Gwyneth: The Biography opens, where else, with the vaginal egg, an episode that has come to stand for Paltrow’s general ability to sell dumb ideas to credulous rich women using widespread mockery as her marketing rocket fuel. (In case you need a reminder: this was the $66 jade egg Paltrow sold via her lifestyle brand Goop that promised various health benefits upon insertion.) Amy Odell’s book, billed as delivering “insight and behind-the-scenes details of Paltrow’s relationships, family, friendships, iconic films”, as well as her creation of Goop, takes no particular stand on this, nor on many of Paltrow’s more divisive episodes, instead offering us what feels like an earnest jog back through the actor and wellness guru’s years of fame. The author writes in the acknowledgments that she spoke to 220 people for the book, in which case we have to assume that a great many of them had little to say.

To be fair to Odell, whose previous biography was of Anna Wintour, another difficult and controlling subject – although Wintour did give Odell some access – Paltrow’s world is notoriously hard to break into if she’s not on board with a project; the author quotes numerous hacks tasked with profiling Paltrow for magazines who found themselves iced out of her networks, and the same happens to her in the early stages of research. Odell’s task only gets harder in the second half of the book, which tackles the Goop years. Since, she claims, many of its staff signed NDAs, those sections lack even the modest stream of gossip that enlivens the first half.

Which, by the way, is perfectly enjoyable. I ripped through Odell’s account of Paltrow’s youth as the simultaneously indulged and benignly neglected daughter of two showbusiness big guns, the actor Blythe Danner and the producer and director Bruce Paltrow. Danner is prim and unemotional; Bruce Paltrow is more demonstrative but still emotionally evasive, and Odell reheats some well-documented episodes between father and daughter, such as the trip they made to Paris when Paltrow was around 10, during which Bruce told her: “I wanted you to see Paris for the first time with a man who will always love you, no matter what.” (Paltrow, in interviews, has always offered up this story as a moving tribute to her dad’s love for her.) Odell also tells us the (I think) new detail that, when Paltrow was older, “her dad once gave her lace underwear as a gift”. It’s a small addition but it stands out against what feels like the book’s trove of reconstituted material.

In 1984, when Paltrow was 12, the family moved from LA to New York. We learn that she felt out-classed at Spence, the Upper East Side private school where the money is older and the blood bluer than in the Danner-Paltrow household. We also learn that, in spite of this, Paltrow – whose biggest nightmare is listed in the senior school yearbook as “obesity” – manages to form a clique around herself that may or may not have been involved in the drawing of a penis on the library wall. It’s small potatoes but we’ll take it.Odell goes into great depth about the Williamstown theatre festival – presumably because the old theatre lags actually agreed to talk to her – a storied annual event in rural Massachusetts where Danner takes her daughter every summer, first to watch her mother on stage, and later, to act herself. I liked these passages, in which you get a real sense of a summer stock scene that has always attracted top actors and their nepo babies. At one point, a barely teenage Paltrow takes the assistant director’s seat and the head of the festival fails to ask her to move. Paltrow is entitled, wan, sometimes foul-mouthed, intensely focused and in these scenes, really comes alive. By studying her mother on stage, she learns how to be an actor.

And so on to the Hollywood years, where everything becomes less fresh and more familiar. We slog through the background to productions of Emma, Shallow Hal and Shakespeare in Love and then we get to Harvey Weinstein, who during the first flush of #MeToo, Paltrow accused of making a pass at her. Odell quotes from Jodi Kantor and Megan Twohey’s book, She Said, but there’s not much more to be harvested on a story broken and pursued by such good reporters. What’s left is a trawl through a lot of things we already know – although there is one very funny motif from those years, which involves Paltrow miming throwing up behind the backs of people she dislikes, one of whom is Minnie Driver. (Team Driver all the way, here, obviously.) Also an old friend of Paltrow’s claims “she invented ghosting”, which sounds about right.

Finally, Goop: this was a story I hadn’t been paying much attention to lately, and so a genuine surprise of the book is to learn that the company founded by Paltrow in 2008 has been a much shakier business than advertised. We know that Goop paid to settle a lawsuit brought by the California Food, Drug and Medical Device Task Force over false claims about the health benefits of the vaginal eggs. And we also know it accepted judgments by the National Advertising Division about other false claims. But, as Odell puts it, Paltrow’s “middling run as the CEO of Goop” has ensured that the company “hasn’t experienced sustained profitability … and has lacked a clear business strategy as it ping-pongs from one of Gwyneth’s ideas to the next”.

Here’s a reveal: that Paltrow is such a massive cheapskate she used Goop’s food editors to cook for her. “In the office,” writes Odell, “it was common knowledge that the food editors would go to Gwyneth’s house after work and make her dinner under the guise of ‘recipe testing’. When she and Brad Falchuk were living apart, the food editor would bring dinner to his house, too, which wasn’t a light lift in LA traffic.” She also asked vendors to donate their services to her and Falchuk’s wedding in return for advertising.

The difficulty with all this is that Paltrow is a charmless subject who never rises to the level of monstrous. She’s an OK actor, a so-so businesswoman – Kim Kardashian, as Odell points out, has had much greater success with her company, Skims. The story, then, is less about how Paltrow became this figure in the culture than why on earth she was elevated in the first place. Odell doesn’t have the time or the inclination to get into this, instead offering pat lines such as, “love her or hate her, for over 30 years, we haven’t been able to look away”.

At the very end, Odell draws a line between Paltrow’s peddling of pseudoscience on Goop and Robert F Kennedy Jr, “a fellow raw milk drinker” and Trump’s vaccine-sceptical health secretary, which feels like a sudden turn towards a more interesting and confident authorial voice. If only it had piloted the whole book.

• Gwyneth: The Biography by Amy Odell is published by Atlantic (£20). To support the Guardian, order your copy at guardianbookshop.com. Delivery charges may apply.