Silk Sunscreen SPF 50 – Tatcha

50 may refer to:

• 50 (number)
• one of the following years 50 BC, AD 50, 1950, 2050
• .50 BMG, a heavy machine gun cartridge also used in sniper rifles
• .50 Action Express, a large pistol cartridge commonly used in the Desert Eagle
• .50 GI, a wildcat pistol cartridge
• .50 Beowulf, a powerful rifle cartridge used in the AR-15 platform
• .50 Alaskan, a wildcat rifle cartridge
• 50 Cent, an American rapper
• Labatt 50, a Canadian beer
• Fifty (film), a 2015 film
• "The Fifty", a group of fifty airmen murdered by the Gestapo after The Great Escape in World War II
• 50 (Rick Astley album), 2016
• 50 (Chris de Burgh album), 2024
• Benjamin Yeaten, widely known by his radio call sign "50", a Liberian military and mercenary leader
• "Fifty", a song by Karma to Burn from the album V, 2011
• 50 Virginia, a main-belt asteroid
• Audi 50, a supermini hatchback
• Dodge Ram 50, a compact pickup truck sold in the United States as a rebadged Mitsubishi Triton

Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm Bombyx mori reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colors.

Silk is produced by several insects; but, generally, only the silk of moth caterpillars has been used for textile manufacturing. There has been some research into other types of silk, which differ at the molecular level. Silk is mainly produced by the larvae of insects undergoing complete metamorphosis, but some insects, such as webspinners and raspy crickets, produce silk throughout their lives. Silk production also occurs in hymenoptera (bees, wasps, and ants), silverfish, caddisflies, mayflies, thrips, leafhoppers, beetles, lacewings, fleas, flies, and midges. Other types of arthropods produce silk, most notably various arachnids, such as spiders.

Sunscreen, also known as sunblock, sun lotion or sun cream, is a photoprotective topical product for the skin that helps protect against sunburn and prevent skin cancer. Sunscreens come as lotions, sprays, gels, foams (such as an expanded foam lotion or whipped lotion), sticks, powders and other topical products. Sunscreens are common supplements to clothing, particularly sunglasses, sunhats and special sun protective clothing, and other forms of photoprotection (such as umbrellas).

Sunscreens may be classified according to the type of active ingredient(s) present in the formulation (inorganic compounds or organic molecules) as:

• Mineral sunscreens (also referred to as physical), which use only inorganic compounds (zinc oxide and/or titanium dioxide) as active ingredients. These ingredients primarily work by absorbing UV rays but also through reflection and refraction.
• Chemical sunscreens, which use organic molecules as active ingredients. These products are sometimes referred to as petrochemical sunscreens since the active organic molecules are synthesized starting from building blocks typically derived from petroleum. Chemical sunscreen ingredients also mainly work by absorbing the UV rays. Over the years, some organic UV absorbers have been heavily scrutinised to assess their toxicity and a few of them have been banned in places such as Hawaii and Thailand for their impact on aquatic life and the environment.
• Hybrid sunscreens, which contain a combination of organic and inorganic UV filters.

Medical organizations such as the American Cancer Society recommend the use of sunscreen because it aids in the prevention of squamous cell carcinomas. The routine use of sunscreens may also reduce the risk of melanoma. To effectively protect against all the potential damages of UV light, the use of broad-spectrum sunscreens (covering both UVA and UVB radiation) has been recommended.

As of 2021, only zinc oxide and titanium dioxide are generally recognized as safe and effective (GRASE) by the U.S. Food and Drug Administration (FDA) since there is currently insufficient data to support recognizing petrochemical UV filters as safe.