Teach Soap

I made a wintergreen lotion bar (for my own use only) for my neck and back pain from arthritis. I've been reading about it and one book I have recommends diluting into a carrier oil at a 1:4 ratio, making it a 25% wintergreen solution. I wanted a lotion bar instead of a carrier oil alone because I was thinking that it would be easier to store, carry, and maybe instead of being absorbed rapidly it would be over a greater length of time due to the thicker lotion bar sitting on the skin. Any thoughts on lotion bar vs oil or cream?

I have been reading as much as I can find from reliable sources (not easy to find reliable sources on the net!) on topical absorption of wintergreen. It's kind of scary that 5 ml of wintergreen oil is equal to 7000mg of methyl salicylate, or about 21 adult aspirin. However, one site I was reading cited a published journal article written by Ron Guba, who of course is supposed to be some sort of expert, stated that 10 ml (a heck of a lot!) of a 25% solution would result in topical absorption of 1 aspirin. I looked around the web and can't find anything else to substantiate that.

I am wondering if anyone knows of any research done on topical absorption of essential oils?

Edited to add that I began wondering if the company can tell me what percent of methyl salicylate their product has, if it is 98% like a real undiluted oil or if they dilute it. I emailed them and am awaiting an answer.

10ml of a .25 solution is equivalent to 2.5ml of non diluted EO. Dilution shouldn't change the absorption rate significantly unless the absorption rate of the carrier oil is vastly different from that of the EO. One would need to look at the absorption rate of the specific carrier oil to calculate any change in EO absorption. IE: jojoba has an incredibly fast absorption rate due to its similarity to human skin oils and sebum, dilution of 25% wintergreen into jojoba would increase the absorption properties of the EO, making it enter the body faster than straight EO. This would mean that a 25% solution of wintergreen in jojoba would be more concentrated (in the body) than 2.5ml of straight, undiluted, EO.

In a solid lotion bar absorption from a 25% solution would be considerably slower due to the wax (and slightly dependent on the heaviness of the oils used).

That's my science for the day! I'll leave the EO chatter to those who know tons more than me! *looks for irena*

[PS hope your arthritis pain feels better asap!!!]

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~~Heather~~
Mad [soaping] Scientist

In my research, most of the wintergreen oil available on the market in the US is a synthetic. With that said, here is an article and replies from Robert Tisserand, whom I trust. http://roberttisserand.com/2012/03/wint ... il-safety/
Here is another post worth reading. http://www.naturesgift.com/birch.htm

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Irena
Closed minds are like faulty parachutes; they refuse to open.

Thanks for the science info and links Hetsey and Soapbuddy! I agree, I think the wax in a lotion bar may decrease absorption rate, but it's still hard to know just how much is absorbing. I looked up Bengay and their strongest cream is 30% to be used not more than 3-4 times/day.

The company I purchased from sent me their MSDS sheet and the methyl salicylate content is >99% so it's a true EO. It doesn't have absorption rates listed, but they do state the general usage rate is 0.5-5% in a soft carrier oil depending on the use. I can say that my lotion bar works wonderfully for a few hours, I had to try it once, but I think I am going to reformulate using a much smaller percent. I want to use the smallest percent that will help. (I've had arthritis for years, I was relatively young when it started, and I take a lot of Ibuprofen or Naprosyn when I have exacerbations. I was thinking a nice lotion bar would take the place of taking soaps but the soaps definitely last longer and give a predictable dose, so not sure it will benefit me.)

Although the links are wonderful (I'm going to fully explore both sites after reading those pages!) I'm pretty sure I'm not going to find info about topical absorption rates. My guess is that there haven't been studies done, and most people who site amounts to use are just guessing based on the lethal ingestion data. I'm going to keep looking and ask around when I go to work tomorrow.

Edit: Wow, the word p.i.l.l.s gets changed to soaps for some reason. I take p.i.l.l.s, not soaps, lol.

When you said "taking soaps" I thought you were meaning to say soaks, like soaking in a warm tub.... that is just funny!
I am interested in this as I also have arthritis... and we all know that it rarely just goes away!
I am thinking that there would be several variables to account for in the absorption: covered or left open, clothing warn over, how clean the skin is, skin temp... maybe even time of day, say having to do with metabolism, Skin types. And then bring in all of the inert ingredients with their rates of absorption. That would be quite the study.
I will spend some time tomorrow reading the links Soapbuddy gave us... interested in the real stuff vs synthetic?? My pain rub (like a bengay) states 30% mentyl salicylate. At work the doc's are moving away from the pain rub to capsasin or lidocaine gels.

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Susie
Sometimes A Mistake is so much fun, You just have to do it again!

Let us take Wintergreen oil as an example. The acute oral rat LD50 is 1.2. In humans, however, methyl salicylate does appear to be more toxic. Given the numbers of fatalities in years past, with the amount ingested being known in a number of cases, we can estimate a human LD50 of 0.3. For a 60 kg adult, this would translate to the ingestion of about 18 grams. (5)
Now, let us say that we want to apply a 2.5% dilution of Wintergreen oil to our sore lower back. We then apply 1 mL of this preparation...
http://www.agoraindex.org/Frag_Dem/toxicitymyths.html
1mL x 2.5% = approximately 0.025 grams of methyl salicylate.
0.025 gms ö 18 gms (LD50 dose) = 0.00139 or 0.139%.

Hence, the applied dose is only 0.139% of the lethal dose - or more than 700 times less!

Of course, if we increase the amount applied of the 2.5% formula, we increase the dosage received. Hence, if we applied 10mL of the formula all at once, the dose would now be 0.25 grams or 250 milligrams. Putting this into perspective, even if the methyl salicylate was totally absorbed, this dose would represent the same amount of salicylate compounds as found in one tablet of aspirin...
Wintergreen and Sweet Birch essential oils are routinely mentioned as oils to avoid in Aromatherapy, even for trained practitioners. Members of the International Federation of Aromatherapists take a "vow" not to use Wintergreen essential oil. (6)
Yet, we have the strange contradiction of many methyl salicylate-containing topical products (containing from 10% to 30% methyl salicylate) being readily available to the untrained public - with very few negative side-effects reported (methyl salicylate, even used topically, is contraindicated in people taking the anti-coagulant drug, warfarin). (7)
Even with this relatively toxic compound (as I would suggest that any essential oil with an LD50 of less than 1.0 is), an effective anti-inflammatory preparation can be used with no potential for toxic effects.

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Irena
Closed minds are like faulty parachutes; they refuse to open.

Don't they add absorption blockers to most of the topicals though? I read that somewhere, that they add compounds that stop absorption into the blood stream / liver, but allow for absorption into the muscles and soft tissues.

No idea where I read that though

Edit: I asked my hubby (a medical professional) and he agrees that they add a carrier molecule that blocks blood stream / liver absorption.

_________________
~~Heather~~
Mad [soaping] Scientist

Who is the "they" Heather? Certainly a molecule can be added, but EO's do not contain such. Maybe I missed a comment and am not on the right page, if so, my apologies, just ignore me! Lol
Anyway, the max use rate for Wintergreen EO is 5% for almost all categories of product, those that are not 5% are 2% (nail, hair and makeup remover items) and 2.5% (pet shampoo, wipes, cleaners and laundry and dish detergents). As long as you are not allergic to aspirin and stay at or below the 5% use rate, the concentration should not be an issue.
**As a reminder, anyone who sells or gives away anything with wintergreen in it should place warning labels for those unaware that cross sensitivities may exist for those with aspirin allergies.

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Remember, it's not just that we weather the storm, but how we dance in the rain.

Tammy

I wouldn't bet on anything like that being added, they would have to list it as an additive, wouldn't they? I've read so many things on line that don't hold true. One being that Wintergreen is supposed to come with a child proof cap, and mine is in a regular bottle just like my other oils. Something else I read said that Wintergreen is now made diluted to a safer level, but the MSDS sheet shows what I would expect for the real EO.

I would not even venture to use this as an additive at a safe level in something I would sell, I feel like the liability is just too high. I wanted to use it for myself, but don't want to overdose myself in the process. My mom said she would like to try it, but I am hesitant because I worry that once out of my hands it might get into someone elses hands who have a reaction or over use it, and I would not like if one of my products was the cause of harm to anyone.

No, you are right, there is no such additive in an EO's. It wouldn't be an EO if there was, but there is in certain drugs, like time released patches and such. No, wintergreen doesn't have to come with a childproof cap, nor have I ever seen one come that way. But drugs don't have to either. It may be a standard practice for safety concerns, but if you don't want a childproof cap you can ask for a regular one.
The amounts of salicylate in EO's is now lower than years ago, so yes, it is safer now than in years past. There are other components in various plant materials that have been lowered over the years as well. As science and studies prove out, the world and standards change, such is life.

As long as you stay at or under the 5% and have no adverse reactions to aspirin, there should be no problem using wintergreen eo. I understand you not wanting the liability, but there again, if you use it properly and give the proper warning (since many people are unaware that it contains salicylate or even that having that means that they may be allergic - if also allergic to aspirin) there should be no issue.
I have some wintergreen, but I rarely use it for anything because I am allergic to aspirin, as are many others. For this reason, I do not set anything made with wintergreen on my open shelves. I do, however, have requests for products that require its use. When I do use it, I am careful to wear gloves and to properly label the final product so that anyone who may come in contact with it, the purchaser as well as others, will know that it contains something they may have issues with. I also suggest that everyone performs a patch test when using new products and new scents (eo's and fo's), just in case there is an issue. I have never had any problems or complaints in doing business this way, but we all need to be comfortable with what we do. If I didn't have a certain few of my longtime customers, I probably wouldn't ever sell another wintergreen product. But, if I weren't allergic to aspirin, I probably would use it in my personal liniment! Those that use it seem to find good relief from doing so!

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Remember, it's not just that we weather the storm, but how we dance in the rain.

Tammy

"They" being the producers of the high percentage topicals that were one of the centers of topic before my previous post.

_________________
~~Heather~~
Mad [soaping] Scientist

http://www.essentialoils.co.za/banned-oils.htm here is a link to essential oils that should not be used in B&B or soap.

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Irena
Closed minds are like faulty parachutes; they refuse to open.

Good link, thanks!