambition. (Though, as some influencers and DIY hair devotees have pointed out, you don’t need to go blonde. Products like Sun-In can, theoretically, produce sunkissed results on all shades and types of hair.)

Videos about hair lightening spray have around 1.3 billion views on TikTok, with people of all ages spritzing more modern alternatives, like Sun Bum, Suntouched and Sunbabe Solar Hair Lightener. In this new lineup of summer potions, Sun-In is still the nostalgic classic.

Jacobs says, if it’s lightening your hair, the rest is just window dressing.

“The formulas are basically all the same,” she says.

Will we never learn? Probably not. We’ve had thousands of years to not put questionable stuff in our hair in pursuit of a shiny new look, and here we are, still frying our locks and vexing hair professionals. It just shows there’s some truth to all of those old Sun-In ads: It’s not just about the hair. It’s about the experience, too.