In this article, we will discuss sunscreen.
Sunscreens are commonly used to maintain skin function and for cosmetic reasons.
People who are interested in beauty or who have skin problems will even check the ingredients of the products they use to make sure they are safe for their skin.
Sunscreen is easy to apply, but does it have any disadvantages, even though it provides UV protection? I have wondered.
There have been studies on the advantages and disadvantages in these respects, so I will briefly introduce them.
Safety of ingredients, etc.
As of February 2019, the FDA has recognized 22 UVF compounds used in sunscreen products and established a classification for their safety.
GRASE (Category I)
Those that are non-GRASE (Category II)
Necessary evaluation classification (Category III)
However, several compounds were unclassified because they were awaiting investigation.
At this time, two UVF agents
Titanium dioxide (TiO2)
Zinc oxide (ZnO)
were designated as GRASE Category I.
The 20 UVF compounds, most of which are approved in Europe, are classified as GRASE Category II and need to be approved by the FDA in a New Drug Application before they can be sold.
Two of these 20 UVFs are
Aminobenzoic acid
Trolamine salicylate
were classified as non-GRASE-Category II.
As a result, they were not approved for sale as sunscreen products in the United States.
The reason was that PABA was found to cause allergic contact dermatitis, a tendency to stain clothing, as well as endocrine abnormalities in some people, especially changes in thyroid activity.
Trolamine salicylate, an ingredient in some OTC topical analgesics to relieve arthritis and muscle pain, is also a UVBUVF.
However, trolamine salicylate may be absorbed systemically across the skin into the underlying tissues, potentially leading to increased serum concentrations of salicylic acid due to salicylic acid.
Unclassified ingredients include.
Lawson + dihydroxyacetone
DEA methoxycinnamate
Digalloyl triolate
Red petrolatum
and red petrolatum.
And there are also indications of human and environmental toxicity associated with these agents, along with many other compounds that are not typically used in sunscreen products.
As of 2019, 12 currently marketed UVF compounds that were under proposal and needed further study were.
Avobenzone
Cynoxate
Dioxybenzone
Enthrizol
Homosalate
Meladimate
Octocrylene
Octinoxate
Octisalate
Oxybenzone
Pazimate O
Slisobenzone
The FDA has also expressed concern about the lack of data on the toxicity of all UVF ingredients in spray and powder formulations in terms of inhalation risk and flammability risk.
And sunscreen products that also contain insect repellent ingredients are also considered to be in need of further research.Research on more effective sunscreen ingredients is more advanced in European countries than in the US.
The reason for this is that the process of FDA approval and safety testing takes more time.
Usage and Benefits
According to the American Academy of Dermatology, sunscreen is considered a safe and effective sun protection.
To protect against UV rays
Seek shade between 10 a.m. and 2 p.m.
Wear long-sleeved shirts, pants, wide-brimmed hats, and sunglasses.
Apply sunscreen with SPF 30 or higher to areas not covered by clothing.
Wear UV-protected clothing.
The following are some of the most important factors to consider.
Use of a water-resistant sunscreen with SPF 30 or higher, which protects against both UVA and UVB rays.
Reduced risk of developing skin cancer
Reduce the incidence and severity of sunburn
Prevent signs of aging
The following are some of the benefits.
The sunscreen factor, also known as SPF, is a measure of sunscreen effectiveness and is primarily related to the amount of UVB protection it provides.
For example, using a sunscreen with SPF 30 requires 30 times more UV exposure for sunburn than not using a sunscreen.As for the timing of application, it should be used 15 minutes before leaving the house, and an ounce (about 2 cups) is considered necessary to adequately cover the entire body.
For lasting protection, it should be applied every two hours and reapplied immediately after swimming and after excessive sweating.
And while UVF is added to many cosmetic products, it is considered rare for a cosmetic product to provide adequate protection against both UVA and UVB radiation.Cosmetics alone can provide inadequate protection, so appropriate sunscreen protection is still needed.
Risk aspects
Studies published in 2019,2020 measured plasma concentrations of UVF agents applied under maximal use conditions to meet time and range of application.
In these studies, the UVF ingredients in seven commercial products were tested.
Avobenzone
Oxybenzone
Octocrylene
Homosalate
Octisalate
Octinoxate
Ecamsule
These ingredients were shown to be absorbed systemically, but no evidence of systemic toxicity was provided and it was clearly stated that they should not interfere with sunscreen use.
In using sunscreens, some people find that the sunscreen on their face does not completely disappear even after a good scrubbing, or it leaves a subtle white tint on the skin, like that of a Kabuki actor.
This residual pallor is often noticeable.
Another concern is that applying makeup on top of sunscreen can lead to the "pilling" phenomenon.
This often happens when different products are applied to the skin, making it difficult to create an even and smooth surface.
This can lead to peeling and pilling.
Currently, many facial sunscreen products are tinted, but color matching is difficult because not all shades and skin tints match.
Also, tinted sunscreens can stick to clothing and stain it.
However, colored sunscreens are not the only ones that have the potential to stain clothing.
While both chemical and physical sunscreens can leave residue, those with higher amounts of physical blockers such as titanium dioxide and zinc oxide can rub off on clothing and leave behind stains like chalk dust.
In this situation, powder brush-on sunscreen products are considered to be innovative.
They are ideal for reapplication, easy to apply and blend well over makeup.
On the other hand, it should be noted that they contain a number of added ingredients that can cause irritation or allergic contact dermatitis.
Sunscreens with chemical ingredients have these concerns, which is one of the reasons why oxybenzone, with its UVA effect, can cause irritation, allergic contact, or photo contact dermatitis.
Other sunscreens that may also cause photoallergic reactions include
Cinnamic acid salts
Dibenzoylmethane
Dibenzoylmethane - Benzophenone
and benzophenone.
In addition, the FDA does not recommend the use of sunscreens for infants under 6 months of age.
This is because of the influence of the aforementioned story about absorption into the bloodstream and the lack of approval.
Sabzevari N, Qiblawi S, Norton SA, Fivenson D. Sunscreens: UV filters to protect us: Part 1: Changing regulations and choices for optimal sun protection. Int J Womens Dermatol. 2021;7(1):28-44. Published 2021 Jan 23. doi:10.1016/j.ijwd.2020.05.017
Summary
The previous descriptions are different in Japan due to differences in laws regarding medicinal ingredients.
The amount of ultraviolet rays is also different, and due to differences in race, it is necessary to consider whether all of these things are applicable to all people, but at least in the U.S., there are many people of different races living there, so I think we can use this as a reference.
We can reconfirm the details of the application, ingredients, allergens, etc., as they will be familiar to the people involved.
Countermeasures against viral infections are important, but let's not forget about this kind of care.
