Over the past 70 years, sunscreens have evolved from beach products designed to prevent sunburn to more cosmetically elegant skincare products intended to protect against multiple long-term adverse consequences of characteristically low-intensity daily UV and visible light exposure. Sunscreen testing and labeling intended to quantify such protection are unfortunately often misunderstood by users and have also led to illegal misleading and potentially dangerous industry practices. Changes in regulatory requirements, better policing, and more informative sunscreen labeling would benefit users and their physician advisors.

In recent years, sunscreens\' adverse impacts on the environment and biology have gained wide attention. The improvement of sunscreen safety has become one of the major priorities in skin photoprotection research. It is an effective strategy to develop bionic photoprotective materials by simulating the photoprotective mechanism existing in nature. Inspired by the photoprotective mechanisms of skin and plant leaves, the bionic photoprotective material CS-SA-PDA nanosheet was developed using the free radical grafting method and Michael addition, with natural melanin analogue polydopamine (PDA) nanoparticles and plant sunscreen molecular sinapic acid (SA) as sun protection factors and natural polymer chitosan (CS) as the connecting arm. The results show that CS-SA-PDA can effectively shield UVB and UVA due to the possible synergistic effect between PDA and SA. The introduction of polymer CS significantly improved the photostability of SA and reduced the skin permeability of PDA nanoparticles. The CS-SA-PDA nanosheet can also effectively scavenge photoinduced free radicals. Furthermore, in vivo toxicity and anti-UV evaluations confirm that CS-SA-PDA has no skin irritation and is excellent against skin photodamage, which makes it an ideal skin photoprotective material.

A wide range of applications are available for kraft lignin (KL). However, the dark color and wide size distribution of KL make it challenging to use in cosmetics and nanoparticle preparation. In this study, we fractionated KL from a paper-making enterprise using ultrafiltration membrane fractionation, and obtained four kinds of lignin with different molecular weights, namely ultrafiltration lignin (UL). Following that, lignin nanoparticles (ULNPs) were formed by self-assembly from four types of UL. Analyzing the UL and ULNP properties, the low molecular weight lignin, such as ULA, exhibited good antioxidant properties (89.47 %, 5 mg/mL), high brightness (ISO% = 7.55), high L⁎ value (L⁎ = 72.3) and low polydispersity index (PDI = 1.41). The ULNP showed a narrow size distribution (0.8-1.4 m) and high dispersibility in sunscreen. When ULNP was added to sunscreen with 5 % load, its sun protection factor (SPF) value increased from 14.93 to 63.74. Therefore, this study offered an effective way for the comprehensive utilization of pulping waste KL.

Lignin has great potential as a natural, green, and sustainable broad-spectrum sunscreen active ingredient. However, the coexistence of dark color and sunscreen properties hinders its application in cosmetics. In this study, we focus on the effects of the molecular weight of lignin on tis UV-protecting property and color in order to prepare lignin-based sunscreen with high performance. A prepared sunscreen containing low molecular weight lignin (F5, <1000 g/mol) exhibits good UV-protecting property (sun protection factor (SPF) = 7.14) and light color advantages (ΔE = 46.2). Moreover, a strong synergistic effect on UV-protecting property exists between low molecular weight lignin and ethylhexyl methoxycinnamate (EHMC), resulting in high SPF of F5@EHMC-based sunscreen (55.56). Additionally, added TiO2 can efficiently mitigate the dark color of lignin-based sunscreens due to prominent covering power of TiO2. Moreover, lignin-based sunscreens have good biocompatibility with HaCaT cells. This work is useful for understanding the mechanism of the UV-protecting property and dark color of lignin, and for designing an efficient and safe lignin-based sunscreen.

The vermilion of the human lip, covered by a skinny epithelium with little melanin, is quite susceptible to damage from ultraviolet (UV) radiation exposure. However, commercial sunscreen filters and indelible dyes used in lipsticks can cause health hazards after percutaneous absorption or accidentally oral administration. Inspired by plant pigmentation as natural filters to protect themselves against overexposure to UV, safer bio-based sunscreens of cellulose enveloped with anthocyanin (AN) were developed using bionic design. Cellulose nanocrystals (CNC), derived from acid hydrolysis of cellulose, reinforced enhancement of UV absorption and shielding properties of AN. This innovation addresses the issue that naturally sourced UV filter application to sunscreen does not achieve a desired sun protection factor (SPF) value because of the low specific extinction value (E1,1). We also stated that the diverse formula of anthocyanin sunscreen lipsticks with CNC exhibited 10 times more SPF value than AN alone. Furthermore, they possess competitive benefits such as pleasing texture, superior adhesion, impermeable, nonphototoxicity, ease of application, and removal. This work provides a promising proof-of-concept for studying the features of natural sunscreens in the design of simple, safe, efficient, and green sunscreens.

In February 2019, the US Food and Drug Administration issued a proposed rule (84 FR 6204), an amendment to the Sunscreen Innovation Act of 2014, that would require listing active ingredients on the principal display panel of sunscreens to allow consumers to \"more readily compare products and either select or avoid a given product accordingly.\"
To understand consumers\' perceived importance of active ingredients in sunscreen and their ability to recall these ingredients when comparing, avoiding, or selecting sunscreen products.
In this qualitative study, participants were recruited from Fors Marsh Group and User Works, Inc consumer panels and interviewed in person in November and December 2019. Eligible participants were 18 years or older, reported sunscreen use in the past 12 months, and were residents of the Washington, DC, area. After viewing 2 mock sunscreen labels (1 that meets current US Food and Drug Administration requirements and 1 designed to meet proposed requirements), participants were asked questions to assess their perceived importance of active ingredients in sunscreen products, whether they could recall any of the active ingredients on the labels, and whether they typically looked for active ingredients on a sunscreen label.
The main outcomes were the sunscreen label information used by participants to select a sunscreen and their ability to recall the active ingredients after viewing 2 mock sunscreen labels.
The mean (SD) age of the 47 participants was 42.8 (13.6) years, 32 (68%) were women, and 40 (85%) had a bachelor\'s or graduate degree. Of the total, 13 (28%) participants stated that sunscreen ingredients influenced their sunscreen selection, but only 5 (11%) said it was the most important information. Instead, 34 (72%) participants stated that the sun protection factor rating was the most important information. After viewing the mock sunscreen labels, only 5 (11%) participants recalled any of the active ingredients, although 10 (21%) reported typically looking at active ingredients when choosing a sunscreen.
This qualitative study investigated the US Food and Drug Administration\'s proposed new rule requiring that active ingredients be listed on the front of sunscreen labels to facilitate product comparison for consumers. However, active ingredients were not reported to be a primary reason for consumers\' sunscreen selection. Recall of active ingredients was low, and few consumers reported typically looking at the active ingredients, which were more commonly used to avoid ingredients rather than to select a sunscreen. Therefore, listing active ingredients on the front label alone may not have the intended usefulness for consumers.

Artificial sunscreens are already gaining traction in order to protect the skin from sunburns, photoaging and photocarcinogenesis. However, the efficacy and safety of most artificial sunscreen constituents are hindered by their photostability, toxicity and damage to marine ecosystems. Natural selection and evolution have ensured that plants and animals have developed effective protective mechanisms against the deleterious side effects of oxidative stress and ultraviolet radiation (UV). Hence, natural antioxidants such as sun blockers are drawing considerable attention. The exact mechanism by which natural components act as sunscreen molecules has not been clearly established. However, conjugated π system is reported to play an important role in protecting the vital genetic material within the organism. Compared to artificial sunscreens, natural sunscreens with strong UV absorptive capacities are largely limited by low specific extinction value and by their inability to spread in large-scale sunscreen cosmetic applications. Previous studies have documented that natural components exert their photoprotective effects (such as improved skin elasticity and hydration, skin texture, and wrinkles) through their antioxidant effects, and through the regulation of UV-induced skin inflammation, barrier impairment and aging. This review focuses on natural antioxidant topical formulations with sun protection factor (SPF). Lignin, melanin, silymarin and other ingredients have been added to high sun protection nature sunscreens without any physical or chemical UV filters. This paper also provides a reference for adopting novel technical measures (extracting high content components, changing the type of solution, optimizing formulation, applying Nano technology, et al) to design and prepare nature sunscreen formulations equated with commercial sunscreen formulations. Another strategy is to add natural antioxidants from plants, animals, microorganisms and marine organisms as special enhancer or modifier ingredients to reinforce SPF values. Although the photoprotective effects of natural components have been established, their deleterious side effects have not been elucidated.

Dark color of lignin puts brakes on its development as sunscreen ingredient. In order to address this issue, the color of lignin was whitened by facile and economical approach via solvent fractionation and follow-up acetylation. After the two-step treatment, the color of lignin was highly lightened by 313.5% owing to the separation of dark-colored condensed structures and the blocking of free hydroxyls. The UV absorbability of the light-colored lignin was investigated, which indicated that the UV absorbance of the light-colored lignin are not as strong as commercial sunscreen actives under certain wavelengths, however it presented broad-spectrum absorbability and obvious synergistic effects with the commercial sunscreen actives. Based on that, lignin-based sunscreen was prepared by blending light-colored lignin with an SPF15 lotion, and the SPF of the as-prepared lignin sunscreen was boosted from 15.3 to 75.2 under a lignin addition amount of 8%. The as-prepared lignin sunscreen is stable enough under UV irradiation and exhibits outstanding color performance, which make it possible to satisfy the daily requirement of consumers. Briefly, an effective approach was demonstrated in this work to prepare light-colored lignin, which makes lignin a green alternative to replace synthetic sunscreen actives and imparts lignin potentials in cosmetics applications.

Several plants found rich in flavonoid, polyphenols, and antioxidants reported antiaging, oppose inflammation and carcinogenic properties but have rarely been applied in dermatology. The present study was an active attempt to formulate a stable phytocosmetic emulsion system loaded with 2% pre-concentrated Prosopis cineraria bark extract, aiming to revive facial skin properties. In order to obtain potent therapeutic activities, we first prepared extracts of stem, leaves, and bark and screen them on basis of phenolic, flavonoids contents and antioxidant, antibacterial, lipoxygenase and tyrosinase inhibition activities. Furthermore, cytocompatibility of the extract was also determined prior starting in vivo investigations. Then the in vivo performance of 2% bark extract loaded emulsion formulation was determined by using non-invasive probe cutometer and elastometer with comparison to base formulation. The preliminary experiment showed that bark extract has a significant amount of phenolic and flavonoid compounds with eminent antioxidant potential. Furthermore, indicated an efficient antibacterial, lipoxygenase, and tyrosinase enzyme inhibition activities. Importantly, the bark extract did not induce any toxicity or apoptosis, when incubated with HaCat cells. Moreover, the in vivo results showed the formulation (size 3 μm) decreased the skin melanin, erythema and sebum contents up to 2.1-,2.7-and 79%, while increased the skin hydration and elasticity up to 2-folds and 22% as compared to the base, respectively. Owing to enhanced therapeutic effects the phytocosmetic formulation proved to be a potential skin whitening, moisturizer, anti-acne, anti-wrinkle, anti-aging therapy and could actively induce skin rejuvenation and resurfacing.

BACKGROUND: Sunscreens are an important component of healthy sun-protection behavior. To achieve satisfactory protection, sunscreens must be applied consistently, evenly and correctly. Consumers do not apply sunscreen properly and, therefore, do not achieve the protection indicated by the label \'sun protection factor\' (SPF). The objective of the present study was to determine the actual sun(burn) protection given by a range of sunscreen application thickness levels for both low and high SPF formulas.
METHODS: Forty study subjects were recruited from each of three geographical regions in China. Sunscreens with label SPFs of 4, 15, 30, and 55 were tested at application levels of 0.5, 1.0, 1.5, and 2.0 mg/cm(2) in three laboratories using a standard SPF protocol.
RESULTS: Sunscreens with lower SPFs (4 and 15) showed a linear dose-response relationship with application level, but higher SPF (30 and 55) product protection was exponentially related to application thickness.
CONCLUSIONS: Sunscreen protection is not related in one uniform way to the amount of product applied to human skin. Consumers may achieve an even lower than expected sunburn protection from high SPF products than from low SPF sunscreens.