# Harvesting



## woodchuck (Dec 22, 2009)

Will harvesting Marijuana get on your skin and make you test posotive for smoking it.


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## ftw2012 (Dec 23, 2009)

i really dont know but i would guess no...ive never caught a buzz from it soaking through my skin..


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## 420benny (Dec 23, 2009)

I have trimmed for hours in one session with very sticky fingers covered with finger hash and I swear I got a buzz from the experience. I may be full of it, or I was already stoned and forgot, lmao. benny thinks a contact high is possible. Discuss, lol


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## GeezerBudd (Dec 23, 2009)

Benny,
I had exactly the same experience just the other day.
Could it have been adrenaline?

Is it live or is it Memorex!!-lol

Get you some exam cloves, woodchuck.
oh yeah..
Here..
:48:
pass it on..

Gb


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## pcduck (Dec 25, 2009)

*1green* one should make their own thread when they have a question, after researching and not try to hijack someone else's :bolt::bong2:


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## gmo (Dec 25, 2009)

This thread got me to google'ing.  I found a very interesting article about the "THC Limits for Food".  This is an exert that should somewhat answer the OP's question.

From *hxxp://www.hempfood.com/thclimits2a.html*


*
Excursus II: THC in cosmetics and dermatics*



Substances that are applied to the skin can be systemically absorbed to an unknown extent. However, there have not yet been any quantitative studies of the dermal absorption of THC that would allow quantification. Nevertheless, this question is vital for the use of THC-containing products that are externally applied (cosmetics, dermatics for the treatment of neurodermitis). The physico-chemical characteristics of THC, however, allow a rough estimation of the amount of THC assimilated (Kalbitz et al. 1996, 1997).

Generally, the human skin is well protected against penetration by external substances. Many topically applied substances attain a systemic bioavailability of only a few percent (Hadgraft 1996). The main barrier to penetration is the cornea (stratum corneum), or more accurately, the cornified layer of the stratum corneum. In principle, substances can penetrate the space between the cells of the stratum corneum (intercellular), the cells themselves (intracellular), or the sebaceous and perspiratory glands and hair follicles. Only the first pathways of penetration generally play a relevant role (Hadgraft 1996, Kalbitz et al. 1996, Berti et al. 1995). For example, the route through the hair follicles and glands is of importance for polar molecules only. As a lipophilic molecule, THC does not belong to that group.

The permeation coefficient or, respectively, the permeability constant (Kp) constitute a quantitative expression for the ability of a substance to permeate the skin. The flux or absorption rate of a chemical results from a multiplication of the concentration (C) of a chemical on the skin surface with the permeability constant: flux = KpC (Mattie et al. 1994). The basic principles of absorption through the skin correspond to those of diffusion through semi-permeable membranes (Berti et al. 1995). Factors that influence the penetration through the skin are the thickness and condition of the skin, as well as the size of the penetrating substance and the carrier.

Molecules that enter and diffuse through the skin have to penetrate a number of lipid bilayers in the intercellular space, thereby repeatedly alternating from lipophilic to hydrophilic areas. Those molecules that are sufficiently lipophilic, such as glucocorticoids, easily cross those lipophilic phases. Thus, most publications still maintain as a rule that "highly lipophilic compounds with low molecular weights demonstrate the greatest flow rate through the stratum corneum" (Berti et al. 1995).

Occasionally, a direct relation between the coefficient of permeation and the octanol/water distribution coefficient is postulated (Guy 1995). The latter is a measure of a chemical's lipophilic and hydrophilic properties, respectively. A higher coefficient indicates stronger lipophilic characteristics. However, such a correlation could not be verified in experimental studies. Mattie et al. (1994) examined 13 substances with octanol/water coefficients ranging from zero to 1,400. The constant of permeability correlated only weakly with the octanol/water distribution coefficient (r2 = 0.04).

Instead, there is evidence that only a small fraction of strongly lipophilic substances, such as THC, overcomes the hydrophilic phases of the intercellular space. Gabriele Bast (1997) carried out a large number of experiments that involved different substances of differing lipophilic characteristics in different carriers, and stated: "When substances are applied in a lipophilic carrier the permeation coefficient Kp is notably decreased when the distribution coefficient (n-octanol/perfusion buffer (pH 7.4)) Poct exceeds 2000."

*Conclusion: It may validly be assumed that, with an octanol/water distribution coefficient of 6,000 (Agurell et al. 1986), i.e. a strong lipophilic tendency, only a small amount of THC permeates the skin-and is systemically absorbed only on a small scale-when administered in an oily base, such as in cosmetics containing hemp oil. Based on experimental evidence obtained for other chemicals with known physico-chemical properties, the transdermal systemic bioavailability of THC thus is likely considerably less than the oral systemic bioavailability. Corresponding experimental studies should be conducted that quantify the exact rate of skin permeation.
*


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