Did you know there are two types of hair that can grow on the scalp? They are vellus and terminal.
The first type can lead to the appearance of hairline recession and balding, while the second type is what you need for a healthy full head of hair.
In this article, you’ll learn the difference between vellus and terminal hairs. This will include an in-depth look at the hair growth cycle, and where vellus hairs fit in.
I’ll then explain whether it’s possible to turn vellus hairs terminal. (Hint: the answer is a bit complicated.)
Finally, I’ll share some tips for healthy hair regrowth.
The Hair Growth Cycle: An Introduction
There are three distinct stages within the hair growth cycle. They are anagen, catagen, and telogen (1).
The first stage is anagen which is when active growth occurs.
The majority of your follicles are in anagen at any given time. And this stage lasts anywhere from two to eight years.
The second stage, catagen, is a brief transitional stage. It lasts just four to six weeks as the hair strand begins to detach from the dermal papilla.
This stage turns the hair strand into a club hair, and the bulb at the bottom of the hair will completely detach from the blood supply.
Last is telogen phase. The hair strands are finally shed from the follicle as the new anagen hair pushes through.
The telogen phase lasts about two to three months and a small percent of your follicles are in this phase at any given time.
Now, let’s learn more about where vellus hairs fit into the above cycle.
The Vellus Hair Growth Cycle
Vellus hairs, as they generally appear on the body, are short, lightly-colored strands. Both children and adults have this type of hair.
They are found throughout the body, except for the soles of the feet and palms of the hands.
Vellus hairs insulate the body, and they also act as a sensory warning with the help of the arrector pili muscle.
So, where do vellus hairs fit into hair loss?
Well, first, it helps to understand how vellus hairs compare to other “types” of hair found on the body.
The three main hair types are: lanugo, vellus, and terminal (2).
Lanugo hairs are thin and soft downy hairs that cover large parts of a fetus or newborn baby. These hairs are often unpigmented, and they will shed within a few days to a few weeks of birth.
Vellus hairs are also thin, unpigmented hair strands that cover the body. And these are actually the hairs that replace lanugo once it’s been shed.
Peach fuzz is another term for vellus hairs, and they play a role in temperature regulation.
Terminal hairs are thicker, pigmented hairs found on the scalp, but also the face (beard), armpits, and pubic region.
Now, where do vellus hairs fit into hair loss?
The vast majority of hairs on the scalp are terminal hairs. These are darker and stronger than vellus hairs.
But follicles that are miniaturized can cause terminal hairs to become vellus and, eventually, to fall out entirely.
So, what is miniaturization?
Follicle miniaturization is a process that occurs due to inflammation of the follicle.
As the follicle inflames, it slowly detaches from the blood flow. This leads to weaker hairs which eventually become too short to breach the scalp.
The most common cause of miniaturization is Androgenetic Alopecia (AGA), a genetic condition also known as Male-Pattern Baldness (MPB) (3).
This is due to a genetic sensitivity to the androgen hormone DHT (Dihydrotestosterone) (4).
Miniaturization may also occur due to an untreated scalp infection, or chronic inflammation.
If this condition is left untreated, the terminal hairs will become vellus. And, eventually, the follicle will die entirely.
Can Vellus Hair Become Terminal?
If terminal hairs can become vellus hairs, then is the reverse also possible?
The answer is complicated.
Vellus hairs become terminal hairs during puberty. This is most noticeable on the face (beard), legs, and armpits.
But what happens when hairs turn from terminal to vellus? Can they return to their previous state?
Possibly. And if we’re feeling optimistic, then probably.
The hair follicles found throughout the body are all the same – the ones that produce vellus hairs, and the ones that produce terminal.
The only difference is the presence of hormones (5).
During puberty, and thereafter, hormones transform vellus hairs into terminal. Or, in the case of scalp hairs, they maintain their terminal state.
If the presence of hormones can trigger miniaturization and revert hairs to vellus, then it makes sense that controlling these hormones would enable the reverse.
However, this isn’t an exact science.
Hormones play a role in the process, but so too does genetics and environment.
How to Turn Vellus Hairs Terminal
As mentioned, there’s no guarantee that vellus hairs can be returned to their terminal state. That doesn’t mean there’s no hope, though.
If you want any kind of a shot at regrowth, there is one thing you’ll absolutely need: healthy follicles.
When you suffer from AGA, this can be difficult to achieve. There are two main approaches to take, however, and they are:
- Reduce scalp DHT levels
- Increase blood flow to the area
Now let’s look more closely at exactly how you may be able to trigger regrowth.
Reduce Scalp DHT Levels
There are two widely accepted ways to reduce DHT at the follicular level: internally, and externally.
The internal method is often done with the help of the FDA-approved medication finasteride.
Finasteride, also known as Propecia, doesn’t directly target DHT. It instead works by inhibiting the activity of the enzyme 5-alpha-reductase (6).
5-alpha-reductase is the enzyme that’s responsible for the conversion of testosterone to DHT. By inhibiting its activity, then, you can naturally lower DHT levels throughout the body.
The internal approach works quite well for combating pattern hair loss.
After all, when less DHT is present at the follicle the follicle can then go through its natural growth cycle uninterrupted.
But as you might imagine, lower DHT levels can also have side effects (7).
This is because DHT is an androgen hormone that’s largely responsible for sexual function.
Are there other internal androgen blockers that achieve the same with less side effects? There are a few that have been considered by researchers — including saw palmetto and chaste tree.
However, the evidence is lacking and the side effects seem to be similar.
The other approach is external, and it can be achieved with topical anti-androgens.
Saw palmetto and chaste tree are two anti-androgens that can be used topically, as well as internally.
And contrary to popular belief, minoxidil is not actually an anti-androgen at all. But we’ll get to that a bit more later.
Topical anti-androgens are often effective for as long as they’re used. They also have less side effects than internal ones.
Aside from saw palmetto and chaste tree, other options include reishi mushroom, licorice, and white peony (8).
Just like the other topical anti-androgens, though, there isn’t a great deal of research to back their claims.
However, further research is needed to understand their potential risks and benefits.
Increase Blood Flow to the Area
When DHT attaches to sensitive follicles, it triggers miniaturization.
As the follicle miniaturizes, the blood flow to the follicle is slowly strangled. This worsens the state of the hair strand until it eventually becomes thin, more lightly-colored, and shorter.
It makes sense that removing DHT from the scalp is the first step that many people take.
But you may also be able to combat the effects of androgen sensitivity by increasing blood flow.
Blood carries oxygen and nutrients to the follicles. These are necessary for healthy hair growth.
By increasing the flow of oxygen and nutrients to the scalp in the midst of miniaturization, you may be able to combat its effects.
The most popular hair loss drug – minoxidil – does just that.
Minoxidil is a topical solution that’s applied to the scalp. There are multiple mechanisms believed to be in play, but the most common are its ability to (12):
- Act as a potassium channel opener
- Upregulate growth hormones at the follicle
- Increase blood flow to the scalp
It’s the last mechanism – an increase in scalp blood flow – that may play the biggest role in regrowth.
And fortunately, the drug appears to be quite effective at it.
A 1984 study tested four solutions: a control, and 1%, 3%, and 5% minoxidil on cutaneous blood flow to the scalp (13).
Laser Doppler Velocimetry (LDV), a technique that measures the velocity of fluids, was used to measure the increase in blood flow after minoxidil application.
After just 15 minutes of applying 5% minoxidil, there was already a noticeable increase shown by LDV. This increase was shown to be three-fold and lasted up to one hour.
And while minoxidil may be a good option, it’s not the only one.
There are alternative methods – namely scalp massage and microneedling – that can similarly increase blood circulation.
Just as it sounds, scalp massage is mechanical stimulation of the scalp using your hands or a specialized tool.
This is a natural and low-cost (or even free) way to stimulate blood flow. And best of all?
It’s been scientifically proven to induce hair growth.
One study followed the hair growth results of nine men who received four minutes of scalp massage daily for 24 weeks (14).
The researchers analyzed dermal papilla cells that were cultured using a 72-hour stretching cycle, and they also performed DNA microarray analyses.
As the results indicated, standardized scalp massage “increased hair thickness 24 weeks after initiation of massage.”
The DNA microarray analyses also showed that stretching dermal papilla cells significantly altered gene expression when compared to their non-stretching counterparts.
Just how significant was this difference?
A total of 2,655 genes were upregulated and 2,823 genes were downregulated.
An added benefit of scalp massage is its ability to reduce mechanical tension.
Why is this such good news?
Because as recent research suggests, mechanical tension may play a role in the progression of AGA (15). More specifically, it appears to activate an androgen receptor coactivator (Hic-5).
This coactivator enables androgen hormones – including DHT – to more easily attach to the follicles.
By reducing activation of Hic-5, the levels of DHT present at the follicles may be significantly reduced.
A technique that is similarly beneficial as scalp massage, and perhaps even moreso, is microneedling.
Microneedling, also known as Collagen Induction Therapy (CIT), is a method that uses tiny needles to penetrate the skin. These needles cause micro wounds.
As these wounds heal, they trigger a healing process that has been proven beneficial in hair regrowth (16).
As wounds heal, they go through three distinct stages:
In simpler terms, the healing process triggers the proliferation of new stem cells.
But even more, the process of microneedling can activate numerous growth factors (17).
These combined can lead to the stimulation of new hair growth.
Does microneedling also increase blood flow? You bet (18).
Microneedling, then, may be a simple but effective way to possibly revert miniaturized hairs back to their terminal state.
Hair loss often occurs as a result of a genetic condition, though illnesses and medications can trigger it, too. And while these may cause your terminal hairs to revert to their vellus state, there may be things you can do to regrow healthy hair.