#15: Hair hydration, more benzene in acne products, book signing, phthalates
December update.
Shorter content
My latest posts on Instagram and TikTok:
Some cool things that happened with my book, The Science of Beauty:
It’s in the Library of Congress?!! Thank you to whoever added it there!
There’s a Mongolian translation in the works
I’ve also figured out how to do signed bookplates! A lot of people asked me about signed books - Australian parcel postage is expensive, so these are basically pretty signed 6.5 x 10.5 cm stickers you can stick in your book, that I can send as a letter. I’ve averaged out the postage so everyone gets free shipping, let me know if your country doesn’t show up and I can add it!
The mail is a bit chaotic at this time of year, so please don’t count on it arriving before Christmas…
New study on benzoyl peroxide (also covered in more detail in a new website article)
Sunscreen isn’t the best sun protection
Head & Shoulders’ new formulas with soluble piroctone olamine
Phthalates in fragrance? (response to Dr Yvonne Burkart’s episode on Diary of a CEO podcast)
Does hair need hydration? The real science
Is water good or bad for hair? There are lots of "hydrating" hair products out there, but lots of hair experts say that water is actually BAD for hair.
I’ve been wanting to do this video for a long time, so I’m glad it’s finally out! It’s a deep dive on what's really going on with hair and hydration, with a bit of a detour into some other related confusing topics:
Whether conditioners and coconut oil really “seal out water”
Tests for porosity (the floating vs sinking hair strand test, water beading up on hair)
Why your hair might feel nicer after washing
Hygral fatigue
You can watch it on YouTube or Nebula.
Benzene in benzoyl peroxide
There’s a new study from Valisure on benzoyl peroxide and benzene - this time they’re warning about using benzoyl peroxide if you go into the sun.
You might remember the Valisure video and articles I did a while back, which covered issues with Valisure’s testing methods, interpretations of their results, and their motives.
This new article is just about benzoyl peroxide, which quite a few dermatologists have started warning people to avoid. It’s not really justified based on the data.
The article covers:
The original Valisure paper from March 2024, which used unrealistically high temperatures and strange comparisons that made the issue sound much scarier than it actually is
The new paper from October 2024, which covers more room temperature measurements, a study with an encapsulated product, and a very unrealistic UV exposure test
Some risk estimates (assuming Valisure’s numbers are actually correct)
A couple of studies from Dr John Barbieri looking at historical data to see if benzene blood levels and cancer risk is actually higher for benzoyl peroxide users
Extra bits
There’s a new article in The Guardian, on whether sunscreen causes skin cancer - you probably know what the answer is! I’m featured in it, talking about benzene recalls, along with some of my favourite experts: dermatologist Dr Deshan Sebaratnam, and epidemiologists Prof David Whiteman and Prof Anne Cust. The bulletproof vest analogy from Prof Whiteman is brilliant!
Conquering Skin Cancer is out in cinemas this week - session info is here.
A lot of people have asked me about the Diary of a CEO podcast episode featuring Dr Yvonne Burkart. As well as my short video on the phthalates claim, BeautySciComm, Mo Skin Lab and The Eco Well have posted about the misinformation she’s spread before:
There is a never-ending list of things to avoid from people who don't care that it's not backed up with hard science. Kudos to you for continuing to try to talk sense into people!