Epsom Salt in a Cleanse: What It Does and Who Should Avoid It

Of everything in a sixteen-hour cleanse, the Epsom salt is the part people remember. The oil gets talked about more, but it is the bitter glass at six in the evening that makes first-timers wonder what they have signed up for. It is also the part of the protocol most often got wrong — wrong grade, wrong dilution, wrong order, or taken by somebody who should have asked a doctor first.

So it is worth understanding properly, because once you know what it is doing, most of the mystery and a fair amount of the discomfort goes away.

What is Epsom salt, actually?

Epsom salt is magnesium sulfate. It is not related to the salt in your kitchen, which is sodium chloride. The name comes from the town of Epsom in Surrey, where in the seventeenth century a farmer noticed his cattle would not drink from a particular spring — the water was bitter. It turned out to be rich in magnesium sulfate, and for the next two hundred years people travelled there to take it.

That bitterness is unavoidable. It is the compound itself, not an impurity, and no amount of good manufacturing removes it. Anyone selling you Epsom salt that tastes pleasant is selling you something else.

What does Epsom salt do in a cleanse?

Two things, and they are the reason it appears where it does in the protocol.

It draws water into the bowel. Magnesium sulfate is poorly absorbed from the gut. It stays in the intestine, and because it is dissolved in water it raises the concentration of dissolved particles there. Water follows by osmosis, moving from the body into the bowel. The bowel contents become bulkier and much wetter, and the bowel responds by moving them along. This is why it is classified as an osmotic laxative and why diarrhoea follows. That is the intended effect. People sometimes report it as a side effect; it is the point.

Its magnesium relaxes smooth muscle. Magnesium is involved in hundreds of processes in the body, and one of them is muscle relaxation — it acts, roughly, as a counterweight to calcium, which makes muscle contract. The bile ducts and the sphincter of Oddi, the small valve where bile enters the small intestine, are wrapped in smooth muscle.

That second effect is why the sequence matters. The Epsom salt comes first, at six and again at eight in the evening, and the olive oil comes at ten. Taking a large dose of oil into a system that has not been prepared is a much less comfortable experience. When someone hands you a booklet with the steps in a different order or the timings moved around, they are not offering a variation — they have copied something without understanding why it was arranged that way.

How much is used?

The protocol uses four doses of roughly 20 g of Epsom salt, each dissolved in about 200 ml of water, taken at set times: two in the evening and two the following morning, with the oil doses between and after them. All four are usually made up in advance in the afternoon and kept chilled.

Two practical points make a real difference. Dissolve it completely — undissolved crystals sitting at the bottom of the glass are far more likely to cause nausea, so stir until the water runs clear. And drink it cold and in one go rather than sipping. Cold blunts the taste, and sipping simply extends the unpleasantness. A straw placed towards the back of the mouth helps some people. So does a mouthful of plain water immediately afterwards.

What does the night actually feel like?

Honestly? Not much happens for the first hour or two, and then it does. Most people find the bowel movements start somewhere between forty minutes and two hours after the first dose, and continue in waves. They are loose and watery, and there tends to be more volume than seems reasonable for what you have taken in — that is the osmosis at work, and it is water coming out of you.

Some people feel queasy. Some are sick, particularly after the oil. The booklet is right that this is not a sign something has gone wrong, but there is a limit to that reassurance: if you cannot keep fluids down at all, if you are still vomiting hours later, or if you feel faint or lightheaded when you stand, that is not the protocol working, and you should stop and speak to a doctor.

Sleep is broken. Plan for that. Nobody should do this the night before something that matters.

Who should not take Epsom salt without medical advice?

This is the section that matters most, and it is the one that tends to be left out of the cheerful version.

Magnesium taken by mouth is cleared from the body by the kidneys. In a person with normally functioning kidneys, an excess is filtered out and passed in urine without difficulty. In a person whose kidneys are not working normally, it is not — and magnesium can accumulate in the blood. High blood magnesium causes weakness, low blood pressure, slowed heart rhythm and, at severe levels, worse. Cases of this following oral magnesium in people with reduced kidney function are documented in the medical literature.

So speak to a doctor first if any of these apply to you:

• Any kidney condition, or reduced kidney function, including a history of kidney stones — this is the most important one on the list
• Heart block or a heart rhythm disorder
• You take diuretics, or any regular prescribed medicine — magnesium interacts with several, and a laxative changes how quickly anything you swallow is absorbed
• You are already dehydrated, unwell, or unable to drink freely
• You are pregnant or breastfeeding
• You are elderly or frail, where fluid loss is less well tolerated
• You have an inflammatory bowel condition, a bowel obstruction, or have had recent abdominal surgery

None of this means the protocol is dangerous in general. It means it is a real physiological intervention rather than a gentle drink, and the people it is not suitable for are identifiable in advance. We would far rather you asked and were told to wait than went ahead because nobody mentioned it. If you are unsure, write to us with your situation and we will tell you plainly.

Food-grade, not bath-grade

Epsom salt is sold for two completely different purposes, and they are not interchangeable.

The large, cheap bags in the bath and personal-care aisle are made for soaking in. They are not manufactured to food standards, not tested for the impurities that matter when something is swallowed, and are often perfumed. Nothing about that packaging suggests it is dangerous, which is exactly the problem — it looks like the same white crystal.

What goes into a cleanse should be food-grade or pharmaceutical-grade magnesium sulfate, in sealed, marked packaging, with the grade stated. Loose salt weighed out in front of you in a shop tells you nothing about what it is. If you are checking a kit, the standard is published here.

Staying hydrated

You are going to lose a lot of water, and the most common way people feel wretched the next day is simple dehydration. Drink plain water through the evening and the following morning, beyond what the protocol itself contains. The morning after, start with fruit juice and go gently on food for the first meal — the digestive system has had a night of it.

What Epsom salt is not

It is not a treatment for anything. It is a laxative and a source of magnesium, used in a specific order for a specific reason within a wellness practice. It does not cure a disease, it does not dissolve anything, and any description of it that reaches for those words is describing something other than the chemistry.

Understood for what it is, it is an unremarkable compound with a well-documented action and a clear list of people who should leave it alone. That is a duller description than the one you may have been given. It is also the true one, and it is the description that lets you make a sensible decision.

If you want to read the full protocol with quantities and timings, it is published here. If you would rather do a first cleanse with a practitioner present, camps run every month.