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FINALLY: a more direct test of the "feedback theory".


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#1 bryan

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Posted 23 January 2006 - 11:57 AM

Ok, several days ago in that earlier thread ("If you stop washing your skin, do you get LESS oily, or do you get MORE oily??"), I presented the results of my experiment which showed that my own forehead gets MORE OILY as the days go by without washing (for up to 12 full days, anyway). However, that's not quite the same as the general idea put forth in the notorious "feedback theory", so I promised that I would do a more direct test of it myself and post my results. Well, HOORAY, I can finally now do that! It's taken me this long because of the annoying amount of time I've had to spend in "grunge mode" and "intense washing mode". This is basically what I've done:

The first phase was in "grunge mode" again: I spent at least another full week (I think it was actually closer to 10 days) without washing my forehead at all, not even with water. No washing, no wiping (similar to what I did in the previous test). Then after that period of time, I de-fatted my forehead by thoroughly washing with Ivory soap, followed immediately by swabbing with 70% ethyl alcohol. Thereafter, I began a series of 9 Sebutape impressions, one every half-hour, for a total of 4 1/2 hours. I marked each test-strip with a "G", followed by the numbers 1 through 9, to indicate that those were made during the "Grunge" or "Greasy" period! biggrin.gif The numbers indicate the amount of time in half-hours following the de-fatting that the impression was made. For example, "G5" is on the strip that was made at the end of the grunge period, 2 1/2 hours after the de-fatting.

The second phase was the period of intense washing: I spent over a full week (about 7 1/2 days) of washing my forehead THOROUGHLY with Ivory soap, 5-6 times per day, evenly scattered throught my waking hours. At the end of that period, I made another set of 9 Sebutape impressions, EXACTLY as I had done earlier: de-fatted my forehead by washing one last time with Ivory soap and swabbing with 70% ethyl alcohol, then made a Sebutape impression every half-hour for 4 1/2 hours. I labeled each test-strip with a "W" (for "Washing"), followed by a number 1 through 9, corresponding to which half-hour after the washing that I made it.

Here's the scan of all 18 Sebutape test-strips, G1-G9 and W1-W9, and I placed them side-by-side for your viewing pleasure and ease of comparison:

http://www.geocities...theory_test.htm

As usual, there's some inevitable fluctuation in those test-strips, even though they were made over a relatively short period of time. During some of those half-hours, the "Grunge" version might seem to be slightly oilier than the "Wash" version, and in other half-hours, the "Wash" version might seem to be slightly oilier than the "Grunge" version. But I think one thing is screamingly obvious: taken as a whole, THERE IS NO SIGNIFICANT OR OBVIOUS DIFFERENCE in the level of sebum production that occurred on my forehead during periods of intense washing, and periods of no washing at all. That's reflected by the fact that my forehead re-fatted itself AT THE SAME RATE after a single de-fatting after those periods. So my own experience with this simple test is right in line with what Kligman and his colleagues found, and what LabGirl81 reported about her company's testing: washing your skin doesn't stimulate it to produce more sebum as a "compensatory" mechanism.

All questions, comments, and flames are welcome! smile.gif

Bryan

#2 L8302

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Posted 23 January 2006 - 01:00 PM

Ivory soap is made with oils and fats (see below). While you were "washing often" with your ivory soap you were actually cleaning it in a way conducive to preserving the acid barrier, i.e. you maintained the pH. (Your use of alcohol might have done some damage, but it sounds like you only swabbed lightly anyway and the alcohol probably evaporates before it can do any significant damage? Not too sure about the alcohol useage...)

But using Ivory soap as your method of "extra-cleaning" sort of destroys your testing credibility. I believe the argument (at least MY argument) is that sebum will start to compensate when your skin pH has become unbalanced or stripped of natural oils (usually happens during the cleansing process with harsh or chemical cleansers) but by cleaning with coconut-oil etc. the balance never actually became unbalanced. Coconut oil is actually a noted moisturizer. In effect you were keeping your skin regulated quite close to its usual sebum levels...

And one final question is why didn't you wash with water in the Grunge phase? I dont know of many people who advocate complete abolishment of wiping off excess oil (especially in the first few days when it supposedly gets more oilier). I think a better test would have incorporated splashing/rinsing your face with cold water (in the shower?) every day (eventually every 2-3 days) in the Grunge phase.

I await your retort!


QUOTE
What are Ivory's ingredients?
Ivory Soap is made of both vegetable oils and animal fats. Two different kinds of vegetable oils are used in Ivory - coconut oil and palm kernel oil. We add a preservative, less than 1/10% of tetrasodium EDTA, to keep the bar as white as its name.
Ivory contains no dyes or heavy perfumes and creams. A light fragrance is added to provide that Ivory clean smell.
http://www.ivory.com/FAQ.htm#soap4


QUOTE(bryan @ Jan 23 2006, 12:57 PM) View Post

Ok, several days ago in that earlier thread ("If you stop washing your skin, do you get LESS oily, or do you get MORE oily??"), I presented the results of my experiment which showed that my own forehead gets MORE OILY as the days go by without washing (for up to 12 full days, anyway). However, that's not quite the same as the general idea put forth in the notorious "feedback theory", so I promised that I would do a more direct test of it myself and post my results. Well, HOORAY, I can finally now do that! It's taken me this long because of the annoying amount of time I've had to spend in "grunge mode" and "intense washing mode". This is basically what I've done:

The first phase was in "grunge mode" again: I spent at least another full week (I think it was actually closer to 10 days) without washing my forehead at all, not even with water. No washing, no wiping (similar to what I did in the previous test). Then after that period of time, I de-fatted my forehead by thoroughly washing with Ivory soap, followed immediately by swabbing with 70% ethyl alcohol. Thereafter, I began a series of 9 Sebutape impressions, one every half-hour, for a total of 4 1/2 hours. I marked each test-strip with a "G", followed by the numbers 1 through 9, to indicate that those were made during the "Grunge" or "Greasy" period! biggrin.gif The numbers indicate the amount of time in half-hours following the de-fatting that the impression was made. For example, "G5" is on the strip that was made at the end of the grunge period, 2 1/2 hours after the de-fatting.

The second phase was the period of intense washing: I spent over a full week (about 7 1/2 days) of washing my forehead THOROUGHLY with Ivory soap, 5-6 times per day, evenly scattered throught my waking hours. At the end of that period, I made another set of 9 Sebutape impressions, EXACTLY as I had done earlier: de-fatted my forehead by washing one last time with Ivory soap and swabbing with 70% ethyl alcohol, then made a Sebutape impression every half-hour for 4 1/2 hours. I labeled each test-strip with a "W" (for "Washing"), followed by a number 1 through 9, corresponding to which half-hour after the washing that I made it.

Here's the scan of all 18 Sebutape test-strips, G1-G9 and W1-W9, and I placed them side-by-side for your viewing pleasure and ease of comparison:

http://www.geocities...theory_test.htm

As usual, there's some inevitable fluctuation in those test-strips, even though they were made over a relatively short period of time. During some of those half-hours, the "Grunge" version might seem to be slightly oilier than the "Wash" version, and in other half-hours, the "Wash" version might seem to be slightly oilier than the "Grunge" version. But I think one thing is screamingly obvious: taken as a whole, THERE IS NO SIGNIFICANT OR OBVIOUS DIFFERENCE in the level of sebum production that occurred on my forehead during periods of intense washing, and periods of no washing at all. That's reflected by the fact that my forehead re-fatted itself AT THE SAME RATE after a single de-fatting after those periods. So my own experience with this simple test is right in line with what Kligman and his colleagues found, and what LabGirl81 reported about her company's testing: washing your skin doesn't stimulate it to produce more sebum as a "compensatory" mechanism.

All questions, comments, and flames are welcome! smile.gif

Bryan



#3 bryan

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Posted 23 January 2006 - 01:33 PM

QUOTE(L8302 @ Jan 23 2006, 01:00 PM) View Post

Ivory soap is made with oils and fats (see below). While you were "washing often" with your ivory soap you were actually cleaning it in a way conducive to preserving the acid barrier, i.e. you maintained the pH.


Really? Let's see if LabGirl81 agrees with you that washing with the very alkaline Ivory soap is "conducive to preserving the acid barrier". What say you, LabGirl?

QUOTE
(Your use of alcohol might have done some damage, but it sounds like you only swabbed lightly anyway and the alcohol probably evaporates before it can do any significant damage? Not too sure about the alcohol useage...)


On the contrary, I swabbed thoroughly. I wanted to remove any traces of remaining fats that could even _possibly_ remain, after the Ivory soap.

QUOTE
But using Ivory soap as your method of "extra-cleaning" sort of destroys your testing credibility. I believe the argument (at least MY argument) is that sebum will start to compensate when your skin pH has become unbalanced or stripped of natural oils (usually happens during the cleansing process with harsh or chemical cleansers) but by cleaning with coconut-oil etc. the balance never actually became unbalanced. Coconut oil is actually a noted moisturizer. In effect you were keeping your skin regulated quite close to its usual sebum levels...


I can assure you that washing with Ivory soap is quite effective at stripping natural oils (I just LOVE that expression). If you don't believe me, you can try it yourself: wash your face with Ivory soap, then immediately apply a Sebutape test-strip. There will be virtually no detectable sebum. Maybe one or two tiny, inconspicuous dots of oil.

QUOTE
And one final question is why didn't you wash with water in the Grunge phase? I dont know of many people who advocate complete abolishment of wiping off excess oil (especially in the first few days when it supposedly gets more oilier). I think a better test would have incorporated splashing/rinsing your face with cold water (in the shower?) every day (eventually every 2-3 days) in the Grunge phase.


You've apparently completely missed the whole point. I'M TESTING IT TO THE LIMIT, so nobody can accuse me of not washing thoroughly enough. Do you think people are going to believe me if all I do is splash cold water on my face, and then try to claim that that proves that washing has no effect on sebum production?? Jesus Christ, you can't be serious...

Edit: Sorry, I misunderstood what you meant. My response now is that regardless of what people advocate, I was in fact testing the fundamental premise of the "feedback theory" by going all the way: comparing sebum production during times of extreme washing to sebum production during times of no washing at all. I doubt that anybody would challenge the validity of that method.

Bryan

#4 LabGirl81

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Posted 23 January 2006 - 02:30 PM

QUOTE
Ivory soap is made with oils and fats (see below). While you were "washing often" with your ivory soap you were actually cleaning it in a way conducive to preserving the acid barrier, i.e. you maintained the pH.


QUOTE
Really? Let's see if LabGirl81 agrees with you that washing with the very alkaline Ivory soap is "conducive to preserving the acid barrier". What say you, LabGirl?



Okay if you want my opinion. Bryan...excellent experiment. Your test of the "feedback theory" was well conducted, and as you probably suspected, it showed no correlation between the sebum production after a period of no washing, when compared to the sebum production after excessive washing.

Proctor and Gamble does not list the ingredients for Ivory soap. (I'd really like to know how they got away with that.) Anyway, it's a traditional soap. So while it's made with "natural oils and fats" it's also made with a strong base (sodium or potassium hydroxide). Soap is a metal salt of a fatty acid. A soap is made by breaking a triglyceride down into glycerol and fatty acids, because the pH of the medium is low the fatty acids loose their hydrogen ions and combine with the very electropositive metal ions from the sodium or postssium hydroxide. Traditional soaps are always alkaline (pH somewhare between 8 and 10.5, but could be as high as 11).

Soap is anything but moisturizing. Not only is it great at removing sebum from skin, it can also strip the skin's natural epidermal lipids (like cerimides and free sphingolipids, and the lipids of the lipid bilayers in between the layers of corneocytes) that make up the skin's water barrier, and hold the cells of the stratum corneum together, which leads to transepidermal water loss.

Soap's alkalinity is also a problem. The pH of skin is usually around 5 (4.2 5.6 actually), which is slightly acidic. The skin's lipid bilayers are made up of mostly phospholipids, which have a phosphatylcholine head and two linoleic acid tails. Also free fatty acids make up a decent chunk of other epidermal lipids. In an alkaline medium the carboxyl groups on a fatty acids loose their hydrogen ions leaving behind a very electronegative oxygen ion (O-), which can easily bond with a metal ion that happens to be floating around in the medium from the soap or just from the tap water.....forming a metal salt of a fatty acid (a soap), which can easily be rinsed away with water. Soap removes way more skin lipids than a gentle non-soap cleanser would....Another downside to cleansing with soap.....at higher pH's the lipid bilayers become stiff and rigid, casuing measureable swelling in the stratum corneum.....

Alcohol is also great at defatting the skin, and is usually used for this purpose in most research that requires defatting of the skin for whatever reason...

#5 ballaballa

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Posted 23 January 2006 - 03:36 PM

haha wow.

Why the heck would u use alcohol? Do you not know that alcohol can refine pores and slow down oil?

There are so many things wrong with your experiment. But i wont tell them to you so you can lie. So i have some questions for you:

So you havent taken a shower in 10 days?

Did you test the same spot everytime?

You dont know the exact amount of times you washed each day?

And finally, Do you even know what the feedback theory is?

#6 LabGirl81

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Posted 23 January 2006 - 03:41 PM

QUOTE(ballaballa @ Jan 23 2006, 04:36 PM) View Post

haha wow.

Why the heck would u use alcohol? Do you not know that alcohol can refine pores and slow down oil production?

There are so many things wrong with your experiment. But i wont tell them to you so you can lie. So i have some questions for you:

So you havent taken a shower in 10 days?

Did you test the same spot everytime?

You dont know the exact amount of times you washed each day?

And finally, Do you even know what the feedback theory is?



Alcohol doesn't actually slow sebum production...It only "refines" pores because it's great at stripping surface lipids, which makes them appear smaller temporarily.....

#7 Daz!

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Posted 23 January 2006 - 04:59 PM

I honestly don't know why you bother Bryan and Labgirl.
Why is it so difficult to comprehend that washing does not affect sebum production.
I guess these guys believe how much you wash your dick affects urine/sperm production and how much you wipe your ass affects shit production.



#8 ballaballa

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Posted 23 January 2006 - 06:26 PM

QUOTE(LabGirl81 @ Jan 23 2006, 04:41 PM) View Post

QUOTE(ballaballa @ Jan 23 2006, 04:36 PM) View Post

haha wow.

Why the heck would u use alcohol? Do you not know that alcohol can refine pores and slow down oil production?

There are so many things wrong with your experiment. But i wont tell them to you so you can lie. So i have some questions for you:

So you havent taken a shower in 10 days?

Did you test the same spot everytime?

You dont know the exact amount of times you washed each day?

And finally, Do you even know what the feedback theory is?



Alcohol doesn't actually slow sebum production...It only "refines" pores because it's great at stripping surface lipids, which makes them appear smaller temporarily.....


i should rephrased that. I really dont know how to phrase it actually. It doesnt slow down the production but the process in which it comes out.

QUOTE(Daz! @ Jan 23 2006, 05:59 PM) View Post

I honestly don't know why you bother Bryan and Labgirl.
Why is it so difficult to comprehend that washing does not affect sebum production.
I guess these guys believe how much you wash your dick affects urine/sperm production and how much you wipe your ass affects shit production.

nice post. You sound pretty smart.


#9 L8302

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Posted 23 January 2006 - 06:51 PM

Ingredients in Ivory Soap:
Sodium tallowate (cleansing agent derived from beef tallow), Sodium cocoate or sodium palm kernelate (cleansing agents derived from coconut or palm oil), Water, Sodium chloride (salt), Sodium silicate (soluble glass), Magnesium sulfate (epsom salts), Fragrance
--questionable source but I doubt it would be incorrect nevertheless: http://www.tarahill....lif/ingred.html

Ivory pH = 9.5 (water pH = 7)
True, Ivory has an alkaline pH and would thus seem like it would be harsh on the skin. However, the pH of something doesn't neccessarily speak to its total or net alkalinity. In fact, there is apparently little actual "free or available alkalinity" in Ivory soap.
"Available or free alkalinity is simply the concentration of alkalinity that is not tied up in formulation and is free and available to do work. Available alkalinity concentrations are measured by percentage. Common household detergent systems have no available alkalinity compared to instrument detergents. For example: Ivory Soap has a pH of 10 which is high on the alkaline scale but has no free or available alkalinity and, therefore, is safe enough to wash your face."
https://www.steris.c...1392-6295_1.pdf

Ivory soap wouldn't have been my product of choice in order to conclusively demonstrate your point that 'excessive washing' or cleansing of the skin doesn't make a difference in sebum production levels. In any case, I think the test would have been more convincing if you had used something a little more harsh...

And then there's also the larger more significant issue (that possibly you weren't concerned with during this experiment) of the interplay of sebum production and acne. I'm playing devil's advocate here, but maybe the skin's regular sebum barrier is more effective at staving off acne when it is undisturbed rather than having it constantly replenished after cleansing/stripping (because of increased chance for bacteria to penetrate surface without the barrier.)


QUOTE(LabGirl81 @ Jan 23 2006, 03:30 PM) View Post

QUOTE
Ivory soap is made with oils and fats (see below). While you were "washing often" with your ivory soap you were actually cleaning it in a way conducive to preserving the acid barrier, i.e. you maintained the pH.


QUOTE
Really? Let's see if LabGirl81 agrees with you that washing with the very alkaline Ivory soap is "conducive to preserving the acid barrier". What say you, LabGirl?



Okay if you want my opinion. Bryan...excellent experiment. Your test of the "feedback theory" was well conducted, and as you probably suspected, it showed no correlation between the sebum production after a period of no washing, when compared to the sebum production after excessive washing.

Proctor and Gamble does not list the ingredients for Ivory soap. (I'd really like to know how they got away with that.) Anyway, it's a traditional soap. So while it's made with "natural oils and fats" it's also made with a strong base (sodium or potassium hydroxide). Soap is a metal salt of a fatty acid. A soap is made by breaking a triglyceride down into glycerol and fatty acids, because the pH of the medium is low the fatty acids loose their hydrogen ions and combine with the very electropositive metal ions from the sodium or postssium hydroxide. Traditional soaps are always alkaline (pH somewhare between 8 and 10.5, but could be as high as 11).

Soap is anything but moisturizing. Not only is it great at removing sebum from skin, it can also strip the skin's natural epidermal lipids (like cerimides and free sphingolipids, and the lipids of the lipid bilayers in between the layers of corneocytes) that make up the skin's water barrier, and hold the cells of the stratum corneum together, which leads to transepidermal water loss.

Soap's alkalinity is also a problem. The pH of skin is usually around 5 (4.2 5.6 actually), which is slightly acidic. The skin's lipid bilayers are made up of mostly phospholipids, which have a phosphatylcholine head and two linoleic acid tails. Also free fatty acids make up a decent chunk of other epidermal lipids. In an alkaline medium the carboxyl groups on a fatty acids loose their hydrogen ions leaving behind a very electronegative oxygen ion (O-), which can easily bond with a metal ion that happens to be floating around in the medium from the soap or just from the tap water.....forming a metal salt of a fatty acid (a soap), which can easily be rinsed away with water. Soap removes way more skin lipids than a gentle non-soap cleanser would....Another downside to cleansing with soap.....at higher pH's the lipid bilayers become stiff and rigid, casuing measureable swelling in the stratum corneum.....

Alcohol is also great at defatting the skin, and is usually used for this purpose in most research that requires defatting of the skin for whatever reason...


#10 bryan

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Posted 23 January 2006 - 09:10 PM

QUOTE(ballaballa @ Jan 23 2006, 03:36 PM) View Post

Why the heck would u use alcohol?


To be as certain as possible that I've removed all traces of fat, prior to starting the series of Sebutape impressions.

QUOTE
Do you not know that alcohol can refine pores and slow down oil?


LabGirl already answered that objection very nicely.

QUOTE
There are so many things wrong with your experiment. But i wont tell them to you so you can lie.


Yeah, right.

QUOTE
So i have some questions for you:

So you havent taken a shower in 10 days?


Took baths, instead of showers. Very careful ones, not getting my face or hair wet. I HATE taking baths.

QUOTE
Did you test the same spot everytime?


Yes I did.

QUOTE
You dont know the exact amount of times you washed each day?


Yes I do. I wrote it down on a piece of paper whenever I did a washing, so I wouldn't lose track.

Bryan

#11 bryan

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Posted 23 January 2006 - 09:33 PM

QUOTE(L8302 @ Jan 23 2006, 06:51 PM) View Post

Ivory soap wouldn't have been my product of choice in order to conclusively demonstrate your point that 'excessive washing' or cleansing of the skin doesn't make a difference in sebum production levels. In any case, I think the test would have been more convincing if you had used something a little more harsh...


So what would have been your product of choice? Suggest something to me that you think would be an even BETTER choice, and I'll entertain the idea of using it in another test.

QUOTE
And then there's also the larger more significant issue (that possibly you weren't concerned with during this experiment) of the interplay of sebum production and acne. I'm playing devil's advocate here, but maybe the skin's regular sebum barrier is more effective at staving off acne when it is undisturbed rather than having it constantly replenished after cleansing/stripping (because of increased chance for bacteria to penetrate surface without the barrier.)


You're right: I wasn't concerned with such peripheral issues. Try to understand where I'm coming from on all this: I WAS ONLY TESTING THE "FEEDBACK THEORY". I wasn't trying to suggest a good way to treat acne, I was only testing a very specific theory about an aspect of sebaceous gland physiology.

BTW, here's a big newsflash for you: the skin's "sebum barrier" IS being constantly replenished, whether you cleanse/strip it or not. You can't stop sebum from continuously coming out.

Bryan

#12 lars11

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Posted 23 January 2006 - 09:40 PM

Nice idea for an experiment but judging the posts I've read from you, you like to always be right and we have no way of proving if this test is flawed or not.

Not to sound like a prick, but I really don't think I could trust you with results after all the bashing I've seen you do about other people *proving* their experiments. Yours offers no proof whatsoever, besides a photo that could have been the product of unreliable testing or photoshop.

#13 L8302

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Posted 23 January 2006 - 10:43 PM

Quite the condescending "newsflash"... but if you must validate your "experiment" with ad hominem attacks against constructive critics be my guest! I thought you were as interested as I in getting down to some real answers but your tone would suggest otherwise...

I never claimed that the skin's sebum barrier remains stagnant or in a state of stasis (nothing in nature does...). I think you misunderstand me on many levels. Of course sebum is continuously being released from our pores but it seems to be that harsh cleansers allow a greater chance of infection/disease/contamination (ex. look for reviews/articles concerning medical handsoaps) once the acid barrier of the skin has been disrupted.

Also, if you think about it, that the skin seemed to have just as much oil on it during the samples taken between cleansing as the samples taken during the Grunge no-wash phase (from what I can tell from your strip tests) indicates that the skin must be producing sebum at a slower rate during the Grunge phase. If it really was producing the same steady amount of sebum then because you never removed the oil it should have shown an obvious difference of having more (accumulated) sebum. From what I can tell, however, the sebum amount is relatively the same whether you had removed the oils or not--this demonstrates that the skin seems to hover around a set sebum level and does in fact produce less sebum with an undisturbed barrier although the net amount on the skin at any given time is relatively constant. (Did that make any sense?)

I don't even think sebum is significantly related to acne (in any direct way) but I just want to point out the *possible* holes in your experiment technique/conclusions that might jeapordize its validity.

Continue on the quest for knowledge, sir Bryan...

~L


QUOTE(bryan @ Jan 23 2006, 10:33 PM) View Post

BTW, here's a big newsflash for you: the skin's "sebum barrier" IS being constantly replenished, whether you cleanse/strip it or not. You can't stop sebum from continuously coming out.

Bryan



#14 bryan

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Posted 23 January 2006 - 10:43 PM

QUOTE(spitfire909x @ Jan 23 2006, 09:40 PM) View Post

Nice idea for an experiment but judging the posts I've read from you, you like to always be right and we have no way of proving if this test is flawed or not.

Not to sound like a prick, but I really don't think I could trust you with results after all the bashing I've seen you do about other people *proving* their experiments. Yours offers no proof whatsoever, besides a photo that could have been the product of unreliable testing or photoshop.


Actually, I take that as a rather backhanded compliment: if you can find no real problem with my methodology or the design of my experiment and all you can do is question my honesty and integrity or the care with which I did the experiment, then I consider that a success! smile.gif I'm sorry you don't believe me, but there's not much I can do about that, other than to invite you to do the same test yourself. And you now have the wherewithal to do it just like I did: I described in sufficient detail what I did, and you can even call CuDerm in Dallas and order yourself a roll of Sebutape test-strips. You don't have to take my word for anything.

Do the experiment yourself, and post your results.

Bryan

#15 bryan

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Posted 23 January 2006 - 11:21 PM

QUOTE(L8302 @ Jan 23 2006, 10:43 PM) View Post

Quite the condescending "newsflash"... but if you must validate your "experiment" with ad hominem attacks against constructive critics be my guest! I thought you were as interested as I in getting down to some real answers but your tone would suggest otherwise...


Oh, don't be such a milquetoast! biggrin.gif Do you think YOU were being the perfect gentleman when you told me that my use of Ivory soap "destroyed my testing credibility"? Or when you told me "I await your retort!"?? When posting on Internet forums, I generally treat other people as well as they treat me.

QUOTE
I never claimed that the skin's sebum barrier remains stagnant or in a state of stasis (nothing in nature does...). I think you misunderstand me on many levels. Of course sebum is continuously being released from our pores but it seems to be that harsh cleansers allow a greater chance of infection/disease/contamination (ex. look for reviews/articles concerning medical handsoaps) once the acid barrier of the skin has been disrupted.


It certainly sounded TO ME like you were claiming that. I wish you would be more careful what you say. And once again, you bring up these unrelated issues of the acid mantle, infection, disease, etc. I DON'T CARE about those things, at the moment. Let's stay focused on the issue here, which is just the feedback theory.

Also, if you think about it, that the skin seemed to have just as much oil on it during the samples taken between cleansing as the samples taken during the Grunge no-wash phase (from what I can tell from your strip tests) indicates that the skin must be producing sebum at a slower rate during the Grunge phase. If it really was producing the same steady amount of sebum then because you never removed the oil it should have shown an obvious difference of having more (accumulated) sebum. From what I can tell, however, the sebum amount is relatively the same whether you had removed the oils or not--this demonstrates that the skin seems to hover around a set sebum level and does in fact produce less sebum with an undisturbed barrier although the net amount on the skin at any given time is relatively constant. (Did that make any sense?)

That statement doesn't make any sense to me, and you don't seem to understand the point of the experiment. After several days of no washing at all and then doing a single de-fatting of the skin, the skin RE-fatted itself at exactly the same rate as it did when I was washing excessively, and did a single de-fatting of the skin. That shows that the RE-fatting rate was the same, whether I was washing excessively, or not at all. Understand now?

The point you seem to be completely overlooking is that when I de-fatted the skin on both of those occasions, I COMPLETELY de-fatted it; I removed every last little bit of oil and fat by washing with soap first, and then followed that immediately with an alcohol washing, just to be sure that I got everything. Capiche?

QUOTE
I don't even think sebum is significantly related to acne (in any direct way) but I just want to point out the *possible* holes in your experiment technique/conclusions that might jeapordize its validity.


I think you have yet to point out any holes.

Bryan

#16 L8302

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Posted 24 January 2006 - 12:30 AM

Ah hah! Yes I do apologize, I was most decidedly missing the bullseye with regard to the specifics of the experiment, but I was thrown off where you said:

QUOTE
taken as a whole, THERE IS NO SIGNIFICANT OR OBVIOUS DIFFERENCE in the level of sebum production that occurred on my forehead during periods of intense washing, and periods of no washing at all. That's reflected by the fact that my forehead re-fatted itself AT THE SAME RATE after a single de-fatting after those periods. So my own experience with this simple test is right in line with what Kligman and his colleagues found, and what LabGirl81 reported about her company's testing: washing your skin doesn't stimulate it to produce more sebum as a "compensatory" mechanism.


You have NOT proven, as you claim, that there is no significant difference between sebum production DURING periods of intense washing and periods of no washing. All you have proven is that the skin bounces back from being stripped/de-fatted/cleaned at the same rate whenever you use the same product/method (Ivory soap and alcohol).

For comparison, imagine you want to test soil water evaporation rates in cloudy v. sunny weather conditions. After a week of cloudy weather you bring the soil inside and test how fast it evaporates under a 60watt lightbulb. After a week of sunny weather you bring the soil inside and test how fast it evaporates under a 60watt lightbulb. SURPRISE, it's the same! In this circumstance you have failed to measure the rate of evaporation DURING the respective weather conditions by levelling the playing field during actual analysis. That the soil is dryer or wetter at the time of analysis doesn't affect the rate of evaporation given the exact same testing conditions.

Do you see what I'm saying?


Your gentlelady,
~L

#17 gloriousbach

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Posted 24 January 2006 - 03:57 AM

First of all, thanks a lot to Bryan for sacrificing his time (and his skin! smile.gif ) to post these results for us.

I think we should all try and bitch less and be more constructive with out criticisms of the experiment, more in the manner of authentic lab researchers.

My own view is that the experiment is interesting, but doesn't properly answer the question that I and some others were interested in, which was does the type of cleanser used (or none at all) affect the rate of sebum excretion over the subsequent day or days.

I agree with the statement:

"You have NOT proven, as you claim, that there is no significant difference between sebum production DURING periods of intense washing and periods of no washing. All you have proven is that the skin bounces back from being stripped/de-fatted/cleaned at the same rate whenever you use the same product/method (Ivory soap and alcohol)."

Made by L8302, but concur that it is an interesting and worthwhile experiment nonetheless.

When I have more time in the evening I should be able to make a few suggestions.

GB

#18 Daz!

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Posted 24 January 2006 - 06:20 AM

"You have NOT proven, as you claim, that there is no significant difference between sebum production DURING periods of intense washing and periods of no washing. All you have proven is that the skin bounces back from being stripped/de-fatted/cleaned at the same rate whenever you use the same product/method (Ivory soap and alcohol)."
Errr no.
The sebutape shows statistically the same sebum production rate, so no bounce back!

"I think we should all try and bitch less and be more constructive with out criticisms of the experiment, more in the manner of authentic lab researchers."

Sorry, the lab in the muppet show is not how things are done in the real world guys?


BTW This may come as a shock.... The world is not flat.
Feel free to discuss and flame me on that!


#19 Daz!

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Posted 24 January 2006 - 06:31 AM

QUOTE(ballaballa @ Jan 23 2006, 05:26 PM) View Post

QUOTE(Daz! @ Jan 23 2006, 05:59 PM) View Post

I honestly don't know why you bother Bryan and Labgirl.
Why is it so difficult to comprehend that washing does not affect sebum production.
I guess these guys believe how much you wash your dick affects urine/sperm production and how much you wipe your ass affects shit production.

nice post. You sound pretty smart.


Thanks, I am.



#20 ballaballa

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Posted 24 January 2006 - 08:22 AM

L8302 is dropping knowledge on you fools(bryan, Daz).

QUOTE

For comparison, imagine you want to test soil water evaporation rates in cloudy v. sunny weather conditions. After a week of cloudy weather you bring the soil inside and test how fast it evaporates under a 60watt lightbulb. After a week of sunny weather you bring the soil inside and test how fast it evaporates under a 60watt lightbulb. SURPRISE, it's the same! In this circumstance you have failed to measure the rate of evaporation DURING the respective weather conditions by levelling the playing field during actual analysis. That the soil is dryer or wetter at the time of analysis doesn't affect the rate of evaporation given the exact same testing conditions.

EXACTLY! This is why this experiment has no credibility.

You cant do all the vigorous washing or non washing for a week, then next day wash your face, and then test. lol.gif Thats not what the feedback theory is. It's the theory that the washing itself will cause the skin to produce more oil. So you have to test same day. Also the use of alcohol really should not have been used because of its refining of pores. It DOES slow down the process in which oil comes out. Also the fact that you tested only your forehead. Oil glands will not only produce in the area you washed, it will produce wherever an oil gland is. So when you were in your "grunge" period, oil glands were still working on your forehead. Also the fact that you tested the same spot only. Testing it will remove the oil that was there and start again. So you didn't see an increase in sebum. It would have been smarter to test one spot at 2 1/2 hours and a different spot at 4 1/2.