Dr_Rudi, I disagree on almost everything in your post, mainly on the topic of UV-A protection.
Originally Posted by Dr_Rudi
Firstly, gupts has asked for an anti-wrinkle moisturiser with SPF 30. So, we're not talking about separate sunscreens and exfoliators.
I disagree strongly.
In my previous post I argued why it would be beneficial for Gupts or anyone to seperate the anti ageing products (e.g. retinoids to stimulate collagen production and/or AHAs/BHAs for skin exfoliation) and the sunscreen product.
AHAs can give irritation to your skin, and therefore it's only practical to have a seperate, non-exfoliating sunscreen on those days when your face needs to recover a bit. As you know, using chemical exfoliants every day can very well lead to over-exfoliation and acid irritation. The method of seperately applying your AHAs and your sunscreen is a much more prudent option to suggest, exactly because that was not what was being asked.
"Broad spectrum" sunscreens offer protection against UVA and UVB. Understand? That's very simple. The Australian standard specifies this - UVA has not been left behind.
Wrong again. It's not as simple as picking any sunscreen with 'broad spectrum' on it.
Have you ever wondered why the measure of UVB protection is quantified on the tubes of sunscreen (a number
in SPF), and UVA isn't? In Australia, it's either it complies to the Australian standard, or it doesn't.
If it complies, it means that less than 10% of the incoming light between the wavelengths of 320nm and 360nm is transmitted, and nothing more. It means that people with high photosensitivity don't have the quantitive information to make a choice out of products with stronger UVA-protection, as well as it does not report anything on UV-A radiation between 360-400 nm, that can penetrate skin deeper than shorter wavelengths.
Actually, it basically means that the Australian standard approx. only measures up to a PPD (Persistent Pigment Darkening, a way to measure UVA-protection) of 6. Which is even worse than the Japanese rating, as its maximum PA+++ tops out at a PPD of 8. Though nobody beats the US system, which has no UVA-measurement standard to put on packaging.
In Europe, you can get an UVA logo when the PPD is at least a third of the specified SPF. The Boots-system that is used in the UK, has a star system in which for example 5 stars it means that the PPD is at least 91% of the SPF number.
So you see, almost every system in the world except for the United States is more detailed than the Australian Standard in terms of quantifying UVA-protection. More information = more knowledge = better informed choices.
Oh and, just a little rant about USA 'broad spectrum' sunscreens: due to FDA regulations, avobenzone is basically the only UVA-absorbing organic sunscreen ingredient allowed, and it breaks down rapidly under sunlight when irradiated when it's not stabilized by for example octocrylene. In the US there are many 'Broad Spectrum' sunscreens that contains unstabilized avobenzone and it's just as useful as buying an umbrella that dissolves under rain.
Dear American friends, remember this next time you shop for sunscreens!
When sunscreens are tested, the solar simulators emit UV up to 360-370 nm which is well into the UVA-1 region and takes into account all of the UVA-II.
Thank you for saying this, and proving that a sunscreen's compliance with the Australian Standard does not say anything about its performance between 360-400nm (Australian standard goes up to 360nm, not 370) within the UVA-spectrum. That is a missed opportunity for the standard, and again, it should be modernized.
UVA does penetrate the skin more readily and may reach deeper. It has been implicated in both premature photoageing and skin cancer.
True, and I agree. I believe proper UVA-protection is at least as important as UVB-protection as a measurement against photoageing. In fact, since UVA-rays can penetrate clouds and are there the whole year, cumulatively they are more responsible for DNA-damage than UVB-rays, that only really make a mess when someone gets sunburned.
In practical terms, whenever I select a sunscreen, my concern is not UVB-protection. I can read my bottle has SPF 30 or such, and it's all clear to me. Getting the best UVA-protection out of several products often requires a better read and often picking out the active sunscreen ingredients for a better understanding.
The Broad Spectrum claim current in Australia attests to a measure performed which indicates that there is some UVA filtering between 320 – 360 nm. Australia is the only country which includes such a test and claim in its mandatory Standard.
Wrong again. Other countries such as Japan and also the EU have their ways with UVA protection measurements as described above, and are generally more informative and quantitative than the '< 10% transmission 320-360nm block = yes/no-sign' of the Australian Standard regarding UVA-protection.
People are quantitatively more informed about the level of UVA-protection when reading Japanese or EU-labels than the Australian Standard.
Also, I have to say, the Australian Standard for UV-A protection is quite low, simply because at the time the rule was invented, there were not that many proper organic UVA-blocking ingredients approved for use! Newer sunscreen formulations with modern UVA-blocking ingredients such as Tinosorb S/M, Mexoryl XL/SX, Neo Heliopan AP or stabilized Avobenzone allow for formulations that offer much much superior UVA protection than the Australian Standard specifies.
Many of these modern ingredients were only approved after
the introduction of the Australian Standard, so perhaps it's time to reconsider and modernize this old (I would almost say: out-of-date) standard, and to put it in line with technological possibilities that just weren't there when the Standard was put in use.
So yup, the Australian standard is not really the most informative out there regarding UVA protection.
Ideally, there should be a clear, quantitative, worldwide standard for indicating several levels of UVA-protection on any product. Just as UVB-protection has its own SPF indicator. I hope that we can see that in the future.