She’s built her brand and business on being honest. Now, skin expert Caroline Hirons is sharing new skincare truths in her latest book, Skin Rules: Expert Advice That You Can Trust.
For someone who loathes writing, Caroline Hirons – who says she “hates writing books” – is surprisingly good at
it.
“I feel bad saying that because I’m a very successful author,” she says during a video call from a black cab during her morning commute.
She’s right, though. Her first two books sold more than 400,000 copies.
“I don’t find [writing] therapeutic. I don’t find it calming. I get really worried about making sure I sound simple, not patronising. I’m never happier than when I’m finished. Me turning out to be a writer would very much entertain my English teachers.”
The London-based skin expert, founder of Skin Rocks and podcast host, has authored four books, all about skin, the most recent scheduled for release on November 10.
Written in Hiron’s signature no-nonsense style, Skin Rules: Expert Advice That You Can Trust dives into how to navigate skin through major life changes like cancer treatment, menopause and using GLP-1s.
Caroline Hirons’ new book is out early next month.
Hirons has been refreshingly honest about her own experience on GLP-1s (she lost about 20kg through diet and exercise, before starting Mounjaro), and wanted to cater skin advice to those who might be on a similar journey.
“I’m post-menopause. I’m on GLP-1s. It seemed appropriate to talk about more. The thing about the previous couple of books is the science doesn’t change – I wanted to offer something different for people who are buying the book for the first time, or the second time, or the third time,” she says.
Hirons published her first book Skincare: The Ultimate No-Nonsense Guide in 2019, then released an updated version with Skincare: The New Edit in 2022.
She says Skin Rules feels very 2026 by comparison.
“Menopause has been a big [topic] for me for quite a few years now. GLP-1s have come to the forefront in the last two years. But really I write books and make products for me,” she says.
“It’s almost like, well this is what I’m going through. Maybe you are too?”
We’re out of the cab. She pays the “lovely cab driver” and pushes the buzzer at Skin Rocks HQ. Next thing we’re in her filming office, a white shelf lined with skincare frames the video screen.
One thing Hirons has been mindful of is sharing her Mounjaro dose online, although she tells me she’s now micro-dosing to help with inflammation and blood sugar.
“I’ve never answered that question because it’s a medical drug. I don’t get into specifics with people because I am not a doctor. I’m only talking about my experience,” she says.
Hirons says the term “Ozempic face” – a non-medical term coined to describe the changes in facial structure or skin laxity after using GLP-1s – is used as a scare tactic towards women.
“It’s a media thing… trying to put shame on people. I just don’t buy into it. I think calling them ‘fat jabs’ is a way to shame women and put people off taking them,” she says.
“I choose to talk about it. I don’t care what your opinion is of me or what I choose to do medically with my life, and that goes across everything.”
Hirons has been transparent about her own use of GLP-1 medication.
It’s Hirons’ hope that the GLP-1 chapter in Skin Rules will educate people about what’s actually possible and what’s not with their skin while they’re on this medication.
Skin laxity, uneven skin tone and texture can be helped by using topicals like peptides and retinoids, but Hirons says people should be realistic about what their creams can achieve.
“Will you get the same effect as you would with a needle? No, but again then you wouldn’t expect to. Some people have lost so much weight that if they wanted to absolutely rid themselves of skin laxity, you’re talking surgery,” she says.
“I’m not for one, and I’m never going to say that that’s something I think you should do. Everyone has their own journey, but I’d rather keep it real so that people know what you can achieve, rather than what a cream will do.”
Hirons adds that cure-all creams and quick fixes breed impatience, and if people want to see real change in their skin, they need to stick with their chosen formula for three months.
“Most clinical trials are done across a 12-week period. So if you use one bottle of product that lasts you a month, you haven’t had the full effects. When people say it didn’t do the same thing for me, you’re not using it the same way,” she says.
“It’s almost like getting the ingredients of a cake, not following the instructions and then being surprised when you don’t get the result of the cake.”
For someone who’s built her business and brand on acting like a filter for the beauty industry, Hirons says she deliberately surrounds herself with people who filter her.
“[My team] has no problem telling me I’ve had a s*** idea. They’ll tell me I have to do this meeting, or no, I can’t get out of this photoshoot. I think that’s healthy – you need that,” she says.
“The monsters that I know in our industry are surrounded by yes people. That will never be me.”
Hirons laughs as she recalls a publishing meeting where the topic of conversation was how many times she said the word “bollocks” in her first book.
“That’s because I didn’t want to say bastard, so let’s go with bollocks,” she says. “They know me, and they know my tone of voice is popular, so I don’t have hassles on that front.”
Hirons has authored four books, but says the writing process is her least favourite part of her job.
At age 40, Hirons launched her blog, Beauty Mouth. A decade later, during what she calls the most pivotal time in her life, she published her first book.
“I wish people knew that just because they’re getting older, it doesn’t mean they have to stay stuck in the rut they’re in. You can work where you want, do what you want, have anything you want,” she says.
“Postmenopause has by far been the happiest time of my life, and I would have been really shocked if I thought I was going to be saying that.”
Hirons says she suffered 10-15 years ago with the effects of perimenopause, which weren’t really talked about at the time.
“I didn’t know what was happening. I was piling on weight, [drinking] red wine and [eating] carbs like they were my two main food groups. I hated everyone, I had brain fog. I had no energy. It was not a pleasant time,” she says.
“The fact I’m now well out of the other side of it and on HRT [hormone replacement therapy] with the advice of great doctors is fantastic.”
No stranger to social media, Hirons says she’s received angry messages in the past when talking about HRT.
“It’s misplaced anger, because either they can’t use it themselves, so they’re annoyed that I’m telling other people to, or they choose not to because they believe that herbs will do the same thing,” Hirons says.
“Either way, I’m not talking to you. I’m talking about me. Yes, it’s a big difference, and it’s one of those differentiations that some people find it hard to make online. If I’m talking about it, I’m literally talking about my experience.”
Her role as a beauty industry watchdog sees Hirons trial thousands of beauty products throughout the year. Given she’s at the forefront of what’s new in skincare, Hirons says the category she’s genuinely surprised by is makeup.
“I just went to LA and bought the Mary Phillips foundation and Hung Van Go foundation. I really like a good foundation,” she says.
“I hate skincare trends. I think trends belong in colour because you can wash your face, no harm done. I like to be pleasantly surprised with colour.”
“If I’m popping to the shop, I’m putting that on so I don’t look dead. It just turns out to be a good colour for me,” she says.
“I use the big fat brush. It takes me three seconds, and suddenly I look like I haven’t just been dug up.”
You won’t find Hirons wearing silicone-based primers, or using a gritty facial scrub. Nor will you stumble across rose scents formulated into her suite of Skin Rocks skincare.
A handful of Hirons’ top skin rules are peppered throughout the new book, but she says if there’s one golden rule to live by, it would be this.
“Consistency is key. It’s great if you wash your face twice a week, it’s better if you do it every day. It’s great you bought that new serum, it’s not great if you can’t really afford, don’t want to use it up, and only use it once a week,” she says.
“The best skincare routine that encompasses everything – but being consistent with it.”
It’s a message she hopes to one day share in person with her fans in New Zealand and Australia.
She says she’s always wanted to visit the Southern Hemisphere (mainly for the music).
“I won’t lie – I’m an INXS and Crowded House girl.”
Backed by a promise of an impending New Zealand visit “one day”, she ends our video call in only a way that Hirons can.
“Thank you so much, it’s so nice to speak to someone who’s actually read the f***ing book.”
Skin Rules: Expert Advice That You Can Trust by Caroline Hirons, $54.99 (HarperCollins) is available from November 10, 2026.
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