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  • Published: 2 July 2026
  • ISBN: 9781804956458
  • Imprint: Penguin
  • Format: EBook
  • Pages: 352

The Shampoo Effect




An accidental pregnancy turns a tight-knit group on its head in this witty and irresistible novel of modern love, sex, and friendship, from the New York Times bestselling author of PINEAPPLE STREET (‘Blissfully enjoyable’ India Knight).

‘I devoured THE SHAMPOO EFFECT . . . it's funny, drama-fuelled, and full of Jackson's breezy wit.’ Coco Mellors, Sunday Times bestselling author of BLUE SISTERS

'So breezily readable and laugh-out-loud funny while excavating the deepest truths about motherhood, family, and forgiveness.' CATHERINE NEWMAN, author of WE ALL WANT IMPOSSIBLE THINGS

'An absolute DELIGHT . . . a must, must, must for your summer reading list' Elin Hilderbrand, New York Times bestselling author of THE PERFECT COUPLE

'Funny, sharp and charming' Rebecca Serle, New York Times bestselling author of IN FIVE YEARS

OVER ONE LONG SUMMER, WHO KNOWS WHAT MIGHT COME OUT IN THE WASH?

When writer Caroline Lash arrives in Greenhead, she falls immediately for its scenic beaches and New England charm – and even harder for Van Whittaker, a gorgeous, fleece-wearing, litter-collecting, kayak enthusiast.

She meets his friends: Augusta, old money and uptight; Fran, drowning in everyone else’s problems whilst keeping two kids (and an inebriated husband) afloat; and Bailey, who is sexy, confident… and inconveniently pregnant with Van’s child.

Determined nothing will dull the shine of her new romance, Caroline joins the friends as they run wild through Greenhead, drinking on houseboats, gossiping on beaches while their children paddle, and playing risky games.

It seems the fun will last forever – until it doesn’t. As decades-old friendships and marriages begin to fracture, Caroline’s place in their world is called into question. And with all the group’s most tightly held secrets at stake, who knows what might come out?

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, and old friends finally growing up – despite all their best efforts.

  • Published: 2 July 2026
  • ISBN: 9781804956458
  • Imprint: Penguin
  • Format: EBook
  • Pages: 352

About the author

Jenny Jackson

Jenny Jackson is Editor at Knopf. She graduated from Williams in 2001 and attended the Columbia Publishing Course in 2002. She began her career at Vintage and has worked at Knopf for 19 years. Jenny's authors include Chris Bohjalian, Jennifer Close, Kevin Kwan, Emily St. John Mandel, Erin Morgenstern, and J. Courtney Sullivan.

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