**This post is mostly for nerds like us, who want to understand the biology behind hair growth, hair loss and hair follicle in general. When we did the SEO search for popularity of the proposed title ‘The Death of a Hair Follicle” – our tool gave back no results. However one cannot call themselves a hair expert if they don’t know whether hair follicle dies and even if it dies, what happens next and whether it can be revived.**
In order to destroy a hair follicle, the bulb or the root of the hair follicle where the blood supplies the hair with oxygen to grow needs to be destroyed, as well as the stem cells which are responsible for hair follicle regeneration need to be absent too. Unless you have had a deep wound or follicles have died during the balding process – it is rather difficult to actually kill off the hair follicle since it is a complex organ which, before dying from “natural causes” – such as hair thinning to balding process – goes through cycles and does not happen overnight.
Role of hair cycle
In animals and evolutionarily speaking, the hair growth cycle is needed to renew the protective covering of body hair, while also enabling the seasonal change in coat quality and colour. The length of the phases of the cycle determines the length of the hair and its replacement rate (think of hair moulting/shedding).
In humans, such cycle determines the characteristics of hair across different body areas and also helps to explain what happens in hair loss. The cyclical nature of hair growth has a distinct purpose, however, biologists and technologists are very keen to understand the transitions between the phases of the cycle in order to manipulate hair growth. Much of this area is still unknown however much advancement has been made
Instead of diving to the stages of anagen (growth), catagen (detachment) and telogen (falling out) – stages of hair growth, we’re looking at the larger cycles that span the entire lifetime of a hair follicle, rather than hair itself. These stages are (1) lanugo (2) vellus and (3) terminal.
What is lanugo hair?
When we are born, some of us retain lanugo hair – a downy-like hair usually found on the body of a fetus or newborn baby. It is the first hair to be produced by the fetal hair follicles, and it usually appears on the fetus at about 5 months of gestation. Lanugo is very fine, soft, and usually unpigmented. It is normally shed before birth, around seven or eight months of gestation, but is sometimes present at birth. It disappears on its own within a few weeks.
What is vellus hair?
Lanugo is replaced by hair covering the same surfaces, which is called vellus hair. This hair is thinner and more difficult to see. This is commonly the “peach fuzz” or just hair on the rest of human body, other than head, eyelashes and eyebrows during childhood.
What is terminal hair?
Some vellus hair changes as we transition into adulthood is called “terminal” hair which forms in specific areas and is hormone-dependent. Such conversion is commonly present in armpit, pubic, chest areas in both genders which react to hormonal changes in human body – whether due to puberty or menopause – or hormonal medication, such as birth control pill. Terminal hair has a medulla – a central “spine” of the hair, which is typically non-existent in finer, vellus hair. The medulla is a portion of the hair’s core that strengthens it, allowing it to grow longer.
Hair follicle miniaturisation
During hair thinning or balding process which could happen due to a variety of reasons – terminal hair progresses back into vellus hair during hair follicle miniaturisation stage, before completely dying. However for the hair follicle to die completely it takes a long time and some research around stem cells in the hair growing areas point to the fact that even after hair follicle does effectively die (i.e. it does not produce any type of hair, including vellus) – some stem cells can create new hair follicles.
For now, it is important to remember, that just because there is no visible hair – it does not mean that hair follicle is dead. Oftentimes even on bald-as-a-knee heads, there is some peach fuzz that points to the fact that the follicles aren’t dead, they are just in a different stage however, going through hair follicle minitiarrisation stage as a vellus hair.
At this stage it is crucial to know that once hair follicle is entering the hair miniaturisation stage, blood flow reduces. Although it is often not the lack of blood flow that leads to baldness, especially in males, but rather it is the result of it – the lack of appropriate blood flow worsens and speeds up the hair loss, since the root no longer receives oxygen and other nutrients normally delivered by blood vessels connected to hair via a nipple-like extension, known as derma papilla.
Stem cells and hair follicle formation
Aside from the differentiation between vellus hair and terminal hair, there is a number of stem cells present in scalp. Those stem cells need to transition to “progenitor” stage before leading to hair growth. You can think about progenitor cells not entirely devoid of purpose, like stem cells, but rather those which already leaning towards a target cell. Interestingly, in balding men, scientists observed the same amount of stem cells in the balding areas as in the non-balding areas, though in the non-balding areas there was a greater number of activated progenitor cells.
Patterns of baldness
In androgenic alopecia – which is commonly the reason behind male pattern baldness, though not only limited to men, there are specific areas that tend to exhibit thinning of the hair first: specifically frontal and vertex (crown) areas. These are the areas with most androgen-receptors – therefore those that react the most to dehydrotestosterone or “DHT” attacking them, ultimately leading to hair follicle miniaturisation and visible baldness. As such, many treatments for baldness attempt to convert vellus hair back to terminal hair by preventing DHT from attacking the hair root. Because it is much easier to reverse the hair thinning, while hair follicle produces at least some type of hair, any hair loss treatments are better applied in the early stages when hair thinning is first noticed.
While this is a commonly researched topic amongst balding men, there are plenty of instances of androgenic female pattern hair loss, especially linked to menopause, due to changes in hormonal balance and increase in production of androgens. The process of hair follicle going back to vellus hair before completely dying applies to all genders.
Act early, if you can
The good news is that if you have ANY hair – even if it just looks like fluff – it means that your hair follicles are alive and kicking. They might need support – through the right nutrients, hormone regulation and stimulated blood flow – but there is absolutely something you can do about it. While balanced, nutrient-rich diet, right supplements and exercise are paramount in achieving hair growth – stimulation of blood flow in scalp is easily overlooked, since it is not as easy as popping pills and spraying some minoxidil on your hair roots. However blood flow stimulation of scalp has been proven to lead to improved hair growth and reduction of hair loss. Some techniques include, scalp massages, derma-rolling or micro needling and alternatively, you can try out The Hair Fuel – our signature hair growth mask that not only stimulates the hair follicles, but also delivers its own nutrients directly on your scalp.
Bottom line is hair thinning and hair loss treatments are most efficient in the early stages of hair loss – when you just start noticing hair thinning and some smaller, often transparent vellus hair taking its place. It is much harder to revive a dead hair follicle and stimulate formation of progenitor cells – than the one which is still operating.
Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells, https://www.jci.org/articles/view/44478
The biology of hair diversity, https://onlinelibrary.wiley.com/doi/full/10.1111/ics.12041
Multivariate analysis of prognostic factors in patients with rapidly progressive alopecia areata, https://www.sciencedirect.com/science/article/pii/S0190962212006305
Subcutaneous blood flow in early male pattern baldness, https://www.ncbi.nlm.nih.gov/pubmed/2715645