Supplements
Adaptogen Was a Category Invented Before It Was Tested
The word describes a substance that helps the body resist stress in whichever direction it needs. That definition was written first, and the search for anything meeting it has been running ever since.
There is a settled way of talking about the adaptogen category and its definition. It is worth asking how much of it survives contact with the detail.
The argument in brief
- The category was defined by criteria rather than discovered from a shared mechanism.
- A claim of normalising in both directions is difficult to design a trial around.
- Several plants in this group interact with prescribed medicines.
Where the word came from
The term was coined in the middle of the twentieth century by researchers looking for substances that would increase resistance to stress in general. Three criteria were proposed: the substance should be non-toxic, should act non-specifically, and should normalise function whichever way it had shifted. That is a definition written in advance of finding anything that met it, which is an unusual way to build a scientific category.
Plants were then assigned to the category on the basis of traditional use and early laboratory work rather than clinical results. The grouping has therefore always been an aspiration about what these plants might share rather than a demonstrated common mechanism.
The problem with normalising
A substance said to raise what is low and lower what is high produces a different predicted result in every participant. That makes a trial difficult to design, because the outcome measure has no single direction to move in. It also makes the claim nearly impossible to falsify, since any change can be described as the substance restoring balance.
On the label, trials in this area therefore tend to use general questionnaires about fatigue, mood or stress rather than a physiological endpoint. Questionnaire outcomes are legitimate but highly susceptible to expectation, which makes blinding more important rather than less.
What the trials actually look like
Studies of individual plants in this category have generally involved small numbers of participants over short periods. Extract preparations differ substantially between studies, using different plant parts, solvents and standardisations, which limits what can be pooled. A good number were conducted or funded by the companies producing the extract, which is disclosed and still relevant.
Follow the mechanism and where independent replication has been attempted, results have often been smaller or absent, which is the ordinary pattern for early promising findings. None of this means the plants do nothing; it means the evidence is not currently strong enough to support the confident claims made for them.
Stress is not one measurable thing
The word stress covers a subjective experience, a hormonal response, an immune shift and a set of behaviours, and these do not always move together. A product might change a hormone measurement without changing how anyone feels, or the reverse, and both are reported as success.
On the label, cortisol in particular varies enormously across the day and between people, which makes single measurements close to meaningless. A trial reporting a cortisol change without a corresponding change in symptoms has reported a surrogate rather than a benefit.
This is why the strongest-sounding results in the category are frequently the ones with the least practical significance.
Not gentle by default
Several plants in this group have real pharmacological activity, which is the reason to be interested in them and the reason for caution. Some affect blood pressure, some affect blood sugar, and some influence the liver enzymes that clear prescribed medicines. Interactions with anticoagulants, immunosuppressants, thyroid treatment, sedatives and antidepressants have been reported for various members of this group.
Thyroid effects in particular have been described with one popular member, which is a specific and checkable concern rather than a general warning. Anyone on regular medication should raise these with a pharmacist before starting, and nobody should adjust a prescription for a supplement.
A fair way to hold the category
Traditional use over centuries is genuine information about tolerability and about what people found worth continuing. It is not information about efficacy, because traditions do not run control groups and do not record the failures. Some of these plants may well turn out to have modest, specific effects that survive proper testing.
On the label, treating them as promising and unproven is accurate, while treating them as established is a claim the literature does not carry. The category label is the part to distrust most, because it groups plants by hope rather than by anything they demonstrably share.
The takeaway
The definition came first and the evidence has been trying to catch up for seventy years. Plants with real activity deserve real testing, not a category name.
An extraordinary mechanism needs better evidence than testimonials, and usually has less.
Questions readers ask
Are adaptogens regulated as medicines?
In most countries they are sold as food supplements, which means no efficacy approval is required before sale. Some jurisdictions have traditional herbal registration schemes that assess quality and safety without requiring efficacy trials.
Why do people feel a difference?
Expectation, routine, the act of taking something for stress, and in some cases genuine pharmacological effects all contribute. Separating those requires blinding, which most trials in this area have done poorly.
