Keratin

Table of ContentsView AllTable of ContentsTypesStructure and FunctionSupplemental KeratinAssociated ConditionsRisks and Side Effects

Table of ContentsView All

View All

Table of Contents

Types

Structure and Function

Supplemental Keratin

Associated Conditions

Risks and Side Effects

Keratinis a protein in the cells on the surface of theskin. The fingernails,hair, and skin need keratin to grow, function, and stay healthy.

Cosmetic treatments to improve hair and nail health are often enriched with keratin. Keratin also occurs naturally in some foods and can be taken in supplement form as well.

This article will explain the different types of keratin, health conditions related to overproduction of keratin, and the possible risks of keratin-enriched cosmetic products.

ljubaphoto / Getty Images

Types of Keratin

Type I

Type I keratins are categorized as being the smaller and more acidic type of keratin.They work to promote and maintain the health of the of epithelial cells on the outside of the body, i.e., areas that are exposed to the outside environment. Type I keratins are the major component of hair and nails. They are also found inside the mouth, urinary tract, vagina, and anus.

Type II

Type II keratins are larger than their type I counterparts and have a neutral pH. They are found in the internal epithelial cells, which line various structures and organs contained within the body, including the lungs, kidneys, liver, and digestive system.

Alpha-Keratins

Alpha-keratins are the exclusive form of keratin found in humans and in the wool of other mammals. The structure of the alpha-keratin is fibrous and helical, and both I and II keratins can fall under the category of alpha.

Beta-Keratins

Beta-keratins are categorized as polypeptide chains and are only found in birds and reptiles, although those species can also possess alpha-keratins. Both alpha and beta keratins help these animals maintain the composition of their claws, scales, beaks, skin, and feathers.

In its natural form, keratin appears as long structures, with filaments arranged in bundles or fibers. These fibers are made up of individual keratin molecules that are cross-linked together, forming a tough and resilient protein. This is what gives keratin the ability to provide structure and protection to the areas of the body it inhabits.

Keratin cannot be dissolved in water, solvents, acids, or alkalines, so its structure remains largely intact when exposed to many of the body’s natural chemicals.

Uses of Supplemental Keratin

Many industries have used keratin or other vitamin supplements that promote production of keratin as a form of maintaining or improving hair, skin, and nail health. The beauty industry in particular advertises keratin as a way to combat damaged hair.

Hair Treatments and Products

Hair is made up of 90% keratin, which is why it is often a component in hair treatments that are used for shinier and stronger tresses.

Keratin hair treatments provided in a salon are chemical protein treatments (sometimes called Brazilian blowouts) that reduce frizz and make the hair look shiny and silky.

A stylist will first wash your hair with a special shampoo and then apply a liquid keratin solution to your hair in small sections. Then your hair will be blown dry. The stylist will use a flat iron to seal the keratin solution.

For optimal results, you should avoid washing your hair for a few days.

Depending on the type of keratin used, the results will vary widely. Studies have found isolated animal keratin to be less efficient overall than a synthetic version of human keratin.

Many people also use shampoos and conditioners infused with keratin oil to make their hair healthier.

Keratin used in hair treatments is often cultivated from animal sources, such as feathers, hooves, and wool, and therefore are not appropriate for people who follow a vegan lifestyle.

Biotin

Biotinis a B vitamin that has also soared in popularity because it is said to have a positive impact on the body’s ability to synthesize proteins such as keratin, thus leading to healthier skin, hair, and nails.

Soluble Keratin

Keratin is not an easily dissolvable protein. A soluble form of the protein is available and has been targeted towards athletes who wish to supplement their protein intake for athletic performance.

Food Sources of Keratin

Nutrients such as biotin, vitamin A, and zinc can boost keratin production in the body. Some food sources rich in these nutrients include:

Forms of hyperkeratosis include:

Treatment

Treatment of hyperkeratosis depends on the specific condition:

The use of formaldehyde in these products can lead to health issues, including:

Extended exposure to formaldehyde has also been shown to have carcinogenic (cancer-causing) effects.

Opt for keratin treatments that are free of unwanted chemicals and substances such as formaldehyde to avoid unnecessary risks to your overall health.

Summary

Keratin is a naturally occurring protein in the body that is found in the hair, skin nails, mouth, and internal organs. It plays a key role in providing structure and protection to the skin and tissues.

Certain foods contain minerals and vitamins that boost the production of keratin. It is also available in supplement form and in various over-the-counter shampoos, conditioners, and cosmetics. Professional keratin treatments are available in salons to make the hair stronger and shinier.

29 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Piipponen M, Li D, Landén NX.The immune functions of keratinocytes in skin wound healing.International Journal of Molecular Sciences. 2020; 21(22):8790. doi:10.3390/ijms21228790Jacob JT, Coulombe PA, Kwan R, Omary MB.Types I and II keratin intermediate filaments.Cold Spring Harb Perspect Biol. 2018;10(4):a018275. doi:10.1101/cshperspect.a018275Kurban M, Christiano AM. (2013).Inherited Disorders of the Hair.Emery and Rimoin’s Principles and Practice of Medical Genetics (Sixth Edition), 1-22. doi:10.1016/B978-0-12-383834-6.00182-8National Library of Medicine. MedlinePlus.Epithelial cells in urine.Greenwold MJ, Bao W, Jarvis ED, Hu H, Li C, Gilbert MT, Zhang G, Sawyer RH.Dynamic evolution of the alpha (α) and beta (β) keratins has accompanied integument diversification and the adaptation of birds into novel lifestyles.BMC Evol Biol. 2014;14:249. doi:10.1186/s12862-014-0249-1Bragulla HH, Homberger DG.Structure and functions of keratin proteins in simple, stratified, keratinized and cornified epithelia.J Anat. 2009;214(4):516-59. doi:10.1111/j.1469-7580.2009.01066.xVilla AL, Aragão MR, Dos Santos EP, et. al.Feather keratin hydrolysates obtained from microbial keratinases: effect on hair fiber.BMC Biotechnol. 2013 Feb 18;13:15. doi: 10.1186/1472-6750-13-15Basit A, Asghar F, Sadaf S, Akhtar MW.Health improvement of human hair and their reshaping using recombinant keratin K31.Biotechnol Rep (Amst). 2018;20:e00288. doi:10.1016/j.btre.2018.e00288Patel DP, Swink SM, Castelo-Soccio L.A review of the use of biotin for hair loss.Skin Appendage Disord. 2017;3(3):166-169. doi:10.1159/000462981Crum EM, McLeay YD, Barnes MJ, Stannard SR.The effect of chronic soluble keratin supplementation in physically active individuals on body composition, blood parameters and cycling performance.J Int Soc Sports Nutr. 2018;15(1):47. doi:10.1186/s12970-018-0251-xNational Institutes of Health. Office of Dietary Supplements.Biotin.U.S. Department of Agriculture.Kale, raw.National Institutes of Health. Office of Dietary Supplements.Vitamin A.Thomas M, Khopkar US.Keratosis pilaris revisited: Is it more than just a follicular keratosis?.Int J Trichology. 2012;4(4):255-8. doi:10.4103/0974-7753.111215American Academy of Dermatology.Actinic keratosis: Overview.MedlinePlus.Epidermolytic hyperkeratosis.Madke B, Gutte R, Doshi B, Khopkar U.Hyperkeratotic palmoplantar lichen planus in a child.Indian J Dermatol. 2013;58(5):405. doi:10.4103/0019-5154Antończak PP, Hartman-Petrycka M, Garncarczyk A, Adamczyk K, Wcisło-Dziadecka D, Błońska-Fajfrowska B.The effect of callus and corns removal treatments on foot geometry parameters, foot pressure, and foot pain reduction in women.Appl Sci. 2023;13(7):4319. doi:10.3390/app13074319Das P, Mounika P, Yellurkar ML, et al.Keratinocytes: An enigmatic factor in atopic dermatitis.Cells. 2022;11(10):1683. doi:10.3390/cells11101683Ramezani M, Shamshiri A, Zavattaro E, et al.Immunohistochemical expression of P53, Ki-67, and CD34 in psoriasis and psoriasiform dermatitis.Biomedicine (Taipei). 2019;9(4):26. doi:10.1051/bmdcn/2019090426Abdulaziz W.Overview of intravenous medications to treating the lichenoid dermatitis.J Dermatitis. 2023;08(03):1000196 doi:10.35248/2684-1436.23.8.196National Institute of Arthritis and Musculoskeletal and Skin Diseases.Ichthyosis.Jakeman A.The effective management of hyperkeratosis.Wounds Int.2012;1:65-73.American Podiatric Medical Association.Corns and calluses.American Academy of Dermatology Association.Eczema types: Atopic dermatitis diagnosis and treatment.National Psoriasis Foundation.Treatment and care.Pierce JS, Abelmann A, Spicer LJ, Adams RE, Glynn ME, Neier K, Finley BL, Gaffney SH.Characterization of formaldehyde exposure resulting from the use of four professional hair straightening products.J Occup Environ Hyg. 2011;8(11):686-99. doi:10.1080/15459624.2011.626259Agency for Toxic Substances and Disease Registry.Formaldehyde and your health.Swenberg JA, Moeller BC, Lu K, Rager JE, Fry RC, Starr TB.Formaldehyde carcinogenicity research: 30 years and counting for mode of action, epidemiology, and cancer risk assessment.Toxicol Pathol. 2013;41(2):181-9. doi:10.1177/0192623312466459

29 Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Piipponen M, Li D, Landén NX.The immune functions of keratinocytes in skin wound healing.International Journal of Molecular Sciences. 2020; 21(22):8790. doi:10.3390/ijms21228790Jacob JT, Coulombe PA, Kwan R, Omary MB.Types I and II keratin intermediate filaments.Cold Spring Harb Perspect Biol. 2018;10(4):a018275. doi:10.1101/cshperspect.a018275Kurban M, Christiano AM. (2013).Inherited Disorders of the Hair.Emery and Rimoin’s Principles and Practice of Medical Genetics (Sixth Edition), 1-22. doi:10.1016/B978-0-12-383834-6.00182-8National Library of Medicine. MedlinePlus.Epithelial cells in urine.Greenwold MJ, Bao W, Jarvis ED, Hu H, Li C, Gilbert MT, Zhang G, Sawyer RH.Dynamic evolution of the alpha (α) and beta (β) keratins has accompanied integument diversification and the adaptation of birds into novel lifestyles.BMC Evol Biol. 2014;14:249. doi:10.1186/s12862-014-0249-1Bragulla HH, Homberger DG.Structure and functions of keratin proteins in simple, stratified, keratinized and cornified epithelia.J Anat. 2009;214(4):516-59. doi:10.1111/j.1469-7580.2009.01066.xVilla AL, Aragão MR, Dos Santos EP, et. al.Feather keratin hydrolysates obtained from microbial keratinases: effect on hair fiber.BMC Biotechnol. 2013 Feb 18;13:15. doi: 10.1186/1472-6750-13-15Basit A, Asghar F, Sadaf S, Akhtar MW.Health improvement of human hair and their reshaping using recombinant keratin K31.Biotechnol Rep (Amst). 2018;20:e00288. doi:10.1016/j.btre.2018.e00288Patel DP, Swink SM, Castelo-Soccio L.A review of the use of biotin for hair loss.Skin Appendage Disord. 2017;3(3):166-169. doi:10.1159/000462981Crum EM, McLeay YD, Barnes MJ, Stannard SR.The effect of chronic soluble keratin supplementation in physically active individuals on body composition, blood parameters and cycling performance.J Int Soc Sports Nutr. 2018;15(1):47. doi:10.1186/s12970-018-0251-xNational Institutes of Health. Office of Dietary Supplements.Biotin.U.S. Department of Agriculture.Kale, raw.National Institutes of Health. Office of Dietary Supplements.Vitamin A.Thomas M, Khopkar US.Keratosis pilaris revisited: Is it more than just a follicular keratosis?.Int J Trichology. 2012;4(4):255-8. doi:10.4103/0974-7753.111215American Academy of Dermatology.Actinic keratosis: Overview.MedlinePlus.Epidermolytic hyperkeratosis.Madke B, Gutte R, Doshi B, Khopkar U.Hyperkeratotic palmoplantar lichen planus in a child.Indian J Dermatol. 2013;58(5):405. doi:10.4103/0019-5154Antończak PP, Hartman-Petrycka M, Garncarczyk A, Adamczyk K, Wcisło-Dziadecka D, Błońska-Fajfrowska B.The effect of callus and corns removal treatments on foot geometry parameters, foot pressure, and foot pain reduction in women.Appl Sci. 2023;13(7):4319. doi:10.3390/app13074319Das P, Mounika P, Yellurkar ML, et al.Keratinocytes: An enigmatic factor in atopic dermatitis.Cells. 2022;11(10):1683. doi:10.3390/cells11101683Ramezani M, Shamshiri A, Zavattaro E, et al.Immunohistochemical expression of P53, Ki-67, and CD34 in psoriasis and psoriasiform dermatitis.Biomedicine (Taipei). 2019;9(4):26. doi:10.1051/bmdcn/2019090426Abdulaziz W.Overview of intravenous medications to treating the lichenoid dermatitis.J Dermatitis. 2023;08(03):1000196 doi:10.35248/2684-1436.23.8.196National Institute of Arthritis and Musculoskeletal and Skin Diseases.Ichthyosis.Jakeman A.The effective management of hyperkeratosis.Wounds Int.2012;1:65-73.American Podiatric Medical Association.Corns and calluses.American Academy of Dermatology Association.Eczema types: Atopic dermatitis diagnosis and treatment.National Psoriasis Foundation.Treatment and care.Pierce JS, Abelmann A, Spicer LJ, Adams RE, Glynn ME, Neier K, Finley BL, Gaffney SH.Characterization of formaldehyde exposure resulting from the use of four professional hair straightening products.J Occup Environ Hyg. 2011;8(11):686-99. doi:10.1080/15459624.2011.626259Agency for Toxic Substances and Disease Registry.Formaldehyde and your health.Swenberg JA, Moeller BC, Lu K, Rager JE, Fry RC, Starr TB.Formaldehyde carcinogenicity research: 30 years and counting for mode of action, epidemiology, and cancer risk assessment.Toxicol Pathol. 2013;41(2):181-9. doi:10.1177/0192623312466459

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.

Piipponen M, Li D, Landén NX.The immune functions of keratinocytes in skin wound healing.International Journal of Molecular Sciences. 2020; 21(22):8790. doi:10.3390/ijms21228790Jacob JT, Coulombe PA, Kwan R, Omary MB.Types I and II keratin intermediate filaments.Cold Spring Harb Perspect Biol. 2018;10(4):a018275. doi:10.1101/cshperspect.a018275Kurban M, Christiano AM. (2013).Inherited Disorders of the Hair.Emery and Rimoin’s Principles and Practice of Medical Genetics (Sixth Edition), 1-22. doi:10.1016/B978-0-12-383834-6.00182-8National Library of Medicine. MedlinePlus.Epithelial cells in urine.Greenwold MJ, Bao W, Jarvis ED, Hu H, Li C, Gilbert MT, Zhang G, Sawyer RH.Dynamic evolution of the alpha (α) and beta (β) keratins has accompanied integument diversification and the adaptation of birds into novel lifestyles.BMC Evol Biol. 2014;14:249. doi:10.1186/s12862-014-0249-1Bragulla HH, Homberger DG.Structure and functions of keratin proteins in simple, stratified, keratinized and cornified epithelia.J Anat. 2009;214(4):516-59. doi:10.1111/j.1469-7580.2009.01066.xVilla AL, Aragão MR, Dos Santos EP, et. al.Feather keratin hydrolysates obtained from microbial keratinases: effect on hair fiber.BMC Biotechnol. 2013 Feb 18;13:15. doi: 10.1186/1472-6750-13-15Basit A, Asghar F, Sadaf S, Akhtar MW.Health improvement of human hair and their reshaping using recombinant keratin K31.Biotechnol Rep (Amst). 2018;20:e00288. doi:10.1016/j.btre.2018.e00288Patel DP, Swink SM, Castelo-Soccio L.A review of the use of biotin for hair loss.Skin Appendage Disord. 2017;3(3):166-169. doi:10.1159/000462981Crum EM, McLeay YD, Barnes MJ, Stannard SR.The effect of chronic soluble keratin supplementation in physically active individuals on body composition, blood parameters and cycling performance.J Int Soc Sports Nutr. 2018;15(1):47. doi:10.1186/s12970-018-0251-xNational Institutes of Health. Office of Dietary Supplements.Biotin.U.S. Department of Agriculture.Kale, raw.National Institutes of Health. Office of Dietary Supplements.Vitamin A.Thomas M, Khopkar US.Keratosis pilaris revisited: Is it more than just a follicular keratosis?.Int J Trichology. 2012;4(4):255-8. doi:10.4103/0974-7753.111215American Academy of Dermatology.Actinic keratosis: Overview.MedlinePlus.Epidermolytic hyperkeratosis.Madke B, Gutte R, Doshi B, Khopkar U.Hyperkeratotic palmoplantar lichen planus in a child.Indian J Dermatol. 2013;58(5):405. doi:10.4103/0019-5154Antończak PP, Hartman-Petrycka M, Garncarczyk A, Adamczyk K, Wcisło-Dziadecka D, Błońska-Fajfrowska B.The effect of callus and corns removal treatments on foot geometry parameters, foot pressure, and foot pain reduction in women.Appl Sci. 2023;13(7):4319. doi:10.3390/app13074319Das P, Mounika P, Yellurkar ML, et al.Keratinocytes: An enigmatic factor in atopic dermatitis.Cells. 2022;11(10):1683. doi:10.3390/cells11101683Ramezani M, Shamshiri A, Zavattaro E, et al.Immunohistochemical expression of P53, Ki-67, and CD34 in psoriasis and psoriasiform dermatitis.Biomedicine (Taipei). 2019;9(4):26. doi:10.1051/bmdcn/2019090426Abdulaziz W.Overview of intravenous medications to treating the lichenoid dermatitis.J Dermatitis. 2023;08(03):1000196 doi:10.35248/2684-1436.23.8.196National Institute of Arthritis and Musculoskeletal and Skin Diseases.Ichthyosis.Jakeman A.The effective management of hyperkeratosis.Wounds Int.2012;1:65-73.American Podiatric Medical Association.Corns and calluses.American Academy of Dermatology Association.Eczema types: Atopic dermatitis diagnosis and treatment.National Psoriasis Foundation.Treatment and care.Pierce JS, Abelmann A, Spicer LJ, Adams RE, Glynn ME, Neier K, Finley BL, Gaffney SH.Characterization of formaldehyde exposure resulting from the use of four professional hair straightening products.J Occup Environ Hyg. 2011;8(11):686-99. doi:10.1080/15459624.2011.626259Agency for Toxic Substances and Disease Registry.Formaldehyde and your health.Swenberg JA, Moeller BC, Lu K, Rager JE, Fry RC, Starr TB.Formaldehyde carcinogenicity research: 30 years and counting for mode of action, epidemiology, and cancer risk assessment.Toxicol Pathol. 2013;41(2):181-9. doi:10.1177/0192623312466459

Piipponen M, Li D, Landén NX.The immune functions of keratinocytes in skin wound healing.International Journal of Molecular Sciences. 2020; 21(22):8790. doi:10.3390/ijms21228790

Jacob JT, Coulombe PA, Kwan R, Omary MB.Types I and II keratin intermediate filaments.Cold Spring Harb Perspect Biol. 2018;10(4):a018275. doi:10.1101/cshperspect.a018275

Kurban M, Christiano AM. (2013).Inherited Disorders of the Hair.Emery and Rimoin’s Principles and Practice of Medical Genetics (Sixth Edition), 1-22. doi:10.1016/B978-0-12-383834-6.00182-8

National Library of Medicine. MedlinePlus.Epithelial cells in urine.

Greenwold MJ, Bao W, Jarvis ED, Hu H, Li C, Gilbert MT, Zhang G, Sawyer RH.Dynamic evolution of the alpha (α) and beta (β) keratins has accompanied integument diversification and the adaptation of birds into novel lifestyles.BMC Evol Biol. 2014;14:249. doi:10.1186/s12862-014-0249-1

Bragulla HH, Homberger DG.Structure and functions of keratin proteins in simple, stratified, keratinized and cornified epithelia.J Anat. 2009;214(4):516-59. doi:10.1111/j.1469-7580.2009.01066.x

Villa AL, Aragão MR, Dos Santos EP, et. al.Feather keratin hydrolysates obtained from microbial keratinases: effect on hair fiber.BMC Biotechnol. 2013 Feb 18;13:15. doi: 10.1186/1472-6750-13-15

Basit A, Asghar F, Sadaf S, Akhtar MW.Health improvement of human hair and their reshaping using recombinant keratin K31.Biotechnol Rep (Amst). 2018;20:e00288. doi:10.1016/j.btre.2018.e00288

Patel DP, Swink SM, Castelo-Soccio L.A review of the use of biotin for hair loss.Skin Appendage Disord. 2017;3(3):166-169. doi:10.1159/000462981

Crum EM, McLeay YD, Barnes MJ, Stannard SR.The effect of chronic soluble keratin supplementation in physically active individuals on body composition, blood parameters and cycling performance.J Int Soc Sports Nutr. 2018;15(1):47. doi:10.1186/s12970-018-0251-x

National Institutes of Health. Office of Dietary Supplements.Biotin.

U.S. Department of Agriculture.Kale, raw.

National Institutes of Health. Office of Dietary Supplements.Vitamin A.

Thomas M, Khopkar US.Keratosis pilaris revisited: Is it more than just a follicular keratosis?.Int J Trichology. 2012;4(4):255-8. doi:10.4103/0974-7753.111215

American Academy of Dermatology.Actinic keratosis: Overview.

MedlinePlus.Epidermolytic hyperkeratosis.

Madke B, Gutte R, Doshi B, Khopkar U.Hyperkeratotic palmoplantar lichen planus in a child.Indian J Dermatol. 2013;58(5):405. doi:10.4103/0019-5154

Antończak PP, Hartman-Petrycka M, Garncarczyk A, Adamczyk K, Wcisło-Dziadecka D, Błońska-Fajfrowska B.The effect of callus and corns removal treatments on foot geometry parameters, foot pressure, and foot pain reduction in women.Appl Sci. 2023;13(7):4319. doi:10.3390/app13074319

Das P, Mounika P, Yellurkar ML, et al.Keratinocytes: An enigmatic factor in atopic dermatitis.Cells. 2022;11(10):1683. doi:10.3390/cells11101683

Ramezani M, Shamshiri A, Zavattaro E, et al.Immunohistochemical expression of P53, Ki-67, and CD34 in psoriasis and psoriasiform dermatitis.Biomedicine (Taipei). 2019;9(4):26. doi:10.1051/bmdcn/2019090426

Abdulaziz W.Overview of intravenous medications to treating the lichenoid dermatitis.J Dermatitis. 2023;08(03):1000196 doi:10.35248/2684-1436.23.8.196

National Institute of Arthritis and Musculoskeletal and Skin Diseases.Ichthyosis.

Jakeman A.The effective management of hyperkeratosis.Wounds Int.2012;1:65-73.

American Podiatric Medical Association.Corns and calluses.

American Academy of Dermatology Association.Eczema types: Atopic dermatitis diagnosis and treatment.

National Psoriasis Foundation.Treatment and care.

Pierce JS, Abelmann A, Spicer LJ, Adams RE, Glynn ME, Neier K, Finley BL, Gaffney SH.Characterization of formaldehyde exposure resulting from the use of four professional hair straightening products.J Occup Environ Hyg. 2011;8(11):686-99. doi:10.1080/15459624.2011.626259

Agency for Toxic Substances and Disease Registry.Formaldehyde and your health.

Swenberg JA, Moeller BC, Lu K, Rager JE, Fry RC, Starr TB.Formaldehyde carcinogenicity research: 30 years and counting for mode of action, epidemiology, and cancer risk assessment.Toxicol Pathol. 2013;41(2):181-9. doi:10.1177/0192623312466459

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