UVA Protection: Current & Proposed FDA Regulations
What is up with UVA protection in sunscreens sold in the United States?
The FDA hasn't updated their sunscreen regulations in a robust way since 2011. Due to recent research and the Sunscreen Innovation Act of 2014, the FDA has issued some proposed new rules regarding sunscreens. Several of these new proposed rules address problems with UVA protection. As it stands, there are a few issues with UVA regulations in the United States, and it makes sense to begin with the regulation and the Broad Spectrum designation.
In the US, the designation “Broad Spectrum” is used to determine the UVA protection of a product. It is a Pass/Fail test.
What does Broad Spectrum currently mean?
Currently, Broad Spectrum testing is done in a machine called a spectrophotometer. The sunscreen is put on a receptor tray, battered with four MEDs (minimal erythemal doses; or an amount of UV that can cause a visible skin reaction). Then the machine runs the spectrum of UV through the sunscreen, measures how much gets through, and prints a report. The relationship between UV sent out and the amount that got through is indicated by A, or absorbance, per wavelength:
Since 2011, Broad Spectrum sunscreens have had a Critical Wavelength of at least 370 nanometers.
What is a critical wavelength?
The critical wavelength is the wavelength below which 90% of a product’s protection is offered. So, the area beneath the whole of the absorbance curve is calculated. The critical wavelength is the wavelength below which 90% of the area of the sunscreen’s protection is offered.
What are the pros of this regulation?
Currently, the biggest pro for broad spectrum designations is the fact that it is simple and easy to understand. If a sunscreen is Broad Spectrum, that means the protection offered by the sunscreen (the SPF) offers some protection through the specific UVA wavelength of 370nm.
What are the problems with this regulation?
It’s just not very good. If UVB absorbance is high but UVA II and UVA I are low, it is possible to have a broad spectrum classification with very little UVA protection at all. In essence, a Broad Spectrum designation suggests that there is some UVA protection, which is really not good enough.
Fortunately, the FDA is seeking to make this better through new regulation.
The New Regulation
The FDA now wants broad spectrum sunscreens to be at least SPF 15, and have a ratio of UVA I to UV ≥ 0.7.
So, if you calculate the absorbance of the sunscreen across all of UV, and then the absorbance in only UVA I, and divide the UVA I by the total UV, the value must be greater than or equal to 0.7.
This is to say, UVA I protection must be 70% as good as the sunscreen’s protection against all of UV.
This is a better regulation than the previous broad spectrum requirement. Comparing products 1 & 2 shows better UVA I protection in product 2.
This regulation makes a product’s SPF an indicator of its UVA I protection: the higher the product’s SPF, the higher the UVA I protection must be for the sunscreen to be broad spectrum.
Put another way, the higher a sunscreen’s SPF, the higher its UVB absorbance. With this new regulation, sunscreens with higher UVB absorbance must also have higher UVA I absorbance in order to be Broad Spectrum.
What are the issues with the new proposed rule?
The new, proposed Broad Spectrum regulation is a lot better than the old regulation, and I am grateful for this, but I wish the American consumer had transparency regarding the specific UVA protection of a given product. This exists in other parts of the world, and allows consumers to have confidence in the specific UVA protection a given sunscreen offers.
UVA in the EU
In the EU, they follow the Colipa guidelines to determine a product’s UVA protection. Like Broad Spectrum testing, it is conducted in a lab.
If a sunscreen’s UVA protection is at least one third of its UVB protection, it is classified as Broad Spectrum, and the product is allowed to display a UVA symbol with a circle around it on the packaging.
This is a good system, and a system which I would like the FDA to consider. I prefer this method because the consumer has access to the product’s SPF, and can easily divide by three to determine the minimum UVA protection offered. The FDA’s regulation lacks this transparency, as brands do not need to communicate the whole absorbance spectrum for a product, and it is this full spectrum on which the FDA’s new broad spectrum guideline is based.
The thing that the FDA's regulation gets right in comparison to the EU is focusing on UVA I protection. Most sunscreens have better UVA II protection than they do UVA I, because many UVB filters are also somewhat effective at absorbing radiation in the UVA II range. By testing UVA I specifically, the consumer can have confidence that there is reasonable UVA I protection. Based on the fact that there is reasonable UVA I and UVB protection, it can be confidently assumed that UVA II protection is also reasonable.
Some companies, like L’Oréal, use a test called PPD, or persistent pigment darkening, which is like the SPF test, but with UVA. Like SPF, it is done on actual people, not in a machine. It measures protection against a tan. Some brands like La Roche-Posay include a product's PPD rating in its marketing materials.
PPD is a logarithmic expression like SPF is. So a PPD of 10 is going to block around 90% of UVA, and a PPD of 15 will block 93% of UVA, and a PPD of 30 will block 97% of UVA, on and on. More on the math can be read here.
UVA in Asia
In many countries in Asia (South Korea, Japan, China), the PPD test is conducted, and the results are communicated via a PA rating. PA, which stands for Protection Grade of UVA, has four classifications:
|PA Rating||PPD Score||Min. % UVA Absorbed|
UVA, PPD, and PA ratings are more transparent in regards to the specific UVA protection factor which a product offers. This gives consumers greater confidence in the UVA protection offered by a product.
The other issue: UVA filters in the US
There is a significant limiting factor in regards to the UVA protection offered by Broad Spectrum sunscreens in the United States: the USA has remarkably limited, old fashioned, and generally insufficient active ingredients which provide UVA protection.
In my mind, this pass/fail system was likely introduced because the United States only allows two good UVA blocks in its sunscreens: Zinc Oxide and Avobenzone. Both of these filters have problems.
Zinc oxide is a fabulous UV filter. Magnificent. It’s really great. Its selling point is its consistency: it’s great at UVB and UVA, and the absorbance doesn’t have notable peaks or valleys. Zinc oxide is effectively an opaque hunk of white rock, and it needs to be ground up into little pieces to be remotely tolerable in sunscreens. Different companies have different tricks to make zinc more elegant. All of these zincs are different: they are different sizes, have different coatings, and lump together in different ways. All of these factors influence how zinc absorbs radiation: smaller particles of zinc are less efficient at UVA, and scatter different wavelengths, have more vast valleys in absorption spectra. While they don’t make zinc a bad UV filter – it will be a good filter regardless of its particle size – they do alter its absorption in a significant way.1
The problem here is the fact that these different zincs are not named. A sunscreen won’t tell you if it’s zinc is ZinClear, Z Cote, the one Colorescience patented, the one from Kobo, or whatever it is. Since there is no transparency for consumers in regards to which zinc is being used, one can’t assume that one is getting the best protection from a given zinc. So, I find that it is hard to have confidence in the actual UVA protection provided by zinc, as the assumed value cannot be relied upon. While a Broad Spectrum classification will inform the consumer that the critical wavelength is greater than 370 nanometers, it must be stated that it is hard to have confidence in anything more than that.
The other problem with zinc is that it is opaque, and gives a white cast on the skin. Many lighter skinned people can make this work. However, many people with darker skin tones cannot. It isn’t socially acceptable to walk around with a gray face. I don’t know how the FDA can simultaneously recommend that sunscreen be used daily by all Americans, but that they must coat their faces in white particulates in a manner that is simply socially unacceptable. It’s as if nutritional guidance stated “eat a balanced diet consisting only of foods you cannot stand, and that make you smell badly, so that friends and strangers give you bizarre looks.”
The other available UVA filter, Avobenzone, is also phenomenal, and is also flawed. As synthetic UVA filters go, Avobenzone is really a superstar. It’s very efficient and it covers all of UVA. However, Avobenzone containing sunscreens marketed in the US face two major limitations: one, the fact that Avobenzone is photo unstable and two, the fact that US sunscreens can only use up to 3% of it.
I will begin with the latter (which I acknowledge is more of a personal gripe than an actual problem). Basically every other country on earth allows Avobenzone in concentrations of up to 5%. This includes Northern Europe, where there is no sun for half of the year. This literally includes Siberia. The US is not so lucky: the maximum allowed concentration of Avobenzone is 3%. God knows why. L’Oréal asked the FDA why this was a few years ago and the FDA basically responded by telling L’Oréal to stop whining. Due to this restricted amount of Avobenzone, the best Avobenzone containing sunscreens in the US aren’t as effective as Avobenzone containing sunscreens in Novosibirsk. Literally.
The other issue is Avobenzone’s photostability, and this is a big, big issue. From the bottle, Avobenzone is one of the best UVA filters on Earth. It efficiently covers all of UVA and one needn’t use a lot of it to get great UVA protection. However, when exposed to UV light, it changes structure, and rapidly degrades into a form in which it can no longer filter UVA. It is this issue which informs the FDA’s advisory that sunscreens must be reapplied every two hours, as without a stabilizer, Avobenzone will degrade at a rate of 60-90% after 1 hour of UV exposure.2
Now, there are a variety of molecules which can stabilize Avobenzone, which will result in it being an effective UVA absorber for a longer period of time. Some of these are UV filters (Octocrylene and Oxybenzone, and among the filters not allowed in the US, Tinosorb S), some are emollients (like Diethylhexyl 2,6 Naphthalate), and antioxidants are sometimes used.3
While these stabilizers will impact the longevity of the Avobenzone, the consumer has no access to the efficacy of the photostabilization. This leaves the consumer unprotected from UVA, as there is no transparency regarding for how long the Avobenzone can be expected to remain stable. Indeed, even a hugely significant 25% increase in Avobenzone stability will fail to provide lasting UVA coverage, as one will still be left with as much as 45% - 67% degradation after an hour of sun exposure.
UVA Filters Worldwide
Other countries allow the use of Avobenzone at up to 5%, and they also have a full cast of other terrific filters which block UVA radiation, including:
- Diethylamino Hydroxybenzoyl Hexyl Benzoate (Uvinul A Plus)
- Bisdisulizole Disodium (Neo Heliopan AP)
- Terephthalylidene Dicamphor Sulfonic Acid (Mexoryl SX, or Ecamsule)4
- Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine (Tinosorb S, or Bemotrizinol)
- Methylene Bis-Benzotriazolyl Tetramethylbutylphenol (Tinosorb M, or Bisoctrizole)
- Drometrizole Trisiloxane (Mexoryl XL)
- Tris-biphenyl Triazine (Tinosorb A2B)
These molecules offer UVA protection, and are photostable. They are transparently presented. There is no fear of them not working as well as one expects them to. They can be formulated into a variety of products which people like using. Their lack of availability in the US is a shame.
The Food and Drug Administration has a hard job. They are responsible for making sure that the citizens of the United States are provided with accurate information about the treatment and prevention of all kinds of disease. They take this work seriously, and allow the US to be a global leader in the development of life-saving medical treatment. I am grateful for this.
Yet, due to the reasons outlined above, the FDA has made a series of judgements which severely limit the ability of Americans to protect themselves from UVA radiation. Their new regulatory framework for UVA protection fails to provide transparency regarding the specific UVA protection offered by a given sunscreen, and their list of allowed UVA filters leads to a lack of confidence in the possible UVA protection offered by a product. These factors make it challenging to have confidence that sunscreens in the United States offer excellent UVA protection.
It is my steadfast and secure belief that expanding the list of allowed UVA filters and greater transparency regarding the rate of UVA protection will be beneficial to the health of Americans. And I do wish that this would change.
3 Osterwalder, U., & Herzog, B. (2009). Chemistry and Properties of Organic and Inorganic UV Filters. In Editor H. W. Lim & Z. D. Draelos (Eds.), Clinical Guide to Sunscreens and Photoprotection (pp. 33). New York, NY: Informa Healthcare USA, Inc.
4 Okay, there is Ecamsule in 1 sunscreen in the US, but it isn’t technically allowed – it is only allowed in that specific sunscreen. More to come.