Hair Series - Hair Loss

Ainsley Highland

Why is hair loss distinct from a lack of hair growth?

A lack of visible hair growth occurs when your hair follicles continue to follow the normal hair growth cycle, but the growth is then offset by some other factor. Hair loss occurs when the hair growth cycle itself is disrupted, and comes in two forms.

In temporary hair loss, something pushes all or some hair out of the anagen, or growth, phase, and into the telogen, or shedding, phase. Hairs are cut off from nutrients, “killing” the hair, which then subsequently falls out. Once whatever caused hair follicles to shift to the telogen phase is removed, the hair growth cycle resets and normal growth recommences with no lasting damage. These types of hair loss are usually known medically as a type of “effluvium” (or outflow), such as telogen effluvium or anagen effluviem.

In permanent hair loss, the hair follicle itself is damaged, and either slowly or quickly loses the ability to grow new hair, period. Temporary hair loss can become permanent if the catalyst is not removed, and whatever interrupted the follicle slowly destroys it. Or, some problem can directly and permanently destroy the hair follicle. These types of hair loss are classed as “alopecia.”

What can cause temporary hair loss?

Temporary hair loss events are actually extremely common, and usually revolve around some sudden shock to the system.

Stressful events, traumatic events, or actual literal medical shock, can all cause this type of temporary shedding. Similarly, forms of physical stress, such as weight loss exceeding 10lbs, severe illness, or surgery as well as emotional stress can cause hair fall events.

Another extremely common form of temporary hair loss in women results from sudden dramatic hormonal changes such as starting, stopping or changing hormonal birth control, pregnancy and childbirth. One of the reasons hair loss around childbirth is so common is that it is both incredibly physically stressful, emotionally stressful (especially if there are complications) and involves extreme hormone changes.

Changes in some medications, such as antidepressants, retinoids (in some acne medications), antibiotics and antifungals, anti-clotting drugs, cholesterol lowering drugs and immunosuppressants, as well as birth control can all cause hair loss. In some cases, hair will regrow once the body gets accustomed to the new normal, in other cases, hair will not regrow until the medication has been stopped, and fully left the body, which can take weeks or months.

Types of temporary hair loss that can become permanent involve more severe disruptions: some illnesses, such as thyroid disorders, scalp infections, high blood pressure, arthritis or high blood pressure, among others, and extreme medical interventions such as radiation therapy or chemotherapy. In many cases, hair regrows after the disease is treated, or in the months following radiation/chemotherapy. However, if the disorder is not diagnosed and successfully treated for a long time your scalp can become permanently damaged.

Permanent hair loss, the white whale of hair care

Permanent’ hair loss includes all other types of hair loss where the growth cycle is damaged. Unfortunately, this type of hair loss is the most extreme, the least understood, and the least treatable. The most common forms are alopecia areata, male pattern hair loss, and female pattern hair loss, and each are believed to have a genetic component making them more or less likely.

Alopecia areata is believed to be autoimmune, occurring when the immune system stops recognizing hair follicles as native to the body (called “immune privilege). This may occur in spots - in which case it is known as spot baldness - or it can affect the entire head or entire body.

In a minority of cases, hair regrows and the condition does not recur. In the remainder, hair follicles are gradually destroyed by the immune system, making hair loss permanent. There is no known cure, and treatments are of limited success.

Male pattern hair loss

MPHL is believed to be partly genetic, and partly due to male sex hormones. It cannot be cured, but, if treated early enough, can be slowed. Women with hormonal conditions such as PCOS that result in an overabundance of male hormones can also suffer from MPHL.

There are two approved treatments for MPHL. The drug finasteride can improve hair growth for androgen-dependent types of MPHL and is approved in parts of Asia, but not the US. Counterintuitively, in women with hormonal imbalances, finasteride lessens excess hair growth (hirsutism), rather than improving hair loss.

Minoxidil - known in the US by the brand name Rogaine - is approved for androgen-independent MPHL. Interestingly, minoxidil’s medical effect is to dilate small blood vessels, but it remains unclear how or why this causes hair to grow.

Both minoxidil and finasteride lose effectiveness as hair loss progresses, meaning that they are both ineffective if begun after significant hair loss has occurred, and that they cannot wholly stop hair loss. Additionally, if treatment is stopped or interrupted for a length of time, regrown hair will promptly fall out again.

Female pattern hair loss

FPHL is the least understood form of hair loss, with no known cause and the least number of treatment options. Finasteride has no effect on FPHL, and minoxidil can work if begun early, changes in dosage have no appreciable impact on effectiveness. As such, the only medically approved treatment for FPHL is 2% minoxidil.

Up next time: what all this means for resolving hair problems…

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Hair Growth Series Pt 1

Ainsley Highland

In last week's blog post, we mentioned that ginseng may be able to prevent hair loss and promote hair growth. Since there are many, many myths out there about hair growth, and even more ineffective products to go with them, we thought it would be a good idea to follow up on the mention with a deep dive into facts how hair grows, why it falls out, and what is actually possible in the hunt for longer, thicker hair.

Several single spaced pages into the project, we decided there was far more really important information to be said on the topic than could fit comfortably into one blog post. So, we’re breaking it down into a semi-regular ongoing series where we’ll tackle a different aspect in each installment. So without further ado, the basics:

Get your science hat, we’re exploring the hair growth cycle.

In order to understand problems with hair growth/loss, it is important to understand what is happening when hair grows. This is doubly true because hair growth is complicated. For one thing, it really does occur in a cycle, consisting of three stages:

Anagen phase, when growth occurs
Healthy hair remains in the anagen phase 3-5 years on average, and at any given time 85%-90% of the hairs on a healthy human’s head are in the anagen phase. In this phase, hair grows at 1cm - or ~0.5in - per month. The length of the anagen phase is primarily controlled by genetics, but can be shortened by chemicals, disease or stress.

Catagen phase, when hair rests
When hair has ‘finished’ growing, the hair follicle needs to rest, renew, and prepare for the stress of growing the next hair. This resting period lasts approximately 2 weeks. During this time, the hair is detached from the papilla - the structure that actually grows the hair - which cuts it off from any additional nutrients that would be necessary for further growth.

Telogen phase, when all the shedding happens
The entire hair follicle shrinks in its resting phase, pulling back from the detached hair. This removes the last anchor keeping hair in place, and the hair sheds. For healthy hair, the telogen phase lasts 1-4 months, and the cycle starts over with the emergence of a new hair within 2 weeks of the old hair being shed.

What this means for claims about hair growth products

The reason we spilled so much ink on the science behind hair growth is that it should immediately dispel some pretty common misconceptions - and false claims - about growing longer, thicker hair.

The rate of hair growth is constant, you can’t actually speed it up.

Hair appears to grow faster when it is short because that half inch of growth is a greater percentage increase than on long hair.
Hair appears to grow slower if you have a lot of breakage because the shortening of your hair through breakage is offsetting some percentage of new growth.

At minimum, a half inch of growth a month for the minimum 3 years of growth in the anagen phase means the minimum possible growth for a healthy individual is 18,” or a foot and a half of hair. Straightened, this would reach the bottom of the shoulder blade on most women.*

If you want longer and/or thicker hair, the rate of hair growth isn’t what you need to improve anyways.

There are two ways to get longer hair, up to your genetic limit: eliminate underlying health problems that may be shortening your anagen phase or reduce breakage.
Thicker hair is slightly more complicated, because it could be the result of breakage, or it could be the result of alopecia (hair loss) - which we will get to next. Either way, growing hair faster won’t resolve the problem of sudden induced hair fall, failure of the hair follicle to enter a new anagen phase, or breakage.

Up next time: the science behind hair loss...

*If you are extra clever and mathematically inclined, you may have noticed that the hair growth ‘limit’ for the average person is 6”x 5years or 30”/2.5’. This would be about butt length for the average height woman. For people of Asian descent, the average anagen phase tends to be longer, with an average limit up to 7 years or 42”/3’. This means that any long hair models you see with thigh, knee or floor-length hair truly are the exception. Their hair length isn’t the result a secret formula or rigorous hair care routine, but genuine genetic exceptionalism, like extremely tall people or extremely short people.

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