Colorants In Cosmetics Research Articles

Characterization of banned colorants in cosmetics: A tandem mass-based molecular networking approach

Colorants have been a staple in the cosmetics industry for a considerable time, although certain varieties have been banned owing to health risks. Detecting and confirming these banned colorants simultaneously poses several challenges when employing LC–MS/MS. Molecular networking is a promising analytical technology that can be used to predict the structure of components and the correlation between them using structural and MS/MS spectral similarities. Molecular networking entails assessing the number of fragmented ions and the cosine score (the closer it is to one, the higher the similarity). In this study, we developed and verified a method for the simultaneous quantitative analysis of the 26 banned colorants in cosmetics using LC–MS/MS. Additionally, we propose a novel approach that combines LC–Q–TOF–MS and molecular networking technology to detect banned colorants in cosmetics. For successful molecular networking, a minimum of six fragment ions with cosine scores exceeding 0.5 is required. We developed a screening method for characterizing banned colorants using molecular networking based on LC–TOF–MS results for 26 banned colorants. Furthermore, we demonstrated that our established method can be used for screening by analyzing actual cosmetics (eyebrow tattoo, lipstick tattoo, and hair tint) spiked with three non-targeted banned colorants with similar structures (m/z 267.116, 315.149, and 345.157) in cosmetics. The combination of molecular networking techniques and LC–MS/MS proves highly advantageous for the swift characterization and screening of non-targeted colorants in cosmetics.

Nurturing Natural Beauty: Empowering MAN 1 Model Bengkulu's Female Students with Red Dragon Fruit (Hylocereus polyrhizus) Cosmetics Crafting Workshop

Introduction: The use of lipstick, blush-on, and various colored cosmetic products is highly popular among teenage girls. However, the adverse effects of hazardous colorants in cosmetics include respiratory irritations, skin irritations, eye injuries, gastrointestinal toxicity, and carcinogenic properties. Red Dragon Fruit contains a significant amount of red anthocyanin antioxidants, making it a viable natural colorant for food, cosmetics, and textiles. This community engagement project aimed to enhance the understanding of teenage girls, especially students of MAN 1 Model City of Bengkulu, regarding illegal cosmetics containing harmful and prohibited ingredients. It also aimed to improve the girls' skills in crafting natural Lip Tint and Blush-On preparations from Red Dragon Fruit (Hylocereus Polyrhizus), promoting a return to nature in cosmetic choices. This initiative was expected to inspire creative ideas among teenagers for designing alternative economic activities centered on producing natural and halal cosmetics made from herbal ingredients. Methods: The project involved educational and awareness-raising activities about the dangers of forbidden cosmetic ingredients, followed by workshops on making Lip Tint and Blush-On formulations. These workshops were led by faculty members from the School of Medicine and the School of Pharmacy, with assistance from students of the Faculty of Mathematics and Natural Sciences at the University of Bengkulu. Results: Evaluation results showed that workshop participants experienced a 63.2% increased in knowledge and gained the ability to independently create Lip Tint and Blush-On products from red dragon fruit. Conclusion: The workshop successfully produced natural Lip Tint and Blush On and the project also heightened the students' interest in the Pharmacy Program.

Safety of titanium dioxide (E171) as a food additive for humans.

Titanium dioxide (TiO2), also known as E171, is commonly used as a white colorant in food, pharmaceuticals, cosmetics, and toothpaste. However, in May 2021, the European Food Safety Authority (EFSA) expert panel, in evaluating the safety of titanium dioxide (E171) as a food additive, concluded that a concern for genotoxicity could not be ruled out. This occurred several years after EFSA had previously considered titanium dioxide to be safe as a food additive. EFSA based this new interpretation on the results of genotoxicity tests of TiO2 nanomaterials. EFSA noted that available data are insufficient to define threshold doses/concentrations of TiO2 particles below which genotoxicity will not occur in tissues containing these particles. Here, it is argued that EFSA made a manifest error regarding the safety of titanium dioxide (E171) particles as a food additive for humans. First, the notion of particle size distribution of TiO2 particles is explained. Second, the changing opinions from the various EFSA evaluations in 2016, 2018, 2019 vs. 2021 are discussed. Third, the low toxicity of TiO2 particles is described in rats exposed by oral gavage and feeding studies in rats and mice. Fourth, the importance of low absorption rates from the gastrointestinal tract vs. circulation in rats and humans but not in mice is identified. Fifth, other international health scientists have weighed in on the EFSA (EFSA J, 2021, 19 (5), 6585) decision and generally disagreed with EFSA's opinion on the safety of E171 TiO2. A common theme voiced by the United Kingdom, Canada, Australia, and New Zealand agencies is that it is inappropriate to compare nanoparticle toxicity studies of dispersed/sonicated nanoparticles with the content of E171 TiO2 in foods because the test materials used in key studies considered by EFSA (EFSA J, 2021, 19 (5), 6585) are not representative of E171 TiO2 particles. Finally, a group of experts recently considered the genotoxicity of TiO2 and could not find support for a direct DNA damaging mechanism of TiO2 (nano and other forms). For these reasons, it is suggested that EFSA made a manifest error on the safety of E171 as a food additive.

New Insights into the Cosmetic Behaviour of Bearded Vultures: Ferruginous Springs Are Shared Sequentially.

Different hypotheses have been proposed to explain the function of cosmetic behaviour of bearded vultures, being the signalling individual dominance status the most accepted. However, no advances have been made in understanding this mysterious behaviour, in part due to the secrecy of this species. With the help of camera traps and GPS devices we monitored the use of a ferruginous spring in the Pyrenees (Spain) providing new insights into this aspect of their behavioural ecology. Most of the visits (93.5%) involved a single bearded vulture and bathing behaviour only occurred when a single individual was present, confirming their secretive behaviour. A total of 50% of individuals that visited the site were non-adults, suggesting that cosmetic coloration functions as an attenuating signal that may also benefit subordinate individuals. Future studies with the help of new technologies could help to disentangle some questions about the real function of cosmetic coloration and their social relevance.

Analysis of 13 Banned Colorants in Cosmetics via Liquid Chromatographic and Mass Spectrometric Techniques

Even though synthetic colorants can cause side effects such as allergies and pigmentation, they have not been sufficiently researched. Herein, high-performance liquid chromatography, liquid chromatography-tandem mass spectrometry, and liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS) were used to detect 13 banned synthetic colorants in cosmetics and characterize their fragmentation. The developed HPLC method was validated following the International Conference on Harmonisation guidelines (specificity, limit of detection, limit of quantification, recovery, linearity, accuracy, and precision) and applied to 120 distributed cosmetic products, one of which was found to contain three illegal synthetic colorants, namely Basic Blue 26 (0.33 mg/g), Basic Red 2 (0.53 mg/g), and Basic Yellow 28 (31.50 mg/g). Additionally, based on their fragment ions obtained using LC-Q-TOF-MS, the fragmentation pattern of synthetic colorants was predicted. Thus, our work paves the way for the reliable detection of illegal synthetic colorants and may help to prevent the distribution of cosmetics containing the same.

Extraction of Bio-pigments from the Green Microalgae Chlorella pyrenoidosa Under Different Solvent Ratios

Nowadays, the use of microalgae biomass is evolving rapidly for their various applications such as food, pharmaceutical, and cosmetics. One of the essential compounds in microalgae that have good perspectives in the market is pigment since it can be used as a natural colorant in food or cosmetics. However, the extraction of bio-pigments from the green microalgae Chlorella pyrenoidosa under different solvent ratios is still rarely reported. Therefore, this study aims to investigate the bio-pigment potential from C. pyrenoidosa extracted under different ethanol ratios. The algae-to-ethanol ratios of 1:5, 1:7.5, and 1:10 were employed in this study. Overall, C. pyrenoidosa contains total chlorophyll content much higher than carotenoids due to the fact that C. pyrenoidosa is the autotrophic microorganism that performs photosynthesis. The total chlorophyll content decreased with an increase in ethanol ratio, i.e., 134.47, 133.74, and 129.46 μg/mL at the ratio of 1:5, 1:7.5, and 1:10, respectively. In contrast, the carotenoid content slightly increased with an increase in ethanol ratio, i.e., 86.64, 87.08, 88.45 μg/mL at the ratio of 1:5, 1:7.5, and 1:10, respectively. The main chlorophyll compounds in the ethanol extract with the algae-to-ethanol molar ratio of 1:5 were identified as chlorophyll c (47.09 μg/mL), followed by chlorophyll b (38.50 μg/mL), chlorophyll a (28.67 μg/mL), and chlorophyll d (20.23 μg/mL).

A Study on the Color Arrangement of Personal Color & Beauty and Fashion

Recently, there is a growing tendency to decide and purchase cosmetic colors according to individual skin color or to style appearance images. However, there is a possibility of misdiagnosis and accuracy of personal color diagnosis, and after personal color diagnosis, how to match and wear colors according to TPO is becoming a more important issue. This is because it is actually difficult to do things like this unless you are an expert in personal color image consulting. Therefore, in this study, after personal color diagnosis, a color matching program is developed to help consumers find a product that goes well with their skin color, and to contribute to the development of the beauty and fashion industries by utilizing this program. This study was conducted between August and December 2022. The subjects of the study were randomly selected 4 women who were sensitive to beauty and fashion and interested in personal color, and voluntarily consented to the study. For an in-depth study of the psychology of personal color and the difficulty of color selection after diagnosis, a questionnaire method and a qualitative research method based on interviews were mixed and used. After analyzing the skin color of the research subjects and diagnosing the personal color, a total of 12 products were proposed with a design that applied a beauty/fashion color matching program suitable for the skin color of the four seasons such as spring, summer, autumn, and winter according to the personal color system.

Color‐Tunable Elastic Photonic Shells With High Color Saturation and Deformability

AbstractPhotonic microspheres containing colloidal arrays are useful as structural colorants in inks and cosmetics. However, low color saturation and low deformability of the microspheres restrict the uses. To overcome the limitations, elastic photonic shells with enhanced color saturation and high deformability using water‐in‐oil‐in‐water (W/O/W) double‐emulsion templates are designed. The elastic shells are produced by photocuring acrylate‐based resin containing non‐close‐packed arrays of silica particles in the middle oil layer. The presence of two concentric interfaces and water‐soluble molecules in the inner and continuous water phases at high concentrations improve the crystalline order of silica particles. In addition, the absence of a relatively disordered core reduces incoherent random scattering, thereby enhancing color saturation. Although the shells themselves are elastically deformable, the liquid core renders them significantly more deformable with small stiffness and negligible hysteresis, which is potentially beneficial for improving the fluidity of suspensions. Moreover, the structural colors of the elastic shells are post‐tunable by osmotic inflation of the semipermeable shells in hypotonic conditions. The high color saturation and high deformability as well as color tunability will provide a new opportunity for structural coloration with the elastic photonic shells as a colorant in inks and cosmetics.

Biopigments of Microbial Origin and Their Application in the Cosmetic Industry

Along with serving as a source of color, many microbial pigments have gained attention as interesting bioactive molecules with potential health advantages. These pigments have several applications in the food, agrochemical, medicine, and cosmetic industries. They have attracted the attention of these industries due to their high production value, low cost, stability, and biodegradability. Recently, many consumers worldwide have noted the impact of synthetic dyes; thus, natural pigments are more in demand than synthetic colors. On the other hand, the cosmetic industry has been moving toward greener manufacturing, from the formulation to the packaging material. Microbial pigments have several applications in the field of cosmetics due to their photoprotection, antioxidant, and antiaging properties, including inhibiting melanogenesis and acting as natural colorants for cosmetics, as some microorganisms are rich in pigments. More investigations are required to estimate the safety and efficacy of employing microbial pigments in cosmetic products. Furthermore, it is necessary to obtain information about DNA sequencing, metabolic pathways, and genetic engineering. In addition, unique habitats should be explored for novel pigments and new producing strains. Thus, new microbial pigments could be of consideration to the cosmetic industry, as they are ideal for future cosmetics with positive health effects.

Woaded Blue: A Colorful Approach to the Dialectic between Written Historical Sources, Experimental Archaeology, Chromatographic Analyses, and Biochemical Research

Research into the sustainability of natural, potentially renewable, resources is one of the major issues of our time. It naturally includes the quest for sustainable sources of colorants for textiles, cosmetics, and food. In industrialized countries, natural dyeing with plants and a few species of coccid insects was practiced on a large scale for centuries before synthetic colorants were developed. Therefore, historical documents on the growing of dye plants and dyeing processes offer a relevant basis from which to start reconsidering the potential of natural colorants in our time. However, written sources need to be completed by experimental archaeologists to allow a scientific understanding of the biochemical reactions at work in the historical processes described. The results of such interdisciplinary research can then inspire contemporary programs to revive the production of natural dyes. The long history of dyeing blue with woad, Isatis tinctoria L., is revisited here as an illustration of the fruitful complementarity of sources and approaches. This article presents a step-by-step re-assessment of the production chain of woad as described in historical texts, from the growing of the plant to its use as a source of indigo in the woad and indigo vats. The experimental reconstitution of the processing of woad leaves into couched woad allowed us to follow the evolution of the composition and proportions of indigoid colorants in the leaves by HPLC analyses. Additionally, HPLC analyses allowed a comparison of the respective indigoid contents of couched woad and sukumo, the form of indigo dye resulting from another couching process, traditionally used in Japan for dyers’ knotweed, Persicaria tinctoria (Ait.) H. Gross. The reconstitution of the 18th century woad and indigo vat process allowed investigations into the bacterial flora associated with the use of couched woad in vat liquors, which were found to contain different indigo-reducing bacteria, including two distinct strains of a new indigo-reducing species.

Antioxidant Activity of Plant-Derived Colorants for Potential Cosmetic Application

Application of plant-derived colorants in products, i.e., cosmetics or food, apart from imparting the desired color without harming the environment, may provide other benefits. Valuable ingredients in cosmetic formulations include antioxidants showing an advantageous effect on the skin by neutralizing free radicals that accelerate the aging process and cause skin defects. Antioxidant activity can be determined by chemical-based methods. The aim of this study was to determine the antioxidant activity of plant-derived colorants (purple and red colorant) by two methods: CUPRAC and DPPH free-radical scavenging activity. Antioxidant activity evaluation using both methods for colorants samples was also performed after 5, 15, 30, and 60 min of exposure to UVC irradiation. The results obtained by CUPRAC method were for purple and red colorant unexposed samples as follows: 6.87 ± 0.09 and 4.48 ± 0.14 mg/100 mg colorant expressed as caffeic acid equivalent, respectively. UVC treatment did not affect the results of the antioxidant activity for red colorant and for the purple one only a slight influence was observed. DPPH free-radical scavenging activity for unexposed samples was 70.06 ± 7.74% DPPH/100 mg colorant for the red colorant and 96.11 ± 3.80% DPPH/100 mg colorant for the purple one.

DX in Cosmetic Color

DX in Cosmetic Color

Brief review on herbal lipsticks using natural colorants over synthetic colorants

Nowadays herbal lipsticks are gaining popularity because natural cosmetics are safe to use. Synthetic coloring agents may cause allergic reactions and are found to be carcinogenic. We will study how the coloring matter from natural sources such as beetroot, grapes, blueberry, papaya, tomato, strawberry, watermelon, pomegranate, etc is beneficial over synthetic colorants in the preparation of lipsticks.Natural ingredients such as beeswax, carnauba wax, white soft paraffin, vanilla essence, castor oil, and vitamin E formulate herbal lipstick. Natural colorants in cosmetics also show different activities such as anti-anti-cancer, anti-oxidant, anti-microbial, anti-inflammatory, rich in vitamins, reducing the appearance of dark spots, fine lines, and wrinkles, and protecting from UV radiation, etc.

Made-up mouths with preen oil reveal genetic and phenotypic conditions of starling nestlings.

Animal coloration results from pigments, nanostructures, or the cosmetic use of natural products, and plays a central role in social communication. The role of cosmetic coloration has traditionally been focused in scenarios of sexual selection, but it could also take place in other contexts. Here, by using spotless starlings (Sturnus unicolor) as a model system, we explore the possibility that nestlings cosmetically use their intensely yellow-colored uropygial secretion to signal their genetic and/or phenotypic quality. In agreement with the hypothetical cosmetic use of the uropygial secretion, (i) video recorded nestlings collected secretion with the bill at the age of feathering, (ii) cotton swabs turned to the color of secretion after rubbing with them nestlings’ gape, and (iii) gape and skin colorations correlated positively with that of secretion. Furthermore, we found that (iv) secretion coloration has a genetic component, and (v) associated positively with Vitamin E supplementation and (vi) with plasma carotenoid concentration, which highlights the informative value of nestling secretion. Finally, (vii) coloration of begging-related traits and of secretion of nestlings predicted parental feeding preferences. Consequently, all these results strongly suggest that the cosmetic use of colored uropygial secretion might also play a role in parent-offspring communication, complementing or amplifying information provided by the flamboyant colored gapes and skin of nestlings. The use of makeups by offspring for communication with relatives has been scarcely explored and we hope that these results will encourage further investigations in birds and other taxa with parental care.

Microencapsulation of natural blue dye from butterfly pea ( Clitoria ternatea L.) flowers: The application of different carriers

The blue butterfly pea (Clitoria ternatea L.) flowers have been traditionally used as food colorants and source of anthocyanins and other flavonoids, particularly as antioxidants. Encapsulation aims at preserving natural pigments from several factors that cause their degratation. This work aimed at producing powdered butterfly pea flower extract by spray drying, using maltodextrin, cassava starch, and gelatin as carrier agents, generating a product ready to use, easy to handle, and with long shelf life. Physicochemical and colorimetric properties of the powders were assessed, resulting in high anthocyanin retention (>90%), good solubility (around 99%), low moisture (less than 5%), and good reconstitution property, with color attributes very similar to the original extract at different pHs. Gelatin-maltodextrin blended formulations resulted in powders with the best physicochemical and morphological characteristics, as well as better color preservation. Practical applications This study investigated the production by spray drying of a powdered, natural blue dye extracted from butterfly pea (Clitoria ternatea L.) flowers, using maltodextrin, cassava starch, and gelatin as carrier agents, obtaining a product that is easy to handle, ready to use, and with a long shelf life. The produced powders showed high anthocyanin retention, good solubility, low moisture and good reconstitution properties, with color attributes very similar to the original extract at different pHs. The formulation using maltodextrin-gelatin blend resulted in the powder with the best physicochemical and morphological characteristics, in addition to better color preservation, enabling its application as natural colorant in food, beverages, pharmaceuticals, and cosmetics.

Heterologous expression of Bixa orellana cleavage dioxygenase 4-3 drives crocin but not bixin biosynthesis.

Annatto (Bixa orellana) is a perennial shrub native to the Americas, and bixin, derived from its seeds, is a methoxylated apocarotenoid used as a food and cosmetic colorant. Two previous reports claimed to have isolated the carotenoid cleavage dioxygenase (CCD) responsible for the production of the putative precursor of bixin, the C24 apocarotenal bixin dialdehyde. We re-assessed the activity of six Bixa CCDs and found that none of them produced substantial amounts of bixin dialdehyde in Escherichia coli. Unexpectedly, BoCCD4-3 cleaved different carotenoids (lycopene, β-carotene, and zeaxanthin) to yield the C20 apocarotenal crocetin dialdehyde, the known precursor of crocins, which are glycosylated apocarotenoids accumulated in saffron stigmas. BoCCD4-3 lacks a recognizable transit peptide but localized to plastids, the main site of carotenoid accumulation in plant cells. Expression of BoCCD4-3 in Nicotiana benthamiana leaves (transient expression), tobacco (Nicotiana tabacum) leaves (chloroplast transformation, under the control of a synthetic riboswitch), and in conjunction with a saffron crocetin glycosyl transferase, in tomato (Solanum lycopersicum) fruits (nuclear transformation) led to high levels of crocin accumulation, reaching the highest levels (>100 µg/g dry weight) in tomato fruits, which also showed a crocin profile similar to that found in saffron, with highly glycosylated crocins as major compounds. Thus, while the bixin biosynthesis pathway remains unresolved, BoCCD4-3 can be used for the metabolic engineering of crocins in a wide range of different plant tissues.

Adult coloration of the Bearded Vulture (Gypaetus barbatus) in the Pyrenees: relation to sex, mating system and productivity

Cosmetic coloration is not a common phenomenon among bird species. Adult Bearded Vultures Gypaetus barbatus typically show orange coloration in head, chest, belly and tarsus feathers that is the result of mud baths in ferruginous substrates. Several non‐mutually exclusive visual signalling hypotheses can be proposed to explain this phenomenon. Coloration could be used to signal: (1) dominance towards conspecifics, with darker birds being dominant (status signalling hypothesis); (2) sex (gender signalling hypothesis) because females are usually more intensely coloured; (3) individual quality for mate choice (quality signalling hypothesis); or (4) different reproductive strategies between individuals (e.g. in polyandrous trios). Here we report results from systematic monitoring of breeding Bearded Vultures in the pre‐laying period in the central and western Pyrenees (Spain and France) between 2016 and 2020, including 162 individuals from 70 reproductive units (48 pairs and 22 trios). We classified individuals as being white, pale, medium or dark, and analysed the relationship with sex, mating system (pair or trios) and average productivity across years. Our results showed that the most common form was medium (67%), then pale (22%), dark (9%) and white (2%) morphs. Overall, females were darker than males, but with a large overlap in coloration. In trios, dominant males were darker than subordinate males, although differences were not statistically significant. The mating system (pair or trio) did not influence female coloration. A multimodel comparison showed that the number of years of territory occupation, mating system and their combination (but not coloration) were the best predictors of average productivity. Our results do not support the gender signalling hypothesis. The reproductive strategy signalling hypothesis might be supported because beta males were, on average, paler than males in pairs, but this topic requires further investigations because our results were inconclusive. Finally, that females (thought to be dominant because of their slightly larger size) were on average darker than males agrees with the status signalling hypothesis, although an experimental approach would be needed to formally test this hypothesis.

The color of greater flamingo feathers fades when no cosmetics are applied.

Greater flamingos use cosmetic coloration by spreading uropygial secretions pigmented with carotenoids over their feathers, which makes the plumage redder. Because flamingos inhabit open environments that receive direct solar radiation during daytime, and carotenoids bleach when exposed to solar radiation, we expected that the plumage color would fade if there is no maintenance for cosmetic purposes. Here, we show that the concentrations of pigments inside feathers and on the surface of feathers were correlated, as well as that there was a correlation between the concentrations of pigments in the uropygial secretions and on the surface of feathers. There was fading in color (becoming less red) in feathers that received direct solar radiation when there was no plumage maintenance, but not so in others maintained in darkness. When we controlled for the initial color of feathers, the feathers of those individuals with higher concentration of pigments on the feather surfaces were those that lost less coloration after experimental exposure of feathers to sunny conditions. These results indicate that exposure to sunlight is correlated with the fading of feather color, which suggests that individuals need to regularly apply makeup to be more colorful. These results also reinforce the view that these birds use cosmetic coloration as a signal amplifier of plumage color. This may be important in species using highly variable habitats, such as wetlands, since the conditions experienced when molting may differ from those when the signal should be functional, usually months after molting.

Fe-N Co-Doped Titanium Dioxide Nanoparticles Induce Cell Death in Human Lung Fibroblasts in a p53-Independent Manner.

The advancement of nanotechnology in the last decade has developed an abundance of novel and intriguing TiO2-based nanomaterials that are widely used in many sectors, including industry (as a food additive and colorant in cosmetics, paints, plastics, and toothpaste) and biomedicine (photoelectrochemical biosensing, implant coatings, drug delivery, and new emerging antimicrobial agents). Therefore, the increased use of engineered nanomaterials in the industry has raised serious concern about human exposure and their unexpected cytotoxic effects. Since inhalation is considered the most relevant way of absorbing nanomaterials, different cell death mechanisms induced in MRC-5 lung fibroblasts, following the exposure to functionalized TiO2 NPs, were investigated. Long-term exposure to TiO2 nanoparticles co-doped with 1% of iron and nitrogen led to the alteration of p53 protein activity and the gene expression controlled by this suppressor (NF-kB and mdm2), DNA damage, cell cycle disruptions at the G2/M and S phases, and lysosomal membrane permeabilization and the subsequent release of cathepsin B, triggering the intrinsic pathway of apoptosis in a Bax- and p53-independent manner. Our results are of major significance, contributing to the understanding of the mechanisms underlying the interaction of these nanoparticles with in vitro biological systems, and also providing useful information for the development of new photocatalytic nanoparticles that are active in the visible spectrum, but with increased biocompatibility.

Cosmetic plumage coloration by iron oxides does not confer protection against feather wear

The active acquisition of plumage cosmetic coloration by iron oxides has been described in several bird species (notably the Bearded Vulture Gypaetus barbatus, but also in cranes, pelicans and other vulture species) but its function remains controversial. We tested the hypothesis that iron oxide acquired through mud bathing protects feathers from wear. We experimentally stained 13 breast feathers collected from two White Storks Ciconia ciconia with mud from a ferruginous pond regularly used by Bearded Vultures, while another 13 feathers (controls) were treated with water. All feathers were exposed to a controlled physical abrasion treatment. We found no differences in wear between control and stained feathers, which is counter to predictions of the wear protection hypothesis for the acquisition of this cosmetic plumage coloration.