Hair miniaturization is the conversion of thick, pigmented terminal hair into short, fine and hypopigmented vellus-like hair (peach fuzz). The process is symptomatic of various types of hair loss, which can be temporary or permanent. In this guide, you’ll find out the essentials of this hair-thinning process.
What Is Hair Miniaturization?
Hair miniaturization refers to the shrinking of the hair follicles on the scalp. Most commonly, it’s seen in androgenetic alopecia, where it results in permanent baldness. Research shows that dihydrotestosterone (DHT) – a byproduct of testosterone – is primarily responsible for this process.
Source illustration designed by Freepik/Modifications made
A study, published in PRS Global Open, noted the following regarding DHT’s role in miniaturizing hair follicles in androgenetic alopecia:
- The activity of the 5-alpha reductase enzyme increases (this enzyme is responsible for converting testosterone into DHT)
- Dihydrotestosterone itself increases in the balding scalp
- Hair follicles contain a greater number of DHT receptors
The enzyme 5-alpha reductase converts testosterone into the more potent DHT, which then binds to the androgen receptors in the dermal papilla cells at the base of hair follicles. That, in turn, modifies the hair growth cycle. The anagen (growing) phase is reduced to a few weeks or months instead of 2-8 years.
Does hair miniaturization only occur in androgenetic alopecia?
Though hair follicle miniaturization is often associated with androgenetic alopecia, it can also occur in other types of hair loss, some of which may include:
- Alopecia areata, in which the immune system attacks healthy hair follicles, also results in hair miniaturization. In fact, miniaturization, in this case, is possibly completely reversible with treatment unlike what may be expected with androgenetic alopecia.
- Traction alopecia, a type of hair loss that occurs due to prolonged and repeated stress on the hair, can also show miniaturization of the follicle. An individual with traction alopecia along the hairline exhibited this phenomenon in a case study.
- Fibrosing alopecia in a pattern distribution is a type of scarring hair loss which occurs in the same areas in which androgenetic alopecia occurs, and this has also been shown to cause follicle miniaturization, per research.
What Causes Hair Miniaturization?
Dihydrotestosterone influences miniaturization of hair follicles in androgenetic alopecia. However, there are other theories that also explain why it happens.
According to research published in the International Journal of Trichology, the arrector pili muscle (APM) plays an important role in this regard.
APM is a small band of muscle that connects the hair follicle to the skin (it’s the one that causes goosebumps). Researchers propose that permanent baldness in androgenetic alopecia occurs because hair follicles lose attachment to this muscle.
So, if the hair has miniaturized but it maintains contact with the arrector pili muscle, the hair loss will be reversible. And this is exactly what’s believed to reverse the miniaturization process in alopecia areata.
In addition to the above factors, miniaturization also occurs due to ageing. According to a study published in Nature Aging, with age, the adhesiveness of the hair follicle stem cells decreases. As a result, these cells escape from the bulge of the hair follicle, which results in their death. And without these cells, it’s not possible for new hair to grow.
Therefore, essentially, hair miniaturization can occur due to a combination of factors, such as hormones, genetics, ageing, and health problems. It can also be exacerbated by external factors, such as taking steroids.
What Are The Signs and Symptoms of Hair Miniaturization?
If your hair is miniaturizing, you might notice the following signs:
- Hair is losing colour.
- Hair is becoming finer and wispier.
- Hair is becoming sparse.
- The scalp is becoming more visible.
A closer look also reveals a decrease in the number of hairs in each hair follicle. For instance, a healthy hair follicle contains around 2-3 strands of hair. With miniaturization, this number goes down to 1 hair per follicle until there is none left.
Keep in mind that miniaturization doesn’t affect all the hair in a follicular unit at once. It occurs at varying rates. So, at any time, within a follicular unit, a few hair strands might be miniaturized.
However, there might be others that are still healthy. This “hair diameter diversity” – the research on which is published in the Archives of Dermatology – is helpful with the diagnosis of androgenetic alopecia.
Other than that, the distance between each follicular unit on the scalp also increases, which is what makes the hair look sparse and increases scalp visibility.
The thickness of each hair shaft also decreases, and in general, its quality becomes poor.
These symptoms can vary, however, depending on the cause of miniaturization.
Can Hair Miniaturization Be Reversed?
If miniaturization of hair follicles is occurring due to androgenetic alopecia, it’s irreversible. However, in the case of alopecia areata, it can be fully reversible.
In any case, early treatment is important to slow down hair loss. If you’ve already experienced significant thinning and baldness, it can be very difficult to have good hair density again (without surgery).
How Long Does Hair Follicle Miniaturization Last?
Hair follicle miniaturization can occur in a matter of 6-12 months, according to research. Previously, it was believed that hair miniaturization occurred over a number of hair cycles for a long period of time. However, as noted in the same study, there’s now a wide consensus that miniaturization occurs abruptly as a “large step process during one cycle transition” and not over a number of cycles as that would take years and not months.
Men with androgenetic alopecia can start losing and miniaturizing their hair as early as their teenage years. Usually, however, the incidence increases with age. Women, however, usually develop androgenetic alopecia after menopause, which occurs between the ages of 40 and 50.
How Do You Treat Miniaturized Hair?
Among the non-surgical options, minoxidil and finasteride are considered the most effective for hair miniaturization.
How minoxidil works isn’t exactly understood, but it’s believed to increase the duration of the anagen (growing) phase and improve blood flow to the scalp. On the other hand, finasteride works by blocking the enzyme that converts testosterone to dihydrotestosterone.
To improve hair thickness and encourage growth, platelet-rich plasma (PRP) injections may also be helpful. As well, low-level light therapy (LLLT) may be beneficial for the thickness and growth of hair in androgenetic alopecia, as one study found.
A hair transplant is considered another treatment option for hair miniaturization and baldness. It doesn’t cure the problem, but it takes care of it by making use of DHT-resistant hair follicles.
Do transplanted hairs miniaturize?
Scalp hair miniaturization typically affects the crown, top, and front. Only in those regions the hair follicles are sensitive to dihydrotestosterone.
However, the same does not apply to the hair in the back and sides. That’s because those hair follicles have a genetic resistance to DHT (the reason for this is not known).
Even when these follicles are moved to the bald areas, they remain DHT-resistant. So, transplanted hair doesn’t miniaturize or fall off permanently.
Sometimes, however, miniaturization can extend all the way to the back of the head. It’s more common in women who experience diffuse hair loss and don’t have a stable donor area. If this happens, you won’t be able to have hair transplant surgery.
And you should also keep in mind that there’s no clear demarcation of DHT-resistant follicles on the scalp. There’s a “safe donor area” from where surgeons usually extract hair grafts. Still, there is no way to predict whether the donor hair will stay stable forever and not shrink.
How Is Hair Miniaturization Diagnosed?
A scalp trichoscopy is usually done to see if the hair is actually miniaturizing. It involves the use of a small handheld device that shows the close-up of the follicles on the scalp.
Having a lot of fine vellus hair with follicular groups all spaced out is an indication of miniaturization due to androgenetic alopecia. However, for an accurate diagnosis, the doctor will likely ask about your family history, general health, diet, lifestyle, and any active medication/treatment that you’re on.
Any pattern of hair loss will also be taken into account. Norwood scale is usually used for genetic hair loss.
Other than that, a few tests might be done, such as a hair pull test, blood test, skin culture, or a biopsy.
Once you have a diagnosis, the treatment plan will be prepared accordingly. Keep in mind that hair miniaturization isn’t always permanent. For example, if you have alopecia areata, you might be prescribed corticosteroids for treatment.
Frequently Asked Questions
Hair miniaturization does eventually cause baldness. As the hair follicle shrinks, the hair becomes thinner and the scalp more visible. It is, however, possible to stimulate hair thickness and growth with proper treatment.
Hair thinning can naturally occur due to ageing, and you may have a certain degree of miniaturized hair even normally. However, when it occurs extensively, it could be indicative of alopecia.
Propecia, one of the brand names for finasteride, has been reported as having the ability to reverse hair miniaturization in male pattern baldness. However, you shouldn’t expect a complete reversal.
In some cases, the miniaturization of hair can indeed be temporary. For instance, it’s possible to reverse miniaturized hair in alopecia areata.
Dr Cagla
Dr Cagla earned her medical degree at Trakya University’s Faculty of Medicine in Bulgaria and has almost 6 years of hair transplantation experience. She is a specialist in FUE, DHI and Sapphire hair transplants of the scalp, eyebrows and beard and has performed over 6,000 surgeries. Dr Cagla is multilingual, with fluency in English, Bulgarian and Turkish.
