The Shampoo Effect

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"Funny, drama-fueled, and full of Jackson's breezy wit... Brilliant." -Coco Mellors, New York Times bestselling author of Blue Sisters

"The platonic ideal of a beach read." -The New York Times

An ambitious young woman insinuates herself into a tight-knit social set, shaking up friendships and marriages in a small seaside town. A frothy novel of love, money, sex, and friendship, from the New York Times bestselling author of Pineapple Street

When Caroline Lash arrives in Greenhead, Massachusetts, she falls head-over-heels for Van Whittaker, a fleece-wearing, litter-collecting kayak enthusiast with long, floppy hair and the personality of a Border collie. Born and raised in this picturesque coastal village, Van runs with the same crowd he did as a kid: His ex-girlfriend, Bailey, a beautiful girl who attracts men like moths to a flame; Augusta, old money, horsey, and snobbish; and Fran, surrounded by brothers and sons, too fed up with boys to ever consider marrying one.

Together, the group runs wild through the marshes, beaches, and bars of Greenhead, drinking on houseboats, spending long afternoons sunbathing with their children, and playing games the way they always have. But when Bailey discovers that she is pregnant with Van's baby, the delicate balance of the group's friendship is thrown off. Soon Caroline is cast out of the circle and what she does next-in a potent mix of fury and heartbreak-exposes long-held secrets and works the entire town of Greenhead into a lather.

Dazzlingly funny, sexy, and as juicy as it is astute, The Shampoo Effect is a story of late-night parties, early mornings with small children, the dawn of midlife, and a group of old friends finally growing up despite all their best efforts to the contrary.

From the publisher

Penguin Random House / Pamela Dorman Books | Jun 30, 2026 | 352 PAGES | ISBN-13 9798217059959 | Literary Fiction / Women's Fiction

"A frothy, exuberant book." -People "The platonic ideal of a beach read: fun and fast-paced, with a cover that screams, "Can I borrow your sunscreen?" It also features one of my favorite setups (dating back to "Up Island," by Anne Rivers Siddons), in which an outsider arrives in a clubby enclave and makes waves. Here it's Caroline Lash, who lands in Greenhead, Mass., and falls for an outdoorsy local who's almost too good to be true. The problem is, his on-again-off-again girlfriend is pregnant and still very much in the picture. In her debut novel, Pineapple Street, Jackson brought us into the storied world of Brooklyn Heights; here, she delivers us to the land of clam rolls with the same anthropological eye." -The New York Times

"Delightfully satisfying." -NPR

"The Shampoo Effect is Jenny Jackson's sophomore follow-up to her bestselling debut, Pineapple Street, and in her new novel she leaves the streets of wealthy Brooklyn for a seaside town in Massachusetts. Caroline is a classic fish out of water-a New Yorker thrust into a tight knit small-town friend group-and left to navigate years of history and entanglements while attempting to write a novel. Heavily influenced by John Updike's then-scandalous 1968 novel Couples, I predict Jackson's latest will be the book gracing every book girlie's beach bag this summer." -Sarah Gelman, Amazon Editor (Editors' Picks)

"An absolute DELIGHT. This book has everything I love in a beach read: a coastal setting, multiple points of view, compelling storylines, and a delicious specificity to the writing that makes every single sentence feel fresh and alive. Jenny Jackson's The Shampoo Effect is a must, must, must for your summer reading list." -Elin Hilderbrand, #1 New York Times bestselling author of Swan Song

"I binged The Shampoo Effect and am now bereft. Jenny Jackson has written a book that's so breezily readable and laugh-out-loud funny while excavating the deepest truths about motherhood, family, and forgiveness. What an unforgettable cast of characters. What an accomplishment." -Catherine Newman, New York Times bestselling author of Wreck

"There's no more quintessential beach read than a buzzy novel set in a coastal town. Consider Greenhead, Massachusetts, where Caroline, a twenty-eight-year-old writer, settles into a residency and a relationship with sexy environmentalist Van, "a real person instead of some impossible man-child." Except this real person has a kid on the way: his former girlfriend is pregnant. Against her better judgment Caroline falls in with Van and his high school crew. Doubts linger in Jenny Jackson's rocky romance–will love triumph? As she texts a friend: No Hallmark movie has the Good Guy knock up his ex-girlfriend from high school." -Time

"I devoured The Shampoo Effect. Jackson has a rare knack for capturing the intensity of old friendships and the way love, jealousy, money, and history combust until everyone is behaving (deliciously) badly. It's funny, drama-fueled, and full of Jackson's breezy wit, but what stayed with me most was how honestly and insightfully it captures the grit beneath the gloss of these characters. A brilliant story of marriage, motherhood, and the difficult work of breaking old patterns to become someone new." -Coco Mellors, New York Times bestselling author of Blue Sisters

"The Shampoo Effect is a delicious, unputdownable portrait of a group of friends navigating love, marriage, and young parenthood. Jackson's characters are fully drawn, complex and flawed, each traveling a true arc of growth, arriving in the final pages at a deeper understanding of the ties that bind them to one another. I loved it." -Belle Burden, #1 New York Times bestselling author of Strangers

"A fun and poignant story as frothy as the suds its name evokes." -Elle

"Funny, sharp, and charming." -Rebecca Serle, New York Times bestselling author of One Italian Summer

"A smart, sly gloss on Updike's tales of marital unrest. So funny, so compelling, this novel hit home with me in its examination of the ways secrets can erode families and friendships." -Joanna Rakoff, international bestselling author of My Salinger Year

"Unexpected pregnancies, marital revelations, sibling rivalries, emotional (and actual) infidelities... and all of it presented by Jenny Jackson with a combination of great humor and profound wistfulness. I loved this novel. You will, too." -Chris Bohjalian, New York Times bestselling author of The Jackal's Mistress

"Meant to be read on a sweltering July day, with sand between your toes. Like Jackson's popular debut, Pineapple Street, this is one of those rare books that feel both breezy and meaty, sharp but empathetic." -Toronto Star

"The Shampoo Effect is a stylish, sharply observed novel about image, reinvention, and the chaos simmering beneath polished lives. It's perfect for readers who love emotionally messy characters with great taste…" -The Sunday Series

"Jackson has a knack for local color and well-rounded character work... [The Shampoo Effect] has plenty of heart." -Publishers Weekly

"Jackson rotates the point of view around the set of friends, deftly depicting the practices and pressures of modern parents ...This easy read combines a literary rom-com with an acute portrait of midlife among millennials." -Kirkus

"Giving off vibes of Thirtysomething and The Big Chill, Jackson's follow up to the best-selling Pineapple Street is a frothy, funny ode to old friends and new challenges. Set in coastal Greenhead, Massachusetts, summer's in full swing when 30-ish Caroline Lash falls for hometown beach boy Van Whittaker. When his ex discovers she's pregnant with Van's baby, it upsets the balance of his longtime friend group and these high-schoolers-at-heart have to navigate the realities of finally growing up." -Canadian Living