Hair Lipids Research Articles

Characterization of hair lipid and protein dynamics using EPR spectroscopy and treatment effects

Electron paramagnetic resonance (EPR) spectroscopy of a lipid spin label indicated that hair membrane fluidity is low in the cuticle region and high in the inner region comprising the cortex and medulla. This study evaluated the effect of hair treatments and dehydration on membrane fluidity and protein dynamics. In the cuticle region, treatment of hydrated hair with the ionic surfactants, sodium dodecyl sulfate (SDS, anionic), cetyltrimethylammonium chloride (cationic), and N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (zwitterionic), as well as the non-ionic Tween 80, caused notable increases in fluidity, with the anionic surfactant SDS having a lesser effect. Furthermore, oleic acid and the monoterpene linalool increased fluidity, while propylene glycol (at 50 %) reduced fluidity and showed the ability to extract the lipid spin label from hair membranes. In the cortex and medulla region, where lipid fluidity is high, the treatments did not cause any changes. For dry hair, membrane fluidity was significantly reduced both in the cuticle and in the inner region. For lipid-depleted hair (containing only covalently bound lipids), the spin label found membranes of high rigidity both in the cuticle and inner regions. In addition, protein dynamics in the peripheral and inner regions of the hair was evaluated using a protein spin label covalently attached to sulfhydryl groups. Dehydration was found to decrease protein dynamics while treatments with oleic acid, linalool, and ethanol caused small increases in the dynamics. Lower molecular dynamics of hair lipids and proteins could be associated with dehydration, lipid depletion, and stiffness through EPR spectroscopy analysis, while the physical presence of softeners and hair cleansers, such as surfactants, leads to an increase in lipid dynamics. EPR spectroscopy has potential application in determining how the molecular dynamics of lipids and proteins are related to the external appearance of hair.

Research Progress in Composition, Classification and Influencing Factors of Hair

Human hair is a natural fiber with keratin and keratin-related proteins as a main component. Externally, hair is a thin, pliable tube of dead, fully keratinized epithelial cells, while inside the skin, it is part of a single living hair follicle. In addition to a large amount of protein, hair also contains low levels of lipids and pigments. The hair also has its own ecological balance system. Although the lipid content in hair is much lower than the protein content, it plays an important role in hair and influences hair texture to some extent. For example, prevent hair breakage and thinning; To act as a barrier to moisture loss; and improve the gloss, elasticity and tensile strength of the hair stem. Environment, hair dressing and daily care can all cause hair damage to varying degrees. Factors such as ultraviolet light and chemicals can make hair dry, rough, dull, stiff and brittle by destroying the proteins, pigment sand lipid sin the hair. In this paper, the composition, classification and influencing factors of hair were reviewed. The composition and function of lipids in hair were investigated emphatically. It aims to improve people's understanding of the physical and chemical properties and structure of hair. It provides reference value for the research and development of hair cosmetics for different hair states and washing purposes. The function of hair lipids on hair is not accurate. In addition, there is still some controversy on the existing role of hair lipids, which needs further research.

Hair Lipid Structure: Effect of Surfactants

Human hair fibres are mainly comprised of proteins (>90%) and lipids (1–9%), which are characterised as exogenous or endogenous, depending on whether they originate from sebaceous glands or hair matrix cells, respectively. Exogenous lipids consist of free fatty acids (FFAs), triglycerides, cholesterol (CH), wax esters, and squalene. Endogenous hair lipids comprise FFAs, CH, ceramides, glycosylceramides, cholesterol sulfate, and 18-methyleicosanoic acid. Lipids were demonstrated to be fundamental against damage and maintenance of healthy hair. Several studies have evaluated the effects of hair lipid content and have shown how hair properties were altered when lipids were removed by solvent extraction. The effect of surfactants on hair lipids is difficult to determine, as the complex structure of the cell membrane complex makes it difficult to determine where surfactants act. Shampoos and conditioners contain surfactants that remove lipids during routine cleansing of hair. However, shampooing does not completely remove all free lipids from the surface layers. The effect of surfactants on the alteration and removal of structural lipids is poorly developed, and there is no consensus on the results. Further research on the lipid composition of the hair could provide information on the penetration pathways of surfactants to improve effectiveness and limit possible damage.

Untargeted hair lipidomics: comprehensive evaluation of the hair-specific lipid signature and considerations for retrospective analysis.

Lipidomics investigates the composition and function of lipids, typically employing blood or tissue samples as the primary study matrices. Hair has recently emerged as a potential complementary sample type to identify biomarkers in early disease stages and retrospectively document an individual's metabolic status due to its long detection window of up to several months prior to the time of sampling. However, the limited coverage of lipid profiling presented in previous studies has hindered its exploitation. This study aimed to evaluate the lipid coverage of hair using an untargeted liquid chromatography-high-resolution mass spectrometry lipidomics platform. Two distinct three-step exhaustive extraction experiments were performed using a hair metabolomics one-phase extraction technique that has been recently optimized, and the two-phase Folch extraction method which is recognized as the gold standard for lipid extraction in biological matrices. The applied lipidomics workflow improved hair lipid coverage, as only 99 species could be annotated using the one-phase extraction method, while 297 lipid species across six categories were annotated with the Folch method. Several lipids in hair were reported for the first time, including N-acyl amino acids, diradylglycerols, and coenzyme Q10. The study suggests that hair lipids are not solely derived from de novo synthesis in hair, but are also incorporated from sebum and blood, making hair a valuable matrix for clinical, forensic, and dermatological research. The improved understanding of the lipid composition and analytical considerations for retrospective analysis offers valuable insights to contextualize untargeted hair lipidomic analysis and facilitate the use of hair in translational studies.

Performance and Tolerance of a Protocol for Idiopathic Chronic Greasy Seborrhea in 18 Dogs Using a Shampoo and Mousse Containing Plant Extracts

The study aimed to evaluate the tolerance, performance and effect on hair lipids and skin hydration of a protocol combining applications of one shampoo and subsequent mousses containing plant extracts (Ophytrium and Seboliance) in dogs with an undiagnosed chronic greasy keratinisation disorder. Six dogs were washed with plain water on day (D)0. Twelve dogs were shampooed on D0 and received eight mousse applications at 48-72 h intervals from D2 to D18. Clinical score (CS), Natural Moisturizing Factors (NMF) and hair lipids (HL) were evaluated on D0, D0 + 4 h, D7, D14 and D24. At baseline, no significant differences were observed in CS, NMF and HL between groups. In the control group, CS and HL remained stable throughout the study while a slight decrease in NMF was observed at D0 + 4 h. CS was significantly reduced in the test group between D0 and D7 (-53%) which reached 91% at D24 (p < 0.05), with no side effects. NMF levels decreased in the test group at D0 + 4 h (-73%, p < 0.0001) and returned to baseline from D14. In conclusion, one shampoo and subsequent mousse applications rapidly and safely improved coat quality in dogs with an undiagnosed keratinisation disorder without affecting NMF and HL contents over the study period.

UV and visible light exposure to hair leads to widespread changes in the hair lipidome.

Scalp hair is among the most exposed parts of the human body, yet the impact of visible and UV light on hair lipids, an important structural component of hair, is poorly researched. We have used lipidomics, a broad-based approach to measure lipids in samples, which has hitherto not been applied to UV-exposed hair in the published literature, and could allow for a wider understanding of how UV light impacts on specific hair lipids. Mixed blonde Caucasian hair switches were divided into two groups of five, with half of the hair switches exposed to UV and visible light mimicking normal daytime exposure and half left unexposed. LC-MS lipidomics was used to profile the lipids in the hair samples. A total of 791 lipids and 32 lipid classes with tentative identifications were detected in the hair samples. Nineteen lipid classes and 397 lipids differed between UV-treated and non-treated hair. The main lipid classes that differed were vitamin A fatty acid esters, sterol esters, several ceramides, mono-, di- and triglycerides, phosphatidylethanolamines (all decreased in UV-exposed hair) and bismonoacylglycerolphosphates, acylcarnitines and acylglycines (all increased in UV-exposed hair). Most detected lipids were decreased in UV-exposed hair, supporting earlier work that has found that UV exposure causes oxidation of lipids which would result in a decrease in most lipid classes. Light exposure to hair has a widespread impact on the hair lipidome. This study also adds to the emerging literature on the hair lipidome, broadening the range of lipid classes reported in hair.

Microbiota-Independent Spontaneous Dermatitis Associated with Increased Sebaceous Lipid Production in Tmem79-Deficient Mice

TMEM79 is a predisposing gene for atopic dermatitis. Tmem79-deficient mice develop spontaneous dermatitis in a biphasic pattern. The first-phase dermatitis is unique because it occurs independent of microbiota status, whereas the second-phase dermatitis is microbiota dependent. In this study, we sought to identify the key factors mediating the development of first-phase dermatitis. Structural analysis showed that sebaceous gland hyperplasia started from first-phase dermatitis. Longitudinal RNA sequencing analysis revealed significant activation of fatty acid lipid metabolism pathways in first-phase dermatitis, whereas T helper 17‒based immune response genes were highly expressed in second-phase dermatitis. Quantitative RT-PCR analysis revealed that genes involved in fatty acid elongation and sebocyte differentiation were upregulated in first-phase dermatitis. The results of thin-layer chromatography supported these findings with an increased abundance of wax esters, cholesterol esters, and fatty alcohols in hair lipids. Further gas chromatography-tandem mass spectrometry analysis showed an increase in total fatty acid production, including that of elongated C20-24 saturated and C18-24 monounsaturated fatty acids. Collectively, these results suggest that aberrant production of sebaceous long-chain fatty acids is associated with microbiota-independent dermatitis. Further investigation of Tmem79-deficient mice may clarify the role of certain fatty acids in dermatitis.

Discrete Nanoscale Distribution of Hair Lipids Fails to Provide Humidity Resistance.

The subcellular distribution of lipids in human hair was investigated to better understand their role in water permeability. Unlike stratum corneum where lipids are organized under a precisely ordered continuous structure, the removal of free lipids in hair does not lead to an increase of water permeability. Esterified and CH2-enriched molecules were tracked at a 10 nm resolution by infrared nanospectroscopy (atomic force microscopy coupled to infrared spectroscopy, AFMIR). Free and bound lipids in the 25 nm thick intercellular spaces were directly detected for the first time, further substantiating the potential of AFMIR to study complex biomaterials. We observed that they were mostly found accumulated in some regions of the external cuticle layers, as "hotspots" in nonkeratinous portions of the internal cortex, and that they do not seem to modulate much the water exchanges due to their discrete distribution throughout the hair fiber.

Analysis of Lipids in the Medulla of Japanese Hair and Their Function

The hair is composed of the cuticle (the outermost surface), cortex (its major part), and medulla (in the hair center). The lipid content of the medulla of Caucasian hair is relatively higher than that of African-American hair. However, the types of lipids therein remain unidentified. The aim of the current study was to analyze the constituent lipids of the medulla of Japanese hair, and to identify their function. A lipid peroxidase fluorescent reagent was used to investigate region-specific differences in the lipid content of the medulla (the tip, middle, and root portions). Since the medulla is important for the hair’s glossiness, we also investigated the relationship between the lipid content and hair glossiness. The lipid content of hair, based on the absence or presence of lipid species in the medulla, was investigated using thin-layer chromatography (TLC). Micro-attenuated total reflectance Fourier-transform infrared spectrophotometry (micro-ATR FTIR) was used to analyze the similarities between the standard and medulla lipids, focusing on the methylene/methyl stretching vibration region. The data indicated that the medulla contained unsaturated lipids, the content of which decreased from the root to the tip of the hair. Hair glossiness was reduced with the decreasing lipid content, suggesting that unsaturated lipids of the medulla play a role in glossiness. The TLC analysis revealed differences in the type and amount of hair lipids in the medulla. While squalene and oleic acid spots were detected in hair with a continuously maintained medulla, these compounds were not detected in hair in which the medulla was not maintained. The medulla constituents similar to oleic acid and squalene were also identified by the micro-ATR FTIR spectrum analysis and the previous report. The findings indicate that the medulla is composed of at least squalene and oleic acid.

The effect of a herbal paste and oil extract on the lipid content of canine hair fibres.

Application of herbal paste and oil to a dog's coat and body before rinsing (often combining with shampooing) is a cosmetic therapy available in Japan. It is highly appreciated by users, who claim that the treatment makes the coat shinier, improves volume and eliminates tangles. However, there has been no scientific evaluation of such treatments. Improvement of hair condition is derived from oils such as sebum and conditioning oils because chemicals are not used. Therefore, we examined nonpolar lipids (the primary lipids in dog hair) and the botanical oils used in this therapy. Hair samples were obtained from six beagle dogs. Groups were based on different combinations of the following processes: rinsing, shampooing, herbal therapy and herbal therapy with oil extract. Analysis of lipids was performed by high performance thin layer chromatography. The processes of shampooing and herbal therapy were associated with an equivalent reduction in cholesterol ester and triglyceride (TG). However, hair treated by herbal therapy combined with oil extract had an almost three-fold higher TG content, even after shampooing. This study demonstrated that the herbal therapy was able to coat hair samples with TG that was not removed with rinsing. Further investigation is required to evaluate the possible benefits of the application of botanical products containing lipids, such as TG, on hair coat quality in dogs.

Relationship between hair nicotine levels with blood pressure, body composition, lipid profile and leptin among healthy male smokers in Kelantan

Abstract Objectives Cigarette smoking has been reported to cause acute blood pressure elevation. Therefore, it is important to assess the relationships between chronic smoking and blood pressure, body composition, and the metabolic profile to gain an understanding of the long-term effects of smoking on an individual's body weight and health. This study examined the relationships between the hair nicotine level, blood pressure, body composition, lipid profile, and leptin in healthy male smokers. Methods For this cross-sectional study, 107 male smokers aged between 20 and 50 years old were recruited as volunteers. The nicotine levels in the volunteers' hair were measured using gas chromatography-mass spectrometry. Moreover, the subjects' blood pressure, body composition (weight, height, body mass index, body fat percentage, visceral fat, waist and hip circumferences, and basal metabolic rate), lipid profile, and leptin concentration were also measured. Results The means for age and BMI among the subjects were 37.00 (9.42) years and 24.59 (4.33) kg/m2, respectively. The average length of time as a smoker was 16.91 years. The hair nicotine level was found to be positively correlated with the total cholesterol (r = 0.314, r2 = 0.099, p = 0.028) and triglyceride (r = 0.351, r2 = 0.0.123, p = 0.013) levels. However, no significant correlations were found between the hair nicotine level and blood pressure, body composition, or leptin concentration. Conclusion The positive correlations between the hair nicotine level and total cholesterol and triglyceride levels highlighted the harmful effects of chronic smoking, even among healthy male subjects.

The influence of hair lipids in ethnic hair properties.

Biochemical studies have mainly focused on the composition of hair. African hair exhibited lower moisturization and less radial swelling when flushing with water compared with Asian or Caucasian hair, and they assumed a possible lipid differentiation among human populations. This study consists in the lipid characterization of different ethnic hairs (Caucasian, Asian and African hairs) and the influence of these lipids in different hair properties such as humidity and mechanical properties. Evaluation of water sorption and desorption of the different ethnic hairs and with and without lipids is also studied mainly to determine permeation changes of the keratin fibres. Extractions of exogenous and endogenous lipids with different organic solvents were performed; lipid analysis and its quantification using thin-layer chromatography coupled to an automated flame ionization detector (TLC/FID) were performed. Absorption and desorption curves were obtained in a thermogravimetric balance equipped with a controlled humidity chamber, the Q5000SA Sorption Analyzer (TA Instruments, New Castle, IL, U.S.A.). Also, mechanical properties (breaking stress and breaking elongation) were analysed using a computer programmable dynamometer (Instron 5500R). Lipid extraction showed the highest amount of total lipids for the African hair which may come from external sebaceous lipids compared with Asian or Caucasian hair. Caucasian fibres were found to be the most hydrated fibre, and a decrease in moisture was found in the extracted fibres, again, which is more important for the Caucasian hair. A superior lineal mass was found for the Asian fibres which supported their higher strength. The results obtained from the analysis of the mechanical properties of delipidized fibres indicate a surprising increase in the strength of African and Caucasian fibres. Perhaps this increase in strength could be related to the humidity decrease in lipid-extracted hair fibres. Results of water uptake and desorption indicate that Asian and Caucasian hairs present the lower diffusion coefficients compared with the African ones. At least for the African fibre, an extraction of its lipids that mainly account for apolar lipids ameliorates the fibre structure, decreasing its permeability to water and increasing its tensile strength. The ethnic hairs were assessed related to their lipid composition, and some differences between them were found in terms of water uptake and mechanical properties.

Distribution of glycolipid and unsaturated fatty acids in human hair.

It has been recognized that human hair lipids play crucial roles in the integrity of cells and matrices, while the details of distribution and structure of the minor lipids are hardly known. Here we investigated the lipids at the hair surface, at the interface between cuticle and cortex and in the interior of hair (cortex, medulla and melanin granules). Hair lipids and fatty acids and their metabolites were detected and characterized by using infrared spectroscopy and several mass spectrometry techniques (FTIR, ToF-SIMS, GCMS, and ESI-MS). As a result, it was found that unsaturated fatty acids were present more in the cortex of hair than at the hair surface. At the interface between cuticle and cortex, it is suggested that steryl glycoside-like lipids containing N-acetylglucosamine were present, and contributing to the adhesion between the cuticle and cortex of hair. Oxidative metabolites derived from integral fatty acids such as linoleic and alpha-linolenic acids were found in the hair bulb and melanin granules. Especially the oxidative metabolites of alpha-linolenic acid were integrated into the lipids non-covalently and tightly bound to melanin granules (namely, melanin lipids) and suggested as being involved in the biosynthetic processes of melanosome.

Sebaceous Lipid Profiling of Bat Integumentary Tissues: Quantitative Analysis of Free Fatty Acids, Monoacylglycerides, Squalene, and Sterols

White-nose syndrome (WNS) is a fungal disease caused by Pseudogymnoascus destructans and is devastating North American bat populations. Sebaceous lipids secreted from host integumentary tissues are implicated in the initial attachment and recognition of host tissues by pathogenic fungi. We are interested in determining if ratios of lipid classes in sebum can be used as biomarkers to diagnose severity of fungal infection in bats. To first establish lipid compositions in bats, we isolated secreted and integral lipid fractions from the hair and wing tissues of three species: big brown bats (Eptesicus fuscus), Eastern red bats (Lasiurus borealis), and evening bats (Nycticeius humeralis). Sterols, FFAs, MAGs, and squalene were derivatized as trimethylsilyl esters, separated by gas chromatography, and identified by mass spectrometry. Ratios of sterol to squalene in different tissues were determined, and cholesterol as a disease biomarker was assessed. Free sterol was the dominant lipid class of bat integument. Squalene/sterol ratio is highest in wing sebum. Secreted wing lipid contained higher proportions of saturated FFAs and MAGs than integral wing or secreted hair lipid. These compounds are targets for investigating responses of P. destructans to specific host lipid compounds and as biomarkers to diagnose WNS.

Keratins and lipids in ethnic hair

Human hair has an important and undeniable relevance in society due to its important role in visual appearance and social communication. Hair is mainly composed of structural proteins, mainly keratin and keratin associated proteins and lipids. Herein, we report a comprehensive study of the content and distribution of the lipids among ethnic hair, African, Asian and Caucasian hair. More interestingly, we also report the study of the interaction between those two main components of hair, specifically, the influence of the hair internal lipids in the structure of the hair keratin. This was achieved by the use of a complete set of analytical tools, such as thin layer chromatography-flame ionization detector, X-ray analysis, molecular dynamics simulation and confocal microscopy. The experimental results indicated different amounts of lipids on ethnic hair compositions and higher percentage of hair internal lipids in African hair. In this type of hair, the axial diffraction of keratin was not observed in X-ray analysis, but after hair lipids removal, the keratin returned to its typical packing arrangement. In molecular dynamic simulation, lipids were shown to intercalate dimers of keratin, changing its structure. From those results, we assume that keratin structure may be influenced by higher concentration of lipids in African hair.

Relationship between hair fatty acid profile, reproduction, and milk performance in Holstein Friesian cows

The aim of this study was to analyze the relationship between the fatty acid profiles of hair of first parity cows and their reproduction and milk performance. Hair samples from 46 German Holstein cows, 50 to 62 d postpartum, were analyzed to assess the relationship. All cows were fed the same diet. The lipid composition of hair was determined by gas chromatography. The fat content in the hair was 0.86%. Hair lipids contributed 75.14% SFA, 15.81% MUFA, and 9.92% PUFA. Cows were classified into a high and a low performance group according to their a) length of the interval from calving to first insemination (CFI), b) 100-d protein yield (100-d PY), and c) length of the interval from calving to conception (CC) and 100-d PY. Cows with short CFI or high 100-d PY or short CC and high 100-d PY had significantly greater proportions of de novo synthesized C12:0 (P < 0.05) compared with the corresponding low performing groups. Increased proportions of C12:0 in the hair were associated with shorter CFI (r = -0.32, P = 0.033) and greater 100-d PY (r = 0.34, P = 0.021). Furthermore, a discriminant analysis with C12:0 as a variable best predicted short CC and high 100-d PY (error rate 33.5%). Greater proportions of de novo synthesized fatty acids in the hair, in particular C12:0, are likely to reflect a sufficient energy availability that is required for fatty acid synthesis in ruminants.

The Ethnic Differences of the Damage of Hair and Integral Hair Lipid after Ultra Violet Radiation

BackgroundGenetic factors account for the majority of differences in skin color and hair morphology across human populations. Although many studies have been conducted to examine differences in skin color across populations, few studies have examined differences in hair morphology.ObjectiveTo investigate changing of integral hair lipids after ultraviolet (UV) irradiation in three human ethnic groups.MethodsWe studied the UV irradiation induced hair damage in hairs of three human populations. UV irradiation had been performed with self-manufactured phototherapy system. Damaged hair samples were prepared at 12 and 48 hours after UVA (20 J/sec) and UVB (8 J/sec) irradiation. We evaluated the changes of hair lipid using scanning electron microscopy (SEM), transmission electron microscopy (TEM), lipid TEM and HP-TLC. After UV irradiation, hair surface damage was shown.ResultsAfrican hair showed more severe damage on hair surface than others. The lipid compositions across human populations were similar, but Asian hair had more integral hair lipids than other groups as a whole. Especially, free fatty acid contents were higher than other lipids. After UV irradiation, lipid contents were decreased. These patterns were shown in all human populations. Asian hair has more integral hair lipid than European or African hair. After UV irradiation, European and African hair samples exhibited more damage because they have less integral hair lipids. However, Asian hair samples have less damage.ConclusionWe conclude that integral hair lipid may protect the hair against the UV light.

Deletion of the Sox21 gene drastically affects hair lipids

The effects of Sox21 gene deletion on hair lipids have been studied. For the cuticle-specific bound lipid 18-methyl eicosanoic acid (18-MEA), which was found to predominantly exist as the free form in Sox21(-/-) hair, total levels and distribution were unexpectedly unchanged. This indicates that while the biosynthesis of 18-MEA is unaffected, its covalent attachment to the cuticle surface is disrupted by loss of keratin-associated protein binding partners. Although the class compositions differed, the total ceramide (CER) levels were found to be comparable between Sox21(+/+) and Sox21(-/-) hairs. Deletion of the gene was also found to increase cholesterol sulphate (CS) levels. The biosynthesis process might be associated with cuticle keratinocyte maturation, because both CS and CERs are known bioactives in keratinocyte differentiation.

Comparison of Hair Fatty Alcohols by N‐Alkylpyridinium Isotope Quaternization and Matrix‐assisted Laser Desorption/ionization Mass Spectrometry for Drug Abuse Monitoring

AbstractBased on our previous report on N‐alkylpyridinium isotope quaternization (NAPIQ) for the analysis of alcoholic and α,β‐unsaturated ketone compounds, we have further applied NAPIQ method in the screening of hair lipids in drug abusers. Relative isotopic quantification was used for comparison of fatty alcohols between normal and drug abuse group. The NAPIQ strategy was proven to be a high‐throughput method in the metabolic comparison studies of different group samples. The attached N‐cationic pyridinium significantly improved the detection sensitivity for these fatty alcohols in matrix‐assisted laser desorption/ionization Fourier transform ion cyclotron resonance mass spectrometric (MALDI‐FTMS) analysis. The experimental results showed that the levels of fatty alcohols in the hair of heroin abuse group decreased significantly compared with the normal groups, which may be the results of the inducing of peroxidation enzyme. NAPIQ was proven to be an effective and alternative method in the research of fatty alcoholic metabolism for drug abuse monitoring.

Identification of Breast Cancer-Associated Lipids in Scalp Hair

A correlation between the presence of breast cancer and a change in the synchrotron-generated X-ray diffraction (XRD) pattern of hair has been reported in several publications by different groups, and on average XRD-based assays detect around 75% of breast cancer patients in blinded studies. To date, the molecular mechanisms leading to this alteration are largely unknown. We have determined that the alteration is likely to be due to the presence of one or more breast cancer-associated phospholipids. Further characterization of these lipids could be used to develop a novel, sensitive and specific screening test for breast cancer, based on hair initially, and potentially extendable to other biological samples.