The Arrector Pili Muscle (aka Goosebump Muscle)

Update: August 7, 2020 — Yesterday, Taiwanese and US researchers published an important paper titled: “Cell Types Promoting Goosebumps Form a Niche to Regulate Hair Follicle Stem Cells.” The work was led by Dr. Lin Sung-jan of National Taiwan University. In collaboration with researchers from Harvard University (US).

Goosebumps, the Sympathetic Nervous System and Hair Growth

Lin’s team found that the biological mechanism behind baldness in men is closely connected to the sympathetic nervous system. Hair follicle stem cells activate after receiving signals via what are known as ADRB2 receptors. Based on these findings, the researchers hope to develop small molecule drugs that can activate ADRB2 receptors as a means of regenerating hair.

Goose bumps are a sympathetic nerve response involving the contraction of tiny muscles all over our bodies. These arrector pili muscles causes hair to stand up straight on the skin when we are fearful and under threat. The scientists aim to ultimately control the muscle-nerve system that drives hair regeneration. A video of these findings was published here. It is quite something to see Dr. Lin Sung-jan being mobbed by the media.

Goosebumps and Arrector Pili Muscle
Goosebumps, Arrector Pili Muscle and Hair Growth.

Jan 10, 2017

Several weeks ago, the arrector pili muscle got significant coverage in a few newspapers around the world. Famed Australian dermatologist Dr. Rodney Sinclair co-authored an important paper titled “The arrector pili muscle, the bridge between the follicular stem cell niche and the interfollicular epidermis” that was just published this month.

Dr. Sinclair has been involved in this area of hair loss research for a few years and already published similar findings several times in the past decade, including material on his own site. Nevertheless, Australian newspapers were especially interested in this latest study and its findings as evidenced by articles such as this one and this one.

The Arrector Pili Muscle

Arrector pili muscles are small muscles attached to individual human hair follicles on both the scalp as well as body (so we have millions of these muscles throughout our bodies). Contraction of these muscles causes hairs to stand up, a phenomenon that is known as goosebumps. Therefore, the musculus arrector pili is often referred to as the goosebump muscle.

Every hair root is connected to the arrector pili. This smooth muscle contracts in response to signals from the “fight or flight” sympathetic nervous system.

The Arrector Pili Muscle Degeneration and Hair Loss

In recent years, a few studies have come out that suggest a possible connection between the arrector pili muscle degenerating (where it gets replaced by fat) and hair loss due to the subsequent disconnection between various hair follicle stem cell populations. It is possible that an intact arrector pili muscle plays a crucial role in the maintenance of follicular integrity and stability.

However, there are many uncertainties about this theory that I discuss in the next section. It seems that while in alopecia areata (AA) patients the arrector pili muscle remains intact, this is not true in androgenetic alopecia (AGA) patients (and unfortunately over 95 percent of balding men suffer from AGA). So this could be why it is much easier to grow back hair for people with AA compared to people with AGA. However, the rate at which the arrector pili muscle degenerates and gets replaced by fat varies substantially between patients and between individual hairs on the same scalp. Some miniaturized vellus hairs in balding regions might even never lose most of their arrector pili muscle connection.

Points of Contention

  • According to Dr. Sinclair’s own quote from a past paper, “It remains unclear whether arrector pili muscle regression is a cause or effect of permanent follicle miniaturization“. I think this is the crux of the issue surrounding this theory/hypothesis.
  • It seems like hair that is transplanted from the back of a person’s scalp to the front of that same person’s scalp regenerates the arrector pili muscle. A very important related study from 2012 comes to us from Japan. So it might be very possible to regenerate this muscle.
  • In Dr. Tsuji and his team’s groundbreaking technology (hoped to be released in 2020): “the transplanted primordium also forms connections with surrounding tissues (arrector pili muscle and nerves) and repeats normal hair cycles”.
  • There are 100s of anecdotal reports on the internet of people regrowing long-lost hair in bald scalps. On the internet, you can find many reports of old men who recently started taking dutasteride for enlarged prostate issues and have subsequently noticed hair regrowth on areas of their scalps that have been totally devoid of any visible hair for decades. Maybe they regenerated their arrector pili muscles; or maybe those muscles always remained intact in spite of severe AGA; or maybe one can regenerate hair without the need for having any intact arrector pili muscles?
  • It is unclear when exactly we have a point of no return where the arrector pili muscle is largely or entirely replaced by fat and hair stops growing (either as a cause or effect — see first bullet point above). It seems like there is significant variation depending on person and hair follicle. In many cases, the arrector pili might not be entirely degenerated and replaced by adipose tissue even in areas of the scalp where one has been bald for several decades. In such cases, subsequent hair and muscle regeneration could perhaps even be possible via something like Dutasteride or Finasteride?

Viviscal and Nutrafol Supplements for Hair Growth

When it comes to hair loss supplements, the two most widely cited brand names that I have kept hearing about for years are:

  1. Viviscal.
  2. Nutrafol.

Many hairdressers and dermatologists have recommended Viviscal and Nutrafol (both trademarked) to me in the past. However, most were too pushy in trying to sell them, so I was skeptical. The prices are also somewhat expensive, especially since you have to take these pills daily.


It should be noted that, nowadays, there are a number of other vitamin and mineral containing hair loss products that seem to be even more popular than Viviscal or Nutrafol.

Among the ones with a huge number of reviews on Amazon include Hair Rush and HairAnew and HairFluence. As always, look out for fake reviews and ratings. Many product reviews on Amazon are based on people getting free samples in exchange for reviews.

Pattern Hair Loss Can’t be Cured by Supplements

Vitamins, minerals and related supplements can never permanently reverse male pattern hair loss (aka androgenetic alopecia). Neither can they usually help stop the progression of hormone driven female pattern baldness.

Having said that, some can modestly reduce testosterone and its hair destroying derivative dihydrotestosterone (DHT). See my post on natural DHT blockers. However, usually, all this does is reduce your hair shedding slightly and cause modest hair regrowth in absolute best case scenarios. Even then, the effect is often temporary in nature.

Natural products for hair loss can almost never match the efficacy of synthetically made drugs Finasteride and Dutasteride. Even the latter two drugs do not work in many people, or often stop working and loose efficacy after a few years. People often prefer to start with natural products due to fears of side effects.

Vitamins and Minerals for Thicker Hair

For a very small fraction of hair loss sufferers, nutritional deficiencies are causing their hair loss rather than genetic susceptibility to DHT. Sudden changes in diet can cause telogen effluvium. In such cases, vitamin and mineral supplements could help boost hair growth and reverse thinning hair.

Sadhu with Long Hair
An Indian ascetic (sadhu) with great long hair. Most of these holy men partake in prolonged periods of fasting, and are usually vegetarian.

However, it should also be noted that in many poor countries with massive starvation and nutritional deficiency problems, residents often have better hair than in developed countries.

In fact, high-protein and fat heavy meat based diets in Japan have been blamed for increased rates of hair loss at younger ages. So it is also possible that excessive nutrient and caloric intake can worsen hair loss. Perhaps via altering hormones such as estrogen, testosterone and dihydrotestosterone (DHT).

In my life, I have known numerous people who were anorexic or had extremely strange and unhealthy diets. Many of them still had excellent scalp hair and no baldness in old age. Genetics usually trumps lifestyle in the case of hair loss. All of us know homeless people, alcoholics and drug addicts with great heads of hair.

I am not too much of a believer in nutritional deficiencies causing permanent hair loss. Nevertheless, I am not a doctor or medical professional and you should always take my theories with a grain of salt.

Viviscal vs Nutrafol Comparison

Both Viviscal tablets and Nutrafol capsules are oral dietary supplements and nutraceuticals that have to be taken daily. The Viviscal women’s tablet is supposed to be taken twice daily. The Nutrafol women’s capsule is supposed to be taken four times daily. Best results are seen after at least 3 months of daily ingestion.

It seems like for both brands, the women’s product is far more popular than the men’s product. Viviscal has a separate site for its men’s products. Nutrafol’s Instagram is filled with women’s before and after photos and testimonials.

Both Nutrafol and Viviscal also sell shampoos. And you can buy their products in various versions such as Viviscal Extra Strength, Viviscal Professional and Nutrafol Women’s Balance. Neither of these neutraceutical and dietary supplement brands require FDA approval. Make sure to search Reddit for opinions on Viviscal versus Nutrafol for your receding hairline.

Dosage and Price of Viviscal and Nutrafol

Viviscal recommends taking 2 tablets per day. Nutrafol recommends taking 4 capsules per day.

As of 2020, the price of 120 capsules of Nutrafol Women’s Supplement is $88. And the price of 60 tablets of Viviscal is $34.

So taking 4 Nutrafol capsules per day would cost around $3 per day. And taking 2 Viviscal tablets per day would cost around $1 per day.

Both the companies that make these products tout their clinical trials. However, I have not tried to analyze the quality, rigor and thoroughness of these trials. Nor whether there is any potential bias in the various trials’ sponsorship or otherwise.

Clinical trials and research pdf booklet for Viviscal.

Clinical trials for Nutrafol. With before and after photos.

Nutrafol Ingredients

Among the main ingredients in Nutrafol, the ones that stand out in uniqueness are: Marine Collagen (made from North Atlantic Cod); Ashwagandha (root and leaf); Japanese Knotweed Extract; Horestail Extract; Curcumin; Tocotrienol Complex; and Resveratrol.

Well known hair growth promoters such as biotin, zinc and saw palmetto are also contained in the Nutrafol Synergen Complex. In the Nutrafol Blend, one also finds L-Cysteine, L-Lysine, L-Methionine and Keratin.

For vegetarians, vegans and those concerned with mercury in seafood, this product is not ideal.

Nutrafol Ingredients
Nutrafol Hair Loss Supplement Ingredients.

Viviscal Ingredients

Viviscal Ingredients
Viviscal Ingredients.

The most unusual ingredient in Viviscal hair loss supplements is its AminoMar Marine Complex (trademarked). It is derived from shark cartilage and oysters and supposedly nourishes hair.

I wish they would find some other ingredient from the ocean to replace this marine complex shark powder. Especially since there are so many studies from Asia that show various seaweeds and sea vegetables to be helpful in growing hair.

Other ingredients in Viviscal include Vitamin C, Niacin, Biotin, Iron, Zinc and Horsetail Extract.

For vegetarians, vegans and those concerned with mercury in seafood, this product is not ideal.

Hair loss cure news blog. Hair cloning and multiplication for baldness. The latest news in hair regeneration treatments for androgenetic alopecia.