Skin, absorption, soap

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Jan 14, 2014
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While I am not an expert, I have spent many hours over the hears researching and consulting experts on the what skin really absorbs, and what can soap do or not do. Some of those experts are pharmacists, anatomists and physiologists. I've been taking college science courses like biology, anatomy and physiology lately as well. My anatomy professor LOVES my salt bars - so we traded soap for hours of my picking his brain about these issues.

In short:

Mommy bloggers, bath/body companies (big and home-based), MLM companies, and others wanting to find a clever marketing pitch to sell products - have perpetuated a bunch of falsehoods, exaggerations, and fears.

Social media has launched that misinformation and falsehoods in a frenzy that has taken on a life of its own. This certainly makes it EXTREMELY difficult for intelligent people to sort through the fray and find the facts.

Fact is: the skin does NOT absorb the degree of stuff the internet says. The skin's function is a barrier; it's pushes outward. Cell operation is very, very, specific about what can enter it due to its chemistry of proteins and enzymes, size of receptors and other factors. If the molecule doesn't fit or have the right chemical charge - it doesn't get it.
*one example of this comes from Vitamin C lotions and serums. There are a few different forms of vitamin C (ascorbic acid, magnesium ascorbyl phosphate, sodium ascorbate, etc) and they come in different sizes of molecules and some are too big to fit into the cell - therefore they aren't absorbed and your money is wasted.

Edited to add: The skin does absorb heavy metals like lead, arsenic. Mixing heavy metals with oil increases the body's ability to absorb heavy metals. This is why I don't use clays (clays contain lead and often other metals in trace to small amounts) in any bath/body product. Now - I doubt a few clay colored bars of soap are going to do anyone any harm due to the tiny amount the lead in the clay, along with the even tinier amount one is exposed to in the soap, plus the fact that soap is a wash off product. However, I have a child in the house; children are always more susceptible to these things, and to simplify my life I just don't use clay.

There are things can encourage the skin to absorb *some* things. Some make it into the blood stream, many don't. Even if they are absorbed, it doesn't necessarily mean that its used by the body. Foreign material is often immediately tossed into the filters of the liver and kidneys.
*One example of this is Emu oil which is sometimes used in the pharmacy to compound items that a doctor wants to be absorbed trans-dermally. However, the two ingredients have to be compatible in order for the process to work.

There are sources of information that claim that oils contain all sorts of vitamins, minerals and other stuff that can cure, treat, or cause a miraculous increase of health and beauty by applying to your skin. Here again - just because the oils contain them - doesn't mean the skin can absorb them because the electrical charge and the size of the molecule are key. (I have some information that *seems* to imply that oils are more inclined to be absorbed by the skin but I have nothing I can offer as fact)

***Even MORE importantly is the way vocabulary terms are used. There's a physiological difference between skin absorption and skim permeability. The internet, bloggers, bath body companies etc. ( and myself throughout this post) do not use the terms accurately. Thereby adding to the confusion.

This article is hopefully helpful for us non-experts:

Last point: soap as medicine or beauty treatment. Any vitamin rich oils used in soap making are transformed by the lye to salt form of fatty acids. They are no longer oils. Lye destroys a huge amount of the vitamins, tears apart the molecular structures of the fats and creates a new thing.

Soap doesn't medicate. (A soap box with the term "medicated" on it isn't the thing. It only means it contains an ingredient that is considered a medicine. That doesn't make it 'act' like a medicine. Ask your local pharmacist or read the FDA pages yourself)

The same is true of using essential oils: most of the essential oils constituent parts are altered/destroyed by the lye - Robert Tisserand himself said so. Lavender is the winner as it actually only loses about 40 - 50%.

My personal experiences: its hard to find a soap maker that doesn't claim that their soap cures rashes, acne, eczema or other skin issues. Some have just drunk the Kool-Aid from FB posts. But there are people who come back to re-purchase their product because they do think their skin improved. I've had people tell me the same. I figure there are 2 possibilities for this: 1) other factors improved their skin - diet, less stress, better environment OR 2) it's what ISN'T in my soap that soothed their skin. Fragrances and detergents are some of the most well known skin irritants.

Post is finished. Anyone still awake??

ETA: clarified some vitamin C details. Also stated that skin does absorb heavy metals.
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Moderator Emeritus
Supporting Member
Apr 2, 2012
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Very well stated. Those are the same conclusions I’ve come to by speaking with dermatologists and other physicians I work with. I’ve worked in the medical field for 40 years next week. I have many physicians who purchase my products because of what they don’t have. I make no claims and I have a problem with those who do. It’s misleading and I hope they have good insurance. I’ve seen people selling soap as a sunscreen. Which is totally irresponsible.

Your research goes even deeper than mine did. Thank you!


Well-Known Member
Nov 22, 2018
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So well said!! This should be tagged/flagged/pinned so that it’s readily available for all to read!
Sep 19, 2011
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Southern California
Well said and thankyou that someone posted this. I think several of us over the years have mentioned this.
It is rather logical that our skin cannot absorb everything put on it. What a lot of trouble we would be in...It is a barrier.

Medicated patches have to be formulated so our systems get use from the medication in them.

Some soap such as salt bars can ease some of the topic issues, but soap will only help momentarily and on the skin surface. We can exfoliate, salt helps ease my itching and heal a little (no miracle), if I use in on any area that is itching and leave it on as long as possible.


Staff member
Feb 11, 2008
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Right here, silly!
Well spoken, lenarenee! I've tried to say as much to a family member who has drunk the Young Living/DoTerra koolaid, but so far it hasn't sunk in/absorbed (maybe I should've coated my advice in emu oil first. Just kidding of course. :p )

IrishLass :)


Well-Known Member
Jun 13, 2008
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Stuck in my head
But there are people who come back to re-purchase their product because they do think their skin improved. I've had people tell me the same.
I think it's the Placebo effect. They think it does, so it does type thing.
And IMO if they were/are using commercial or syndet soaps, and moved to using handmade/lye soaps, honestly, their skin probably has improved, but not to the point of "curing" any ills.

Your post was very well thought out, and written well. As the others have said, thank you for posting. :)


Well-Known Member
Jan 3, 2016
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Thank you for this.

I’ve been musing about the question of absorption for a bit now. I got a soap/lotion set for Christmas labeled “conditioning” with “added vitamin C.” I knew the soap labeling was bunk but wasn’t sure how well the lotion was labeled (not that it matters at the moment, the lotion is no way near holding up to this weather)


Well-Known Member
Dec 29, 2017
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Kranj, Slovenija
The first time it occurred to me that what you put into soap is changed and does not have the original "healing" properties was years ago when someone was selling soap made with mare's milk, claiming its many beneficient effects. And they put the price quite high - for nonexistent benefits. It's good to hear this from experts, thank you for sharing it with our community.

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