Sunscreen , also known as sunblock , sun cream or lotion sunbathing , is lotion, spray, gel or other topical products that absorb or reflect some ultraviolet (UV) solar radiation and thus help protect from sunburn. Diligent use of sunscreen can also slow or temporarily prevent the development of wrinkles, moles and sagging skin.
Depending on the mode of action, sunscreens can be classified into physical sunscreens (that is, which reflect sunlight) or chemical sunscreens (ie, which absorb UV light).
Medical organizations such as the American Cancer Society recommend the use of sunscreens as it helps the prevention of squamous cell carcinoma. Many sunscreens do not block UVA radiation, which does not primarily cause sunburn but may increase melanoma and photodermatitis levels. The use of broad-spectrum sunscreen (UVA/UVB) can solve this problem.
Sunscreen is generally assessed and labeled with a sun protection factor (SPF) that measures the fraction of UV rays that produce sunlight reaching the skin. For example, "SPF 15" means that 1 / 15 of the burning radiation reaches the skin through recommended sunscreen thickness. Another rating system shows the level of protection from unburned UVA radiation.
Video Sunscreen
Health effects
Benefits
The use of sunscreen can help prevent melanoma and squamous cell carcinoma, two types of skin cancer. There is little evidence that it is effective in preventing basal cell carcinoma.
A 2013 study concluded that persistent and daily sunscreen applications can slow or prevent the development of sagging skin and sagging skin for a while. The study involved 900 whites in Australia and required some of them to apply broad-spectrum sunscreen every day for four and a half years. It was found that those who did it had stronger and smoother skin than those assigned to continue their usual practice.
Minimizing UV damage is very important for white children and individuals and those with solar sensitivity for medical reasons.
Risk potential
In 2009, the Australian Therapeutic Goods Administration updated the sunscreen safety study review and concluded: "The potential of titanium dioxide (ZO) and zinc oxide (ZnO) nanoparticles in sunscreens to cause adverse effects depends primarily on ability nanoparticles to achieve viable skin cells.For now, the current weight of evidence suggests that TiO 2 and ZnO nanoparticles do not reach viable skin cells. "Sunscreen ingredients usually undergo extensive reviews by government regulators in various countries, and materials that present significant security issues (such as PABA) tend to be withdrawn from the consumer market.
Concern has also arisen about potential vitamin D deficiencies arising from long-term use of sunscreen. Use of a typical sunscreen usually does not cause vitamin D deficiency; however, widespread use is possible. Sunscreens prevent ultraviolet rays from reaching the skin, and even moderate protection can substantially reduce vitamin D synthesis. However, adequate amounts of vitamin D can be produced with moderate sun exposure on the face, arms and legs, averaging 5-30 minutes in two times per week without sunscreen. (The darker the complexion, or the weaker the sunlight, the more minutes of exposure it takes, about 25% of the time for minimal sunburn.Overdose of vitamin D is not possible from UV exposure thanks to the balance achieved by the skin where vitamin D decreases as fast it is created.
Maps Sunscreen
Protective measurements
Sun protection and labeling factors
The sun protection factor (SPF rating, introduced in 1974) is a measure of the fraction of UV rays that produce sunlight reaching the skin. For example, "SPF 15" means that 1 / 15 of the burning radiation will reach the skin, assuming the sunscreen is applied evenly at dose thickness 2 milligrams per square centimeter (mg/cm 2 ). A user can determine the effectiveness of sunscreen "by multiplying the SPF factor with the length of time it takes for him to suffer burns without sunscreen." So if a person develops sunburn within 10 minutes when not wearing sunscreen, the same person in the same intensity of sunlight will avoid sunburn for 150 minutes if wearing sunscreen with SPF 15. It is important to note that sunscreen with more SPF high does not last long or remains effective on the skin longer than the lower SPF and should continue to be applied as directed, usually every two hours.
SPF is an imperfect measure of skin damage due to unseen damage and skin aging is also caused by type A ultraviolet (UVA, wavelength 315-400 or 320-400 nm), which does not cause bruising or pain. Conventional sunscreens block very little UVA radiation relative to the nominal SPF; broad-spectrum sunscreens are designed to protect against UVB and UVA. According to a 2004 study, UVA also causes DNA damage to deep cells inside the skin, increasing the risk of malignant melanoma. Even some products labeled "broad-spectrum UVA/UVB protection" do not always provide good protection against UVA rays. Titanium dioxide may provide good protection, but it does not completely cover the UVA spectrum, since a preliminary study in 2000 showed that zinc oxide is superior to titanium dioxide at wavelengths of 340-380 nm.
Due to consumer confusion over the actual rate and duration of protection offered, labeling restrictions apply in some countries. In EU, sunscreen labels can only rise to SPF 50 (initially listed as 30 but soon revised to 50). The Australian Therapeutic Goods Administration increases the upper limit to 50 by 2012. In the draft rules of 2007 and 2011, the US Food and Drug Administration (FDA) proposes a maximum SPF 50 label, to limit unrealistic claims. (In February 2017, the FDA has not yet adopted the SPF 50 limit.) Others have proposed limiting the active ingredient to an SPF of no more than 50, due to a lack of evidence that higher doses provide more meaningful protection. Different sunscreen materials have different effectiveness against UVA and UVB.
SPF can be measured by applying sunscreen to the skin of the volunteers and measuring how long it will take before sunburn when exposed to artificial sunlight. In the US, such as in vivo tests are required by the FDA. It can also be measured in vitro with the help of specially designed spectrometers. In this case, the actual transmittance of the sunscreen is measured, along with the degradation of the product due to exposure to sunlight. In this case, the sunscreen transmittance must be measured at all wavelengths in the UVB-UVA range of the sun (290-400Ã, nm), together with the table on how effective various wavelengths cause sunburn (spectrum of erythemal action /i >) and the standard sunlight intensity spectrum (see figure). These in vitro measurements correspond to the measurements in vivo .
Many methods have been designed for the evaluation of UVA and UVB protection. The most reliable method of spectrofotokimia removes the subjective properties of erythema grading.
The ultraviolet protection factor (UPF) is the same scale developed for rating fabrics for sun protective clothing. According to recent testing by Consumer Reports , UPF ~ 30 is typical for protective fabrics, while UPF ~ 6 is typical for standard summer fabrics.
Secara matematis, SPF (atau UPF) dihitung dari data yang diukur sebagai
di mana adalah spektrum radiasi matahari, spektrum tindakan erythemal, dan faktor perlindungan monokromatik, semua fungsi dari panjang gelombang . MPF kira-kira kebalikan should be transmitted by Pan Pan-Gang gelombang.
The above means that SPF is not just the inverse of the transmittance in the UVB region. If that's true, then applying two layers of SPF 5 sunscreen will always be equivalent to SPF 25 (5 times 5). Real combined SPF may be lower than the SPF one-tier square.
UVA Protection
Dark persistent pigment
The method of persistent pigment darkening (PPD) is a method for measuring UVA protection, similar to the SPF method for measuring sunburn protection. Originally developed in Japan, it is the preferred method used by manufacturers such as L'OrÃÆ'Â © al.
Instead of measuring erythema or flushing the skin, the PPD method uses UVA radiation to cause persistent darkening or tanning. Theoretically, sunscreen with a PPD rating of 10 should allow a person 10 times more UVA exposure such as without protection. The PPD method is an in vivo test like SPF. In addition, Colipa has introduced a method that is claimed to be able to measure this in vitro and provide parity with the PPD method.
SPF Equality
As part of the revised guidelines for sunscreen in the European Union, there is a requirement to provide a minimum UVA protection level to users with respect to SPF. It should be "UVA PF" at least 1/3 of the SPF to carry the UVA seal.
A set of US FDA final rules effective from the summer of 2012 defines the phrase "broad spectrum" as UVA protection comparable to UVB protection, using standard test methods.
Star rating system
In the UK and Ireland, the Boots star rating system is an exclusive in vitro method used to describe the UVA protection ratio against UVB offered by sunscreen creams and sprays. Based on the original work by Brian Diffey at Newcastle University, the Shoe Company in Nottingham, England, developed a method that has been widely adopted by companies that market these products in the UK.
One-star products provide the lowest UVA protection ratio, the highest five-star product. This method was recently revised in light of the Colipa UVA PF test and the revised EU recommendations on UVA PF. This method still uses a spectrophotometer to measure UVA absorption versus UVB; the difference comes from the requirement for pre-radiation samples (where this is not required beforehand) to provide a better indication of UVA protection and photostability when the product is used. With the current methodology, the lowest rank is three stars, the highest being the five star.
In August 2007, the FDA issued a consultation proposal that the protocol version was used to inform US product users about the protection it provides against UVA; but this is not adopted, for fear it would be too confusing.
PA System
Asian brands, especially Japan, tend to use the UVA Protection System (PA) to measure UVA protection provided by sunscreen. PA systems are based on PPD reactions and are now widely adopted on sunscreen labels. According to the Japan Cosmetics Industry Association, PA corresponds to UVA protection factors between two and four, between four and eight PA, and PA over eight. This system was revised in 2013 to include PAs that fit the rank of sixteen or more PPDs.
Sunblock
Sunblock usually refers to an opaque sunscreen that is effective for blocking UVA and UVB rays and using heavy carrier oil to keep from being washed. Titanium dioxide and zinc oxide are the two minerals used in sunblock.
The use of the word "sunscreen" in the marketing of sunscreen is still controversial. Since 2013, the FDA has banned such use because it can lead consumers to overestimate the effectiveness of labeled products. Nevertheless, many consumers use sunscreen words and sunscreen synonymously.
For total protection against damage from the sun, the skin should be protected from UVA, UVB, as well as IRA (infrared A-rays). About 35% of solar energy is an IRA. Note, however, that there is ongoing debate within the dermatology community about the impact of solar-based IRAs: Some sources suggest that early morning IRA exposure can protect against further sun exposure by increasing cell proliferation. and start an anti-inflammatory cascade; this effect is not observed for intense IRA-made sources.
Active ingredients
In addition to moisturizers and other inactive ingredients, sunscreens contain one or more of the following active ingredients, which are chemicals or minerals in nature:
- Organic chemicals that absorb ultraviolet light.
- Inorganic particulates that reflect, diffuse, and absorb UV light (such as titanium dioxide, zinc oxide, or a combination of both).
- Organic particles that mostly absorb UV light are like organic chemicals, but contain some chromophores that reflect and disperse shards of light like inorganic particles. An example is the Tinosorb M. The action mode is about 90% by absorption and 10% by scattering.
The main active ingredient in sunscreen is usually a conjugated aromatic molecule with a carbonyl group. This common structure allows molecules to absorb high-energy ultraviolet rays and release energy as low-energy rays, preventing ultraviolet rays from damaging the skin from reaching the skin. Thus, in UV exposure, most materials (with the exception of avobenzone) have not undergone significant chemical changes, allowing these materials to retain UV-absorbing potential without significant photodegradation. A chemical stabilizer is inserted in some sunscreen containing avobenzone to slow down its decomposition; examples include formulations containing Helioplex and AvoTriplex. The stability of avobenzone can also be enhanced by bemotrizinol, octocrylene and various other photostabilisers. Most of the organic compounds in the sunscreen slowly decrease and become less effective for several years if stored properly, so the expiration date is calculated for the product.
Sunscreening agents are used in some hair care products such as shampoos, conditioners and styling agents to protect against protein degradation and color loss. Currently, benzophenone-4 and ethylhexyl methoxycinnamate are the two most commonly used sunscreens in hair products. Sunscreen commonly used on the skin is rarely used for hair products because of its texture and heavy effects.
Here is the active ingredient FDA allowed in sunscreen:
Zinc oxide has been approved as a UV filter by the European Union in 2016.
Other approved ingredients in the EU and other parts of the world, which have not been included in the current FDA Monographs:
* Time and Broad Application (TEA), Proposed Regulations on FDA approval were originally expected in 2009, now expected 2015.
Many materials awaiting approval by the FDA are relatively new, and are developed to absorb UVA. The Suncreen 2014 Innovation Act was passed to speed up the FDA approval process.
Apps
The dose used in the FDA sunscreen test is 2 mg/cm 2 on exposed skin. If one assumes the "average" adult builds a height of 5Ã, ft 4Ã, at (163Ã, cm) and weighs 150Ã, Â £ (68Ã, kg) with a 32-inch (82-cm) waist, adults wearing a swimsuit covering the groin area should apply about 30 g (or 30 ml, about 1 oz) evenly to the uncovered area of ​​the body. This can be more easily regarded as the number of "golf balls" of the number of products per body, or at least six teaspoons. Larger or smaller individuals should scale this quantity accordingly. Considering only the face, this means about 1/4 to 1/3 teaspoon for the average adult face.
Some studies have shown that people generally only apply 1/4 to 1/2 of the recommended amount to achieve measurable sun protection (SPF), and as a result an effective SPF should be lowered to the square root or the 4th root of the ad advertised. value. Subsequent studies found a significant exponential relationship between SPF and the amount of sunscreen applied, and the results were closer to linearity than was expected by the theory.
Rule
- United States
Standard sunscreen labeling has evolved in the United States since the FDA first adopted SPF calculations in 1978. The FDA issued a comprehensive set of rules in June 2011, which come into force in 2012-2013, designed to help consumers identify and select the appropriate sunscreen products. offering protection from sunburn, premature skin aging, and skin cancer:
- To be classified as "broad spectrum", sunscreen products should provide protection against UVA and UVB, with special tests required for both.
- Product claims that are "waterproof" or "anti-sweat" are prohibited, while "sunscreen" and "instant protection" and "protection for more than 2 hours" are all prohibited without specific FDA approval. The "water resistance" claims on the front label should show how long the sunscreen remains effective and determine whether this applies to swimming or sweating, based on standard testing.
- The sunscreen should include standard "Facts of Medic" information in the container. However, no regulation considers it necessary to mention whether the contents contain nanoparticle mineral materials. (The EU has strict regulations on the use of nanoparticles, and in 2009 introduced labeling requirements for nanoparticle materials in certain sunscreens and cosmetics.)
Environmental effects
Certain sunscreens in water under ultraviolet light can increase the production of hydrogen peroxide, which damages phytoplankton. Oxybenzone destroys corals. Nanoparticles of titanium dioxide, a material in some sunscreens, can accumulate in coastal waters and are digested by marine animals.
History
Early civilizations used a variety of plant products to help protect the skin from sun damage. For example, the ancient Greeks used olive oil for this purpose, and the ancient Egyptians used rice extract, jasmine, and lupine plants whose products are still used in today's skin care. Zinc oxide paste has also been popular for skin protection for thousands of years.
The first synthetic sunscreen was first used in 1928. The first major commercial product brought to market in 1936, was introduced by the founder of L'Oreal, the French chemist EugÃÆ'¨ne Schueller.
Among the most widely used modern sunscreens, one of the earliest was produced in 1944 for the US military by Benjamin Green, a crew member and then a pharmacist, because the dangers of exposure to sunlight became apparent to troops in the Pacific tropics at the height of the War World II.. The product, named Pet Vet Merah (for petrolatum red animals), has limited effectiveness, working as a physical inhibitor of ultraviolet radiation. It is an unpleasant red substance similar to petroleum jelly. Sales increased when Coppertone upgraded and commercialized substance under Coppertone girls and the Bain de Soleil brand in the early 1950s.
In 1946, Swiss chemist Franz Greiter introduced what might be the first effective modern sunscreen. The product, called Gletscher CrÃÆ'¨me (Glacier Cream), later became the basis for the company Piz Buin, who is currently a marketer of sunscreen products, is named in honor of the mountain where Greiter allegedly receives burning skin that inspires the potion. In 1974, Greens adapted the early calculations of Friedrich Ellinger and Rudolf Schulze and introduced a "sun protection factor" (SPF), which has become a worldwide standard for measuring the effectiveness of sunscreen. It is estimated that Gletscher CrÃÆ'¨me has SPF 2.
Waterproof sunscreen was introduced in 1977, and recent development efforts focused on addressing later concerns by making sunscreen protection more durable and wider in its spectrum, as well as more attractive to use.
Research
New products are under development such as sunscreen based on bioadhesive nanoparticles. This works by encapsulating a commercially used UV filter, while not only attaching to the skin but also not penetrating. This strategy inhibits primary UV-induced and secondary free-radical damage.
Note
Source of the article : Wikipedia
0 Comments