Glyphosate through your skin

April 2015
Your skin is the largest organ of your body. It consists of an underlying layer of living 'dermal' cells which grow continuously, and at the same time undergo a special form of programmed death. This proliferation and die-off is carefully orchestrated to produce, and continuously maintain, the protective outer 'epidermis'. The epidermis is waterproof, elastic, and provides a barrier to biological, physical and chemical damage.

Skin function is vital to health. Its function depends on the integrity of its structure. And its structure depends on the integrity of the living dermal cell physiology.

In the modern world, our skin is exposed to a host of potentially harmful chemicals.

One such chemical is glyphosate herbicide, widely used in rural and urban weed control, and heavily sprayed on GM crops, most of which have been genetically transformed to survive it.

Glyphosate has long been percived as 'safe as salt' [1], and any risks arising from normal skin exposure have not been an issue. Because the herbicide is highly water-soluble, it's assumed to have little tendency to enter the 'waterproof' epidermis and even less tendency to move through the fatty cell membranes of the living dermis below.

Guidelines from the OECD (Organisation for European Co-operation and Development) specify the use of healthy skin in laboratory tests. In the field, farmers are exposed to glyphosate all the time they are spraying, but are expected to be using prescribed agri-chemical handling techniques, including personal protective equipment. 

But, do these ideal circumstances of healthy skin and good handling practice reflect the real-life situation? 

Skin, by its nature is often compromised, especially in outdoor workers, by cuts, scrapes, chemical damage, water-submersion, burns, sensitivity reactions, eczema, and infections. Science has shown that glyphosate deposition in damaged skin is five times that of healthy skin,and penetration through damaged skin is increased twenty-fold. 

The quantities of glyphosate entering the skin are low. However, with repeat doses, especially coupled to a failure to rinse the glyphosate off before it can be absorbed, the situation is changed because science shows that glyphosate penetration of skin increases linearly with time. If you've got glyphosate on your skin and allow it to dry on because you didn't know it was there (for example, from contaminated washing water, rain or air), or because you got splashed with herbicide formula and didn't think it was important to remove it (familiarity breeds contempt especially in the case of chemicals with no obvious noxious appearance), your skin will keep on absorbing it. 

Limited case studies of farmers and their families suggest that, even in developed countries, both glyphosate handlers and their close relatives routinely absorb the herbicide during the time of spraying. In developing countries agricultural workers are significantly more exposed to glyphosate: they often don't have the equipment needed to protect themselves, or can't wear it because of the heat (especially when carrying a 20-litre metal sprayer for several hours on end); they often use higher-than-recommended concentrations of glyphosate in the hope of getting better results; their access to facilities for washing contaminated skin may be limited; and no one's checking up on their compliance with instructions nor on their exposure to the weedkiller. 

The OECD testing guidelines used by the agrichemical industry and accepted by regulators seem appropriate only if the the glyphosate entering our bodies really is "safe as salt". 

But the science says otherwise.

There's no longer any doubt that glyphosate can enter cells despite the fatty barrier of their outer membrane.

Dermal cells exposed to low levels of glyphosate have been shown to induce a stiffening of the cytoskeleton (the cell's internal structural support) while higher levels of glyphosate cause gross changes in cell shape. Such physical effects will impair skin elasticity, and compromise vital contact, adhesion, continuity, and communication between the dermal cells. This spells a loss of protective function and vulnerability to disease.

Evidence of glyphosate interference with mitochondrial function is increasingly emerging in the scientific literature. Mitochondria are bodies within cells which are key to the orchestrated cell death needed to form skin: a loss of mitochondrial function impairs the transition of dermal to epidermal cells. Add to this that skin cells are adapted for rapid multiplication and you get a loss of control of skin cell growth which could contribute to cancer [2].

The actual risk might be much worse than that indicated above. The experiments are based on stored skin samples or cultured skin cells treated with pure glyphosate only. Real-life, skin on a body is exposed to glyphosate in the form of 'Roundup' formula. The formula is a combination of glyphosate with adjuvants to help it enter cells. Roundup on skin could present a very different, and much more harmful, scenario.

Indeed, all the science indicates that Roundup is more toxic than chemical glyphosate, and the penetrating properties of Roundup could be the reason for the unexpected readings of bodily glyphosate in farmers and their families during spraying.

Verifiable evidence of what happens when skin is drenched in Roundup and not washed of is scant. However, there is one case study which paints a telling picture.

Two days after being accidently sprayed with a diluted commercial Roundup used in a plant nursery, the skin of the unfortunate subject presented with exuding wounds, bullae (huge blisters), and 2nd degree necrosis with detachment of the epidermis. The affected limb and digits were swollen and blood tests indicated muscle damage and acute phase reactants (tissue trauma markers). In the course of subsequent months, nerve damage emerged with associated bone-loss around the joints.

Other cases of accidental dermal exposure to Roundup have reported local impairment of sensation and rigidity of the extremities leading to Parkinsons' Disease (also see [3]).

Standard skin safety tests don't look beyond acute irritation. We clearly need to take our skin's exposure to glyphosate much more seriously. 

We also need to start testing glyphosate in all the forms our skin actually experiences it, and testing our skin in all condition in which it actually experiences glyphosate. 

As Roundup formulations become ever more varied, sophistated and secret, they all need to be tested for safety. It's time to tell the regulators to throw out all previous 'glyphosate' risk assessments, and start again with Roundup.




  • Celine Heu, et al., 2012, Glyphosate-induced stiffening of HaCaT keratinocytes, a Peak Force tapping study on living cells, Journal of Structural Biology, 178
  • Celine Heu, et al., 2012, A step further toward glyphosate-induced epidermal cell death: Involvement of mitochondrial and oxidative mechanisms, Environmental Toxicology and Pharmacology 34
  • Celine Elie-Caille, el al., 2010, Morphological damages of a glyphosate-treated human keratinocyte cell line revealed by a micro- to nanaoscale microscopic investigation, Cell Biology and Toxicology 26
  • T. P. Mariager, et al., 2013, Severe adverse effects related to dermal exposure to a glyphosate-surfactant herbicide, Clinical Toxicology 51
  • Jesper Bo Nielsen, et al., 2007, Defense against dermal exposures is only skin deep: significantly increased penetration through slighly damaged skin, Archives of Dermatological Research
  • Robin Mesnage, et al., 2012, Glyphosate Exposure in a Farmer's Family, Journal of Environmental Protection

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