Tuesday 8 May 2012

The science of sex toys

It has always been our intention with this blog not only to review specific sex toys, but also to discuss more general issues around sex, sexuality and sex toys. So we decided to start off with a nice and easy, uncontroversial topic (hmmm...): materials.

There is much discussion and concern about the health risks associated with certain materials used to make sex toys. However, many of the arguments (made by a variety of people who reach a variety of conclusions) seem to be based on anecdote, or designed deliberately to mislead. What is needed is some impartial scientific evidence (as a scientist, I would say that though). Unfortunately, this is an area where little systematic research has been done (it is understandable that few organisations would want to stump up the money for this, and many researchers would be concerned about the damage to their reputations from working in such a supposedly "seedy" field).

This is why I was very pleased to have dug out this report. It is titled "Survey and health assesment[sic] of
chemicals[sic] substances in sex toys". It was published a while ago, in 2006; others may have seen it before, but I personally had not come across it until recently, nor any discussion of it in the sex toy blogosphere (urgh, but whatever) or elsewhere. It is authored by the Danish Technological Institute, and financed and published by the Danish Environmental Protection Agency. The language used and style comes across as impartial, and the authors take care to present and discuss all their selection methods and testing strategies. The report is fairly well referenced for such a poorly studied area. These are all things I look at to see if a paper is likely to be scientifically sound and impartial, but are of course no guarantee. One issue is that as a technical report, it is probably not peer-reviewed (the process whereby the thoroughness and accuracy of a piece of scientific work is assessed by other experts in the field before publication).

The work basically consists of a two stage analysis of firstly the chemical composition of a targeted selection of sex toys, and then the risk of harm to users posed by these (based on the known toxicity of the materials present coupled with tests of the leaching rate in several simulated use environments). The second part of this is important and often neglected. It is well-established (please note that this link goes to a news article discussing a piece of commissioned research. I cannot find the research itself published anywhere) that many sex toys contain chemicals which have been shown to cause harm to humans (or often animals). This obviously isn't a good thing, but it does not automatically follow that those toys are themselves harmful. The chemicals maybe present in such small quantities so as to be irrelevant (almonds have cyanide in them), or in an inaccessible state (mercury in a thermometer is pretty bad for you).

I would encourage anyone interested to read through it and check they agree with my summary. Although it weighs in at a seemingly hefty 85 pages and the English is not perfect (better than my Danish however), it is pretty readable, and at times amusing. I find hearing things such as the "preliminary visit to the sex fair", discussed in as dispassionate a scientific voice as possible, hilarious. I'm just a bit like that though.

The broad conclusions will probably not surprise many people: A sub-set of a variety of jelly, PVC and latex toys contain a variety of chemicals, including phthalates (used as plasticizers and implicated in risk to foetuses as well as kidneys and liver damage), trimethyltin chloride (related to a commonly used PVC stabilizer, neuro-toxic) and organic solvents such as THF and Toluene (likely used in the production process, and which can cause developmental issues and cause neurological damage) at levels which may present some minor risk of harm under worst use scenarios.

The key here is worst use scenario. The time periods they discuss are 15 minutes a day for normal use, and one hour a day for max use. These might be slightly low, but bearing in mind they are averaged figures, they don't seem unreasonable to me (and are derived from questionnaires distributed to sex toy shop employees). The thing that most shocked me however was the difference lubricants made. Using a water-based lubricant increased the rate of migration of the tested phthalates by roughly a factor of 10 as compared to simulated sweat. This is a lot, but still kept the levels within accepted limits. But an oil-based lubricant increased the leaching by almost a factor of 1000! This shouldn't really be surprising, as these chemicals are oil-soluble, and water-insoluble (in fact you can occasionally feel a "greasy" sensation with a jelly toy). Now you have probably heard not to use oil-based lubricants with rubber or jelly toys as they will be degraded. But this report suggests it will also massively increase your health risks. It also makes me wonder if rather than any effect on the rubber itself, much of the degradation caused by oil-based lubricants is actually the phthalates and other oil-soluble components being washed out.

Because that is another thing that surprised me. I have always thought of plasticizers as materials added in comparatively small volumes to PVC to just increase the flexibility a little. However, one dildo analysed in this study consisted of over 70% phthalates by weight. That I find shocking; the vinyl is basically just a medium to convey the phthalate component. It is however important to note that even with heavy use with a non-oil-based lubricant none of these toys were found to release phthalates in quantities hazardous to adult human health. I would stress that this was under lab conditions, and it is possible that the situation in real world use could be significantly different. For example, there is no mention made here of mechanical exfoliation and abrasion of the surface (which I might expect given vigorous thrusting), which I could conceive of making a difference. But although alarming in some aspects, the situation with phthalates appears to be less dangerous than many might fear. And at least the solution is clear; if you are concerned about the effects of these chemicals, buy phthalate-free toys from one of the many companies that provide this information (the same applies to latex if you have a latex allergy, or are concerned about latex sensitisation).

However, in the concern regarding the use of phthalates in some sex toys, other aspects of safety are often overlooked. In fact, this report suggests that the greatest risks posed by sex toys came not from ingredients as such, but rather from impurities resulting from the manufacturing process (such as the aforementioned organic solvents, and also a chemical called phenol). This is troubling, because even if a toy is nominally manufactured from 100% pure medical grade silicone, considered by most to be the gold standard in polymer-based sex toy safety, there is as far as I am aware nothing intrinsic to the manufacturing process which means that the same contaminants could not also be present. The researchers in this study did not test any silicone toys, so no light is shed on this issue there.

A couple of points serve to reduce this fear though. Firstly, generally speaking silicone toys tend to be of a higher quality and so possibly manufactured in a better environment with a more controlled process. Also, they are often made by smaller manufacturers who have a greater control of their manufacturing processes and are often more connected to and concerned about the welfare of the end user (indeed just the other day I was reading a fascinating post about what happens when a big manufacturers supply line appears to get out of control). Both of these are of course big generalisations (you can tell by the italics), and there are probably many exceptions. Obviously the consumer can make educated guesses from companies' public attitudes and actions as to which toys are likely to be of high quality and produced with care, but ultimately cannot know for certain and therefore there must be an element of health risk attached to buying any sex toy.

So should we all just get a bin liner (or two!) and empty our toy drawers into them? Well I think not. Rather I think we need to accept that there is an element of risk, and act to minimise it as much as possible to the point where the benefits outweigh the risk. We do this in our everyday lives. We accept a certain level of risk for a certain level of reward. If you have surgery to fit a prosthetic hip, there is a risk you will die on the operating table. Many of us drive cars every day. Over one million people every year die in car accidents. You may argue that these things are necessary. But even more of us drink alcohol, causing over two million deaths a year. Or, as David Nutt once got in a lot of trouble for saying, it's pretty risky riding horses.

When it comes to sex toys I believe we can minimise the risks in a number of ways. Buy dildos made of silicone, not rubber, PVC or jelly (I have not looked into it as carefully but borosilicate glass and stainless steel are almost universally considered ok too). Silicone toys are likely to be made in a higher quality manner, and thus have fewer impurities (and also last longer, smell better, and be biologically safer due to being less porous and sterilisable: issues for another day). Buy from manufacturers who have a good reputations (especially amongst those bloggers and reviewers who appear knowledgeable and impartial) and appear ethical and at least acknowledge some of these issues. If you do use jelly toys, ideally use condoms (and definitely if sharing), and if this report shows one thing then absolutely do not use oil-based lubricants. If a toy feels odd then stop immediately. Many of the chemicals discussed are implicated in developmental abnormalities in foetuses, so if you are pregnant then err further on the side of caution.

I am a scientific researcher. I make no claim to much in the way of specialist knowledge in this area though. In the interests of time and space, I have not been able to cover all the issues in as much depth as I would like (it would probably require a tome of literally biblical proportions). We would love to hear what others think on this issue; what you think of this research, its conclusions, my conclusions, your conclusions. We would also love to hear if anyone else knows of any reliable, independent evidence out there!


p.s. Many of the links in this article are to Wikipedia, which of course means the factual accuracy cannot be guaranteed. Most of these are purely for additional information and hopefully shouldn't alter the main thrust of my argument. I shall consider the comments on this article my own form of peer-review.


  1. Thank you for taking the time to put together such a fantastic article! I appreciate your impartial and reasonable approach to presenting the material that you've found. I completely agree that in areas where scientific research is thin on the ground, it's very hard to draw a factual conclusion. And as you mentioned, you have to look with a critical eye to the study methodology as well.

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