× Didn't find what you were looking for? Ask a question
Top Posters
Since Sunday
y
2
m
2
m
2
u
2
m
2
B
2
M
2
e
2
k
2
N
2
y
2
m
2
Home Q & A Board Discussion News Articles and Discussion
New Topic  
Ethan Gascoigne Ethan Gascoigne
wrote...
Posts: 23
Rep: 0 0
4 years ago
Hi, just to start the post by saying I’m not sure if this is being posted in the right place, I struggled to find a forum for this type of question. I am a layman about most of this stuff, but I figured this was the right place to ask.
   
I have been looking at hair glues (adhesives used to attach non surgical hair replacement systems to ones head), and researching the toxicity of some of the glues. We (have been discussing it on a hair loss forum) came to the conclusion that a brand called “ghost bond” was probably the safest, as it is water based not acrylic based. Having read the MSDS sheet for it however, it apparently contains “Acrylate/Copolymer-dispersion” or “Chemical characterisation (substance): Dispersion of acrylic polymers in water.” (listed differently for different products). Having researched this a bit, I found out this in itself probably isn’t harmful, however the monomers used to create it are, and some can be left over after the polymer is produced. I found a study that mentioned this (https://www.researchgate.net/publication/10941612_Final_Report_on_the_Safety_Assessment_of_Acrylates_Copolymer_and_33_Related_Cosmetic_Ingredients) found this exact text block on multiple sites, not sure if there is an original study available for free.

Based on this, and the usage of hair adhesive, I have a few questions about the possible implications of this in regard to health:

1.   Would it be likely that applying an adhesive (which according to the study can be in concentrations of 25% of the polymer in glues), potentially could pose a risk, considering the fact the hair system is re-applied with the adhesive once or twice a week?
2.   I have heard that most of the absorption of chemicals from substances placed on the skin happens in the first few minutes, and that once the glue has set then there is no more absorption. However as this glue is water based it can sometimes “re-liquify” (not to the original extent, but it can go from solid to “a gooey mess” (direct quote from people who have used it). Would this “gooey mess” potentially mean more chemicals can be absorbed?
3.   How applicable are studies like this to humans? They are done on mice, is there a possibility that the chemicals could be much more carcinogenic to humans and therefore be dangerous at lower concentrations?
4.   Why is the amount that is dangerous quoted in terms of concentration? Is the volume not also important?
5.   If the chemical is dangerous at x concentration, how some it isn’t dangerous at all concentrations? Is it something to do with the liver flushing the chemicals out of the body?
6.   If the chemicals are carcinogenic, is there anyway to know how carcinogenic they are (i.e. do they increase your risk 40%, 400% or 4000%)?
I appreciate any and all help with this, we have been discussing it on another forum for a while but I figure some more specific insight could be helpful. Apologies again if this is posted in the wrong place, if there is a better place to post this I am happy to remove it and repost.
Read 1352 times
41 Replies

Related Topics

Replies
wrote...
#1
Educator
4 years ago
I'm not an expert in adhesives, but I am a biologist, so I might be able to chime in

Quote
3.   How applicable are studies like this to humans? They are done on mice, is there a possibility that the chemicals could be much more carcinogenic to humans and therefore be dangerous at lower concentrations?

Generally speaking. mice are excellent models for humans, but definitely not a replacement for human studies. Nonetheless, our skin is both permeable and impermeable. Depending on the (a) concentration, (b) molecular weight of the molecule, (c) duration of contact, (d) solubility of medication, and (e) other physical condition of the skin, etc., the absorption process varies.

Take nicotine patches, for instance, they stick to the skin via an adhesive, and are supposed to be applied for up to 16 hours so that the nicotine can fully absorb. Therefore, an adhesive applied to the scalp would definitely be a concern, especially if it needs to be applied multiple times a week. Maybe you could look into whether the adhesive found in nicotine patches are harmful, since they're more extensively studied that hair glue.

Quote
4.   Why is the amount that is dangerous quoted in terms of concentration? Is the volume not also important?

Concentration matters more, as they say, the dose makes the poison. Volume is only applicable when you're trying to cover more surface area.

Quote
5.   If the chemical is dangerous at x concentration, how some it isn’t dangerous at all concentrations? Is it something to do with the liver flushing the chemicals out of the body?

The liver use various enzymes and chemicals to break a substance down to make it less toxic. However, the liver can also suffer from poisoning, known as liver toxicosis. Some substances contain hepatotoxic substances or compounds that are metabolized to hepatotoxic chemicals.

Quote
6.   If the chemicals are carcinogenic, is there anyway to know how carcinogenic they are (i.e. do they increase your risk 40%, 400% or 4000%)?

Every chemical as a LD50 level. You need to research that for the compound you're concerned about.

Let me know if you have any more follow-up questions Happy Dummy
Ethan G. Author
wrote...
#2
4 years ago
Quote from: bio_man (4 years ago)
I'm not an expert in adhesives, but I am a biologist, so I might be able to chime in

Quote
3.   How applicable are studies like this to humans? They are done on mice, is there a possibility that the chemicals could be much more carcinogenic to humans and therefore be dangerous at lower concentrations?

Generally speaking. mice are excellent models for humans, but definitely not a replacement for human studies. Nonetheless, our skin is both permeable and impermeable. Depending on the (a) concentration, (b) molecular weight of the molecule, (c) duration of contact, (d) solubility of medication, and (e) other physical condition of the skin, etc., the absorption process varies.

Take nicotine patches, for instance, they stick to the skin via an adhesive, and are supposed to be applied for up to 16 hours so that the nicotine can fully absorb. Therefore, an adhesive applied to the scalp would definitely be a concern, especially if it needs to be applied multiple times a week. Maybe you could look into whether the adhesive found in nicotine patches are harmful, since they're more extensively studied that hair glue.

Quote
4.   Why is the amount that is dangerous quoted in terms of concentration? Is the volume not also important?

Concentration matters more, as they say, the dose makes the poison. Volume is only applicable when you're trying to cover more surface area.

Quote
5.   If the chemical is dangerous at x concentration, how some it isn’t dangerous at all concentrations? Is it something to do with the liver flushing the chemicals out of the body?

The liver use various enzymes and chemicals to break a substance down to make it less toxic. However, the liver can also suffer from poisoning, known as liver toxicosis. Some substances contain hepatotoxic substances or compounds that are metabolized to hepatotoxic chemicals.

Quote
6.   If the chemicals are carcinogenic, is there anyway to know how carcinogenic they are (i.e. do they increase your risk 40%, 400% or 4000%)?

Every chemical as a LD50 level. You need to research that for the compound you're concerned about.

Let me know if you have any more follow-up questions Happy Dummy

Thank you for replying. In regards to the part about mice studies, a lot of studies say the chemicals are unlikely to pose a risk (example one https://www.sciencedirect.com/science/article/pii/S0300483X18300635#:~:text=With%20evidence%20that%20these%20chemicals,pose%20a%20human%20cancer%20hazard.) . Does this say anything about the potential very long term risk though, i.e. if it could cause cancer in 20 years or something? Or is that simply impossible to determine in a study like these ones?
wrote...
#3
Educator
4 years ago
Quote from: Ethan Gascoigne (4 years ago)
Does this say anything about the potential very long term risk though, i.e. if it could cause cancer in 20 years or something? Or is that simply impossible to determine in a study like these ones?

I think it's impossible to tell. With all the research they've done on cigarette-smoking, they still cannot conclusively say that long-term cigarette smoking leads to lung cancer x-years from now. All they can say is that there's a correlation between cigarette smokers and lung cancer.

The review you've linked to is quite extensive, with excellent information distributed throughout the whole paper. Have you read it thoroughly, and if so, were you able to come up with the same conclusions as the author? It's important that you do your due diligence as well, because your interpretations of the results may be different than theirs. Read the discussion section, it holds all the juice you're looking for...
Ethan G. Author
wrote...
#4
4 years ago
Quote from: bio_man (4 years ago)
Quote from: Ethan Gascoigne (4 years ago)
Does this say anything about the potential very long term risk though, i.e. if it could cause cancer in 20 years or something? Or is that simply impossible to determine in a study like these ones?

I think it's impossible to tell. With all the research they've done on cigarette-smoking, they still cannot conclusively say that long-term cigarette smoking leads to lung cancer x-years from now. All they can say is that there's a correlation between cigarette smokers and lung cancer.

The review you've linked to is quite extensive, with excellent information distributed throughout the whole paper. Have you read it thoroughly, and if so, were you able to come up with the same conclusions as the author? It's important that you do your due diligence as well, because your interpretations of the results may be different than theirs. Read the discussion section, it holds all the juice you're looking for...
So if you did a study like these ones with cigarettes, it's entirely possible it wouldn't show them as being harmful? Should that be a cause for concern for these chemicals, as there are some documented negative effects in these studies, or could that be said about anything?

I will have to take a closer look at the review one. One thing that stood out to me from the first link was they said the concentration "may be as high as 1500 ppm, typical levels are 10 to 1000 ppm", however I looked up the recommended maximum dose and it's something like 6-8 ppm. This study which is of a specific acrylate says it's 1.2mg/kg, however that's weird because it also says on the same page that there was no observed effect at 100mg/mk (https://www.who.int/ipcs/publications/cicad/en/cicad04.pdf?ua=1 page 5 (9 of PDF)).

It's weird that the studies seem to give a much higher level of safe exposure than the decided safety regulation.
wrote...
#5
Educator
4 years ago
Quote from: Ethan Gascoigne (4 years ago)
So if you did a study like these ones with cigarettes, it's entirely possible it wouldn't show them as being harmful? Should that be a cause for concern for these chemicals, as there are some documented negative effects in these studies, or could that be said about anything?

There can never be a study that proves anything of that nature because there are too many variables that cannot be controlled, including the subject's genetic makeup, age they started smoking, the number of cigarettes smokes per day, (the list goes on). In addition, there are too many chemicals that exist inside of a cigarette, so a scientist would have to investigate each one individually. And even if they investigated each ingredient individually, that would still be insubstantial evidence to consider that smokes actually *cause* lung cancer. You can only make a connection once the facts have been established, but science cannot prove it.

In the case of hair adhesives, if it's a single component that makes up the glue, then it'd be easier to make a connection that component-x, at this specific concentration, for this set amount of time, of this specific skin type leads to cancer, for example.

Science aside, here's my opinion: if it's concerning you, then the idea that using it might lead to something in the future becomes a self-fulling prophecy in itself, and hence should be avoided. Remember, the skin is permeable and breathable, so even if the stuff is harmless, you wouldn't want it seeping into your bloodstream anyway.

Don't mean to pry, but why wouldn't you consider a more permeant hair transplant instead?

Quote
I will have to take a closer look at the review one. One thing that stood out to me from the first link was they said the concentration "may be as high as 1500 ppm, typical levels are 10 to 1000 ppm", however I looked up the recommended maximum dose and it's something like 6-8 ppm. This study which is of a specific acrylate says it's 1.2mg/kg, however that's weird because it also says on the same page that there was no observed effect at 100mg/mk (https://www.who.int/ipcs/publications/cicad/en/cicad04.pdf?ua=1 page 5 (9 of PDF)).

1 ppm = 1 mg/kg

1.2 mg/kg there is 1.2 ppm.

Quote
It's weird that the studies seem to give a much higher level of safe exposure than the decided safety regulation.

Perhaps, but you'd be surprised how many regulations are outdated.
Ethan G. Author
wrote...
#6
4 years ago
Quote from: bio_man (4 years ago)
Quote from: Ethan Gascoigne (4 years ago)
So if you did a study like these ones with cigarettes, it's entirely possible it wouldn't show them as being harmful? Should that be a cause for concern for these chemicals, as there are some documented negative effects in these studies, or could that be said about anything?

There can never be a study that proves anything of that nature because there are too many variables that cannot be controlled, including the subject's genetic makeup, age they started smoking, the number of cigarettes smokes per day, (the list goes on). In addition, there are too many chemicals that exist inside of a cigarette, so a scientist would have to investigate each one individually. And even if they investigated each ingredient individually, that would still be insubstantial evidence to consider that smokes actually *cause* lung cancer. You can only make a connection once the facts have been established, but science cannot prove it.

In the case of hair adhesives, if it's a single component that makes up the glue, then it'd be easier to make a connection that component-x, at this specific concentration, for this set amount of time, of this specific skin type leads to cancer, for example.

Science aside, here's my opinion: if it's concerning you, then the idea that using it might lead to something in the future becomes a self-fulling prophecy in itself, and hence should be avoided.
Not sure what you mean, do you mean it could cause some kind of placebo, or just that if your going to worry about it then it isn't worth it.

Quote
Remember, the skin is permeable and breathable, so even if the stuff is harmless, you wouldn't want it seeping into your bloodstream anyway.
If it's harmless would it not be okay in your bloodstream?

Most of these studies seem to use inhalation, is that less harmful than being in your blood?

Quote
Don't mean to pry, but why wouldn't you consider a more permeant hair transplant instead?
I would prefer that as an option, but they don't tend t give them to younger people as if hair loss continues after the transplant it ends up looking worse. Hair transplants often aren't possible if you have lost too much hair. I probably will get one if it's possible when I reach the right age.

wrote...
#7
Educator
4 years ago Edited: 4 years ago, bio_man
Quote from: Ethan Gascoigne (4 years ago)
Not sure what you mean, do you mean it could cause some kind of placebo, or just that if your going to worry about it then it isn't worth it.

Precisely that. If it doesn't feel right instinctually, then it should be avoided. I feel that way about marijuana, so I've always avoided smoking it. For all I know, it could actually be good for me - who knows? - but my gut instinct tells me otherwise.

Quote
If it's harmless would it not be okay in your bloodstream?

When you inhale something, it potentially has a direct pathway to your bloodstream. However, inhaling a gas is far less concentrated than in liquid form, so I wouldn't say they're equivalent. Many adhesives contain solvents that are toxic by inhalation and skin contact. Acrylic plastic glues that contain methyl methacrylate, and instant bonding glues contain cyanoacrylates. See this section on Wikipedia regarding their toxicity.

Quote
I would prefer that as an option, but they don't tend t give them to younger people as if hair loss continues after the transplant it ends up looking worse. Hair transplants often aren't possible if you have lost too much hair. I probably will get one if it's possible when I reach the right age.

Transplants have gone a long way. I'd look into FUE as opposed to the incision kind (worst). You can get it for relatively cheap if done overseas, namely in Turkey. If your case is advanced enough to require a headpiece, than I'd say you're in the correct age range. How far along is your hair line? And, what type of hair loss is occurring?
Ethan G. Author
wrote...
#8
4 years ago
Quote from: bio_man (4 years ago)
Quote from: Ethan Gascoigne (4 years ago)
Not sure what you mean, do you mean it could cause some kind of placebo, or just that if your going to worry about it then it isn't worth it.

Precisely that. If it doesn't feel right instinctually, then it should be avoided. I feel that way about marijuana, so I've always avoided smoking it. For all I know, it could actually be good for me - who knows? - but my gut instinct tells me otherwise.

Quote
If it's harmless would it not be okay in your bloodstream?

When you inhale something, it potentially has a direct pathway to your bloodstream. However, inhaling a gas is far less concentrated than in liquid form, so I wouldn't say they're equivalent. Many adhesives contain solvents that are toxic by inhalation and skin contact. Acrylic plastic glues that contain methyl methacrylate, and instant bonding glues contain cyanoacrylates. See this section on Wikipedia regarding their toxicity.

Non of the studies saw about methyl methacrylate talked about skin contact. I assume, given blood circulates around the whole body and as you said inhalation will lead to it getting into the blood anyway, that it's unlikely to be significantly more toxic if applied to the skin?

I asked the company about the ingredients, they didn't seem to want to be more specific than "Acrylate Copolymers" which is a bit annoying, do you know which one it is likely to be? Product is called Ghostbond, it's a water based adhesive.
Quote
Quote
I would prefer that as an option, but they don't tend t give them to younger people as if hair loss continues after the transplant it ends up looking worse. Hair transplants often aren't possible if you have lost too much hair. I probably will get one if it's possible when I reach the right age.

Transplants have gone a long way. I'd look into FUE as opposed to the incision kind (worst). You can get it for relatively cheap if done overseas, namely in Turkey. If your case is advanced enough to require a headpiece, than I'd say you're in the correct age range. How far along is your hair line? And, what type of hair loss is occurring?
At the moment I am only a norwood 3 ish (forehead further back than is typical, receeded temples, no thinning on top). I'd say there's a decent chance it won't get worse, as my Dad's hair is exactly the same as mine, same with my Uncle, so I think my family just has naturally receeded hairlines, but nobody is bald.

I'm looking into all this more to reassure myself that if I do go bald that I can do something about it, more than needing to do anything now. I suppose along with that comes the slight reassurance that in 5-10 years we may have a new treatment for it and transplants or systems will be a thing of the past.
wrote...
#9
Educator
4 years ago
Quote from: Ethan Gascoigne (4 years ago)
Non of the studies saw about methyl methacrylate talked about skin contact. I assume, given blood circulates around the whole body and as you said inhalation will lead to it getting into the blood anyway, that it's unlikely to be significantly more toxic if applied to the skin? I asked the company about the ingredients, they didn't seem to want to be more specific than "Acrylate Copolymers" which is a bit annoying, do you know which one it is likely to be? Product is called Ghostbond, it's a water based adhesive.

I would assume that the liquid form is more concentrated than the vapor form discussed in the study. That being said, it's the dose (concentration) that makes the poison. According to Ghostbond's purchase page on Amazon, it mentions that it "contains no latex or harsh solvents so reduces irritation as well as being low odour and bacteria resistant." So it contains solvents, but aren't "harsh" -- doesn't sound too convincing to me.
 Another website states:

"Ghost Bond XL is a water based acrylic co-polymer which contains very minimal parabens. In fact, so minimal that they are not even required by state law to list it on the ingredients label but the company opted to do so to be full disclosure.

The parabens which are contained in Ghost Bond are Methylparaben and Propylparaben. The amount is 0.0001% and the purpose of this is to preserve the shelf life of the product. Without it, the product would only last a matter of weeks rather than years."

Quote
I'm looking into all this more to reassure myself that if I do go bald that I can do something about it, more than needing to do anything now. I suppose along with that comes the slight reassurance that in 5-10 years we may have a new treatment for it and transplants or systems will be a thing of the past.

Forgive my ignorance, but how'd you use a hairpiece for a Norwood 3? They're the most difficult to conceal, since you're still at the earlier stages of hair loss. Have you tried using minoxidil foam? It's pretty good in keeping your hair vital; I believe it acts as a vasodilator, increasing blood circulation to the scalp. You can get a 3-month supply on eBay for like ~$60.

Quote
At the moment I am only a norwood 3 ish (forehead further back than is typical, receeded temples, no thinning on top). I'd say there's a decent chance it won't get worse, as my Dad's hair is exactly the same as mine, same with my Uncle, so I think my family just has naturally receeded hairlines, but nobody is bald.

What's your grandfather's hair like on your mom's side?
Ethan G. Author
wrote...
#10
4 years ago
Quote from: bio_man (4 years ago)
Quote from: Ethan Gascoigne (4 years ago)
Non of the studies saw about methyl methacrylate talked about skin contact. I assume, given blood circulates around the whole body and as you said inhalation will lead to it getting into the blood anyway, that it's unlikely to be significantly more toxic if applied to the skin? I asked the company about the ingredients, they didn't seem to want to be more specific than "Acrylate Copolymers" which is a bit annoying, do you know which one it is likely to be? Product is called Ghostbond, it's a water based adhesive.

I would assume that the liquid form is more concentrated than the vapor form discussed in the study. That being said, it's the dose (concentration) that makes the poison. According to Ghostbond's purchase page on Amazon, it mentions that it "contains no latex or harsh solvents so reduces irritation as well as being low odour and bacteria resistant." So it contains solvents, but aren't "harsh" -- doesn't sound too convincing to me.
 Another website states:

"Ghost Bond XL is a water based acrylic co-polymer which contains very minimal parabens. In fact, so minimal that they are not even required by state law to list it on the ingredients label but the company opted to do so to be full disclosure.

The parabens which are contained in Ghost Bond are Methylparaben and Propylparaben. The amount is 0.0001% and the purpose of this is to preserve the shelf life of the product. Without it, the product would only last a matter of weeks rather than years."

Quote
I'm looking into all this more to reassure myself that if I do go bald that I can do something about it, more than needing to do anything now. I suppose along with that comes the slight reassurance that in 5-10 years we may have a new treatment for it and transplants or systems will be a thing of the past.

Forgive my ignorance, but how'd you use a hairpiece for a Norwood 3? They're the most difficult to conceal, since you're still at the earlier stages of hair loss. Have you tried using minoxidil foam? It's pretty good in keeping your hair vital; I believe it acts as a vasodilator, increasing blood circulation to the scalp. You can get a 3-month supply on eBay for like ~$60.

Quote
At the moment I am only a norwood 3 ish (forehead further back than is typical, receeded temples, no thinning on top). I'd say there's a decent chance it won't get worse, as my Dad's hair is exactly the same as mine, same with my Uncle, so I think my family just has naturally receeded hairlines, but nobody is bald.

What's your grandfather's hair like on your mom's side?

Most of the studies seemed to be 1 or 2 years, I haven't seen any reports of people using ghostbond having any of the things in the studies happening to them after 2 years, so I assume the dose must be less. Are all solvents bad or are they just a category?

In regards to the hair piece, I wouldn't be planning on getting one yet, if my hair stays as it is now I would be happy with it and wouldn't really do much with it. I would only get one if it got significantly worse.

I asked my Mum a while and she said she didn't know of any bald relatives, so I assume my grandfather wasn't bald. The only 2 male relatives I know are my Dad, and my Uncle (Mum's side). So I don't think baldness runs in my family.
wrote...
#11
Educator
4 years ago
Quote from: Ethan Gascoigne (4 years ago)
Most of the studies seemed to be 1 or 2 years, I haven't seen any reports of people using ghostbond having any of the things in the studies happening to them after 2 years, so I assume the dose must be less. Are all solvents bad or are they just a category?

Any solvent other than water should be avoided when considering a biological system because you never know what they can dissolve.

It's very possible that your hairline could stop receding; I would still vouch for using minoxidil foam or Propecia if it's still concerning you. The fact that your mom's side doesn't have a history of hair loss is a positive thing, so it's either you inherited your dad's gene or a generation was skipped on your mom's side.
Ethan G. Author
wrote...
#12
4 years ago
Quote from: bio_man (4 years ago)
Quote from: Ethan Gascoigne (4 years ago)
Most of the studies seemed to be 1 or 2 years, I haven't seen any reports of people using ghostbond having any of the things in the studies happening to them after 2 years, so I assume the dose must be less. Are all solvents bad or are they just a category?

Any solvent other than water should be avoided when considering a biological system because you never know what they can dissolve.

It's very possible that your hairline could stop receding; I would still vouch for using minoxidil foam or Propecia if it's still concerning you. The fact that your mom's side doesn't have a history of hair loss is a positive thing, so it's either you inherited your dad's gene or a generation was skipped on your mom's side.

Is the Solvent in this glue not the water, is that why it's called water based, instead of the acrylic based glues where I assume acrylic is the solvent?

Hopefully it will stop where it is now, I'll have to keep an eye on it over the next few months to see if it gets any worse.

Also going back to the PPM and mg/kg thing, I didn't realise mg.kg was mg per kg of body weight. Is that the same with PPM I assume when they talk about it in studies (i.e. rats exposed to 400ppm, means they were exposed to 400mg per kg of their weight)?
wrote...
#13
Educator
4 years ago
Quote from: Ethan Gascoigne (4 years ago)
Is the Solvent in this glue not the water, is that why it's called water based, instead of the acrylic based glues where I assume acrylic is the solvent?

If the solvent was water, it wouldn't a concern. Water-based means that the components dissolves in water; compare to lipid-soluble -- then it's get absorbed in fat tissue, which is dangerous. Alcohols are soluble in water, but are also considered solvents.

Quote
Hopefully it will stop where it is now, I'll have to keep an eye on it over the next few months to see if it gets any worse.

But don't obsess over it. Remember that each hair follicle follows a cycle of growth and shedding, so collectively your follicles might be in their growth stage; therefore, you'll experience better hair days than say next season. Watching this progress is like watching plants grow; try your best not to worry - easier said than done - and don't stair at the mirror too much! You'll end up developing a case of body dysmorphic disorder...

Quote
Also going back to the PPM and mg/kg thing, I didn't realise mg.kg was mg per kg of body weight. Is that the same with PPM I assume when they talk about it in studies (i.e. rats exposed to 400ppm, means they were exposed to 400mg per kg of their weight)?

It's a 1-to-1 ratio so 400 ppm = 400mg per kg of their weight. You can use either or to describe the concentration of one compound dispersed in another. Assuming that the parts per million value is a mass per mass value, then the conversion can be done.
  New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  565 People Browsing
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Live Chat
Related Images
  
 855
  
 485
  
 855
Your Opinion
Which 'study break' activity do you find most distracting?
Votes: 824
Previous poll results: Who's your favorite biologist?