Grab your lab coats, it's time to learn about sex toy chemistry.

If you tend to do your research before buying sex toys (in which case: kudos!), you may have encountered the term “phthalates.” It’s become a big buzzword in the adult toy industry over the past few years, as awareness of material safety has risen. So what are phthalates, exactly, and why do they matter?

Phthalates are a group of chemicals used as plasticizers, or softeners, in many low-end sex toy materials like jelly and rubber. You would think that if an ingredient was being included in objects we put inside ourselves, it would be safe, but that’s sadly not the case: phthalates have been linked with impairment of the endocrine and reproductive systems, developmental difficulties in babies, and even infertility. Despite having been banned from children’s toys for years due to the scientific evidence condemning them, phthalates still show up in sex toys regularly, because the adult toy industry is unregulated and lots of toys are produced overseas as cheaply (and carelessly) as possible. Some companies may not even know their toys contain phthalates, because they don’t oversee their production process themselves.

Phthalates have smaller, more short-term effects as well: many people report a burning or stinging sensation when they use toys containing phthalates, as well as general skin irritation and recurring vaginal infections. Due to the prevalent misinformation and silence around sexuality in our culture, some people assume their skin is just sensitive or there’s something wrong with them when they experience these symptoms, when the real culprit is phthalates. Needless to say, these ingredients are best avoided!

So how can you know whether you’re buying a toy with phthalates in it? Many toys are marked “phthalate-free,” but due to the unregulated nature of the market, some toys that make this claim are actually chock full of these harmful chemicals. However, there are a few “tells” you can look out for. If a toy is inexpensive and made of a squishy, translucent material, it probably contains phthalates. Ditto if it has a strong chemical smell – that’s the phthalate molecules offgassing into the air! Phthalate-ridden toys will also often leave an oily residue on your hands – eww.

If you want to avoid phthalates, look for toys made of non-porous materials known to be body-safe, like hard plastic, pure silicone, stainless steel, glass, and acrylic. Yes, these tend to be more expensive than unsafe toys, but they’ll last you a lot longer (material quality isn’t the only area where some toymakers skimp!) and won’t give you the health problems you can expect from phthalates.

If you’re not yet able to upgrade, you can start using a new condom on your phthalate-filled toy every time you use it. The jury’s still out about the effectiveness of this, but condoms are better than nothing.

There’s another reason buying body-safe sex toys is an important thing to do: it’s a way of “voting with your dollar” and letting toy companies know that safety matters to consumers. While there have been significant pushes from sexual health advocates to reduce phthalate rates in the sex toy industry – or ban them altogether – in the U.S.A. this still has not happened. But the more we kick up a fuss about it, the more the industry will change – and many, many people will be safer and healthier as a result.