Magnesium has quietly become one of the most talked about minerals going. It is in sprays, in sleep gummies, in half the supplements on the pharmacy shelf. And Epsom salt, the old-fashioned stuff your grandmother put in the bath after a long day, is having a moment again too. If you have ever wondered what magnesium actually does, whether Epsom salt is the same thing, and why we put 550kg of it into every float room, here is the plain English version.
What magnesium actually does
Magnesium is a mineral your body needs to function. It is not a wellness trend, it is basic plumbing. It plays a part in hundreds of processes inside you, but the ones most people notice are these:
- Muscles letting go. Calcium helps a muscle contract, magnesium helps it relax again. That is a simplification, but it is the reason magnesium comes up in every conversation about cramps and tight shoulders.
- Nerve signals. It helps regulate how excitable your nervous system is. Low magnesium is associated with feeling wired, jumpy and on edge.
- Energy production. Your cells need it to turn food into usable energy. Persistent tiredness is one of the common signs of running low.
- Sleep. It is involved in the systems that help your brain wind down at night, which is why so many sleep products lean on it.
Most of us get magnesium from food: leafy greens, nuts, seeds, wholegrains, beans, dark chocolate if you are lucky. Plenty of people in Ireland do not quite hit the recommended intake, and things like heavy sweating, hard training, a lot of alcohol or a very processed diet can nudge you lower still. That said, please do not diagnose yourself off a blog post. If you are exhausted or cramping regularly, that is a conversation for your GP or a pharmacist, not for us.
So what is Epsom salt?
Here is the bit that surprises people. Epsom salt is not really salt in the way table salt is. Table salt is sodium chloride. Epsom salt is magnesium sulphate, a completely different compound. It got its name from Epsom in Surrey, where it was first drawn from a spring back in the 1600s, and it looks like coarse white crystals.
That distinction matters for two reasons. First, it is magnesium you are putting in the water, not sodium. Second, it explains why float water feels the way it does. It is silky and slightly slippery rather than harsh, and it does not sting the way sea water does. It does taste desperately bitter, so keep it out of your mouth and eyes, but on the skin it is gentle.
The honest bit about absorption
You will see plenty of claims online that soaking in Epsom salt floods your body with magnesium. We are not going to tell you that, because the research does not firmly support it.
The truth is that skin is a very good barrier, and that is its job. Some small studies suggest a degree of magnesium can pass through it, while others find little to no measurable change in blood levels. It is a genuinely unresolved question, and the studies that exist are mostly small. Research suggests the effect, if there is one, is far more modest than the marketing implies.
What we can say honestly is this: floaters tell us, week after week, that they climb out of the room looser and calmer than they got in. That is a real and repeatable experience. It is just probably not down to magnesium alone.
Then why 550kg of it?
Because the salt is doing a different job, and it is doing it brilliantly. Dissolve 550kg of Epsom salt into ten inches of water and you make that water denser than the Dead Sea. You cannot sink in it. You lie back and the water holds every part of you, with no effort and nothing to brace against.
That is the real mechanism, and it has nothing to do with absorption:
- Your joints and muscles come off duty. No gravity pressing down, no pressure points, no part of you holding another part up. Even a good mattress cannot manage that.
- The water disappears. We keep it at skin temperature, about 35C, so within a few minutes your brain stops registering where you end and the water starts.
- The inputs stop. No light, no sound, no phone, nothing to react to. The nervous system gets the quiet it needs to shift out of fight-or-flight, which we wrote about in fight, flight or float.
So the salt is not a supplement you are soaking in. It is what makes an hour of true weightlessness physically possible. If a little magnesium comes along for the ride, grand, but the weightlessness and the quiet are what people come back for.
Epsom salt at home, and where floating differs
A warm bath with a couple of cups of Epsom salt is a lovely thing, and it costs very little. Many people find it eases tired legs before bed, and we would never talk anyone out of it.
The difference is scale and silence. A home bath holds a few hundred grams of salt, so you still weigh what you weigh, and you can still hear the house. A float room holds 550kg, so you weigh nothing at all, and nothing reaches you for a full 60 minutes. It is a different order of experience rather than a stronger version of the same one.
One note to be straight about: floating is rest and recovery, not a treatment, and it is not a replacement for professional care. If something has been sore or off for weeks, get it properly looked at.
An easy next step
If your shoulders are up around your ears reading this, an hour of weighing nothing is a good place to start. A 60-minute float is €69, members float for €49, and everything you need is provided. We are open 7 days from 9:30am to 9:30pm in Raheen. Have a read of discover floating or before you float if you like knowing what to expect, then book your float or ring us on 061 424 765 and we will mind you from there.
