How often do you wash your hair?

[michael barry]

I read an interesting article concerning sodium nitrite and how the body uses it to make nitric oxide when needed a while back. Scientists determined that nitrite, which used to be thought of as useless for over one hundred years by science, was found to be not just beneficial, but crucial in health (the body converts the nitrite to nitric oxide which dialate blood vessels and helps repair certain tissues apparently----docs in the experiment injected nitrite into rats who had arteries severed and they healed much faster and suffered a great deal less damage to the heart than controls).

It may be possible that sebaceous glands may have a purpose in human beings, but its not fully understood and recognized yet. I wouldnt write them off too quickly. Is anyone born without them completely? Do they have skin or hair problems?

 

[ronaldkia]

do you wash your hair at night? morning??

 

[Bryan]

So answer this very simple question: does sebum IN FACT get "injected" into human hair shafts??

Yes, the philosebaceous design indicates that Bryan.

LOL! Stephen, I really don't care what you think the pilosebaceous design supposedly "indicates". Let's stick with the known FACTS! :wink: I don't know of any evidence that sebum gets "injected" into hair (and can't you think of a less-goofy word than "injected"?)

What is more, the big difference in Klingmans sebum absorbtion tests and the real situation is this.

Klingman used `old' hair, that is fully `shrunken' . In the in-vivo follicle however, newly forming hair is exposed to the sebum `injection'. the gaps between the hair cells are more open at this time, and it is likely in my opinion that the sebum can penetrate between the layers and upwards.

"Old" hair? "Fully shrunken" hair? "Sebum injection"? You're going a little off the deep-end. I suppose it's possible that a molecule or two of lipid might find its way into a hair shaft as the hair passes through its sebum-laden duct, but the Big Picture I'm trying to get across to you is that any larger, more obvious, MACROSCOPIC amount of sebum that you see or feel on your hair got there by the kind of physical transfer that Kligman talked about (combing your hair, scratching or touching your head, sleeping on a pillow, etc.).

BTW, it's "Kligman", not "Klingman".

Bryan

 

[powersam]

so if i just sat there and didnt move and didnt scratch my head etc, my hair wouldnt get oily?

 

[The Gardener]

My dermitologist validates what Bryan says. He says that sebum might be cosmetically beneficial to the skin, but has no impact on the underlying cell structures whatsoever.

For example, the face. Facial skin is covered with a lining of dead cells. Lipids help keep these cells 'plumped up', which makes them look smooth. However, sebum also contains excreted toxins, and dirt, and can clog pores. He says that these "non-soap" facial cleansers are baloney. You really need to clean the sebum OFF of your skin, and a little exfoliation of the dead stuff is beneficial as well. He suggests washing with a good ph-balanced soap and water, the intent being of completely removing the sebum from the skin. If you can do it twice a day, all the better, the sebum is NO GOOD for you, and removing it does no harm to skin condition.

Now, after washing the dirty shiit off, it is your choice whether or not you want to apply a moisturizer. Moisturizers add the lipids back to the dead cell layer, 'puffing up' the dead cells again, and potentially making your skin look more smooth. But, don't confuse this cosmetic effect with any real improvement in the skin itself, all you are doing is 'rounding off the rough edges' of cells that are already dead, in effect 'reducing the appearance of wrinkles' as the many adverts claim, but really not helping the skin itself at ALL.

The only thing he DOES recommend is a sunscreen, every day. The sun, and age, is what makes our skin degrade.

Sebum is an excretion, and often times is filled with toxins similar to the ones excreted in urine. It is full of stuff your body wants to get rid of, and not let sit on your skin for another day.

 

[Bryan]

so if i just sat there and didnt move and didnt scratch my head etc, my hair wouldnt get oily?

That's what Kligman says. If you scrupulously avoided touching your hair in any way, it wouldn't get oily. He says that hair seems to have an actual sort of aversion to oil.

Bryan

 

[S Foote.]

So answer this very simple question: does sebum IN FACT get "injected" into human hair shafts??

Yes, the philosebaceous design indicates that Bryan.

LOL! Stephen, I really don't care what you think the pilosebaceous design supposedly "indicates". Let's stick with the known FACTS! :wink: I don't know of any evidence that sebum gets "injected" into hair (and can't you think of a less-goofy word than "injected"?)

But you `SHOULD' care about the evolved design of the structures we are interested in Bryan. Thats what scientists consider when evaluating if an in-vitro experiment, is `truly' reflective of the in-vivo situation.

I didn't think i would have to point out this very basic of scientific principles to you :roll:

Such consideration of the `design function' of hair follicles, has been sadly lacking in my opinion historicaly, and that is why we are now in the `dead end' the theory you support has lead us.

What is more, the big difference in Klingmans sebum absorbtion tests and the real situation is this.

Klingman used `old' hair, that is fully `shrunken' . In the in-vivo follicle however, newly forming hair is exposed to the sebum `injection'. the gaps between the hair cells are more open at this time, and it is likely in my opinion that the sebum can penetrate between the layers and upwards.

"Old" hair? "Fully shrunken" hair? "Sebum injection"? You're going a little off the deep-end. I suppose it's possible that a molecule or two of lipid might find its way into a hair shaft as the hair passes through its sebum-laden duct, but the Big Picture I'm trying to get across to you is that any larger, more obvious, MACROSCOPIC amount of sebum that you see or feel on your hair got there by the kind of physical transfer that Kligman talked about (combing your hair, scratching or touching your head, sleeping on a pillow, etc.).

BTW, it's "Kligman", not "Klingman".

Bryan

If you want to go along with an in-vitro study, that `cannot' possibly replicate the known in-vivo situation, just because you want to believe it, go ahead. I am not arguing that there is some sebum pickup by the hair as `Kligman' describes, but that is far from the whole story given the follicle design. :wink:

However `both' senarios of how sebum gets on, or into the hair shaft, are not what this topic is about. I think the vunerability of the balding scalp to sebum lies in the secondary inflammation that could happen for various reasons.

S Foote.

 

[Armando Jose]

Hi friends;


This study (*) is real but not in humans.
The migration of sebum and suint components along wool fibres of Merino sheep

JB Hay and SC Mills

Abstract
It has been shown that isotopically labelled sheep wool wax is carried passively along the wool fibre as a band by growth of the wool, and that it does not flow along the fibre to any large extent during experiments of several months. This supports the view that the function of sebum, in mammals in general, is to protect the hair (wool) fibre and the condition of the coat, and contrasts with the reported rapid spread of sebum over the human skin surface. It also seems unlikely that wax lost from the fleece during exposure to rainfall is replenished with sebum freshly secreted onto the surface, since sebum does not migrate. Two methods were used to obtain labelled wax, direct application of labelled cholesterol to the skin surface and intradermal injection of labelled sebum substrate. Prior washing of the wool with detergent showed that wax already on the fibre was not the cause of the observed lack of flow of newly formed wax. Isotopically labelled suint components were also carried passively by wool growth. It is unlikely that wax is transported to any extent by suint in the wool; this is in contrast to the suggested role of sweat in facilitating the spread of sebum over the human skin surface. Some spreading of radioactive wax and suint bands was noted however, possibly because of diffusion and mechanical disturbance of the wool.

Australian Journal of Agricultural Research 33(5) 817 - 825

This discussion is very interesting and I would post my opinion but my english is not very good and I need the help of my friend to translate it.

Regards
Armando

(*) http://www.publish.csiro.au/paper/AR9820817.htm

 

[Bryan]

LOL! Stephen, I really don't care what you think the pilosebaceous design supposedly "indicates".

But you `SHOULD' care about the evolved design of the structures we are interested in Bryan. Thats what scientists consider when evaluating if an in-vitro experiment, is `truly' reflective of the in-vivo situation.

Go back and re-read that sentence I wrote above. I definitely care about evolved design structures, but not YOUR particular eccentric theory! :wink:

If you want to go along with an in-vitro study, that `cannot' possibly replicate the known in-vivo situation, just because you want to believe it, go ahead. I am not arguing that there is some sebum pickup by the hair as `Kligman' describes, but that is far from the whole story given the follicle design. :wink:

<shrug>

If you want to insist on believing (for some odd reason that suits your eccentric purposes) that sebum gets "injected" into human hairs despite a lack of physical evidence for that, be my guest. All I know is that Kligman and his colleagues bent over backwards in an effort to get sebum to "track" or be absorbed or be "wicked-up" along the length of human hairs, and they were utterly incapable of forcing it to do that. That just ain't the function of sebum.

Case closed.

Bryan

 

[S Foote.]

LOL! Stephen, I really don't care what you think the pilosebaceous design supposedly "indicates".

But you `SHOULD' care about the evolved design of the structures we are interested in Bryan. Thats what scientists consider when evaluating if an in-vitro experiment, is `truly' reflective of the in-vivo situation.

Go back and re-read that sentence I wrote above. I definitely care about evolved design structures, but not YOUR particular eccentric theory! :wink:

It's just basic common sense Bryan, for all to see for themselves given the `hardware'. It's funny that anything against your own opinion's somehow has to be `eccentric' :roll:

If you want to go along with an in-vitro study, that `cannot' possibly replicate the known in-vivo situation, just because you want to believe it, go ahead. I am not arguing that there is some sebum pickup by the hair as `Kligman' describes, but that is far from the whole story given the follicle design. :wink:

<shrug>

If you want to insist on believing (for some odd reason that suits your eccentric purposes) that sebum gets "injected" into human hairs despite a lack of physical evidence for that, be my guest. All I know is that Kligman and his colleagues bent over backwards in an effort to get sebum to "track" or be absorbed or be "wicked-up" along the length of human hairs, and they were utterly incapable of forcing it to do that. That just ain't the function of sebum.

Case closed.

Bryan

So let's be `VERY' clear about this Bryan :wink:

Are you trying to tell people here that Kligmans testing, is truly representitive of what happens in the follicle itself? Because if that's what you `genuinely' think, you made the right choice in not persuing a career in professional science. :wink:

I have no personal interest one way or the other about how sebum coats the hair, and it is not relevant to my theory anyway.

What i am interested in trying to get across to people, is `PROPER' science, and that in-vivo context is vital in the proper interpretation of `ANY' in-vitro experiment like Kligman's.

Kligman proved `nothing' about the in-vivo situation regarding sebum, simple. :roll:

I could just as well argue that in the `in-vitro' context of my back yard, i have `PROVEN' with a spirit level that the earth is flat!!

S Foote.

 

[michael barry]

Kevin McElwee, moderator of Keratin.com believes that either very cold or very hot water will make sebum secretion increase according to Tom Hagerty. Dont know if Kev posted this on his site or if Tom got it from Kev via a personal email.

Havent checked Keratin.com in quite a while, it seems like McElwee hardly ever updates it anymore. (reminding myself to take a peek at it again). Hope McElwee is having luck in his cloning experiments............................. :lol:

 

[S Foote.]

Here is interesting study, that indirectly clearly proves an `internal injection' of sebum into the hair shaft within the follicle, as i have proposed here.

http://www.clinchem.org/cgi/content/full/47/12/2114

This study was intended to measure the content of fatty acid ethyl esters, (FAEE'S) in the hair shaft, to provide information about previous alcohol use.

For the purposes of this discussion, the important conclusion of this study is that FAEE'S are deposited `INTO' the hair shaft by sebum! Quote:

"It follows from the results that the FAEEs are deposited mainly from sebum into hair. This deposition route can best explain the presence of high FAEE concentrations in hair segments that grew during periods of abstinence (e.g., see Fig. 2 ) and the lack of agreement between drinking history and segmental concentrations generally found in these investigations. "

In order for the `banding' of FAEE'S within the hair shaft to match the drinking/abstinence reported, the sebum `MUST' be `injected into the hair shaft, and `NOT' just picked up by `rubbing' as Kligman's flawed study suggested :wink:

S Foote.

 

[Bryan]

For the purposes of this discussion, the important conclusion of this study is that FAEE'S are deposited `INTO' the hair shaft by sebum! Quote:

"It follows from the results that the FAEEs are deposited mainly from sebum into hair. This deposition route can best explain the presence of high FAEE concentrations in hair segments that grew during periods of abstinence (e.g., see Fig. 2 ) and the lack of agreement between drinking history and segmental concentrations generally found in these investigations. "

In order for the `banding' of FAEE'S within the hair shaft to match the drinking/abstinence reported, the sebum `MUST' be `injected into the hair shaft, and `NOT' just picked up by `rubbing' as Kligman's flawed study suggested :wink:

You seem to be totally confused! The researchers told you in plain English the the 'banding' of the FAEE's did NOT match the drinking/abstinence reported!! And THAT is what suggests that FAEE's come from sebum. Moreover, it further implies that it was from sebum picked-up from rubbing over a period of time, rather than being "injected" (as you so colorfully describe it) at one specific point in time (as the hair is being bathed in sebum in the pilary canal).

I'm amazed that you didn't even understand the fundamental point they were making.

Bryan

 

[S Foote.]

For the purposes of this discussion, the important conclusion of this study is that FAEE'S are deposited `INTO' the hair shaft by sebum! Quote:

"It follows from the results that the FAEEs are deposited mainly from sebum into hair. This deposition route can best explain the presence of high FAEE concentrations in hair segments that grew during periods of abstinence (e.g., see Fig. 2 ) and the lack of agreement between drinking history and segmental concentrations generally found in these investigations. "

In order for the `banding' of FAEE'S within the hair shaft to match the drinking/abstinence reported, the sebum `MUST' be `injected into the hair shaft, and `NOT' just picked up by `rubbing' as Kligman's flawed study suggested :wink:

You seem to be totally confused! The researchers told you in plain English the the 'banding' of the FAEE's did NOT match the drinking/abstinence reported!! And THAT is what suggests that FAEE's come from sebum. Moreover, it further implies that it was from sebum picked-up from rubbing over a period of time, rather than being "injected" (as you so colorfully describe it) at one specific point in time (as the hair is being bathed in sebum in the pilary canal).

I'm amazed that you didn't even understand the fundamental point they were making.

Bryan

Just read it properly Bryan for God's sake!

It is the mismatch in the banding, that given the time delay of sebum processing, `THEN' reflection in the hair shaft, that `proves' the disposition route!!!

The author is very clear, even if the article confuses you :wink:

This section should at least give you a clue, quote:

"The cell transition time, i.e., the time between the germinative cell division and cell disintegration, has been determined as 9–25 days (16)(17). The average time between synthesis of sebum and its excretion was estimated at 8 days, leading to an overall transit time from germinative cell division to sebum of 13–14 days."

But what really screws your idea that sebum is `just' deposited `on' the hair shaft by `rubbing', is the simple proven existence of `ANY' banding effect at all!!

If substances in the body are transfered to the hair shaft by sebum by mechanical rubbing as you claim, there will be no banding concentrations in the hair shaft `WHATSOEVER'! The substance, whatever it is will be `EQUALLY' distributed over the entire hair shaft. :roll:

Give it up Bryan, before you just make a fool of yourself. :wink:

S Foote.

 

[Dave001]

[quote="S Foote.":dc1cf]For the purposes of this discussion, the important conclusion of this study is that FAEE'S are deposited `INTO' the hair shaft by sebum! Quote:

"It follows from the results that the FAEEs are deposited mainly from sebum into hair. This deposition route can best explain the presence of high FAEE concentrations in hair segments that grew during periods of abstinence (e.g., see Fig. 2 ) and the lack of agreement between drinking history and segmental concentrations generally found in these investigations. "

In order for the `banding' of FAEE'S within the hair shaft to match the drinking/abstinence reported, the sebum `MUST' be `injected into the hair shaft, and `NOT' just picked up by `rubbing' as Kligman's flawed study suggested :wink:

You seem to be totally confused! The researchers told you in plain English the the 'banding' of the FAEE's did NOT match the drinking/abstinence reported!! And THAT is what suggests that FAEE's come from sebum. Moreover, it further implies that it was from sebum picked-up from rubbing over a period of time, rather than being "injected" (as you so colorfully describe it) at one specific point in time (as the hair is being bathed in sebum in the pilary canal).

I'm amazed that you didn't even understand the fundamental point they were making.

Bryan

Just read it properly Bryan for God's sake!

It is the mismatch in the banding, that given the time delay of sebum processing, `THEN' reflection in the hair shaft, that `proves' the disposition route!!!

The author is very clear, even if the article confuses you :wink:

This section should at least give you a clue, quote:

"The cell transition time, i.e., the time between the germinative cell division and cell disintegration, has been determined as 9–25 days (16)(17). The average time between synthesis of sebum and its excretion was estimated at 8 days, leading to an overall transit time from germinative cell division to sebum of 13–14 days."

But what really screws your idea that sebum is `just' deposited `on' the hair shaft by `rubbing', is the simple proven existence of `ANY' banding effect at all!!

If substances in the body are transfered to the hair shaft by sebum by mechanical rubbing as you claim, there will be no banding concentrations in the hair shaft `WHATSOEVER'! The substance, whatever it is will be `EQUALLY' distributed over the entire hair shaft. :roll:

Give it up Bryan, before you just make a fool of yourself. :wink:
[/quote:dc1cf]

For the record, I'm not making any claims about the propensity of sebum for the hair shaft or its method of distribution. It's simply not at the top of my list of concerns.

I did not read the entire article that you posted, but from a quick skim it would seem that the authors had speculated that the sebum would be distributed onto the hair surface, rather than into the hair shaft (which is somewhat difficult to envision) as you propose:

Because of their lipophilic character, the FAEEs could be excreted by the sebaceous glands and be distributed from there onto the hair surface. For this reason, FAEEs from the hair surface [external FAEEs (e-FAEEs)] and FAEEs deposited in the hair matrix [internal FAEEs (i-FAEEs)] were analyzed separately for all hair segments. From the results, information about the mechanism of the incorporation of FAEEs into the hair matrix could be obtained.

Further:

There are three possible main routes for the incorporation of FAEEs into hair: (a) incorporation of the esters from systemic blood circulation or surrounding tissues into the cells of the hair root; (b) diffusion of ethanol into the cells of the hair roots and synthesis and incorporation of the esters there; and (c) synthesis from ethanol in the sebaceous glands, excretion with sebum in the upper region of the hair root, distribution on the hair surface with sebum, and diffusion into the hair matrix. The synthesis of FAEEs from ethanol via routes b or c is probable because, according to the results of Laposata (13)(14), almost all human tissues contain FAEE synthase activity.

[...]

The increase in FAEE concentrations from proximal to distal found in most cases could be explained by the sebum deposition route. The hair is continuously bathed by sebum, and this leads to an accumulation of the concentrations with increasing age, i.e., distance of the hair from the skin. Furthermore, long hair is usually shampooed more intensively near the skin. This may decrease the deposition rate from sebum in the proximal segments. Another reason for higher distal FAEE concentrations could be that aging hair allows better diffusion of the external lipids into the hair matrix

 

[ShedMaster]

I amazed this thread went from "how many times do you wash your hair? to this!

 

[michael barry]

In plain english are you guys arguing whether sebum is secreted onto the hair shaft about eight days before that part of the shaft grows enough to break the skin and be secreted on the skin surface?

vs.
Sebum being injecte inside the hair follicle under the outer root sheath layers and getting spread onto the skin surface when it emerges? That seems kinda far-fetched to me. But hell, lots of things about the philosebaceous unit seems far-fetched to me also.

 

[S Foote.]

As i have said, the route's of sebum distribution to both hair shaft and skin is of no particular interest to me, and i don't think there is much relevence to the male pattern baldness situation.

I only post this study to highlight Bryans `cherry picking' of `certain' studies, just to try to convince people of his personal opinion.

This is not a scientific atitude on Bryans part, and people should be aware of information that Bryan just ignores if it doesn't fit his opinion. In this thread, Bryan has claimed that sebum `ONLY' gets on the hair shaft by rubbing.

The author of this study concludes Quote:

"It follows from the results that the FAEEs are deposited mainly from sebum into hair"

Note `INTO' hair!

For this deposition to produce the `banding' reported, it `has' to happen within the follicle.

Banding of sebum transfered substances in the hair shaft, just cannot happen by the rubbing process Bryan `insists' is happening!

S Foote.

 

[S Foote.]

In plain english are you guys arguing whether sebum is secreted onto the hair shaft about eight days before that part of the shaft grows enough to break the skin and be secreted on the skin surface?

vs.
Sebum being injecte inside the hair follicle under the outer root sheath layers and getting spread onto the skin surface when it emerges? That seems kinda far-fetched to me. But hell, lots of things about the philosebaceous unit seems far-fetched to me also.

I dont think the hair is transfering sebum to the skin. Sebum is also just coming out of the follicle on to the skin.

As far as the hair shaft is concerned, the author of that study makes an important comment quote:

"A sebaceous gland exits into the pilary canal of each hair follicle, and the hair is already bathed in sebum before it reaches the skin surface."

The hair shaft is actually being produced in a `bath' of sebum. It stands to reason that it is at this time that sebum can easily get `INTO' the outer layers of the hair shaft. I think it is at this early hair growth point that the sebum and any substance in it are `injected' into the hair shaft.

I think it is clear from the banding effect shown in that study, that at least some sebum is `injected' into the hair within the follicle, which was my original argument.

S Foote.

 

[Bryan]

Just read it properly Bryan for God's sake!

It is the mismatch in the banding...

Geez, make up your mind, Stephen! First you said there's a MATCH in the banding, now you're saying there's a MISMATCH. Which one is it?? :wink:

...that given the time delay of sebum processing, `THEN' reflection in the hair shaft, that `proves' the disposition route!!!

Really? How does it do that? Please explain.

But what really screws your idea that sebum is `just' deposited `on' the hair shaft by `rubbing', is the simple proven existence of `ANY' banding effect at all!!

If substances in the body are transfered to the hair shaft by sebum by mechanical rubbing as you claim, there will be no banding concentrations in the hair shaft `WHATSOEVER'! The substance, whatever it is will be `EQUALLY' distributed over the entire hair shaft. :roll:

Not necessarily. For example, look at the authors' own comments about the effect of shampooing being one possible explanation for that uneven 'banding'.

Bryan