I found some of bryan's posts on another site:
http://www.acne.org/messageboard/index. ... user=10176
What really constitutes a good "moisturizer"?
Many of you here are too young to know anything about the enormously popular book "Life Extension", written more than 20 years ago by Durk Pearson and Sandy Shaw. Below is an excerpt from the chapter "Looking as Young as You Feel". I took the liberty of putting the first sentence of the second paragraph in bold, to emphasize the obvious relevance to what some of us have been discussing here lately (whether or not sebum really has anything to do with skin moisturization):
"Skin appearance can be markedly improved by using Na-PCA, the sodium salt of 2-pyrrolidone-5-carboxylic acid, the principal natural humectant (moisturizer) in your skin. The ability of skin to hold moisture is directly related to its Na-PCA content. The ability of Na-PCA to pull water out of the air is amazing. If you put out a small amount of dry Na-PCA in the Sahara Desert, in a few hours it will become a puddle because of the water removed from the very dry air there! Older people have about 50 percent less Na-PCA in their skin than young people, thus contributing to a dry, hard skin condition. Bathing and swimming can lead to dry skin because your natural Na-PCA is leached out. Na-PCA can be found in some premium quality skin-care cosmetics. Look at the labels to see if it is listed as an ingredient.
"Here's a simple experiment you can do that will demonstrate the fact that it is water, and not oil, that keeps skin soft and supple. Cut some small pieces of hardened leather from an old shoe, and soak one piece overnight in baby oil, another piece in water, and a third in a 15 percent solution of Na-PCA in water (see Appendix I for a supplier of Na-PCA). Next day, remove the pieces of leather from the liquids, dry them off with a paper towel, and compare them for flexibility and softness. The pieces soaked in the Na-PCA and water and the water alone will both be soft, whereas the oil-soaked piece will be much less soft. Now hang the pieces up to dry. The piece soaked in plain water will rapidly dry out and harden, whereas the piece soaked in the Na-PCA solution will remain moist, soft, and supple."
Does sebum help "moisturize" the skin??
Journal of Investigative Dermatology. 1987 Mar;88(3 Suppl):2s-6s.
"Skin lipids: an update"
Downing DT, Stewart ME, Wertz PW, Colton SW, Abraham W, Strauss JS.
(excerpt from this study follows below, including the references...)
Sebum and Dry Skin "...skin can be healthy and have charming cosmetic properties in the virtual absence of sebum." (14)
Kligman drew attention to prepubertal children, who produce almost no sebum, to support his thesis that skin does not depend upon sebum for maintaining its barrier to water loss: "...there can be no doubt of the insignificance of sebum as a waterproofing material." (14) Our recent studies at the other end of the human age spectrum have supported this conviction. In a survey of sebum secretion rates and the incidence of dry skin among subjects aged 65 to 97, no correlation was found between sebaceous gland activity and the presence or severity of dry skin (34). Kligman recognized that sebum could mask the scaliness of dry skin without producing any actual change in the condition: "Sebum, like any oil, has some emollient or smoothing effect when a sufficient quantity is rubbed into dry, scaling skin." (14) In spite of the clear inference to be drawn from the cutaneous characteristics of children and the experimental data obtained from the elderly, it remains difficult to dispel the myth that low sebum secretion rates cause dry skin. It is a rare individual who realizes that "dry" is not the obverse of "oily".
(14) Kligman AM: The uses of sebum. Br J Dermatol 75: 307-319, 1963
(34) Frantz RA, Kinney CK, Downing DT: A study of skin dryness in the elderly. Nursing Res 35: 98-100, 1986.
http://www.acne.org/messageboard/index. ... user=10176
What really constitutes a good "moisturizer"?
Many of you here are too young to know anything about the enormously popular book "Life Extension", written more than 20 years ago by Durk Pearson and Sandy Shaw. Below is an excerpt from the chapter "Looking as Young as You Feel". I took the liberty of putting the first sentence of the second paragraph in bold, to emphasize the obvious relevance to what some of us have been discussing here lately (whether or not sebum really has anything to do with skin moisturization):
"Skin appearance can be markedly improved by using Na-PCA, the sodium salt of 2-pyrrolidone-5-carboxylic acid, the principal natural humectant (moisturizer) in your skin. The ability of skin to hold moisture is directly related to its Na-PCA content. The ability of Na-PCA to pull water out of the air is amazing. If you put out a small amount of dry Na-PCA in the Sahara Desert, in a few hours it will become a puddle because of the water removed from the very dry air there! Older people have about 50 percent less Na-PCA in their skin than young people, thus contributing to a dry, hard skin condition. Bathing and swimming can lead to dry skin because your natural Na-PCA is leached out. Na-PCA can be found in some premium quality skin-care cosmetics. Look at the labels to see if it is listed as an ingredient.
"Here's a simple experiment you can do that will demonstrate the fact that it is water, and not oil, that keeps skin soft and supple. Cut some small pieces of hardened leather from an old shoe, and soak one piece overnight in baby oil, another piece in water, and a third in a 15 percent solution of Na-PCA in water (see Appendix I for a supplier of Na-PCA). Next day, remove the pieces of leather from the liquids, dry them off with a paper towel, and compare them for flexibility and softness. The pieces soaked in the Na-PCA and water and the water alone will both be soft, whereas the oil-soaked piece will be much less soft. Now hang the pieces up to dry. The piece soaked in plain water will rapidly dry out and harden, whereas the piece soaked in the Na-PCA solution will remain moist, soft, and supple."
Does sebum help "moisturize" the skin??
Journal of Investigative Dermatology. 1987 Mar;88(3 Suppl):2s-6s.
"Skin lipids: an update"
Downing DT, Stewart ME, Wertz PW, Colton SW, Abraham W, Strauss JS.
(excerpt from this study follows below, including the references...)
Sebum and Dry Skin "...skin can be healthy and have charming cosmetic properties in the virtual absence of sebum." (14)
Kligman drew attention to prepubertal children, who produce almost no sebum, to support his thesis that skin does not depend upon sebum for maintaining its barrier to water loss: "...there can be no doubt of the insignificance of sebum as a waterproofing material." (14) Our recent studies at the other end of the human age spectrum have supported this conviction. In a survey of sebum secretion rates and the incidence of dry skin among subjects aged 65 to 97, no correlation was found between sebaceous gland activity and the presence or severity of dry skin (34). Kligman recognized that sebum could mask the scaliness of dry skin without producing any actual change in the condition: "Sebum, like any oil, has some emollient or smoothing effect when a sufficient quantity is rubbed into dry, scaling skin." (14) In spite of the clear inference to be drawn from the cutaneous characteristics of children and the experimental data obtained from the elderly, it remains difficult to dispel the myth that low sebum secretion rates cause dry skin. It is a rare individual who realizes that "dry" is not the obverse of "oily".
(14) Kligman AM: The uses of sebum. Br J Dermatol 75: 307-319, 1963
(34) Frantz RA, Kinney CK, Downing DT: A study of skin dryness in the elderly. Nursing Res 35: 98-100, 1986.
