How are amber teething necklaces supposed to work?

Do amber beads have medicinal properties?

Amber, as anyone that was paying attention during Jurassic Park will tell you, is fossilised resin from trees that lived at least twenty million years ago (although some scientists have speculated it could be older). It takes the form of clear yellow through to dark brown stones, seemingly warm to the touch, smooth and surprisingly hard. It is certainly beautiful. But does it also have medicinal properties? And if it does, are they risk-free?

In 2016 a one year-old boy was found dead at his daycare centre in Florida. The cause of death was a necklace, which had become tangled and tightened to the point that he was unable to breathe.

Why was he wearing a necklace? Surely everyone knows that babies shouldn’t wear jewellery around their necks where it could so easily cause a terrible tragedy like this? No one needs a necklace, after all – it’s purely a decorative thing. Isn’t it?

Yes. Yes, it is. However, this particular type of jewellery was specifically sold for use by babies. Sold as a product that parents should give their children to wear, despite all the advice from medical professionals. Why? Because this jewellery was made from amber, and that’s supposed to help with teething pains.

Teething is a literal pain.

Anyone whose ever had children will tell you that teeth are basically a non-stop, literal pain from about 4 months onward. Even once your child appears to have a full set, you’re not done. The first lot start falling out somewhere around age five, resulting in teeth that can be wobbly for weeks. And then there are larger molars that come through at the back somewhere around age seven. Teenagers often find themselves suffering through braces and, even when all that’s done, there’s the joy of wisdom teeth still to come.

It’s particularly difficult with babies, who can’t tell you what hurts and who probably have inconsistent sleep habits at the best of times. Twenty sharp teeth poking through swollen gums at different times has to be unpleasant. Who could blame any parent for trying, well, pretty much anything to soothe the discomfort?

Enter amber teething necklaces. They’re sold as a “natural” way to soothe teething pain. They look nice, too, which I’m sure is part of their appeal. A chewed plastic teething ring isn’t the sort of thing to keep in baby’s keepsake box, but a pretty necklace, well, I’m sure many parents have imagined getting that out, running their fingers over the beads and having a sentimental moment years in the future.

Amber is fossilised tree resin.

So-called amber teething necklaces are made from “Baltic amber,” that is, amber from the Baltic region: the largest known deposit of amber. It is found in other geographical locations, but it seems that the conditions – and tree species – were just right in the Baltic region to produce large deposits.

Chemically, it’s also known as succinite, and its structure is complicated. It’s what chemists would call a supramolecule: a complex of two or more (often large) molecules that aren’t covalently bonded. There are cross-links within its structure, which make it much denser than you might imagine something that started as tree resin to be. Baltic amber, in particular, also contains something else: between 3-8% succinic acid.

Succinic acid is a dicarboxylic acid.

Succinic acid is a much simpler molecule with the IUPAC name of butanedioic acid. It contains two carboxylic acid groups, a group of atoms we’re all familiar with whether we realise it or not – because we’ve all met vinegar, which contains the carboxylic acid also known as ethanoic acid. If you imagine chopping succinic acid right down the middle (and adding a few extra hydrogen atoms), you’d end up with two ethanoic acid molecules.

Succinic acid (the name comes from the Latin, succinum, meaning amber) is produced naturally in the body where it is (or, rather, succinate ions are) an important intermediate in lots of chemical reactions. Exposure-wise it’s generally considered pretty safe at low levels and it’s a permitted food additive, used as an acidity regulator. In European countries, you might see it on labels listed as E363. It also turns up in a number of pharmaceutical products, where it’s used as an excipient – something that helps to stabilise or enhance the action of the main active ingredient. Often, again, it’s there to regulate acidity.

Basically, it’s mostly harmless. And therefore, an ideal candidate for the alternative medicine crowd, who make a number of claims about its properties. I found one site claiming that it could “improve cellular respiration” which… well, if you’ve got problem with cellular respiration, you’re less in need of succinic acid and more in need of a coffin. Supposedly it also relives stress and prevents colds, because doesn’t everything? And, of course, it allegedly relieves teething pains in babies, either thanks to its general soothing effect or because it’s supposed to reduce inflammation, or both.

Purporters claim succinic acid is absorbed through the skin.

The reasoning is usually presented like this: succinic acid is released from the amber when the baby wears the necklace or bracelet and is absorbed through the baby’s skin into their body, where it works its magical, soothing effects.

Now. Hold on, one minute. Whether this is true or not – and getting substances to absorb through skin is far less simple than many people imagine, after all, skin evolved as a barrier – do you really, really, want your baby’s skin exposed to a random quantity of an acidic compound? Succinic acid may be pretty harmless but, as always, the dose makes the poison. Concentrated exposure causes skin and eye irritation. Okay, you might say, it’s unlikely that an amber necklace is going to produce anywhere near the quantities to cause that sort of effect, but if that’s your logic, then how can it also produce enough to pass through skin and have any sort of biological effect on the body?

The answer, perhaps predictably, is that it doesn’t. In a paper published in 2019, a group of scientists actually went to the trouble of powdering Baltic amber beads and dissolving the powder in sulfuric acid to measure how much succinic acid they actually contained. They then compared those results with what happened when undamaged beads from the same batches were submerged in solvents, with the aim of working out how much succinic acid beads might conceivably release into human skin. The answer? They couldn’t measure any. No succinic acid was released into the solvents, at all. None.

Scientists submerged Baltic amber beads in solvents to see how much succinic acid they released.

They concluded that there was “no evidence to suggest that the purported active ingredient succinic acid could be released from the beads into human skin” and also added that they found no evidence to suggest that succinic acid even had anti-inflammatory properties in the first place.

So amber necklaces don’t work to relieve teething pains. They can’t. Of course, there could be a sort of placebo effect – teething pain is very much one of those comes-and-goes things. It’s very easy to make connections that just aren’t there in this kind of situation, and imagine that the baby is more settled because of the necklace, when in fact they might have calmed down over the next few hours anyway. Or maybe they’re just distracted by the pretty beads.

And, fine. If wearing the jewellery was really risk-free, then why not? But as the story at the start of this post proves, it is not. Any kind of string around a baby’s neck can become twisted, interfering with their breathing. Most necklaces claim to have some sort of “emergency release” mechanism so that they come apart when pulled, but this doesn’t always work.

Don’t fall for the marketing.

Ah, goes the argument. But it’s okay, because we only sell bracelets and anklets for babies. They don’t go around the baby’s neck. It’s completely safe!

No. Because I don’t care how carefully you make it: the string or cord could still break (especially if it’s been chewed), leaving loose beads to pose a serious choking hazard. Not to mention get jammed in ears or nostrils. Even if you’re with the baby, watching them, these sorts of accidents can happen frighteningly quickly. Letting a baby sleep with such an item is nothing short of asking for disaster, and no matter how good anyone’s intentions, babies do have a habit of dozing off at odd times. Will you really wake the child up to take off their bracelet? Every time?

In summary, don’t fall for the marketing. Amber necklaces may be pretty, but they’re not suitable for babies. The claims about succinic acid are completely baseless, and the risks are very real.

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Should you be scared of your shampoo?

I was doing some grocery shopping online recently (I have small children, I’ve started to view traditional supermarket shopping in the same way as beating my carpets with a stick and washing clothes in a stream) when I came across some reviews for a particular brand of shampoo.

Most of the reviews were positive, but some were not. In particular, there were a few one star ones complaining about ingredients called methylchloroisothiazolinone and methylisothiazolinone.



What, you may be wondering, are these monstrosities? Surely with names that long they must be huge great big molecules? Actually no, they’re quite small. Methylchloroisothiazolinone (shown in the graphic) has a mere four carbon atoms and an interesting assortment of other elements. They’re part of a group of compounds called isothiazolinones, which are heterocyclic molecules that include a five-membered ring which contains nitrogen, sulfur and a C=O group.

Not surprisingly considering the unwieldy name, methylchloroisothiazolinone is often shortened to MCI. Likewise, the chemically-similar methylisothiazolinone (imagine the molecule above without the -Cl bit) goes by the moniker MI, or sometimes MIT.

MCl and MI are common preservatives in cosmetic products

MCl and MI are common preservatives in cosmetic products.

Why are these things in shampoo? Well, they are very effective preservatives. They’re antibacterial and antifungal, and work against both gram-positive and gram-negative bacteria, as well as yeast and fungi. This is a good thing, because some of these microbes are pretty nasty. The bacteria, for example, include such lovelies as Nocardia (associated with a particular type of respiratory disease), Staphylococcus (associated with various infections) and Listeria (most famous for causing gastrointestinal distress). It may be a small risk, but showers are warm, moist environments – basically the perfect breeding ground for these sorts of things. If these microbes start growing in your shampoo, shower gel and so on, they would then end up on your hair and skin, possibly be inhaled, and might even make their way into your bloodstream if you had a small cut somewhere.


So, that’s why these chemicals are there. That all sounds good, right? Why are people complaining?

The dose makes the poison is an important principle in toxicology (image credit: Lindsay Labahn, click for link)

The dose makes the poison is an important principle in toxicology (image credit: Lindsay Labahn, click for link)

Well, because they also have their hazards. Now, before I go any further, we should remember a very important principle of toxicology, which is that “the dose makes the poison“. Everything, I really mean EVERYTHING, is dangerous if you’re exposed to too much of it. Oxygen is quite crucial if you want to carry on living, for example, but breathe in too much of it for too long and you’re at risk of developing visual disturbances, tinnitus, nausea and muscle spasms. Too much could even be lethal. Similarly, a pinch of salt is quite nice on chips, but try and drink say, seawater, and you’ll soon regret it. Even plain water can be dangerous if you consume too much in too short a time, particularly if you’re also exercising hard.

Many chemicals that are used industrially have scary lists of associated hazards, but it’s important to remember that these warnings are usually aimed at people who use said chemical in an industrial setting. In other words, they might be handling kilograms or even tonnes of the stuff, all day every day, as opposed to the teeny tiny quantity you’re likely to meet a few times a week.

I could pick literally any ingredient in that shampoo bottle and proclaim that it’s dangerous. This would be perfectly true, but also meaningless. A more pertinent question is: is it dangerous in the quantity that you usually use?

Are methylchloroisothiazolinone and methylisothiazolinone in shampoo dangerous? There’s no evidence that they bioaccumulate (build up in the body) or that they’re linked to any kind of cancer (phew). In 2002, there was an in vitro (i.e. outside of living organisms) study of the neurotoxicity of MI which showed that mature neurons in tissue culture could be killed by 4-12 ppm solutions of the chemical. But these experiments were performed on rat brain cells in culture. Lots of things will damage cells in a petri dish: it doesn’t mean that we necessarily have to worry about them in every day life. A shampoo solution pouring straight into your brain might well be harmful, but I suggest that if that’s happening in the shower you have bigger problems. Namely, major head trauma.

However, in high concentrations, MI and MCl are definitely skin and membrane irritants, which can cause chemical burns. They’re known chemical ‘sensitisers‘. This means that exposure to them, even at fairly low levels, might cause an allergic reaction.


A patient who presented to a medical centre following a severe reaction to methylisothiazolinone in a wipe (SA Government – click image for source).

This is where we get into difficult territory, because exactly how a particular individual is going to respond to something like this can be hard to predict. For example, I’ve never had a nasty reaction to methylchloroisothiazolinone. Give me an aspirin, on the other hand, and I’m likely to be in trouble. Allergies are specific to individuals. But there is no doubt that some people do have nasty reactions to MCI and MI; some sources have suggested it might be as many as 15% of the population (and that this number might, worryingly, have increased in recent years).

These chemicals are, or at least have been, also used as preservatives in other products such as sunscreens, moisturisers and wipes (baby wipes, facial wipes and moist toilet tissue, for example), which is a particular concern because you don’t wash off the the residue from these products – that generally being the point of using them – so it lingers on the skin.

A 2014 report from the International Journal of Toxicology concluded that although MI and MCI are sensitisers at concentrations of 50 ppm and above, they weren’t at concentrations of 15 ppm (and below). And therefore they, “may be safely used in ‘rinse-off’ products at a concentration not to exceed 15 ppm and in ‘leave-on’ cosmetic products at a concentration not to exceed 7.5 ppm”.

However, also in 2014, the European Commission Scientific Committee on Consumer Safety argued that: “For leave-on cosmetic products (including ‘wet wipes’), no safe concentrations of MI for induction of contact allergy or elicitation have been adequately demonstrated.”

People have been particularly worried about children, especially with respect to baby wipes. This is not unreasonable, since not only is the contact dermatitis that can occur painful and unpleasant, but once sensitisation has occurred it can’t be reversed: anyone affected will have to read labels extremely carefully for ever after. As a result, consumer groups have campaigned to have MI and MCI removed from any product that’s left on the skin over the last few years.

I happen to have three different brands of baby wipes in my house at the moment (small children you see), and a quick glance at the ingredients tells me that MI and MCI aren’t in any of them, and nor are they ingredients in the packet of flushable moist toilet tissue in the bathroom. This is hardly a comprehensive survey of course, but it suggests that these substances might be falling out of favour. Big companies aren’t really out to get us: pictures of people with nasty skin lesions after using their products doesn’t do them any favours.

Some consumers have complained about the use of MI and MCl in products.

Some consumers have complained about the inclusion of MI and MCl in products.

Do you really need to worry? Were these consumers right to highlight the fact that the shampoo contains MI and MCI in their reviews? Well, if you know you have sensitive skin then these substances probably are best avoided. But is shampoo likely to cause sensitisation if you’re fortunate enough to be blessed with the sort of skin that generally doesn’t erupt into a rash if the wind so much as changes? No one can say for certain, but it seems unlikely because you wash it off: these substances are only in contact with your skin for a few seconds.

So, whilst it doesn’t hurt to be aware of such things, there’s probably no need to panic and throw out all your shampoo just in case. On the other hand, if you’ve been wondering why your skin seems to be permanently irritated, it might be worth checking a few ingredients labels.

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