A sunscreen scandal shocking Australia
bbc.com
bbc.com
https://labmuffin.com/purito-sunscreen-and-all-about-spf-tes...
In my imagination, the lab would have some a testing process that spreads a precisely-controlled volume over a standard surface area, textured to be similar to skin, then measures UV transmission percentage vs wavelength with a diffraction grating and photocell. Or something like that!
With this approach, how would you measure the effectiveness of the sunscreen when it's been absorbed by the skin (which is necessary for the sunscreen to work properly - that's why they always say to wait ten minutes after applying before going out into the sun)?
There's a reason in vitro and in vivo are both studied for clinical trials of medications. Sunscreen isn't any different: you're using a product making a specific claim about a clinical outcome, so that needs to be tested.
You can eliminate the "can't possibly work" cases much faster and cheaper.
More importantly, it is cheap enough to be always used as a baseline verification when human testing is so expensive that it can only be used as a random sample double-check.
It's like unit testing vs full user acceptance testing. You can and should do both, but the latter isn't for every PR.
> It's like unit testing vs full user acceptance testing. You can and should do both, but the latter isn't for every PR.
You say all this as if it weren't already happening. OP was surprised human testing was being conducted at all, not that non-human testing wasn't being done (which is a claim nobody made, and which isn't true).
They don't always say that. Some say explicitely that it provides instant protection. (there are different ways, that sunscreen provides protection)
We're talking about chemical sunscreens here, and they should say it because they do require it.
The problem is that testing has to be reproducible but usage doesn't.
Easiest hundred bucks I ever made, gotta say.
There are a lot of other factors here, such as your skin's condition (hydrated skin absorbs better), damaged or inflamed skin even more but sometimes to unsafe levels and it is typically contraindicated for almost all cosmetics.
In any case, most cosmetic ingredients act locally (i.e. not supposed to enter into systemic circulation like transdermal drugs), improve hydration, texture, and/or appearance by altering the stratum corneum or slightly beyond. Systemic absorption is limited unless specifically engineered to do so, such as nicotine patches, hormone creams, fentanyl patches, etc. I mentioned this below "transdermal drug delivery".
The curious should look up the differences between cosmetic absorption vs. transdermal drug delivery as well. For example, cosmetics are not intended to penetrate into the bloodstream, hence the surface layer depth. To give you percentages, typically >90% remains on skin surface, but it also depends on what you want to achieve, because for example hyaluronic acid in creams are of large molecule (~3000-5000 Da), meaning it essentially 0% penetrates. It hydrates only by trapping water on the skin surface. Important to note here that sometimes this is exactly what people want, i.e. this surface hydration is what gives the "plump, glowing skin" effect people expect, so if the goal is hydration and surface smoothness, then large HA is ideal (surface action is enough), but if the goal is true wrinkle reduction or anti-aging, then surface HA alone is not sufficient. This is why companies combine HA with retinoids, peptides, or vitamin C, which act deeper and can influence collagen production. If the goal is long-term structural change, then you can have injectables (such as dermal fillers, which are being used for enlarging the lips, for one).
Transdermal Drug Delivery on the other hand are supposed to enter the bloodstream so drugs delivered through skin (e.g., nicotine, fentanyl, estradiol patches) are engineered to bypass the stratum corneum barrier. They use optimized molecular size, solubility, enhancers, and occlusion. If you want percentages here as well, I would say 20-95% systemic absorption of applied dose, but it depends on a couple of factors I have previously mentioned.
Just to stay on topic: sunscreens require only surface layer depth of absorption only, and in fact, many products work at this level. Their effectiveness depends heavily on formulation, proper application, and reapplication. Sunscreens do work when used correctly, they significantly reduce UV damage, premature aging, and skin cancer risk, BUT you must apply it properly and reapply often. You should combine with shade, too.
I love HN because, for every snarky comment that's made or said on a misunderstood, or incorrect basis of knowledge that would set off an alarm on QI, followed by a stern telling off by Stephen Fry.
There's some one like you, who has an endless pit of knowledge to aritculate or better inform with a whole lot of insight thrown in for good measure. Thank you, your post's awesome. :)
Small edit: I immediately thought "Your skin can't be that good as a barrier, nicotine and caffeine patches work through the skin?" when I saw the post you replied to, and loved that you made reference to it too.
I just woke up when I saw the submission, and when I scrolled through the comments I saw the one to which I replied because it did provoke me enough (you can even say it triggered me :D) to make such a reply.
I am glad it was a useful read to some at least! Of course if there are mistakes, I expect them to be called out and corrected, it has been a while since I last studied this. :)
> to articulate or better inform
I hope I did it right, I was still just waking up, and English is not my first language to begin with, but to see you write this does make me glad I made the comment.
FWIW your comment is quite motivating, thank you again, I mean it. You made my day. :)
(I try to encourage or motivate people as well who articulate my thoughts way better than I could ever hope to!)
I had no idea English was your second language! That's awesome.
I'm dyslexic so language is really hard for me, I have to put a lot more effort than most. I'm pretty intolerant of people who get annoyed at others when spelling or grammar is incorrect when we don't know their personal context (I had to triple check my spelling of grammar at least three times there XD).
I never got that impression from your post English wasn't your first language though! But I also wouldn't have stepped in to correct you even if you had. I nearly always find my own errors after a second or third visit, if I want cristicism of how I wrote something. I'll ask for it. If I didn't. I don't. I assume the same for everyone else.
I found this surprising; is halving the incidence of cancer enough to consider it safe? I would expect 90 or 95% reduction in the incidence of cancer to be considered safe.
The actual difference between (say) SPF 30 and 50 is not a lot, 96.7% UV filtering vs 98% but I’m not 100% sure how that translates to actual rates of cancer.
However the worst offenders in the testing advertised SPF 50 but delivered SPF 4 (~75% AFAICT)
https://www.ewg.org/sunscreen/beware-of-benzene-shining-a-li...
Beyond that, no clue.
That the duration of protection is independent of SPF makes this particularly true. There are only a handful of places in the world where atmospheric conditions might give a very high SPF marginal benefits.
(This is why the SPF scale is inverted/measures transmittance. SPF 50 sunscreen theoretically allows through 1/50th of the UVB radiation (or whatever wavelengths are specified by your local regulator).)
99% = 1 unit of UV reaching the skin
Thus 98% filtering lets in 2x as much as 99% filtering
Counterintuitively, higher SPF matters a _lot_. The difference is in the _durataion_ of the protection and in the amount of sloppiness you can afford while applying the cream.
Suppose that for you the half-life for the sunscreen is 1 hour. SPF 30 cream would thus decay to SPF 7 in 2 hours, providing little protection. But an SPF 90 cream would still offer quite reasonable SPF 25 protection.
The same applies to sloppiness. SPFs are measured in perfect conditions, with a prescribed amount of the cream spread evenly. So the higher the SPF, the more mistakes you can make while applying it.
While the US has no regulations around UVA protection, that's not true worldwide.
Europe and Australia both regulate the use of the term "broad spectrum". In Europe, that means the UVA protection needs to be at least 1/3 of the UVB protection to be able to use the term. I believe Australia is even stricter - all sunscreen is expected to have a baseline level of UVA protection.
Japan has PA ratings that go all the way up to PA++++ to specify the exact level of UVA protection.
1/3 the level of protection might sound like a significant difference, but it's not, especially since UVA is far less damaging than UVB is.
Given the context of this post being a sunscreen scandal, do you know how UVA is tested? Someone earlier was saying that sunscreen is tested on humans and you see how long it takes to get burned, if that's the case and UVA doesn't burn you, I'd be curious how these UVA filtering claims are validated.
Even among sunscreens that do a decent job filtering UVA the points in this article are still relevant: https://www.ewg.org/sunscreen/report/whats-wrong-with-high-s...
Basically high SPF allows behavior thats somewhat unnatural. Someone with SPF 15 might get a tiny bit sun sensitive after a few hours and go back inside, where someone with SPF 50+ keeps going all day long and that might not be healthy.
They all swore by zinc, rashies, and wide brim surf hats. 60 year old Trevor who surfs every day and has never had a mole might just be lucky but somehow I doubt it.
And the "water proof" sunscrean is even worse. I know it states on the label that it doesn't last forever, but the average person assumes it'll just persist and relayering it isn't needed as often as you'd think.
Sunscrean does work, absolutely. But if you need to be in sun for an awful lot of time, follow the advice of lifeguards, cricket players. Which is exactly what you said.
Clothing + zinc. In that order. Sunscrean every 1-2 hours for anywhere zinc or clothing can't be used.
https://kagi.com/proxy/Nathan-Lyon.jpg?c=ORiVIG1iR-yXL_2BLhX...
If it wasn't working at all, wouldn't you notice getting sun burned?
Initially i thought it was going to be something advertised as spf 30 but actually 15. However spf 4 or less seems so low it should be noticable i would assume.
The returns on protection are very much diminishing by SPF 30.
Anything over SPF 30 buys you approximately no additional protection.
Using no sunscreen is SPF 1 (at 2 milligrams per square cm). Sunscreen SPF 2 would correspond to halving the rate of instantaneous damage.
SPF 30 compared to SPF 4 would indeed give (30/4)=7.5 times lower rate of instantaneous damage.
The SPF scale is more sensible than your blocking percentage scale.
As with most things, the dose makes the poison.
Source? All things being equal, I'd expect half the UV damage by going from 98% UV protection to 99% UV protection. That's significant even though the protection only went up by only 1%. Moreover as I mentioned in my previous comment, even if you assume that 2% UV exposure (from 98% protection) basically never results in skin cancer, that figure is only achieved if you use sunscreen perfectly, which no one really does.
So SPF 4 you are letting 25% of the sun through. I would assume that would be enough to still be sun burnt on a high uv index day if you spend most of it on the beach.
According to WikiPedia:
"For example, "SPF 15" means that 1⁄15 of the burning radiation will reach the skin, assuming sunscreen is applied evenly at a thick dosage of 2 milligrams per square centimeter[67] (mg/cm2)."
so assuming a linear dose response relationship (obviously oversimplified) when not using the sunscreen 15 times more instantaneous random damage is incurred compared to when using the sunscreen.
This does not translate directly into the rate of cancers though: just like the final damage of a meteorite storm isn't proportional, even though the instantaneous damage is.
Suppose a meteorite strikes a hospital, lots of damage. Then years later a meteorite strikes a school, lots of damage. Obviously if both happen in quick succession more damage will occur.
But if the whole human population takes up sunscreen use, selective pressure on cellular coping mechanisms will be relaxed, and eventually future generations won't be as resilient against sunburn. So just live your life, and don't allow scaremongers to separate you from your money, or thus indirectly scare you into doing your job for them.
Thanks, that is a great observation
I use Banana Boat sunscreen, they have many different types. The water resistance depends on which type you use
I use the spf 50 ‘sport’ version on my legs and arms (not the face, too greasy) and it seems to do the job OK.
I guess if it’s 35 in testing that’s still OK-ish for general use. I do really plaster it on. And as I’m usually doing that before a lot of outdoor work, it draws a further protective layer of sand and dirt to itself…
Absolutely hate mineral ones, literally worst of all worlds - expensive, bad ux and doesn’t work. All while greenwashing. So much so it became my litmus to test people’s literacy.
So, we, as a community knew to avoid them for an awful long time. I can't be specific about when I heard this first but I'm almost certain some one said this to me in the first 12 months I moved to Brisbane (from the UK) 17 years ago.
So, there's been an urban myth for almost, if not longer than 2 decades. And we're only finding out now that it's true? That's the most surprising part of this to me IMO.
Edit: sentence structure, words.
It’s tedious to apply thoroughly. It loses effectiveness with water, sweat, etc — inevitable when outside.
It would work best in indoor conditions but then wouldn’t be needed…
I suppose I could sun bathe on a cool winter day … but that just isn’t fun.
Agreed, partially. There are times one has to do things when it's blazing hot.
On sunscreens, we're still missing:
- amiloxate
- bemotrizinol
- bisdisulizole disodium
- bisoctrizole
- drometrizole trisiloxane
- tris-biphenyl triazine
While continuing to allow:
- 4-MBC (enzacamene)
- avobenzone
- oxybenzone
- homosalate
- octinoxate
- octocrylene
In the US, buying a safe(r) (for humans and reefs) sunscreen requires a medical and a marine biology degree unless you're willing to slather yourself in white pastes like zinc oxide or titanium dioxide. One major barrier is the law demands animal testing prior to approval.
Meanwhile, there are still millions of Americans (mostly men) who routinely venture outdoors for work and projects without sufficient protection and accumulate enough exposure that leads to preventable skin cancer. And I had my fair share of sunburns as an active kid.
I agree with that for the same reasons. Nevertheless, I'll still use sunscreen when I have to. In Australia there are times when it's hard to avoid the sun but I avoid it at every opportunity.
If at the end of a day I feel my skin the slightest bit sore from exposure I know I've not been proactive enough.
Spray goes on easier, not only does spray cover area, but it spreads easier than cream too, but anything is better than nothing. But I have drifted towards preferring long sleeves, hats, and even a sun umbrella so I don’t have to get greased up.
Long sleeve thick cotton shirts, long pants, and a good wide brimmed hat are easily ten times more effective in practice. My old hard as a tack, shearer grandfather used to swear by black picnic umbrellas (great option if you are spending time working in a fixed location).
Of course you can't swim that well in long sleeved clothes hence the popularity of sunscreen. I'm totally against Aussie beaches at this point though, yes they are nice and all but the radiation dose is just nuts.
Would love to see something like the Apple Watch include UV dosimeter functionality.
This is actually a fucking great idea!
I presume, the location and orientation variation at the wrist probably makes for a good baseline exposure measure.
Quite honestly, either direction would be super useful data. Would be nice to get a warning/notification for too much, or too little sun exposure. Long term pooled population data would be invaluable, too.
Also, while we're at it, please throw in an actual dosimeter, x-ray/particle detector too. Not that useful now, but very, very cool, and who knows, if we have to fight giant cockroaches and stuff in the days to come.
1. It’s easy to apply. Slip a sun hoodie over the head - protected.
2. Because it’s so easy to apply it always goes on when needed.
3. It’s impossible to miss spots or under-apply in certain areas. If fabric covers the skin, you’re solid.
4. This is subjective but it’s more comfortable. On a sunny 90F day with a high UV, direct sun on skin feels like sticking your hand on a hot skillet.
My fun fact for all this is that the Bedouins wear black robes in the desert heat. Not white. It’s counterintuitively cooler for the wearer [0]. Sunscreen is a great modern invention with its use cases, but humans have been wearing clothing for eons to ward off the sun for a reason. The only real downside is that you may look a bit silly when everyone else is lathered in sunscreen wearing very little clothing.
Then we moved north and did not get enough sunlight anymore for metabolic processes. Easy solution, we just turn white.
Now we are both freezing and getting sunburnt at the same time. Evolution sucks, we should have kept the fur.
Also, things are changing way faster than adaptation could possibly happen in evolutionary time scales.
> Evolution sucks, we should have kept the fur.
Some say, we shouldn't have left the trees, even.
It is called "Invisible Zinc" and all the times that I've used it I didn't even get the slightest trace that I've been long hours under the sun.
The one I've purchased was rated 50+ and came in a very small package. It was not cheap but it delivered as stated.
You don't even need to apply it many times as is a very dense product. The only downside is that is not easy to remove it and I ended up with my face pretty white as a clown. But besides that it was possibly the best sunscreen I used. I regret that is not available in Europe and shipping costs approach the product cost.
https://www.youtube.com/watch?v=b7nocIenCYg
Slip, Slop, Slap!
Slip on a shirt, slop on sunscreen and slap on a hat
Slip, Slop, Slap!
You can stop skin cancer - say: 'Slip, Slop, Slap!'
Took a quick look and apparently the issue is pretty widespread: https://www.ewg.org/sunscreen/report/whats-wrong-with-high-s...
I use sunscreen myself sometimes but using artificial methods gives me pause. Whenever possible I just wear a UV shirt and a hat instead.
https://landgeist.com/2023/07/22/skin-cancer-prevalence-in-e...
I always laugh when people wear those stupid baseball caps instead of proper hats with brims. They think it's 'cool'. Mate, the main person laughing at your 'cool' is future you - dying from skin cancer on your face.
"Mad dogs and Englishmen go out in the midday sun." - https://www.phrases.org.uk/meanings/mad-dogs-and-englishmen....
https://www.sunsafeaustralia.com.au/headwear/p/uveto-austral...
Although we often think of burning as bad and tanning as good, tanning is nonetheless still actually a symptom of your skin being damaged by the sun - it's just a symptom that looks better than burned skin, to the point that many people think it looks nice enough to be worth the cancer risk (and/or don't understand the risk when they decide to tan).
Australia does have the highest records of skin cancer diagnosis per capita though, and it has for some time. [1] The reason for it is for a few reasons.
A prevalance of outdoors focused lifestyles, exasperated by a higher amount of UV penetration to the ground due to proximity to the equator, and a much smaller/thinner O-zone layer than anywhere else in the world. This applies to both Australia and New Zealand btw.
Both due to the location, and man made causes (e.g., CFC's) [2]. Though fortunately, the O-zone layer is getting much better and quite quickly. The article I linked states the ozone layer will be at pre-1980 levels by 2050. Taking this at face value without much scrutiny though.
Australian's statistically have fairer skin. I'm half Cypriot by mother's, Norweigan. I did not get my fathers complexion ;-).
Throw in the sheer number of people who travel here from places where the ozone is much stronger/better, means people enjoying our lifestyle without the same level of protection warranted. I thiink this risk is overstated though, I made the mistake of not using enough sunscrean or clothing once, and got the most hellish skin burn. You only ever make that mistake once.
[1] https://biologyinsights.com/which-country-has-the-highest-ra... [2] https://cyclimate.com/article/does-australia-have-an-ozone-l...
However, melanoma, the most dangerous form of skin cancer, also sometimes develops in areas hardly ever exposed to UV light. Like inside eyes, or in the groin. Melanocytes originate from the neural crest and are spread all over the body. Due to their ontogenetic origin (loose tissue association), melanoma is always bad news, while other forms of skin cancer hardly ever metastasize.
https://en.wikipedia.org/wiki/Sun_tanning
Personally, I use the UV index charts and avoid extremes, midday sun completely. I put on 50 SPF to my face and neck every time I leave the house. It's just routine. In winter I may skip it, because good sun screen is fucking expensive. Not so much about skin cancer, but rather skin aging. The face is always exposed. I am trying to get a little intentional sun exposure in spring after dark winter, slowly preparing my skin for summer and improving mood. However, I tan easily. If I had the skin type I, I would avoid the sun much more.
Did you notice how many people these days look younger? Even in their 30s? I think that's no smoking, intentional nutrition, exercise and sun screen (from childhood on).
Anything without a published standard and testing regulation, is going to be crap. Because, manufacturers and the free market.
There is no repercussions for these clowns pushing a faulty product into the masses. I guess they actually are the winners here because they walk away with cash while their followers end up with shitty product and the company has to deal with the fallout. I doubt the digital door-to-door salespersons reputation suffers as their audience will still lap up anything they sell like a thirsty dog in the desert.
Why not just link to the original which has a clean infographic? Its honestly super infuriating.
https://www.choice.com.au/health-and-body/beauty-and-persona...
I feel like we're going to be reminded of this a lot more in the coming years...
(Why must this work?)