L rhamnosus HN001 – Another Probiotic for Your Mental Health Toolbox
Lactobacillus rhamnosus HN001 (L rhamnosus HN001), now known as Lactocaseibacillus
rhamnosus HN001, is a
probiotic shown to support mental health, nowadays known as a
psychobiotic.
It had a GRAS (generally recognized as safe) application filed to the US FDA by Fonterra for its use in infant formula in 2009. The strain, which was isolated from a cheddar cheese that has been consumed in New Zealand for more than 20 years, is known commercially as L. rhamnosus DR20 or simply DR20 from the New Zealand Dairy Board and as HOWARU Rhamnosus from Danisco.
So in other words:
Lactobacillus rhamnosus HN001=Lactocaseobacillus rhamnosus HN001=L rhamnosus HN001=Lactobacillus rhamnosus DR20=L rhamnosus DR20=DR20=HOWARU Rhamnosus
Yes, I know, the multiple names are confusing. Thankfully most supplement will list it as L rhamnosus HN001.
What is the Mental Health Probiotic Potential of
L rhamnosus HN001?
Since its patent application was filed, many petri dish, rodent and human studies have investigated its properties. Although this probiotic was studied for many different conditions, including immune support, herein I am focusing only on the mental health studies.
L rhamnosus HN001 was studied for pastnatal depression and anxiety in a randomized, double-blind, placebo-controlled trial in 423 pregnant women in a 2017 study. The women were recruited at 14-16 weeks gestation and received either placebo or 6 billion CFU of HN001 daily from enrollment to 6 months postpartum if breastfeeding. Standardized screening questionnaires were completed by the women to assess postpartum anxiety and depression.
Mothers in the probiotic group reported significantly lower depression and anxiety scores compared to placebo even though the number of women with significant depression did not differ significantly between the probiotic and placebo groups. Understandably, infant colic was associated with higher depression and anxiety. After controlling for colic and delayed questionnaire completion, HN001 treatment was still associated with reduced postnatal depression and anxiety.
In 2018, a randomized, placebo-controlled trial in two centers in 474 children at risk of developing allergic disease took place. Pregnant women received either L rhamnosus HN001, Bifidobacterium lactis HN019, or placebo daily from 35 weeks gestation until six months, if breastfeeding. Their infants received the same treatment from birth to two years. Intelligence, executive function, attention, depression and anxiety were assessed when 342 of the children were 11 years of age. No significant differences between the children were observed. (In my opinion, a lot could have happened in the 9 years between when the probiotics in the children were stopped and when the assessments were performed, making the study irrelevant.)
In 2022, 6 billion CFU of L rhamnosus HN001 was utilized in a randomized, double-blind, placebo-controlled study in 483 undergraduate students for 8-13 weeks to measure stress reduction and improved psychological wellbeing compared to placebo. Only 81% of students completed the questionnaire post-intervention, and the probiotic was stopped 2 days prior to examinations. There was no significant difference between the two groups. (My thoughts: Perhaps the variable treatment time was too short, or the fact that the students only answered the questionnaire retrospectively caused inaccurate recall. Regardless, no significant difference was found.)
In another study published in 2022, male rats exposed to chronic unpredictable mild stress (CUMS) experienced depressive-like and anxiety-like behaviors. After CUMS, rats received L rhamnosus HN001 and/or Bifidobacterium lactis HN019. Levels of neurotransmitters, inflammatory compounds and gut microbiota were measured. Both probiotics improved depressive-like and anxiety-like behaviors in the rats, repaired gut microbial dysbiosis, and normalized neurotransmitters and inflammatory markers. The use of both probiotics together resulted in improved measures compared to the use of either single probiotic.
Another study published in 2022 investigated a randomized, double-blind, controlled trial of L rhamnosus HN001 for 12 weeks
to reduce stress and viral illness in nurses in New Zealand working during the 2020 covid pandemic. No significant differences in perceived stress or the average number of sick days were found between the probiotic and placebo groups, and both groups showed improvement in stress and psychological wellness from baseline to the end of the intervention. (The authors suggested that the improvement in stress and psychological wellbeing for both groups from the start of the intervention until its cessation was unusual and may not have been typical for nurses in other countries during 2020 covid. They theorized that New Zealand's very strict lockdown measures may have lessened job stress over time on the nurses. Nonetheless, for the study design, the probiotic's impact was not significant.)
New, Exciting Research on L rhamnosus HN001
There obviously were mixed results with this probiotic as a psychobiotic.
Several confounding factors may have contributed to this, as I mentioned in parentheses. Newer research may shed light as to how HN001 does
what it does, and also provide more support for its use as a psychobiotic.
L. rhamnosus HN001 was recently tested in 2024 in female rats in a postpartum depression and anxiety model to further elucidate its mechanisms. It reduced many measures of behavioral anxiety, altered brain neurochemistry by decreasing stress hormones in the prefrontal cortex of the brain, and prevented a pregnancy-to-postpartum negative shift in gut microbiome diversity. (The authors speculated about results from previous studies compared to their own and suggested that perhaps HN001 is most effective at moderate stress levels. This remains to be explored.)
HN001 was also tested in 2024 in a randomized, double-blind, placebo-controlled trial with 120 adults with mild to high stress measured by the Perceived Stress Scale (PSS). The intervention was 6 billion CFU/day of HN001 for 28 days. Psychological assessments, including the Oxford Happiness Questionnaire (OHQ), were completed at baseline, day 14, and at the end of the intervention. Secondary measures evaluated changes in PSS scores, as well as depression, anxiety, stress, and total score levels.
While not statistically significant, adults provided HN001 showed an improvement in OHQ and PSS total scores over time, with 39% improving from not happy to happy, compared to adults in the placebo group, with 29% moving from not happy to happy. No significant results were recorded for female participants with a mean age of 46, which researchers theorize may be due to perimenopausal factors dominating the women's outlook. If you read my newsletter series on perimenopause/menopause in2024, you know that women in those stages of life have challenges unique to declining estrogen and its effects on gut and vaginal microbiomes and the gut-microbiome-brain axis.
However, interestingly, a significant effect in total happiness was found in treated men compared to men given placebo. Additionally, the total happiness score increased from
baseline to the end of the study in the treated group as a whole, but not in
the placebo group. Very, very interestingly, a significant change occurred from
day 14 to the end of the study at day 28. This time-dependent shift showed that
the time required for HN001 to start exerting its effect was at least 14 days,
which agrees with other studies that suggest that at least 4 weeks are needed with
a probiotic to improve mental health. It would have been insightful if the study had continued for a longer period of time.
Take-Aways for L rhamnosus HN001 Psychobiotic Studies
L rhamnosus HN001 has studies to support its use as a psychobiotic, a probiotic that influences mental health in a positive way via the gut-microbiome-brain axis.
One of the most important take-aways is that HN001, like all probiotics, is not a drug. The results from probiotics are usually not rapid, such as 20-minute results from taking aspirin for a headache. For HN001, it took at least 2 weeks for participants to begin to notice positive changes. As a side note, prescription medications used to treat mental health challenges also take time to show effects.
Additionally, not every intervention to reduce stress and improve a person's outlook is going to work on every single person, and that includes pharmaceuticals. My go-to for stress is to exercise to feel quick results as well as to sustain wellbeing. Other actions I take, such as a healthy diet, probiotics, meditation, hiking in nature, etc. are for the long-term goals of stress reduction, health, and life satisfaction. Your quick-fix and long-term interventions may be different from mine.
Finally, there are two more things to note: One, we each have our own thresholds as to what is perceived as stressful to us. What sets some people into a tizzy may not faze you at all. And two, very importantly, we each have our own diets and unique gut microbiomes, and the interactions of probiotics such as HN001 may depend on what level of nutrition, dysbiosis, or microbiota disturbance is present.
Where can You Find L rhamnosus HN001?
L rhamnosus HN001 is usually not found alone, but that is fine because as the one study showed, there are synergistic effects when more than one probiotic is used. You can find HN001 in many probiotic supplements in my online Fullscript supplement dispensary, although most are in proprietary formulas. There are too many products to list all of them here, but if you do a search for "HN001" in the search bar, the results will show the available products so you can choose the one that suits your needs. Some of the products are:
Protocol for Life Balance ProtoDophilus Woman – 20 billion CFU with 3 strains
Integrative Therapeutics Pro-Biome – 50 billion CFU with 11 strains
MegaFood MegaFlora – 50 billion CFU with 14 strains
HMF Women’s Daily – 17.6 billion CFU with 7 strains
HMF Multi-Strain (shelf-stable) – 15 billion CFU with 16 strains
Vita Aid Baby & Mom – 15 billion CFU with 13 strains, 2 billion CFU of HN001
Metagenics UltraFlora Biome Pro – 105 billion CFU with 8 strains
Metagenics UltraFlora Acute Care – 4 billion CFU with 3 probiotics
Xymogen ProbioMax Complete DF (shelf-stable) – 45 billion CFU – 18 strains, with 2 billion CFU of HN001
New Chapter Women’s Daily – Contains other ingredients. 10 Billion CFU of HN001.
References:
- https://pubmed.ncbi.nlm.nih.gov/28943228/
- https://pubmed.ncbi.nlm.nih.gov/30246890/
- https://pubmed.ncbi.nlm.nih.gov/35675229/
- https://pubmed.ncbi.nlm.nih.gov/36159940/
- https://pubmed.ncbi.nlm.nih.gov/36042251/
- https://pubmed.ncbi.nlm.nih.gov/38569396/
- https://www.mdpi.com/2072-6643/16/17/2936/
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