MYTH – the feet are the best place to apply essential oils because the feet have the largest amount of pores to absorb the essential oils.

This is a MYTH because chemicals or ingredients are primarily absorbed into the body through the epidermis, not by entering through the sweat glands (invisible pores) or hair follicles (visible pores).

So neither the size or quantity of pores in the skin actually determine how much of a topically applied product is absorbed.

Here is a link to a very basic article that easily explains skin penetration and absorption: http://personalcaretruth.com/2011/01/the-impermeable-facts-of-skin-penetration-and-absorption/

You will notice pores are not mentioned.

583px-skin-291x300That is because the function of pores (aka follicles) are the openings in our skin where a hair comes out, and dead cells, sebum exit. Pores are primarily exits, not entrances. Not for products, ingredients, or chemicals – even essential oils – to enter.

What about our sweaty feet – they aren’t (thankfully) hairy – don’t we have the most pores in our whole body on our feet?

No. Feet have a lot of sweat glands (250,000 each) which are different from pores like we see on our face, for example.

“‘Skin pore’ is a term used by lay people and in the field of cosmetology. It remains misleading when it is not clearly defined. Indeed, lay people use it with at least 3 different meanings. Basically, invisible pores represent the openings of the sweat gland apparatus. By contrast, the visible pores represent enlarged empty funnel-shaped or cylindrical horny impacted openings of pilosebaceous follicles.”

http://www.ncbi.nlm.nih.gov/pubmed/15604536

So the question – do products applied topically get absorbed through the sweat glands?

“Absorption via the pores and follicles is considered to be insignificant because the orifices account for only 0.1% of the skin area and diffusion along sweat ducts is against an outward aqueous flow (4). Lauer et al….”

Percutaneous Absorption: Drugs–Cosmetics–Mechanisms–Methodology: Drugs edited by Robert L. Bronaugh, Howard I. Maibach

skinlayers-300x297So so summarize – how does dermal absorption work?

“The epidermis (and particularly the stratum corneum) is the only layer that is important in regulating penetration of a skin contaminant.”

“The thickness of the stratum corneum varies greatly with regions of the body. The stratum corneum of the palms and soles is very thick (400-600 µM) whereas that of the arms, back, legs, and abdomen is much thinner (8-15 µM). The stratum corneum of the axillary (underarm) and inquinal (groin) regions is the thinnest with the scrotum especially thin. As expected, the efficiency of penetration of toxicants is inversely related to the thickness of the epidermis.”

“In addition to the stratum corneum, small amounts of chemicals may be absorbed through the sweat glands, sebaceous glands, and hair follicles. Since these structures represent, however, only a very small percentage of the total surface area, they are not ordinarily important in dermal absorption.”

http://www.eoearth.org/view/article/149799/

Then there is the reflexology spin that some salespeople put on the reason to use the EOs on the feet – this article addresses that: http://www.thebarefootdragonfly.com/essential-oils-and-the-feet/


 

“The soles of the feet absorb more slowly because they have no hair, and because of the mostly thicker skin. “

“The soles of the feet and palms of the hands contain many eccrine (sweat) glands, through which water is released onto the skin. Since essential oils are not water soluble, they cannot use these glands to bypass the skin barrier. Not even water-soluble substances enter the body through sweat glands. If they did, we would put on weight after a swim or a shower. The palms and soles have no hair follicles. Hair follicles contain sebum, an oily substance, and there is some evidence that essential oil constituents are able to use this route to bypass the skin barrier.”
–Robert Tisserand, Robert Tisserand Essential Training [Facebook Group]

As originally published on Aromatherapy United website; Apr 20, 2014, by Susan Sawhill Apito
MYTH – Apply to Feet
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