Share this article:     

All human pigmentation is controlled by a process called Melanogenesis in which Melanocyte cells produce Melanin, a pigment that provides color to skin, eyes, and hair (1). Melanin production occurs in the hair bulb and during the hair growth phase is transferred into cortical keratinocytes resulting in pigmentation of the entire hair shaft. Melanin only represents 1% of the composition of hair and exists as two types of pigments, Eumelanin (dark) and Pheomelanin (light).

Eumelanin and Pheomelanin

Combinations of these two types of Melanin are responsible for all the different hair colors seen in humans. All Melanin is formed from the enzymatic conversion of Tyrosine by Tyrosinase to form insoluble polymeric pigments. Pheomelanin varies in color from yellow to red and differs from Eumelanin mainly due to the presence of Cysteine, a Sulphur containing amino acid. Our natural hair color is entirely dependent on the type, amount, and distribution of Melanin in the cortex of our hair (the middle layer of the hair shaft). Melanin levels can vary over time causing hair color to change, and it is even possible to have hair follicles of more than one color on the same person. All-natural hair color can be classified as brown, blond, black, red, or white. Grey, and light blond hair colors are all shades of brown. Eumelanin occurs in the form of a small spherical granules having a color varying between brown-red and black. There are two distinct types of Eumelanin, black and brown. Generally, the more Eumelanin that is present, the darker is the color of hair, less Eumelanin results in lighter hair (2).

• Brown hair is characterized by higher levels of brown/black Eumelanin and lower levels of Pheomelanin.
• Blonde hair ranges from nearly white (platinum blonde) to a dark golden blonde.
• Black hair is the darkest hair color and has the largest amount of black Eumelanin.
• Red hair ranges from light strawberry blond shades to titian, copper, and completely red. Red hair has the highest amounts of Pheomelanin.
• Gray hair is caused by a reduced amount of pigmentation and Melanin.
• White hair is due to an absence of any pigmentation and Melanin

Hair graying

Hair graying in Caucasians begins at approximately 25 years of age and increases with age to the point that by age 49 about 50% of the population has 50% gray hair. The incidence and rate of graying is similar in males and females. The onset gray hair for Caucasians generally occurs in the mid-30s, Asians the late 30s, and for those of African descent the mid-40s. Premature hair graying occurs before the age of 20 in whites, 25 in Asians, and 30 in Africans (3). Graying is caused by a gradual decrease in Melanocyte activity and a decrease in Tyrosinase activity in the hair follicle. Hair graying is closely correlated to chronological age, and its onset is largely controlled by genetics. Other factors contributing to gray hair include stress, diet, and smoking. A group of researchers at Harvard University discovered that stress can even cause gray hair by activating nerves that are part of the fight-or-flight response, which in turn causes permanent damage to pigment-regenerating stem cells in hair follicles (4). Smokers also experience hair graying three years before non-smokers and were two and half times more prone to developing premature gray hair (5).

The effects of Hydrogen Peroxide

Hydrogen peroxide, occurring naturally in hair follicles, may contribute to hair graying by inactivating Tyrosinase which is needed to form Melanin. As we get older, Hydrogen Peroxide accumulates due to a loss of Catalase activity which normally helps decompose Hydrogen Peroxide. In a poster presented at the 2014 ISFCC meeting, subjects with premature hair graying demonstrated a 45% reduction catalase activity vs a control group (6). Catalase is a key enzyme of Hydrogen peroxide degradation and a regulator of the oxidative stress. Hair follicles may also not be able to repair the damage caused by excess Hydrogen Peroxide due to low levels of Methionine Sulfoxide Reductase enzymes (MSR A and B), which are inactivated by Hydrogen peroxide. It has been suggested that the inhibition of Tyrosinase activity by Hydrogen Peroxide may be prevented by topical treatment with L-Methionine (7). Another approach to eliminating gray hair may be to activate the Wnt pathway. Scientists at New York University’s Langone Medical Center isolated the Wnt protein, which causes the proliferation of melanocyte and stem cells involved in the earliest stage of skin and hair pigmentation. When the researchers inhibited the Wnt pathway in black mice, they turned gray (8).

Actives claimed to help repigment hair

• Greyverse (Glycerin (and) Water (and) Palmitoyl Tetrapeptide 20-Lucas Meyer) is a biomimetic peptide of Melanin Stimulating Hormone that stimulates Melanin synthesis and promotes Melanin transfer from melanocytes to keratinocytes. Also claims to increase catalase activity and reduces excess Hydrogen Peroxide. In a 3 month clinical, the intensity of hair greyness was reduced by 30% versus at day zero (9).
• Darkenyl (Taxifolin Glucoside and Acetyl Tyrosinase-Givaudan Active Beauty) claims to protect hair follicles from oxidation, stimulate hair follicle stem cells to create new melanocytes, and activate melanogenesis to increase melanin production. In a 4 month double blind placebo-controlled study, 1% Darkenyl was shown to significantly decrease the proportion of white hair by an average of -17% versus day 0 (10).
• Chromafend Biofunctional (Aqua (and) Glycerin (and) Hydrolyzed Linseed Extract-Ashland) is a flax extract claimed to maintain Melanin in the hair follicle. It also targets specific protein markers that help control Melanin synthesis.
• EUK-134 (Ethylbisiminomethylguaiacol Manganese Chloride-Lucas Meyer Cosmetics) is a biomimetic of two natural skin enzymes, Superoxide Dismutase (SOD) and Catalase. EUK-134 may be useful in reducing excess Hydrogen Peroxide.

---

Looking for products for use in cosmetic formulations?

Prospector can help you find the products you need for your next formulation. Find technical data, request samples, and connect with global suppliers in just a few clicks.
Search for ingredients on Prospector.

Search for ingredients on Prospector

---

References

1. https://en.wikipedia.org/wiki/Melanocyte
2. https://en.wikipedia.org/wiki/Human_hair_color
3. https://onlinelibrary.wiley.com/doi/abs/10.1111/jocd.13000
4. https://www.nih.gov/news-events/nih-research-matters/how-stress-causes-gray-hair
5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3673399/
6. IFSCC Poster Paris 2014
7. https://www.ncbi.nlm.nih.gov/pubmed/19237503
8. https://www.newsweek.com/cure-gray-hair-vitiligo-mice-454087
9. https://www.ulprospector.com/documents/1566726.pdf?bs=4501&b=977220&st=1&r=na&ind=personalcare
10. https://www.ulprospector.com/documents/1590911.pdf?bs=829&b=1310602&st=1&r=na&ind=personalcare
11. https://www.ulprospector.com/documents/1044843.pdf?bs=4501&b=124740&st=1&sl=88963864&crit=a2V5d29yZDpbRVVLLTEzNF0%3d&k=EUK-134&r=na&ind=personalcare

The views, opinions and technical analyses presented here are those of the author or advertiser, and are not necessarily those of ULProspector.com or UL Solutions. The appearance of this content in the UL Prospector Knowledge Center does not constitute an endorsement by UL Solutions or its affiliates.

All content is subject to copyright and may not be reproduced without prior authorization from UL Solutions or the content author.

The content has been made available for informational and educational purposes only. While the editors of this site may verify the accuracy of its content from time to time, we assume no responsibility for errors made by the author, editorial staff or any other contributor.

UL Solutions does not make any representations or warranties with respect to the accuracy, applicability, fitness or completeness of the content. UL Solutions does not warrant the performance, effectiveness or applicability of sites listed or linked to in any content.

Share this article:     