Biology of Hair and Why it Matters - May Not Always be Growing... and That's Normal.

[Sieda]

Biology of Hair and Why it matters:

I was searching for a greater understanding of the Biology of hair. I wanted to know what phase I was in and how to tell? What determines the length of my hair? What could I do to help the process? This was touched on earlier this year, by another member... with no replies. Thought I'd give it another try.


I stumbled upon this article written by Dermatologist Heather Brannon, MD @ About.com. It somewhat answers the question that I had. I hope you find it useful.

Major points that hit home for me:

1."Straighter hair is shinier because sebum from the sebaceous gland can travel down the hair more easily. The kinkier the hair, the more difficulty the sebum has traveling down the hair, therefore the more dry or dull the hair looks."

2. Different parts of our head can be at different phases at once
a."3% of all hairs are in this phase at any time." - Catagen Phase
b."Telogen is the resting phase and accounts for 10-15% of all hairs" - "Pulling out a hair in this phase will reveal a solid, hard, dry, white material at the root."

3."Unlike other mammals, [HUMAN] hair growth and loss is random and not seasonal or cyclic."

4.Hair grows ABOUT 6 inches a YEAR IF/WHEN you're in the Anagen phase "Some people have difficulty growing their hair beyond a certain length because they have a short active phase of growth."

Source: http://dermatology.about.com/cs/hairanatomy/a/hairbiology_2.htm

Any thoughts?


THaNks for Reading this loooooong post ;D

 

[Sieda]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

So there may be SOME truth to the saying "Dirty hair grows faster". The "grows faster" part may be incorrect, but DIRTY STRAIGHT/straitened hair may seem healthier (and may not be dirty in all cases, but full of natural sebum), "Straighter hair is shinier because sebum from the sebaceous gland can travel down the hair more easily. The kinkier the hair, the more difficulty the sebum has traveling down the hair, therefore the more dry or dull the hair looks."



I know I still have questions...

1. For those who have a short Anagen phase (me maybe :|)... Is retention the ONLY thing that is on your side (If so, LHCF will help me with that!)? Or will you shed out your current hair and start the phase all over?
2. What phase are you in if you are not in the Anagen phase?

 

[msa]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

I didn't read the article, but it seems like it basic hair science. I'm glad you actually sought it out though.

If you're interested in other science based information check out www.dralisyed.com and thenaturalhaven.blogspot.com.

 

[msa]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

I know I still have questions...

1. For those who have a short Anagen phase (me maybe :|)... Is retention the ONLY thing that is on your side (If so, LHCF will help me with that!)? Or will you shed out your current hair and start the phase all over?
2. What phase are you in if you are not in the Anagen phase?

There are three phases the hair follicle goes through...anagen (growth), catogen (the time right after anagen when the hair becomes a club hair), and telogen (resting phase, when hairs are shed). This wiki article explains it pretty simply.

Hair grows in cycles of various phases:[3] anagen is the growth phase; catagen is the involuting or regressing phase; and telogen, the resting or quiescent phase. Each phase has several morphologically and histologically distinguishable sub-phases. Prior to the start of cycling is a phase of follicular morphogenesis (formation of the follicle). There is also a shedding phase, or exogen, that is independent of anagen and telogen in which one of several hairs that might arise from a single follicle exits. Normally up to 90% of the hair follicles are in anagen phase while, 10–14% are in telogen and 1–2% in catagen. The cycle's length varies on different parts of the body. For eyebrows, the cycle is completed in around 4 months, while it takes the scalp 3–4 years to finish; this is the reason eyebrow hairs have a much shorter length limit compared to hairs on the head. Growth cycles are controlled by a chemical signal like epidermal growth factor.
[edit] Anagen phase

Anagen is the active growth phase of hair follicles.[4] The cells in the root of the hair are dividing rapidly, adding to the hair shaft. During this phase the hair grows about 1 cm every 28 days. Scalp hair stays in this active phase of growth for 2-7 years. The amount of time the hair follicle stays in the anagen phase is genetically determined. At the end of the anagen phase an unknown signal causes the follicle to go into the catagen phase.
[edit] Catagen phase

The catagen phase is a short transition stage that occurs at the end of the anagen phase.[5] It signals the end of the active growth of a hair. This phase lasts for about 2–3 weeks while a club hair is formed.
[edit] Telogen phase

The telogen phase is the resting phase of the hair follicle.[6] The club hair is the final product of a hair follicle in the telogen stage, and is a dead, fully keratinized hair.[2] Fifty to one-hundred club hairs are shed daily from a normal scalp.[2]
[edit] Hair growth cycle times

• Scalp: The time these phases last varies from person to person. Different hair colour and follicle shape affects the timings of these phases.
  • anagen phase, 2–3 years (occasionally much longer)
  • catagen phase, 2–3 weeks
  • telogen phase, around 3 months

• Eyebrows etc:
  • anagen phase, 4–7 months
  • catagen phase, 3–4 weeks
  • telogen phase, about 9 months

And whether you have a short or long anagen phase, retention is the key. It doesn't matter if your growth phase is 10 years long if you abuse your hair the whole time. The hair follicle will always cycle through the phases, so your job is just to treat your hair as good as possible for the time it's on your head. If you focus on retention, then before it sheds you'll see longer lengths.

 

[JenBenCal]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

Thanks for posting that information! I have yet to delve into the science surrounding hair growth, but I think this is a good place for me to start.

 

[vkb247]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

I have always read that straight hair strands are round and shine because they reflect light. Curly hair strands are oval, flat, or even kidney shaped and refract light and naturally have sheen instead of shine.

 

[Sieda]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

I have always read that straight hair strands are round and shine because they reflect light. Curly hair strands are oval, flat, or even kidney shaped and refract light and naturally have sheen instead of shine.

Wondering if I should keep my hair straight for a while...

 

[vkb247]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

Wondering if I should keep my hair straight for a while...

Even if you straighten it you can't change the shape of your strands. I do think it is much easier to make straight hair shiny though.

 

[bbdgirl]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

this is really interesting stuff; i will definitely be reading more up on this. All I know is retention is why I am hear always trying to learn ways to boost my retention levels. I don't know if it is possible to affect or lengthen the anagen phase but I have seen my efforts at protecting my ends being rewarded.

 

[ladytee2]

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

I dont think straightening my hair once a week would help the hair look shinier. Even when I was at the salon every other week faithfully my hair was dull and dry. My scalp has always flaked. I wonder if I have any sedum.

 

[Janet']

Re: Biology of Hair and Why it Matters - May Not Always be Growing... and That's Norm

Interesting...