Update: May 1, 2022: Dr. Rodney Sinclair praised the amino acid cysteine in today’s Reddit AMA:
“The key nutrient is Cysteine. Based on animal studies, cysteine incorporation into the hair follicle is the rate limiting step for hair growth. The relative importance of other nutrients has not been quantified.”
For years, I have read that amino acids are good for your hair. In a similar manner to vitamin D, protein, biotin and vitamin B12. Note that proteins (polypeptides) are just a chain of amino acids (peptides) that are linked and bound together.
On Amazon, one of the most popular hair loss products is HairFinity’s vitamin capsules containing amino acids, biotin and numerous other vitamins. It contains an exclusive Capilsana Complex, which includes: hair strengthening amino acids in hydrolyzed collagen; sulfur-containing MSM; and hair boosting horsetail with silica. Other ingredients include vitamin B3 (niacin), vitamin B5, vitamin A, vitamin C, vitamin D, vitamin B12 and silica. The average rating of this product is currently 4.3/5.
I always assumed the benefits of amino acids to be very limited for hair growth. In my post on Viviscal and Nutrafol, I mentioned how malnourished vitamin and protein deficient people in developing countries often have unbelievable hair. Including Indian ascetics and holy men who are entirely vegetarian and frequently fasting for prolonged periods. I remain skeptical that amino acids and protein can help reverse androgenetic alopecia. Also of note, numerous nutritionally deficient bald men still have tons of robust body hair.
However, a long-time reader from Australia named “Quentin” has made me at least consider that amino acids are good for your hair quality. Perhaps better than protein and biotin. Quentin’s first comment on this blog came in 2016. Almost all of his subsequent 70 or so comments seem consistent and usually helpful to other readers. It is very rare for me to devote most of a blog post to the opinions of one reader.
Amino Acids and Hair Growth
In humans, there exist 21 amino acids of which nine are essential. An essential amino acid cannot be synthesized fast enough by humans, and must therefore come from the diet. Deficiencies can cause dull skin and fragile hair. On Amazon, you can find many essential amino acid supplements for sale.
According to Quentin (via his blog comments and e-mails), there are nine amino acids that benefit hair growth. The first five of these nine (listed below) are the most important. Aminos high in sulphur such as cysteine are the key per Quentin. However, my cursory online research suggests that cystine is more frequently recommended than cysteine.
- Cysteine. Many cysteine-rich products are used in the hair and skin care industry. The ingredients is listed as L-cys or L-cysteine.
- Methionine (essential). Promotes the development of hair follicles via the Wnt/β-catenin signaling pathway in rabbits.
- Lysine (essential). Per one study, the role of l-lysine in hair loss appears to be important and it supports collagen production.
- Arginine. One report found an inositol and arginine solution to benefit hair growth. L-arginine also reduces blood pressure and is a precursor for the synthesis of nitric oxide.
- Cystine. A 2020 study found L-cystine to benefit metabolic activity, cell viability, and proliferation of keratinocytes. Cystine based product Pantogar is a popular hair growth product.
Interestingly, this number of nine exactly matches a very recent article’s findings. However, Quentin also mentioned many of these amino acids in past comments.
Another recent article recommends seven of the above nine amino acids for hair loss sufferers.
Quentin’s before and after photos show clear improvement in hair growth. He previously also posted some photos showing some reduced hair greying. Make sure to read his comments in the past several blog posts (I have pasted the most relevant ones at the bottom of this post).
Note that some people also use liquid amino acids directly onto their scalps. I am sure that other topical versions in cream and spray forms have also been tried. At best, my guess is that such attempts may have temporary benefits towards hair texture, elasticity and thickness.
Amino Acids and Vitamins
Please note that Quentin is not a doctor, and I cannot vouch for any of his suggestions. If you do contact him or get any products from him, I am also not responsible. I do get a strong sense that he is sincere, honest and knowledgeable. However, some of his claims seem exaggerated. The insightful amino acid section in this report claims as follows:
“Overall, the data regarding the use of amino acids to treat hair loss is limited.”
Having said that, I have never tried taking any amino acid supplements in my life. And earlier in the post, I did post some links to favorable studies in regards to the use of amino acids for hair loss.
Per Quentin, these amino acids are to be ingested at 8 grams per day. He splits them up into 4 grams twice a day. 1000mg of vitamin c (ascorbic acid) is added to this mixture when taken orally, as “this will create the building blocks for protein in the body”. Some of these amino could cause side effects in certain people, so please consult a doctor or dermatologist first. Especially if you already have any underlying medical conditions.
Quentin feels that people with the 5AR gene are deficient in these essential and non-essential amino acids. Per Quentin, “Amino acids high in sulphur are what is the key to regrowing and thickening hair“.
Note that Quentin also uses topical Minoxidil in combination with Retin-A. He stresses the need to use Minoxidil in addition to the earlier mentioned nine amino acids. He uses high-strength Minoxidil 7.5% with retinoic acid (tretinoin) at 0.0125%. He thinks that Minoxidil will help the blood flow to the scalp so that these amino acids become more effective.
“I was doing a minox/tretinoin mix. However, I now use them separately. I had the compounder make a separate bottle of retinoic acid in a liquid vehicle and minox in another.”
“The key to regrowing your hair is using minoxidil with these 9 key amino acids. I promise this is the key and I am astonished at how well it works.”
Quentin’s After Treatment Photos
According to Quentin, besides the nine amino acids mentioned earlier, the following is also important (I paraphrase at times):
- A vitamin/mineral mix is crucial to take every day, as the body needs to be healthy and we need energy. Our internal health and organ health also reflects on our skin, nails and hair.
- A multivitamin containing vitamins B1, B2, B3, B5, B6, B7, B12, C and magnesium will help with energy production.
- Zinc taken at an amount of 50mg-100mg a day will help with the body’s immune system. Zinc is also important for hair growth.
- Vitamin C between 1000mg-2000mg.
- I am inclined to also add arginine and methylsulfonylmethane (MSM) to my shampoo.
- A 1994 patent related to using methyl sulphonylmethane (MSM) and a sulphydryl group releasing agent for hair growth. Quentin sent me two of the “recipe” related screenshots from there, including one in relation to the use of castor oil.
Some items of interest from Quentin’s recent e-mails and comments are posted below.
“I am about to start studying trichology at the technical and further education college in Australia. I will be offering 10-minute free online consultations over the next month or so. Thereafter, I will be charging (not much) for longer follow-up consultations.”
“After much thought and research I have changed my mind from studying trichology at the technical and further education college in Australia, I have decided to do it under the World trichology society under Dr. David Kingsley.”
“I am going to create a supplement which is much needed in the hair loss community. It will be a mix of 4 main amino acids and 13 others in smaller amounts. Cystine, lysine, methionine, arginine are the main ones, as well as high amounts of choline and vitamin c, b vitamins and minerals. And high zinc as well as biotin at 10000mcg daily. This will have to be taken twice a day and at 8 grams each time.”
“No-one out there is offering this type of nutrient mix for hair loss so I thought I would do it. Not sure how to market it yet, but it works so well for me that I don’t think it should be kept secret. It has taken me 5 years to get the amino acids in the right ratios, about as long as I have been posting here.”
“I am willing to make these in 50 day supplies. I use “n-acettyl l-cysteine.”
“I hope the admin will write a post about this. I was considering making a blend and selling it online, but you can do it yourself.”
“I have been posting here a long time, and tried almost every shampoo and different minoxidil formula available. ”
Minoxidil, Tretinoin and Rhodanide
“It’s 7.5% minox in one bottle. And 0.0125% tretinoin in the other.
Apply the tretinoin first, maybe 10 minutes before minox. Ask to have a very low PG content so it dries fast. You want the tretinoin to be dried before applying minox. Tretinoin (retin a) will also help with cellular turnover. This is just as important as minoxidil and can be used on its own.”
“The usual prescribed amount with formulated minox is 0.025%. I always found that too strong so I use half of that. For minoxidil, I am using a cincotta in nsw (Australia). Only this particular cincotta will do it at this price. It is cheaper for 100ml of 7% minox with tretinoin than it is for 2 bottles of rogaine, so I am very happy.”
“Retinol at a high amount 0.5% is a great way to get your skin ready for retin a. It will turn into retin a within the skin.”
“I was using c pharmacy (Australia), but they are just too expensive. I learnt a lot from them and now I make my own amino/vitamin mix.”
“I don’t know how, but I was going grey. I am pretty sure that it is the amino acids that have changed that, but I look at my hair now and I see one grey hair? It is incredible what some things that are currently on the market and that are legal can do.”
“Has anyone heard of a compound called rhodanide? It was originally used on sheep to thicken their fur and give farmers a bigger yield. Only a few companies use or know of this and have it in their products. From my experience, it slows shedding but also increases hair growth rate excessively.”