The Shampoo Effect

by Jenny Jackson

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 (“Laugh-out-loud-good.” —Harper’s Bazaar)

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 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.

Genres: Fiction, Romance, Contemporary, Summer

352 pages, Hardcover

Expected publication June 30, 2026

Reviews

[Leah · Rating 5 out of 5]

Jenny Jackson is my new favorite author. She tells simple stories with a lot emotion, a big cast of characters, and a lot of honesty. I loved this book about how it took a complete stranger to get a group of friends to look at their lives and make some tough admissions. I can’t wait for her next book.

[Toni · Rating 5 out of 5]

Definitely worth a read; pubs 6/30/26!

BRB.

[Susan · Rating 4 out of 5]

The ARC was provided by the publisher via Netgalley in exchange for an honest review. Comes out Jun 30, 2026.

Caroline is a nepo-baby fledgling writer from NYC who meets and falls for local guy Van while on a writers residency in a picturesque Massachusetts beach town. It’s told from her POV and that of the women in Van’s friend group - a tight-knit group that have been friends since childhood. Events unfold, secrets are revealed, and all the relationships are thrown into turmoil. Sounds like the set-up of a Hallmark movie, but it’s much smarter and less predictable.

There were mixed reviews of the author’s last book (Pineapple St) but I liked that and I like this one. I thought it was smart, funny, and did a good job depicting the challenges of old friend groups and marriages as people grow and evolve. It’s really hard to break old patterns and I thought Jackson did a good job with the nuances of old friends. I felt like I knew all these women and was rooting for them all by the end. Read it in one day.

[Bernadette · Rating 5 out of 5]

"The Shampoo Effect" was such an engrossing read that I devoured it in just three days. Jenny Jackson has a real gift for creating characters who feel immediately relatable and interesting, and that strength shines throughout this novel. The story is told through alternating points of view, and I never once felt bored or tempted to skim, which is no small feat in a multi-narrator setup.

This is a wonderfully frothy book and exactly the kind of read you want to bring to the beach. Caroline, Bailey, Augusta, and Fran are all distinctly drawn, each with lovable qualities and very real flaws. Those imperfections are not only funny but also integral to the plot, helping the story unfold in a way that feels organic and engaging. The balance between humor and emotional insight makes the reading experience especially satisfying.

I have seen some readers note that Jackson’s earlier work leaned more heavily on character than plot, but here I think she strikes the perfect balance. "The Shampoo Effect" blends strong character work with a compelling, well-paced storyline, and the ending in particular felt spot-on. This is a book readers will be eager to pack for vacation, and I cannot wait to read more from Jenny Jackson.

Thank you to Jenny Jackson, Viking Penguin, and NetGalley for sending me the eARC in exchange for an honest review.

[Chris · Rating 5 out of 5]

THE SHAMPOO EFFECT is one of the smartest, funniest, and most astute novels I've ever read about that liminal period when we're supposed to be responsible parents of small children, but still close enough to our own adolescence that we pine for the teenage freedoms we'd once taken for granted. An aspiring novelist, the single Caroline Lash, is savoring a fellowship to write her first book on a coastal village north of Boston, and there becomes part of a posse of thirty-something parents (and soon-to-be parents), a group that has been bonded together since they were teens. But as everyone walks that tightrope between being grownups -- raising Pokemon-obsessed children and paying the mortgage and trying to be present for their partners -- and the leisurely hedonism they'd all once enjoyed, this new interloper inadvertently upsets the status quo that has kept the peace. 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.

[Brynn Taylor · Rating 4 out of 5]

4.5! Regardless of what critics say, Jenny Jackson’s writing is immediately captivating from the first page. I found myself far more invested in Caroline’s perspective at the beginning than in the other POVs, which made me wonder whether Jackson is subtly self-inserting through this character. That said, the multiple points are reminiscent of Pineapple Street, a novel I loved. While the longer chapters aren’t my personal preference, the novel excels in its portrayal of a perfectly constructed love triangle and its thoughtful exploration of the varied challenges that arise in marriage and parenthood. This novel would make a great beach read for next summer!

Thank you, NetGalley!

[BHK · Rating 5 out of 5]

The Shampoo Effect had me totally hooked! It’s gossipy, funny, and messy. Jenny Jackson captures that coastal New England vibe perfectly where everyone knows everyone, and secrets travel fast. You know drama’s coming, and you can’t look away! I loved the way the author wrote all those long and sun soaked afternoons that seem perfect until the tension starts to bubble underneath. The writing has a breezy and witty tone that’s addictive and perfect for anyone who loves stories about beautiful people behaving badly!

[Katelyn · Rating 5 out of 5]

When Caroline Lash, living in Greenhead, Massachusetts for a writing residency, falls for Van Whittaker, she also inherits his friends, a tight-knit group with years of insider jokes and stories. Caroline doesn't feel like she fits in, and soon she discovers that Van's on again, off again ex-girlfriend is pregnant with his baby. I love Jenny Jackson's writing; I couldn't stop turning the pages. Recommended for fans of Elin Hilderbrand and Jackson's debut novel "Pineapple Street".

[Laura · Rating 5 out of 5]

I am so grateful I could read an advance copy! If you loved Pineapple Street as much as I did, you are going to be in heaven. This is every bit as intimate and layered and generous to its flawed characters, friends and family who are figuring it out as they go, the way all of us have to. I can’t wait to read it again.

[Rosalind]

Shockingly wholesome (shades of the wedding people) but also reminded me of the drama behind the New Yorker short story “Cat Person” where the person the story was based on felt some consequences of the story being published. Recommend 10/10 for summer reading next year.