Some people are so worried about sunscreen that they’re swapping factor 50 for beef tallow. Yes, the fat traditionally used to make roast potatoes is now being promoted online as something you can spread on your skin before going into the sun.
Author
- Katie Edwards
Commissioning Editor, Health + Medicine and Host of Strange Health podcast, The Conversation
Coconut oil and olive oil have their supporters, too. Meanwhile, other social media creators warn that conventional sunscreens contain dangerous chemicals, interfere with our hormones or prevent us from making vitamin D. Some even claim sunscreen causes cancer.
But how much of this is backed by science? And what happens to your skin when you swap a tested sunscreen for something from the kitchen cupboard?
In the latest episode of Strange Health , The Conversation’s podcast about unusual health and wellness trends, I investigate the anti-sunscreen movement with my co-host Dan Baumgardt, a practising GP and lecturer at the University of Bristol.
There’s a revealing twist to the social media story. A 2026 study examining 971 popular sunscreen-related TikToks found that almost 87% promoted sunscreen use. Only 6% included health-related criticism. Yet videos devoted to criticism attracted substantially more likes, shares and comments than those focused solely on promotion.
Can sunscreen really be harmful?
Our guest is Charareh Pourzand, a professor of pharmaceutical biology at the University of Bath, who has spent more than 30 years investigating how sunlight affects skin.
She helps us unpick concerns about sunscreen ingredients. Some UV filters can be absorbed into the bloodstream , and certain ingredients have shown hormonal activity in laboratory studies. But finding a substance in the body, or an effect in a laboratory, doesn’t establish that normal sunscreen use causes harm.
Regulators continue to review the evidence. The UK has recently restricted one UV filter in sunscreen, known as 4-MBC, after a safety assessment. That scrutiny is important, as is the extensive evidence that ultraviolet radiation damages skin and increases skin cancer risk.
Then there’s vitamin D. Sunscreen limits UVB radiation (a specific type of ultraviolet light), which the skin uses to make the vitamin. But that doesn’t justify deliberately exposing yourself to harmful ultraviolet light when vitamin D can also come from food or supplements.
Why a homemade sunscreen is a gamble
Pourzand explains why mixing oils or beef tallow into a homemade sunscreen is risky. Even if an ingredient absorbs some UV radiation, you won’t know how reliably the mixture protects your skin without proper formulation and testing.
We also discuss sunbeds, the myth of a protective “base tan”, and Pourzand’s research into how sunlight can release iron inside skin cells, amplifying damage.
And Dan explains why the most expensive sunscreen isn’t necessarily the best purchase. What counts is choosing tested protection against both UVA and UVB radiation, applying enough and reapplying when needed. We also consider whether you really need SPF (sun protection factor) 50 for a short trip outdoors on a British winter day.
Listen to the episode before your next attempt to turn the kitchen cupboard into a skincare counter.
Have you spotted a bizarre health trend you’d like us to investigate? Email [email protected] . The stranger the question, the better.
Strange Health is hosted by Katie Edwards and Dan Baumgardt. The executive producer is Gemma Ware, with video and sound editing for this episode by Anouk Millet. Artwork by Alice Mason.
If you’ve got a question about a viral trend or video you’ve seen and you’d like us to delve into the science behind it in a future episode, please email us at [email protected].
Listen to Strange Health via any of the apps listed above, download it directly via our RSS feed or find out how else to listen here . A transcript is available via the Apple Podcasts or Spotify apps.
