32-33 The wild west

If you walk into any pharmacy today, you will find shelves full of probiotic products making confident promises about gut health, immunity and well-being. It’s like the wild west out there!

Yet depending on the country, those products may be regulated as foods, supplements, drugs or something in between, and the strain listed on the label may or may not tell healthcare professionals and consumers what that bacterium will do inside the body.

The probiotic market is booming, at $76.59 billion in 2025 and projected to reach $114.95 billion by 2030, and the science underpinning it has advanced dramatically. However, the regulatory frameworks governing probiotic quality have not kept pace.

The result is a fragmented system that leaves consumers confused, clinicians uncertain and scientifically rigorous companies competing alongside products that may not meet even basic standards of transparency or evidence.

The problem starts with a basic question: what does ‘probiotic’ legally mean? The FAO and WHO definition, ‘live microorganisms that, when administered in adequate amounts, confer a health benefit on the host’, has existed since 2001, but global regulation remains inconsistent.

In the United States, probiotics are largely regulated as dietary supplements or food ingredients.

In the European Union, the word ‘probiotic’ is effectively banned on food labels because only one health claim has met the European Food Safety Authority’s evidentiary threshold – the link between live yoghurt cultures and improved lactose digestion, approved in 2010 – leaving the broader probiotic category without regulatory legitimacy on European packaging.

Canada has its own monograph, Japan another framework, while China, India and Southeast Asian markets have developed separate criteria.

This has led to a fragmented marketplace where the same strain can be marketed as a clinically validated health product in one country and a generic food ingredient in another. For companies investing in proper clinical trials, strain characterisation and transparent communication, this patchwork is deeply frustrating.

For consumers, it is confusing. And for healthcare professionals, it creates uncertainty around what evidence they can trust. The Codex Alimentarius Committee on Nutrition and Foods for Special Dietary Uses is now discussing harmonised international probiotic guidelines, recognising that inconsistent standards enable misuse of the term and the sale of non-compliant products. That conversation is important, but it is overdue.

Here is where the science gets both exciting and humbling. Two products could carry the same genus and species name on their labels, say Bacillus clausii, and yet behave in completely different ways inside the human gut.

The research is unequivocal on this: probiotic efficacy is both strain-specific and indication-specific.

A strain shown to prevent antibiotic-associated diarrhoea may have no measurable effect on irritable bowel syndrome. Another strain may influence immune markers in healthy adults but offer little value for microbiome recovery after chemotherapy.

A useful way to think about this is the human analogy: we are all Homo sapiens, yet no one would assume that any two people have the same abilities or roles. One person may be an elite athlete, another a software engineer, another a teacher.

All share the same species classification, but their skills, physiology and responses to training or environment differ widely. Probiotic strains work in a similar way: the shared species name tells you very little about what a specific strain is actually capable of doing.

This matters clinically. When healthcare professionals recommend a ‘probiotic’ without identifying a strain supported by evidence for a specific condition, they are often working with incomplete information. Not because the evidence does not exist, but because current regulations rarely require that evidence to appear clearly on the label.

Dose is another major issue. In many markets, manufacturers are not required to guarantee viable bacterial counts at the end of shelf life.

Independent analyses of commercial products have found discrepancies between label claims and actual viable counts, with some products containing far fewer colony-forming units than advertised or strains that do not fully match their label descriptions.

An analysis from the International Scientific Association for Probiotics and Prebiotics found that 45% of retail dietary supplement products did not provide strain designations, while a similar proportion failed to guarantee potency through end of shelf life.

That is not a minor quality control issue. It is a structural weakness in the market.

Consumers are the most immediate losers. They spend significant amounts on products that may not contain the strains or doses listed on the label. They make decisions based on claims that are often difficult to independently verify.

When probiotics fail to deliver, many consumers conclude that probiotics as a category do not work, rather than recognising that the specific product lacked the evidence to support its claims.

Healthcare professionals face a different challenge. Interest in probiotics is growing rapidly among patients, and the evidence base for certain well-characterised strains is increasingly credible, but because regulation does not consistently link products to supporting evidence, recommending probiotics confidently is harder than it should be.

As a result, clinicians often fall into two extremes: broad generalisations that ‘probiotics are good for gut health’ or blanket dismissal of the category altogether. Neither approach serves patients well.

Researchers have repeatedly identified this heterogeneity as a major barrier to drawing reliable clinical conclusions. Ultimately, this is not simply a data analysis problem. It is a problem of standards and transparency.

When products with fundamentally different strains, evidence bases and clinical effects are grouped under the same broad ‘probiotic’ label, confusion becomes inevitable.

The encouraging news is that the scientific tools already exist. The challenge is applying them consistently.

First, strain-level identification should be a minimum requirement. A label stating only the name of the species, like ‘Bacillus clausii’, tells clinicians and consumers very little. A full strain designation, including genus, species and alphanumeric strain code, provides meaningful information and allows evidence to be properly assessed.

Codex discussions already recognise molecular strain typing as a baseline standard. For manufacturers investing seriously in strain characterisation, this is simply a matter of transparency.

Second, health claims should be tied directly to the strain and dose on the label. If a product claims a clinical benefit, that claim should be supported by studies using the same strain at the same dose.

Not a related species, not a similar formulation, but the actual product being sold.

This principle already underpins pharmaceutical and medical-device regulation.

There is little justification for applying a lower evidentiary standard to probiotic health claims.

Third, the industry and local regulatory authorities should support global harmonisation while also raising standards. International alignment through bodies such as Codex Alimentarius would improve clarity for consumers, clinicians and manufacturers alike, but progress should not depend entirely on regulators.

Industry organisations, alongside responsible manufacturers, can adopt stronger standards now: clear strain identification; verified dose stability; transparent evidence and claims linked directly to published trials. Companies investing in rigorous science should not be competing on equal footing with products that do not meet even basic scientific standards.

Probiotics sit at the centre of one of the most promising areas of modern health research. Advances in microbiome science are opening new possibilities across immunity, metabolic health, gastrointestinal disease and even neurological conditions.

Still, that potential will only translate into meaningful public health benefit if products are trustworthy. It is not about calling for all probiotics to be regulated like pharmaceuticals, but about establishing a common scientific language, meaningful labelling standards and evidence requirements that reflect the sophistication of the science itself.

The microbiome does not recognise regulatory borders. It is time for our standards to stop acting as though it does.

Without a common language

Not all created equal

Paying the price

Three steps forward

Stakes are higher