I wrote the title like that on purpose, to get your attention, I know I’m bad, but I’ve come up with new research and it really needs to be known. Cysteine, also found in garlic and onions, is one of the 22 amino acids our body needs to create protein. We either synthesize it ourselves or obtain it from food sources. Two cysteine molecules produce another important amino acid. Cysteine also helps build the structure of nails, skin, and hair. But first, it has to be converted into a form known as L-cysteine that the skin can use. Here the researchers are not sitting idle, they are now designing controlled studies to understand the role of L-cysteine for hair growth.
But first, let’s take a look at the sources of L-Cysteine for hair loss. The body can produce small amounts of L-cysteine for hair growth. It is also possible to obtain this amino acid from food sources. There are cysteine-rich foods that are broken down into L-cysteine. For example:
More direct sources of cysteine are:
Here we are, where you’ve been waiting, I’ve earned my title, onions and garlic are a good source of cysteine. Researchers are working on L-cysteine for hair. Lentils are the natural, most abundant source of this amino acid, be sure to note. L-cysteine is also available as an oral supplement.
The role of L-cysteine in hair health
L-cysteine is in the form of the amino acid cysteine that our skin can easily use. It is a sulfur-rich compound that our hair follicles need to produce our hair shafts. According to the Journal of Applied Cosmetology, the main role of L-cysteine for hair growth is to stimulate the development process of hair shafts and nails.
Let’s take a look at the research studies to understand how L-cysteine is a building block and how and why it is necessary for follicles to perform at their best.
Hauztartzt published a pilot research study led by Hertel H, Gollnick H, Matthies C. They found interesting information in their study on the use of L-cysteine and retinol to reverse widespread hair loss by reducing the telogen ratio of hair follicles. Telogen is a phase of the hair life cycle where the follicles are at rest. Now you know this. The anagen phase is when the follicles are actively producing hair. In many instances of hair loss, there is a much higher percentage of follicles in the telogen phase. This pilot study was conducted on 36 subjects. After their treatment with L-cysteine and retinol supplementation, participants experienced an 11% increase in anagen ratios and an 8.3% reduction in telogen ratios. Based on these statistics, the researchersconcluded that common hair loss conditions may benefit from high doses of L-cysteine and retinol on a long-term treatment basis.
Researchers Kizawa K Tsuchimoto S. Hashimoto K and colleagues investigated a gene called S100A3, which encodes to form a calcium-binding protein on the hair follicle. This protein is rich in L-cysteine. These scientists observe the gene expression of S100A3 during the anagen growth phase of the hair follicle as well as the regression phase. They also investigate where this gene expression tends to occur within the follicle and the possible role of calcium-binding protein in the process of new hair formation. They cloned a mouse with the S100A3 gene. They observed levels of mRNA that bind to the gene sequence and start the process of putting amino acids such as L-cysteine together in the correct sequences to form the final protein. They found that mRNA levels increased in the anagen hair growth phase and decreased in the regression phase.
Additionally, they discovered that gene expression occurs in follicular cells in the process of differentiation into more specific cells required to form the hair shaft. The researchers also reached supporting data that the protein made from the S100A3 gene is responsible for calcium-dependent processes during the production of hair strands.
What are we to understand from all this, Aziz? If you say: For hair growth, follicles need amino acids, L-cysteine and calcium to form hair strands.
L-Cysteine and Vitamin B6 Prevented Chemo-Associated Alopecia in Mice
Hair loss is often an inevitable part of chemotherapy in most cancer patients. Researchers D’Agostini F, Bagnasco M, Giunciuglio D. and colleagues investigated the roles of L-cysteine and Vitamin B6 in preventing the occurrence of this type of alopecia. They exposed the mice to certain conditions for the tumors to develop. The rodents were then treated with chemotherapy to induce states of baseline hair loss that the researchers could measure.
However, when given varying doses of L-cysteine and vitamin B6, the scientists found that this supplement prevented alopecia on the mice’s backs.
A similar study comes from D’Agostini F and Ganchev G. Researchers have applied two types of treatments that successfully inhibit hair loss: budesonide or N-acetyl-L-cysteine.
Also known as androgenic alopecia, male pattern baldness is caused by a combination of many different biochemical issues. The most well-known is the conversion of testosterone to DHT. Those with a genetic predisposition will have weaker (ie more sensitive) DHT receptors in their hair follicles. Binding of DHT to these receptors will initiate a chain reaction of processes that cause the miniaturization of the follicles. The hair becomes thinner and eventually stops growing.
Besides the formation of DHT, a lesser known pathway also contributes significantly to androgenic alopecia. It is the production of TGF-B1 that supports the continued progression of hair loss.
See Shin H, HG, Inui S et al. used NAC, or N acetyl-L-cysteine, to suppress TGF-B1 secretion. NAC is a version of cysteine that allows the body to produce glutathione, an important antioxidant.
“Scientists treated rat derma papilla cells and found that it helped reduce TGF-B1 secretion.” For human hair, L-cysteine can help stop the progression of androgenic alopecia by suppressing TGF-B1. However, more work is needed on non-animal subjects,” he notes.
In summary, all these studies support the potential of cysteine to reduce hair loss or promote growth. When combined to produce cysteine, it can increase anagen rates in humans through its use with retinol.
L-cysteine for hair loss is still being researched by scientists. This is the starting point of garlic shampoos. Garlic, the natural source of this amino acid, can be consumed not only for focusing on the follicles, but also for general health.
(1) Hertel H, Gollnick H, Matthies C, et al. Low dosage retinol and L-cysteine combination improve alopecia of the diffuse type following long-term oral administration. [Article in German] Hautarzt 1989;40(8):490-5.
(2) Kizawa K, Tsuchimoto S, Hashimoto K, et al. Gene expression of mouse S100A3, a cysteine-rich calcium-binding protein in developing hair follicle. J Invest Dermatol 1998;111(5):879-86. –
(3) D’Agostini F, Bagnasco M, Giunciuglio D, et al. Inhibition of oral N-acetylcysteine of doxorubicin-induced clastogenicity and alopecia, and prevention of primary tumors and lung micrometastases in mice. Int J Oncol 1998;13(2):217-24
(4) Balansky R, D’Agostini F, Ganchev G. Influence of FHIT on benzo[a]pyrene-induced tumors and alopecia in mice: chemoprevention by budesonide and N-acetylcysteine. PNAS 2006;103(20):7823-8. –
(5) Shin H, You HG, Inui S, et al. Induction of transforming growth factor-beta 1 by androgen is mediated by reactive oxygen species in hair follicle dermal papilla cells. BMB Rep 2013;46(9):460-4.