Benefits
Facial skin imaging scores in healthy women
In 120 healthy women in Japan aged 30 to 79, 20 billion CFU a day for 12 weeks did not change the main total facial imaging score compared with placebo. A brown spot score, a secondary measure, was lower than on placebo at weeks 4 and 8, and dryness, redness, wrinkles and self-rated skin did not differ. The maker supplied the product, and half the authors are its employees.
Heart rate and mood ratings during mental stress
In a 6 week placebo-controlled trial in adults in Japan, 20 billion cells a day lowered heart rate during a mental arithmetic task more than placebo. Mood and sleep ratings improved only in the subgroup with high anxiety. The abstract does not state the number of participants or a primary outcome, and most authors were employed by the maker.
Stool comfort ratings in healthy women
In the same 12 week skin trial, a self-rated score for stool passage was higher than on placebo at week 12, with the clearest difference in women over 50, while the number of bowel movements did not differ. Gut bacterial diversity was unchanged and one bacterial group, Blautia, rose. These were secondary measures in a trial with maker-employed authors.
Gut colonization in preterm babies (hospital use only)
In 159 babies born before 33 weeks, 3 billion CFU a day made B. breve detectable in 91 percent versus 38 percent on placebo after 3 weeks, a gut marker. C-reactive protein did not differ, and development at ages 3 to 5 did not differ in the 42 percent followed up. Probiotics for preterm babies are a decision for the neonatal team.
Products that combine M-16V with prebiotics or other strains
Many products pair M-16V with other ingredients, and their results do not apply to the strain alone. A formula with M-16V and prebiotic fibers did not improve infant skin scores more than formula alone in 90 infants. An open trial of M-16V with B. longum BB536 had no placebo group, and results for a three strain mix tested in 128 young children with a respiratory infection apply only to that mix.
Mechanism of action
Gut colonization by a strain from the infant gut
M-16V comes from the infant gut, and in preterm and low birth weight babies it was found in stool weeks after dosing, alongside more Actinobacteria and fewer Proteobacteria than in untreated babies. In healthy women it raised Blautia without changing overall gut diversity. These are gut bacteria measures, not health outcomes.
Gut metabolites and the stress response
In the adult stress trial, the strain raised stool levels of pipecolic acid, a compound the authors describe as GABA-like, and lowered heart rate during a mental task, which they link to the autonomic nervous system. This proposed gut to nervous system route rests on one maker-linked trial and has not been confirmed.
Clinical trials
Randomized, double-blind, placebo-controlled trial at one center in Tokyo; two sticks a day of 10 billion CFU M-16V with maltodextrin, or maltodextrin placebo, for 12 weeks; registered UMIN000045596; run in a joint research department of Juntendo University and Morinaga Milk Industry, which supplied the test foods (the paper states Morinaga had no role in design, analysis or writing); 6 of 12 authors (Xu C, Yoshimoto S, Katsumata N, Iwabuchi N, Tanaka M, Xiao JZ) are Morinaga employees (Nishikawa et al. 2025, Nutrients)
120 healthy women in Japan aged 30 to 79 (59 M-16V, 61 placebo); 119 completed.
The stated primary outcome, change in the total VISIA imaging score, showed no reported difference between groups: it rose (higher means worse) from baseline on placebo at weeks 8 and 12 and on M-16V at week 12. The brown spot subscore fell more than on placebo at weeks 4 (p = 0.013) and 8 (p = 0.041). Physician-rated dryness, redness and wrinkles and self-rated skin did not differ. Adverse events did not differ and were mild. Enrollment stopped at 120 because of the season, below the calculated sample size of 128.
Randomized, double-blind, placebo-controlled trial in Japan using near-infrared brain imaging at rest and during a mental arithmetic task; 20 billion cells a day for 6 weeks; funding source not stated in the abstract; 6 of 11 authors (Mutoh N, Xu C, Kato K, Arai S, Iwabuchi N, Tanaka M) are Morinaga employees and one had a consulting contract with Morinaga (Mutoh et al. 2024, Behav Brain Res)
Adults in Japan; the abstract does not give the number or characteristics of participants.
Heart rate during the stress task fell more than on placebo, and stool pipecolic acid rose. Mood and sleep scores improved only in participants with high anxiety, a subgroup result. The abstract does not name a primary outcome or a trial registration, and these results come from one maker-funded trial.
Randomized, double-blind, placebo-controlled trial in Perth, Australia; 3 billion CFU a day or dextrin placebo from the start of feeds until 37 weeks corrected age; registered ACTRN12609000374268; funded by the Telethon Channel 7 Trust, with product supplied free by Morinaga, which was not the sponsor; no Morinaga authors; secondary reports by Agrawal et al. 2018 and 2020 (Patole et al. 2014, PLoS One)
159 babies born before 33 weeks of gestation (79 M-16V, 80 placebo) in a neonatal unit.
The primary outcome, stool B. breve, rose: detectable in 91 percent versus 38 percent after 3 weeks, median count log 8.6 versus below detection. No adverse effects, probiotic sepsis or deaths occurred. A secondary analysis found no difference in high C-reactive protein (p = 0.102), and development at ages 3 to 5 did not differ in the 67 children followed up. This is hospital use only.
Randomized, blinded trial (SiMPro) comparing M-16V alone with M-16V plus B. longum subsp. infantis M-63 and B. longum BB536, each product at 3 billion CFU a day until 37 weeks corrected age, with no placebo arm; registered ACTRN 12615000940572; funded by Telethon-WIRF and the Princess Margaret Hospital Foundation, with products supplied free by Morinaga, which was not involved in the trial; school-age follow-up in 2026 (Athalye-Jape et al. 2022, BMJ Open Gastroenterol)
173 babies born before 28 weeks (86 M-16V alone, 87 three strain mix) in a neonatal unit.
Time to full feeds, the primary outcome, did not differ (11 versus 10 days, p = 0.92), and secondary clinical outcomes were comparable. Both groups had more Actinobacteria and fewer Gammaproteobacteria than earlier placebo-arm babies. At school age, development, growth and allergy-related outcomes did not differ between the two products. With no placebo arm, the trial cannot show an effect of M-16V itself.
Small controlled study published in Japanese, not described in the abstract as randomized or placebo-controlled; lyophilized M-16V for 1 month in 8 infants, with 7 controls (Hattori et al. 2003, Arerugi)
15 infants with atopic dermatitis and low fecal bifidobacteria, a disease population.
In the M-16V group, the share of fecal bifidobacteria rose (p = 0.0173) and skin and total allergy symptom scores improved from baseline. The abstract describes the improvement as greater than in controls without giving a between-group test, and changes in gut bacteria did not correlate with symptoms. The study is too small and loosely controlled to support a benefit.