Insights & Reports Medical Nutrition & Health Supplements

Boosting both brains – commercial opportunities for probiotic supplements and the gut-brain axis

Published on 24 August 2023
Christopher James-Dewilde
Written by

Christopher-James Dewilde



In recent years, the intricate connection between gastrointestinal and mental well-being has emerged as a promising avenue for scientific exploration. Termed the gut-brain axis, the complex communication network between the gut microbiota and the central nervous system has revealed a new frontier in understanding the interplay between one’s gastrointestinal wellbeing and multiple facets of brain function, most notably mental health and cognitive performance. As our understanding of the link between the gut and the brain deepens, the theoretical case for utilizing probiotics to enhance both mental health and cognitive performance grows stronger. Although the evidence for consuming probiotics for mental well-being is still in its infancy, this class of probiotics, commonly referred to as psychobiotics, has firmly captured the attention of both academia and industry. As psychobiotics become an increasingly popular topic of discussion in mainstream media, consumer demand has also rapidly begun to grow. Amazon sales data from ClearCut Analytics1 showed that whilst the American probiotic market as a whole grew by 18% in 2022, sales of probiotic products marketed for mood support grew by 33%.

In this paper, we delve into some of the key factors driving this consumer demand, and consequently why psychobiotics are a promising investment opportunity for VMHS companies in both the present and future. We provide a quick overview of the current regulatory landscape in some of the largest markets, which depicts a cautiously optimistic outlook for the future. We conclude with some strategic considerations for how manufacturers should position their psychobiotics.

The current state of the evidence

The benefits of consuming probiotics for “gut health”, i.e., helping to prevent and/or alleviate gastrointestinal symptoms and/or illnesses, have been well established2. What is less well established is how, through the gut-brain axis, many of the same probiotic strains can have positive influences on both an individual’s cognitive performance and mental health. This research is still very much in its infancy. A decade ago, much of the evidence supporting this connection came from animal studies, with limited research conducted in humans. In recent years, however, there has been a notable shift towards human studies, demonstrating progress towards establishing proven psychobiotic effects in individuals. Table 1 summarises some of the most prominent literature reviews restricted to humans only.

Eastwood et. al (2021)3 conducted a systematic review on the effect of administering probiotics on cognition and reported a positive effect in 21/25 studies. Den et. al (2020)4focused their meta-analysis on patients with Alzheimer’s and mild cognitive impairment and found that cognitive performance was greatly improved in both groups. Gambaro et. al (2020)5 focused their review instead on the effect on anxiety and depression, demonstrating that probiotics improved depression and anxiety symptoms in 53.83% and 43.75% studies, respectively. Chao. et al (2020)6 conducted a meta-analysis of RCTs comparing patients with anxiety or depression against healthy patients. They found probiotics to reduce depression scores for patients with anxiety and/or depression, as well as healthy patients under stress. However, they found no reduction in anxiety symptoms amongst any of these groups. Similarly, El Dib et. al (2021)7 found probiotics to improve depression and anxiety symptoms only when certain depression and anxiety indices were used. Finally, Silva et. al (2021)found probiotics to have a significant effect on depressive symptoms in patients already diagnosed with depression, but not in healthy patients.

Table 1: A selection of recently published literature reviews limited to human studies

*5 studies on young children were excluded due to confounding factors, particularly neurocognitive development being too rapid at this age to see any effect of probiotic intervention

The evidence to date remains mixed, with most reviews concluding that more large scale RCTs are required. And the lack of available RCTs means strain-specific reviews are, to date, unavailable. That being said, most reviews to date conclude on an optimistic note regarding the potential of strains developed specifically for mental wellbeing. The large number of studies demonstrating at least a modest cognitive benefit, combined with the low cost and risk profiles of probiotics, make it a very appealing area to watch for academics, healthcare professionals, and consumers alike.  

Although more evidence will be needed to achieve widespread acceptance in the eyes of both academia and regulators, increased demand for psychobiotics is likely also being driven by the rapidly growing body of evidence of the gut-brain axis in general. Between 2018 and 2022, the number of papers published referencing the gut-brain axis more than doubled from 15,000 to 32,000 (see below).

Figure 1: Number of published articles available on Google Scholar related to the search term “Gut-Brain Axis”

Meanwhile, a 2021 survey by the IFIC (International Food Information Council)9 found that the most common reason cited for consuming probiotics was to support gut health (51%), ahead of general health and wellness (38%). Since probiotics are considered almost synonymous with the gut, an increased understanding of the gut-brain axis will likely drive probiotic demand without all consumers demanding causal evidence. Despite the relative novelty of the gut-brain axis in contemporary discourse, the same survey showed that 13% of probiotics consumers already claim to take probiotics for their mood and emotional health.

Mental health, wellness, and choosing a supplement

Demand for psychobiotics is also likely being driven by rapidly increasing prevalence rates of mental health disorders. A 2022 study by Healthy Marketing Team found that mental wellbeing has become the top health trend expected to drive consumer supplement choices10. The World Health Organisation estimates that approximately 280 million people in the world have depression, a comparable number of people have anxiety, and that both these figures increased by roughly 25% during the COVID-19 pandemic11.

Increased emphasis, awareness and destigmatisation around seeking treatment for mental health issues, particularly in high-income and western markets, may also be driving demand. A 2019 survey by Alight showed that 2,500 US office workers ranked mental health as the second most important aspect of their wellbeing, ahead of physical and social (the number one aspect was financial)12.

Conversely, mental health still carries a significant stigma in many societies. The simplicity, discretion, and relative affordability of integrating psychobiotics into one’s lifestyle may appeal to those who have been hesitant to explore traditional mental health treatments.

The broader wellness and self-care movements have also heavily contributed to the increase in psychobiotic demand. A 2021 survey by McKinsey of 7500 consumers located in the US, UK, China, Japan, Brazil, and Germany showed an increase in the prioritisation of wellness across all six markets13. 42% of respondents considered wellness to be a top priority, and respondents unanimously defined wellness as encompassing both physical and mental health.

Consumers are now more proactive in taking charge of their health and well-being than ever, seeking out products that offer preventive benefits beyond merely addressing symptoms. Additionally, these consumers have shown increased demand for products which they deem ‘natural’, as well as products which can offer multiple health benefits at once. Psychobiotics align perfectly with this trend, offering a proactive and preventive strategy for maintaining both mental and gastrointestinal wellbeing. As psychobiotics are widely available in multiple forms, including supplements, fortified foods, and functional beverages, the ease of incorporating them into one’s daily routine, as well as finding the psychobiotics best suited to one’s own body, is very appealing to those consumers who value wellness.

The current state of the psychobiotic supplement market

As previously mentioned, sales of probiotics marketed for mood grew at 33% on Amazon in the US in 2022, making it the fastest growing segment of the probiotic market. Despite this sharp increase in demand, the market for psychobiotics has a long way to go to catch up to probiotics marketed for gut health. Sales for probiotics with a pure digestive health focus actually experienced a slight decline (-0.2%) in 2022, but remained the largest segment at $130 million, compared to a mere $4.4m for mood-focused probiotics.

We focused our analysis on the US supplement market as it has a uniquely high use of supplements, with 30% of consumers choosing to get their probiotics from supplements rather than natural foods like yogurt (the next closest market was the EU at 14%)14. provides a good lens through which to analyse the US supplement market, as a survey by Trust Transparency showed that 55% of US consumers purchased their supplements online15  and Amazon naturally accounts for the lion’s share of those sales. Online supplement sales have also been the fastest growing sector for supplement sales throughout the last decade, which was further accelerated due to the COVID-19 pandemic.

A quick analysis of the Amazon marketplace for psychobiotics shows that it is particularly fragmented. Research by Clavis Insights16 shows that the minimum number of reviews needed for a product on Amazon to be competitive is 21. Of the hundreds of psychobiotics available on Amazon which meet this minimum criterion, the average number of reviews is well below 100. Only three products received over 1,000 reviews, of which the clear market leader is Garden of Life’s “Mood+” with 6000 reviews and over 10,000 bottles sold per month. Figure 2 showcases the current top three highest selling psychobiotics on Amazon, contrasted with four of the most popular probiotics positioned for gut health.

Figure 2:’s best-selling probiotic supplements positioned for both gut and mental health.

Such fragmentation may demonstrate a lack of consumer loyalty (a survey by Accelerate Associates showed that 75% of consumers would be willing to switch supplement brands17), but the lack of a dominant company or product can also be interpreted as a signal that the market has yet to be ‘won’. The barrier to entry for psychobiotics will be comparatively lower than other probiotic market segments with strong incumbents, and the lack of consumer loyalty means that anyone can currently compete. Finally, fragmented markets offer a greater opportunity for product differentiation. Manufacturers have the ability to tailor their products to specific mental health concerns and carve out a distinct market presence.

One of the more surprising findings is that, despite the comparative lack of evidence for probiotics and mental wellbeing, consumer reviews are largely comparable to the average of probiotics across categories. An examination of consumer reviews by Lumina Intelligence between 2017 and 2020 across 1400+ brands and 25 markets showed an average review of 4.47 stars out of 5 for probiotics positioned for mental wellbeing, as opposed to 4.53 across all probiotics18.

Analysing the consumer reviews of the top three products on highlights how probiotics align well with the aforementioned trends of holistic health, products with multifaceted benefits, and general wellness, which in turn results in consumer satisfaction.


Although official health claims are not the only way to build credibility with consumers, regulatory hurdles have presented the biggest challenge so far for VMHS companies looking to market their probiotic strains as psychobiotics. Nevertheless, our long-term outlook remains positive, as regulatory authorities in certain EU markets, USA, Canada, and Brazil are gradually adapting to the growing scientific evidence and consumer demand for psychobiotics.

The EU has historically been the most reserved. Guidance issued by the European Commission in 2007 on article 1924/2006 stated that the average consumer perceives the term probiotic as “implying a health benefit”, and the phrase “contains probiotics” should therefore require a health claim authorisation. In practice, “contains probiotics” cannot be authorised as a health claim, due to the fact that a health claim requires the phrase to imply a relationship between a food or supplement and a constituent of health, which it lacks (see information published by International Probiotics Association for more details). As a result, European markets have suffered a de facto ban on using the phrase probiotics on their supplement packaging.

As a result of this, and without any further guidance from the commission, multiple EU markets have instead adopted their own approach on the use of the term probiotic and any associated health claims. National guidelines already exist in Italy, Spain, France, Bulgaria, and the Czech Republic, whereas many other European countries have been turning a blind eye to using the term probiotic on labels and in communication.

Manufacturers seeking regulatory approval from the EU may also consider a riskier but potentially more lucrative route of marketing the product as a Neuromodulator, making it subject to Regulation 1924/2008. Guidance on this regulation published in 2012 covers some of the scientific requirements for health claims related to the nervous system but does not clearly state the data requirements/study outcomes. More than 50 probiotics have attempted to make claims related to cognition under this regulation, but no claims have been authorised so far. That said, Vitamin B7 was granted the claim “contributes to normal psychological function” in 2010, despite academia not knowing the full extent of the role it plays in the nervous system.

The US has been more liberal so far, offering multiple regulatory routes that manufacturers can take to bring their products to market. Firstly, if a dietary supplement has been on the market since before October 15, 1994, the FDA does not need to be notified about the product. If a manufacturer chooses to submit a health claim, defined as “a product that is intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease, and that its intended use affects the structure or any function of the body” then an Investigational New Drug (IND) application needs to be file with the FDA, which requires clinical trials. However, if the manufacturer instead chooses to submit a structure function claim, defined as “the effect that a substance has on the structure or function of the body, which does not make reference to a disease” it does not need to be authorised or reviewed by the FDA. Instead, the manufacturer must cite publicly available literature on human and animal trials which support the truthfulness of the claim.

Finally, two particular cases of encouraging legislation directly related to psychobiotics are Canada (2016) and Brazil (2019), where in both cases strain-specific health claims were approved related to stress and anxiety.

So how should manufacturers position new probiotic products? Assuming for simplicity that the strain(s) in question have shown promise in aiding both gut and mental health, there are still a number of strategic considerations which need to be taken into account.

Positioning for gut health offers a mature market, a large evidence base (leading to more regulatory freedom), and high awareness among the general population, at the cost of lower growth and market saturation. Positioning for mental health allows manufacturers to differentiate themselves and tap into a rapidly growing segment. It also may be easier for manufacturers to create a more compelling emotional connection with their consumers, thereby increasing brand loyalty. Nevertheless, the segment has a long way to go to reach the size of the gut health probiotics market. Furthermore, regulatory concerns may limit market access. Some manufacturers may choose to add extra active ingredients to ease regulatory burden, at the cost of complicating the manufacturing process and impacting margins.

There is an opportunity to capitalise on the trend of holistic health by marketing for digestive and mental health simultaneously. As many consumers are beginning to recognize the interconnectedness of various aspects of health, including gut health and emotional well-being, a comprehensive messaging may resonate better with individuals who understand that a healthy gut can positively influence mood (and vice versa) but are unsure what supplements can aid in this process. In theory, a probiotic marketed for both would have a larger addressable market, as it could address the needs of both consumers seeking primarily gut health solutions as well as those prioritising mood enhancement. By highlighting both benefits, a manufacturer can also amplify the perceived effectiveness and therefore value of the supplement. Not only could this be a way to justify a premium price, but also to differentiate a product within the saturated market for probiotics.

The challenge of this strategy lies in the complexity of the messaging required to reach consumers. Consumer understanding of probiotics and the gut-brain axis has a long way to go before it reaches the public eye (like probiotics for gut health has). Choosing not to address the gut-brain axis may lead to consumer confusion due to two seemingly unrelated health claims.  This may in turn increase scepticism of the supplement’s efficacy. Addressing the gut-brain axis requires condensing an increasingly complex field of ongoing research into a language that not only consumers can understand, but which also resonates with them. Whether manufacturers can unlock the aforementioned benefits will therefore depend heavily on their branding and marketing campaigns.

Mapping out the pros and cons of each strategy reveals a complex landscape with no clear winner or one-size-fits-all approach. Each approach has its own set of pros and cons, and the optimal strategy depends on various factors such as available scientific evidence, target audience, market dynamics, and regulatory considerations.

Sector & Segment has extensive experience supporting companies through every stage of launching a new product or campaign. Some of our areas of expertise include:

  • Sizing market demand and identifying key client segments
  • Conducting digital listening and identifying trends in consumer voices
  • Translating consumer insights into improving your product offering, pipeline, and positioning
  • Developing a tailored go-to-market strategy
  • Concept testing new products or campaigns with consumers and healthcare professionals


Medical Nutrition & Health Supplements

Contact the


Christopher James-Dewilde
Written by

Christopher-James Dewilde


  1. ClearCut Analytics
  2. Das et. al, Current status of probiotic and related health benefits, 2022
  3. Eastwood et. al, The effect of probiotics on cognitive function across the human lifespan: A systematic review, 2021
  4. Den et. al, Efficacy of probiotics on cognition, and biomarkers of inflammation and oxidative stress in adults with Alzheimer’s disease or mild cognitive impairment — a meta-analysis of randomized controlled trials, 2020
  5. Gambaro et. al, “Gut–brain axis”: Review of the role of the probiotics in anxiety and depressive disorders, 2020
  6. Chao et. al, Effects of Probiotics on Depressive or Anxiety Variables in Healthy Participants Under Stress Conditions or With a Depressive or Anxiety Diagnosis: A Meta-Analysis of Randomized Controlled Trials, 2020
  7. El Dib et. al, Probiotics for the treatment of depression and anxiety: A systematic review and meta-analysis of randomized controlled trials, 2021
  8. Silva, The effect of probiotics on depressive symptoms: A meta-analysis of randomized controlled trails, 2021
  9. Consumer Insights on Gut Health & Probiotics,IFIC, 2021
  10. Healthy Marketing Team, 2022
  11. World mental health report: Transforming mental health for all – executive summary, World Health Organisation
  12. The state of employee wellbeing, Alight, 2019
  13. Feeling good: The future of the $1.5 trillion wellness market, McKinsey, 2021
  14. International Probiotics Association
  15. What’s Happening to Consumer Trust in Buying Supplements Online, Trust Transparency, 2021
  16. Turning Amazon traffic into Amazon sales,Clavis Insights, 2018
  17. Food supplements: Consumer buying trends, Accelerate Associates, DATA
  18. The Rise of Psychobiotics, Lumina Intelligence

Similar Insights

See More