Micronized vs. Nanosized
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free skin care · Fri Jun 09, 2006 5:35 pm

I've only ever seen these words used interchangeably with each other. However recently on here with the concern of Nanosized particles brought up, people have said that they have written companies and they told them that they don't use Nanosized minerals but only Micronized minerals or something. What is the difference between the two? They are both particles extremely reduced in size. Is there any significant difference in the size of each type of particle?

"The US Patent Office has defined a nanomaterial as a material with one dimension less than 100 nm, or 0.1 um. Nanomaterials are generally in the 1-100 nm range and can be composed of many different base materials (carbon, silicon, and metals such as gold, cadmium, and selenium)."

"Micronized titanium dioxide (40 nm) is currently being used in sunscreens and cosmetics as sun protection. The nm particles are transparent and do not give the cosmetics the white, chalky appearance that coarser preparations did. The nm particles have been found to penetrate into the stratum corneum and more deeply into hair follicles and sweat glands than um particles though they did not reach the epidermis layer and dermis layers (Laddeman et al., 1999). There is also a concern that nm titanium dioxide particles have higher photo-reactivity than coarser particles and may generate free radicals that can cause cell damage. Some manufacturers have addressed this issue by coating the particles to prevent free radical formation. The FDA has reviewed available information and determined that nm titanium dioxide particles are not a new ingredient but a specific grade of the original product (Luther, 2004)."

http://web.mit.edu/environment/ehs/topic/nanomaterial.html

"Consumer exposure to engineered nanoparticles presents another exposure route for these materials. Engineered nanoparticles are used in personal care products, ranging from cosmetics to sunscreens, where decreasing the size of active ingredients, typically pigments, yields better performance18, 19, 20. It is impossible to assess the quantities and types of nanoparticles in such products as such information is often protected from public disclosure by trade secrets. Moreover, the US Food and Drug Administration (Rockville, MD, USA) ruled in 1999 that for sunscreens, 'micronized' titania was not a new ingredient, thus providing little incentive for toxicological studies of particle additives21."

http://www.nature.com/nbt/journal/v21/n10/full/nbt875.html;jsessionid=C19B4C2F618E843C4607305CC9D09E25#B18

So unless all those "only micronized" mineral companies are using micronized minerals larger then 100 nm, I guess they are just blowing smoke at us that it is any different then "nano" size particles.

To say I am confused is an understatement. Maybe we should just be asking these companies exactly what particle size they use. What NM size is the ingredient and forget what they care to call or label it as to confuse us. Should be over 100nm I guess?

free skin care · Fri Jun 09, 2006 7:05 pm

Thanks for the information BYRG -- I had been wondering about the difference between nanosized particles and micronized since reading that earlier thread on nanoparticles. My sunscreen contains titanium dioxide and since it goes on clear, it must be micronized. I would like more information so I know if I need to be concerned about that. Hopefully, we have an expert on the forum that can shed some more light on this issue.

free skin care · Mon Jun 12, 2006 9:01 am

BRYG let me start by saying that I have no clear cut answer.

The definition that you gave of Nanoparticle 100nm or smaller is the definition I keep seeing over and over again so I believe that is the generally accepted definition for a nanoparticle.

Here is my analysis of the whole micronized v. nanosized based on all I have read and how the terms seem to be used. If anyone knows differently please comment!!

As to the word micronized this word is used ambiguously by manufacturers etc. I don't think it is appropriate to think of micronized as a particle size. Micronizing is a process that you do to something to create very small particles. It seems that from the quotes in your post and just from things that I have read in general that micronized is used to describe things that have been made to a nanoparticle size and things that have been made very small but larger than nanoparticle. So therefore zinc oxide that is 150 nm (not a nanoparticle) can be described as micronized and zinc oxide that is 30nm (a true nanoparticle) can be described as micronized. I don't think that the words micronized and nanosized are strictly interchangable. A particle (let's say 20nm) can be both micronized and nanosized but a particle (let's say 120nm) would be micronized but not nanosized.

If you want to use the terms microparticle and nanoparticle I would think that the analysis would be the same. A microparticle would be anything micron size (a micron is 1000nm) or smaller which could possibly include nanoparticles. I think the definitions work such that a particle could be refered to as both a nanoparticle and microparticle (say a 30nm particle) but a particle that is say 150nm would only be referred to as a microparticle since it does not meet the definition of nanoparticle. I also think that unlike the word micronized, nanoparticles are generally used to describe particles under 100nm while microparticle is generally used to describe particles over 100nm. However, I think this is a matter of conventional language usage so there is also some ambiguity in how the word microparticle is used.

Honestly I don't think that companies are blowing smoke. When they say they are using only micronized minerals yes technically they could be using nanoparticles. But if a company that claims using micronized particles says that they are NOT using nanoparticles I would think it would be safe to assume that they are using micronized particles that are larger than 100nm. Recall a particle does not have to be a nanoparticle to be micronized. In all honestly making a true nanoparticle is not an easy manufacturing process and I honestly don't think that companies are throwing a bunch of nanoparticles in their products and referring to them as only micronized to try to cover up their nano content.

I honestly think that your last statement sums up what we need to do. Since the word micronized is used ambiguously we really do need to check with companies and ask them specifically if they are using nanoparticles. If you want leave nothing to chance: ask for the particle size or define a nanoparticle as any particle 100nm or smaller and ask if their product contains nanoparticles. You could also ask for the trade name of the zinc oxide, etc. that they are using and then research the actual ingredient. I have done this with Z-cote (not a nanoparticle) and with ZinClear (definetly a nanoparticle).

free skin care · Mon Jun 12, 2006 9:04 am

From Wikipedia.org:
A nanoparticle is a microscopic particle whose size is measured in nanometres (nm). It is defined as a particle with at least one dimension <200nm

free skin care · Mon Jun 12, 2006 10:15 am

Thanks TheresaL. That makes perfect sense. Of course. I just meant that it doesn't rule out that it is not nano-size when I see a company list their minerals as micronized. I guess it just means I have to email every company and find out the size and source. Too bad so few companies ever write back when I contact them about a question. The article seems to claim that it's showing up in a lot of cosmetics. I mean it might not be an easy manufacturing process, but these companies don't have to manufacture it themselves. They just buy it from a supplier who could be making the base material for tons of companies and customers. And if it is the cutting edge, hot new thing to do to make their products nicer, esp. sunscreens, I can see a lot switching suppliers of their minerals to keep up with the competition. No one likes pasty sunscreens. I know Lerenim coats their micronized minerals with Dimethicone. I guess that helps. I'll have to find out what size all these companies are using. I wish it all was just listed instead. Only The Organic Makeup company talks about what size particles they use.

free skin care · Mon Jun 12, 2006 11:22 am

BYRG I am with you on this, I really wish we didn't have to be detectives to find out what is in our products!! I have found that most companies will respond to my product questions, although I have not asked too many about nanoparticles. If I email a company several times and they do not respond then in my book that really counts as a mark against them. If it is an ingredient question then a non answer means that I will not use the product!

In reference to the Friends of the Earth report listing a lot of products that have nano content (I believe this is the report you are talking about) I am skeptical about some of the products that they list as having nano content. The FOE report does define a nanoparticle as beign less than 100nm but there are some products on their list that do not have true nanoparticles (Skinceuticles to name one). I am sure that some of the products on their list are nano but I know that they are not all nano.

Sunscreen wise I am not so sure nanoparticles are the best. Yes they may be more transparent and offer a better looking sunscreen but I think that they offer less UVA protection ( I am currently looking into this so I don't want to state this as a fact) even though they advertise otherwise!!

Unfortunately it seems like natural/organic oriented companies are actually using this nanoparticle stuff. The only two products I have seen that contain ZinClear nanoparticle zinc oxide are by Keys and Organic Pharmacy, both natural/organic companies. I hope that this is not a trend that others will follow!!

free skin care · Mon Jun 12, 2006 2:50 pm

Yeah, deffinetely. So far Miessence and Larenim wrote back. Miessence said they do not use nanoparticals. And Larenim said, "With the coating, the titanium ranges around 150 nm." I'm still waiting to hear from Jane Iredale, I wrote them twice so far, weeks ago. I know that it does reflect badly to me when a company doesn't write back, but I know they might have an unorganized email system or an unresponsive employee, rather then them just trying to hide something. Who knows though.

I found another article that said -
"Nanotechnology is the next new thing in cosmetics and skincare. Owen may be ahead of the field, but he's not alone. Very small particles of titanium dioxide (although at 2,000 nanometers, they are 10 times larger than his) are already being used in sunscreens, because they disappear completely into the skin, providing an invisible protective layer."

http://www.organicconsumers.org/bodycare/nanoparticles.cfm

All these numbers being thrown around. First it was <100nm, Wiki lists it as <200nm and now they are saying 2,000 nm is super small and enough to make sunscreen invisible?

Then this one has the 0.1 micron again.
http://organicmakeup.ca/CA/titaniumdioxide.asp

Washington post article:
http://www.washingtonpost.com/ac2/wp-dyn/A1487-2004Jan31?language=printer

"Titanium dioxide, for example, is a generally nonreactive substance used in many products, including skin lotions and house paints. Increasingly, however, it is being made in the form of nano-size particles. And tests show that they are highly reactive, generating chemically "hot" free radicals that can literally burn up bacteria. That has some experts worrying about impacts on soil ecology if the particles are released."

"Scientists also want to know what happens to nanoparticles months and years after their release. Researchers at Rice University's CBEN have shown that like many other nonbiodegradable pollutants, they accumulate in living things over time, with ever-increasing concentrations in microbes, in the worms that eat those microbes, and in animals higher up the food chain."

Brain damage article:
"Regarding the results of her buckyball toxicity study, Dr. Oberdörster
warns, "Given the rapid onset of brain damage, it is important to further
test and assess the risks and benefits of this new technology before use
becomes even more widespread." Though it is known that nanoparticles can
cross the blood/brain barrier in humans, it is not yet known whether they
will cause the kind of damage found in Oberdörster's fish."
http://www.organicconsumers.org/foodsafety/nanobrain040504.cfm

Basically I just want my minerals to sit on top of my skin and not to absorb into my skin cells or bloodstream like chemical sunscreens do etc. That's why I want the minerals in the first place. Just wash it off, it's not supposed to become a part of me. It also sounds like it's bad for the environment and the effects are unknown, like GMO's sort of. Basically no matter what one article or study says and another saying that they are safe for us, it's just too new of a technology for me to trust, esp. since there are so any concerns about it among the scientific community.

And here's a pro interview:
http://www.abc.net.au/rn/science/ss/stories/s1480390.htm

free skin care · Mon Jun 12, 2006 4:46 pm

BYRG I agree that when a company does not respond to an email it doesn't necessarily mean that they are hiding something but it does mean that they do not have good customer service. Personally, I do give them serveral opportunities to respond before I write them off as having poor service.

I am sure that there are several definitions of nanoparticle floating around but the one that seems to be used most often is the 100nm or less one. Obviously not everyone will agree on this definition and that is why I said before that if you are asking a company if their product contains nanoparticles it would be best to give your definition of a nanoparticle so there is no confusion.

I also feel that it is too new a technology to trust, there are just too many unknowns. But I do have a way of looking at this stuff. I have a rough idea in my mind what I am willing to use, what I would need to research more before I would use it and what I would not use. I am not saying that I have made up my mind on this and will do no more research (I love researching stuff!) but I have for the time being developed a way to look at this which allows me to make decisions about whether I will use something or not. Would I use a sunscreen with 90nm zinc oxide? Yes. Would I use a sunscreen with 50nm zinc oxide? Not without researching it to see if there is any evidence to warrant it's safety. Would I use a sunscreen with 30nm zinc oxide? No. Would I use any product with buckyballs (fullerenes)? No.

Your answers to these questions may be different and that is okay. We all have to try to asses things and determine if it is safe or not. In this day and age that is not an easy thing to do!!

free skin care · Thu Feb 01, 2007 9:11 am

BYRG someone posted a link to this thread and I thought I would add some comments since my mind has changed on a few things.

Warning ramble ahead!!!! If you don't want to read about my wonderings and thoughts then stop now!

Do I have anything to add to the debate about what makes something a nanoparticle? No not really. I am not even sure that the scientific community feels a certain way about this. So I don't feel so bad that we couldn't really pinpoint what seperates nanoparticle from microparticle!

Now to reasses what I feel comfortable using. Of course this too is subject to change as I do more research......
Would I use a sunscreen with 90nm zinc oxide? Yes but only if it is coated. I also feel this way about 90nm titanium dixoide but the comfort level with this is a little less than for the zinc oxide.
Would I use a sunscreen with 50nm zinc oxide (or titanium dioxide)? Still researching but would be very close to answering yes as long as it is coated.
Would I use a sunscreen with 20nm zinc oxide or titanium dioxide? No. But the more I research this the more it seems that I may switch to answering yes someday at least for the coated particles.
Would I use a product with fullerenes? Okay here is where I have really changed my mind. Yes I would use a product with fullerenes. I have since learned that there is a difference between C60 and nanoparticle C60 (you actually have to do something to the fullernes to make them nanoC60, they don't naturally occur that way). The C60 that is appearing in skincare products is not nanoparticle. I would have to do more reseach before I felt comfortable using the nanoC60 though.

It really seems that in the case of nanoparticle sunscreen ingredients or fullerenes the more research I do the more comfortable I become with the idea of using these ingredients. It is human nature to be afraid of what we don't know and that is a good thing. Personally I feel very strongly about not messing with something that I don't understand or that might pose a danger. Yet I guess the best thing to do in these situations is to do the research so that I can make a proper decision that is not based on "unknowns".

Here is a little aside but it is somewhat telling. I have not clue what size particle the zinc oxide is in my Sofina sunscreens and in all honesty I don't think I could find out since it is a brand not sold in the US. Yet on some level I continue to use it and don't ask questions. I don't wonder every morning what size the zinc oxide particles are or if they are coated. So maybe somewhere deep in my mind I have drawn some conclusions and they aren't necessarily the same ones that my thinking mind which made the comments above has concluded. Yet once in a while I will say to myself maybe I should really take a close look at this sunscreen to see if I want to continue using it. Is that a contradiction? Am I contradicting everything I said about what size zinc oxide particles I would use and whether I would use uncoated ones? Maybe I should rephrase the above statements about zinc oxide in light of what I am actally willing to use. Well..... I will just leave them as is. I guess my no's mean I still have concerns but am willing to take a chance. For now anyway. Maybe someday I will get too freaked out about the possibility that my Sofina might have uncoated nanoparticle zinc oxide. But then again maybe not?

It is never easy and rarely cut and dry...........

free skin care · Thu Feb 01, 2007 11:59 am

TheresaL - this is a copy of my recent post in the other thread... it is probably more appropriate here anyway.

Titanium dioxide vs. Zinc accordiing to UV Natural:

"Nano Particles - Is there something I should know?

Recently there has been a flood of questions relating to the safety of nano particles. In other words, should you be concerned? The answer is yes. Some nano particles are extremely active and dangerous to the cell BUT not all. It is important not to get caught up in the hype and wave of fear and panic. The only way to be sure is to read broadly and arm yourself with information.

Nano Zinc and nano titanium are often (mostly) grouped together and this is unfortunate as they behave differently. Titanium is toxic to the cell whether it is macro, micro or nano; zinc is not. Titanium is photoreactive (produces free radicals and damages DNA) whether it is coated or uncoated whereas uncoated zinc is slightly photoreactive BUT coated zinc is NOT.

It should not surprise you at all to learn that UV natural uses coated Zinc only. The zinc used in UV Natural does not penetrate into the bloodstream and affect serum zinc levels."

http://www.uvnaturalusa.com/htm/whats-new.asp

This is from one of their doc. downloads: (Nano zinc Vs nano Titanium.)

"I have scoured the documents available on this matter and I have made the following findings:

1. The two ingredients, Titanium Dioxide and Zinc Oxide are often collectively referred to in the heading, introduction and summary of the various articles yet the damming data regarding toxicity in the main body of the document refers to Titanium and not Zinc Oxide. They seem to be referred to collectively as they are both prominent sunscreen ingredients, yet they behave differently as nano particles.
2. The various “tidbits” of information on the internet seem to loop amongst each other referring to the same body of articles and then using each other’s sites as sources of reference. In essence the same thing is being said without any new information, just more people are quoting each other from the same document.
3. Titanium Dioxide is toxic at the macro and nano level whereas Zinc oxide is not. Zinc is in fact required by the cell for a number of essential functions and the cell would die rapidly without it.
4. Titanium Dioxide, coated or uncoated is photoreactive, coated Zinc oxide is not.
5. Titanium Dioxide is not a true physical sunscreen, it absorbs 70% of UV light and only reflects 30% whereas coated Zinc Oxide reflects much closer to the 100% range and is a true physical sunscreen.
6. Coated Zinc Oxide is NOT photoreactive and therefore does not product hydroxyl ions (free radicals in question) whereas uncoated Zinc oxide and Titanium Dioxide, coated or uncoated do.
7. UV Natural uses coated Zinc oxide.
8. UV Natural chose its ingredient list very carefully and we avoided the common sunscreen ingredients due to their toxicity.

UV Natural continues to research and develop new products with a constant vigil of using safe ingredients. We maintain an awareness of current research and data on toxicity issues and develop our products in line with information available at the time."

Are they right? Don't know but thought their opinion was interesting. I came across another producer of natural/organic sunscreen who refuses to use zinc at all, only coated TD.

free skin care · Thu Feb 01, 2007 12:22 pm

Do you know why the other company chose the coated titanium dioxide and refuses to use zinc oxide? It would be interesting to compare their reasons with the reasons given above for zinc oxide.

I have a definite preference for zinc oxide though and would not use a sunscreen that is only titanium dioxide since IMO titanium dioxide does not offer adequate protection against UVA rays. In fact I don't even like sunscreens that are mostly titanium dioxide with just a little zinc oxide. Even safety wise I have to say that I feel alot more comfortable with zinc oxide.

Sat Mar 03, 2012 2:49 am

Thanks for the information BYRG. I found another article:Micronization is the process of reducing the average diameter of a solid material's particles.Nano-sized means having a size measured in nanometers and a nano-sized material is not necessarily a nanoparticle. The average particle size in Micronised Silica powder in below 5 microns.

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