Isovaleric Acid · 20:1 Extract · UK Stock Since 2016
Why Does Valerian Root Smell Like That?
Old socks. Forgotten cheese. Something that died behind the radiator. If you have just opened a tub of valerian and wondered whether you have been sold something off, you have not. Here is the chemistry behind one of the worst smells in the herb trade.
The Short Answer
Isovaleric acid. It is a small fatty acid that builds up in valerian root as the root dries, and it is the same compound behind the smell of certain ripe cheeses and of sweaty feet.
It is not spoilage, it is not contamination, and it is not a sign that your valerian has gone off. A valerian root that smells of nothing is the one worth asking about.
Valerian has the worst reputation of any common herb for smell, and it is entirely deserved. People describe it as sweaty socks, blue cheese, wet dog or stale gym bag. One nineteenth-century writer settled on "the odour of a cheese that has been kept too long."
Almost everyone who buys it has the same reaction the first time they open the tub, and almost everyone wonders the same thing — is this supposed to smell like this?
The compound responsible
The main culprit is isovaleric acid, known more formally as 3-methylbutanoic acid. It is a short-chain fatty acid with the formula C5H10O2.
Here is the detail most people miss
The acid is named after the plant, not the other way round. Isovaleric acid gets its name from Valeriana, because valerian is where chemists first isolated and characterised it. The plant did not acquire a chemical's smell. The chemical acquired the plant's name.
If the compound sounds familiar it is because you have met it elsewhere. Isovaleric acid is a significant contributor to the aroma of several washed-rind and blue cheeses, and it is one of the principal components of foot odour, where it is produced by skin bacteria breaking down the amino acid leucine.
So the comparison people reach for instinctively — cheese, feet — is not a figure of speech. It is literally the same molecule.
The strange part: the esters smell lovely
Isovaleric acid on its own is pungent. Its esters, where the acid is joined to an alcohol, are a different story entirely — they smell fruity and sweet, and several are used in perfumery and food flavouring. The same carbon skeleton, one small change, and the smell flips completely from offensive to pleasant.
That is not a curiosity. It is the key to the next part.
Why dried root smells worse than fresh
Pull a valerian plant out of the ground and the fresh root smells earthy and fairly mild. Nothing that would clear a room. Leave it to dry and the smell develops into the full sweaty-sock experience.
That is because much of the isovaleric acid in dried valerian is not present in the living root in free form. It is bound up in esters, which are relatively stable while the root is alive and moist. As the root dries and ages, those esters gradually break down and release the free acid — and free isovaleric acid is the one you can smell.
What That Means In Practice
A valerian product's smell tends to get stronger with time, not weaker. A tub that has been open a while, or stored somewhere warm, will usually smell more pronounced than a freshly sealed one.
This is the reverse of what people expect. Most things that smell strongly fade. Valerian ripens.
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Why an extract smells different from root powder
If you have used valerian in more than one form you will have noticed they do not smell identical, and the difference comes down to concentration and processing.
Ground root powder is the whole dried root, milled. Everything that was in the root is still there, in its original proportions, including the fibre and starch that make up most of the weight.
An extract has been through a solvent, and only the soluble fraction is kept and dried back to a powder. A 20:1 extract means roughly twenty parts of dried root went in for every one part of finished extract. The aromatic compounds concentrate along with everything else, which is why a small amount of extract can smell more intense than a much larger amount of plain root powder.
| Form | What it is | Smell |
|---|---|---|
| Fresh root | Straight from the ground | Earthy, surprisingly mild |
| Dried root powder | Whole root, dried and milled | The classic valerian smell |
| 20:1 extract | Soluble fraction, concentrated | Sharper and more concentrated |
| Tincture | Alcohol extraction, kept liquid | Pungent, and it lingers on glassware |
The cats
If you keep a cat, you may already know where this is going.
A proportion of domestic cats respond to valerian in much the same way they respond to catnip — rolling, rubbing, becoming briefly very interested in the tub. The compound usually credited is actinidine, which is structurally related to the active component of catnip and also occurs in silvervine, another plant with the same effect on cats.
Not every cat responds. The trait is inherited, and a meaningful minority of cats are simply indifferent to the whole category.
The practical upshot is straightforward: keep the tub shut and somewhere the cat cannot get to it. Several people a year discover this the hard way.
The name has nothing to do with the smell
Given the aroma, you would be forgiven for assuming the name was an insult. It is the opposite. Valeriana comes from the Latin valere, meaning to be strong or to be well — the same root that gives us "valid" and "valour".
The plant has been documented in European herbals for centuries under a long list of regional names, and the smell gets a mention in most of them. Whoever named it chose to ignore the obvious.
What the smell tells you when you are buying
Here is where it becomes genuinely useful rather than just interesting.
The Part Worth Remembering
A valerian product that smells of nothing at all is the one worth a question, not the one that smells strong.
If the smell is barely there, the possibilities are that the material is heavily diluted with a carrier, that it is very old, or that it has been through processing that stripped the volatiles. None of those is what you were buying.
This is one of the few cases in the supplement trade where your nose is a useful instrument. It will not tell you the extract ratio and it will not tell you the valerenic acid content — for those you need a certificate of analysis. But a complete absence of smell in a valerian product is a genuine anomaly.
Living with it
If you have decided the smell is a price worth paying, a few practical points.
Capsules solve most of it. The shell keeps the powder contained until it has been swallowed, which is the entire reason valerian is so commonly sold in capsule form rather than loose. Do not open them to mix the contents into a drink unless you are curious about what regret tastes like.
Keep the lid on and keep it cool. Warmth and air accelerate the ester breakdown that produces the free acid, so a tub left open on a sunny windowsill will develop faster than one kept in a cupboard.
Store it away from food. Isovaleric acid is volatile and it will happily take up residence in a cupboard. Valerian next to the teabags is a decision you make once.
It washes off glassware badly. If you use a tincture, that smell on the measuring spoon is persistent. Hot water and detergent, promptly.
Our Valerian
Yes, ours smells too
We sell a 20:1 valerian root extract at 550mg per capsule, which is equivalent to 11,000mg of dried root. It smells exactly as this article describes, and we are not going to pretend otherwise or tell you we have found a way around it. Nobody has.
What we will tell you is what is in the capsule: valerian root extract and a vegan HPMC shell. No fillers, no flow agents, no bulking powder. Certificate of analysis available on request for any batch — just ask and we will send it.
Questions people actually ask
Has my valerian gone off?
Almost certainly not. The smell is inherent to dried valerian and it gets stronger with age rather than weaker. Signs of actual spoilage are different — visible mould, clumping from moisture, or a musty smell distinct from the sweaty-cheese one.
Can you get valerian that does not smell?
Not honestly. You can mask it with a coating or dilute it until the smell fades, but both mean less valerian per capsule. Capsules are the practical answer — the shell contains it until it has been swallowed.
Does the smell mean it is strong?
Not reliably. Smell intensity tracks free isovaleric acid, which is a function of age and storage as much as of how much extract is present. Strong smell is a reasonable sign that real valerian is in there; it is not a measure of potency. For that you need the specification.
Why does the extract smell different from the root powder I had before?
Concentration. A 20:1 extract has roughly twenty parts of dried root behind every one part of powder, so the aromatics are concentrated alongside everything else.
My cat has gone peculiar near the tub. Is that normal?
Yes, and it is well documented. A good proportion of cats respond to valerian much as they do to catnip. Keep the tub closed and out of reach.
Is isovaleric acid harmful?
It occurs naturally in a range of everyday foods, cheese among them, at the levels found in valerian. The smell is unpleasant; that is a different matter from being harmful.
This article is about the chemistry of a smell. It makes no claim about what valerian does in the body, and none is intended — valerian carries no authorised health claim in Great Britain.
Food supplement. Not a substitute for a varied and balanced diet or a healthy lifestyle. Do not exceed the stated dose. Keep out of reach of young children. Not suitable for anyone under 18, or for those who are pregnant or breastfeeding. If you are taking medication or under medical supervision, speak to your doctor or pharmacist before use.
Charge Products is a trading name of Big Idea Services Ltd, Company No. 11645389. Unit 1, 8 Towerfield Road, Southend-on-Sea, Essex SS3 9QE. 5 Star Food Hygiene Rating. Last updated: October 2026.
