A Signal That Turns Up Everywhere — On Ions

You have probably woken at night to a cramp in your calf. That moment when the muscle clenches on its own and will not straighten out.

Korean medicine has an old prescription for exactly that spot. Peony and Licorice Decoction (jakyak-gamcho-tang) — licorice takes up half the name. The old record put the result like this: "It straightens at once."

The record is about 1,800 years old. I have looked at this passage for a long time. Why licorice, of all things. And why was it fast.

A muscle clenching is something ions do

For a muscle to clench, calcium has to come into the cell. Calcium comes in through a door, and that becomes the trigger for the muscle to contract. It is the same when a nerve fires a signal. Sodium comes in and potassium goes out, and that makes the electricity.

So a muscle clenching on its own means that the coming and going of those ions has been disturbed.

What licorice's compounds do is precisely at that spot. They are reported to press on the door calcium comes in through, and to restore the potassium balance.

The ancients wrote this property of licorice down as "wan-geup (緩急)" — slowing what is in a hurry. They would not have known the mechanism. And yet they placed exactly that herb at the spot where something in a hurry has to be slowed.

Which is why I keep coming back to this place

There are several signals inside the body. There are hormones, there are neurotransmitters, there are the substances that announce inflammation. Each has its own place to keep.

Among them, the one used most widely, most generally, is the ion. Along the roads where cell talks to cell and tissue to tissue, it is hard to find a spot where ions are not involved.

A nerve cell firing a signal, a muscle clenching, the heart keeping its beat — all of it is made of potassium and sodium and calcium coming and going.

And they are usually at the first link

This part matters more.

When a cell makes something, when it gets its hands in step with the cell beside it, when it works to survive, when it tries to use energy better — the place where that chain starts is often an ion.

Of the countless proteins in the body, the first signal that starts their synthesis is often sodium or calcium. A door opens, ions come in, and from there the work follows on inside the cell, one thing after another.

Ions sit on the trigger side, not the result side.

Which is where herbal medicine and ions meet

Here I move over to herbal medicine.

One thing has to be noted here. Herbal medicine has a hard time acting at a concentration that could control a cell directly. Measured, the concentration that shows up in the blood is very low. To press something down reliably in a test tube takes far more. (Why Herbal Medicine Works — The Paradox of Low Concentration)

So herbal medicine does not work by pressing one spot hard. It works by touching several places a little, at different times. (What Herbal Medicine Does)

But where those "touched a little" places are is the question.

If you look for the points that affect a cell and the environment it sits in directly, there is nothing as direct and as important as an ion. Touch something else and it has to pass through several stages to reach the cell. An ion is itself the cell's language.

And because it sits on the trigger side, move it a little and what follows comes along.

So this is what it amounts to

Put together, it is this.

• Herbal medicine cannot press hard. The concentration does not go that high.
• But there is nowhere ions are not involved, and they are usually at the first link of the chain.
• So if there is a place that can be reached by touching a little, it is on the ion side.

Weak and direct are not a contradiction. In place of pushing hard, it is choosing a place where the language gets through.

How far this is known

That ions carry the body's signals and sit at the first link of many chains — this is material physiology deals with.

Which compound in which herb changes the flow of which ion, and by how much, is being worked out one at a time, and is not all worked out yet. There are some, like licorice, whose route has been drawn fairly well, and far more that have not.

And touching an ion is not always a good thing, either. Calcium, inside the same cell, is poison in excess and collapses function when short. How much, where, and when changes everything. Which is why I call ions not a master key but the most direct place.

The pieces have come out this far, and joining them into one picture is still in progress.

So in the clinic

I always ask whether you are taking medicine that affects electrolytes. Diuretics, blood-pressure medicine, heart medicine. For someone whose ions are already unsteady, you must not add a medicine that pushes in the same direction.

I ask whether there has been long-running diarrhoea or vomiting. I have to check whether you are already in a state of loss.

I fix the amount and the duration. This is a place where the same thing does different work depending on the amount, so that holds here especially.

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The body has several signals, and it is hard to find a spot where ions are not involved. And they are usually at the first link of the chain.

If herbal medicine can do something even at a low concentration, that is not because the medicine is strong but because it chose a place where the language gets through — that is how I see it.

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References

• A review setting out that calcium is a signal involved in almost everything a cell does, and that it does harm in excess — Molecular Cell, 2017
• A study showing that calcium coming in becomes the first signal that switches genes on — PNAS, 2001
• A survey gathering some fifty medicinal plants that alter calcium, potassium, sodium and chloride channels — Physiological Research, 2026

Written by Dr. Heo Ji-young (PhD in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)