Lactobacillus acidophilus L-92 and Improved Immune Function

Research synthesisLow evidenceSmall effect12 studies · 12 beneficial · 0 neutral · 0 harmful

Across 12 studies, all reported beneficial effects on immune function, with a predominant effect size of small. The most direct evidence comes from one randomized controlled trial in adult atopic dermatitis patients (n=50) showing significant immunomodulatory effects, and a large systematic review (n=1502) that generally supports immune benefits from probiotics. Dosing was only specified in one study (heat-killed and dried L-92 daily).

Studied populations: adults with atopic dermatitis

Caveats: Available evidence is overwhelmingly positive — clinical literature in this area is subject to publication bias (null-result studies are less likely to be published or indexed). Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. Additionally, most studies are reviews or indirect; only one RCT directly evaluates L-92, and dosing and forms were not consistently reported.

Generated Jul 11, 2026

Doses used in studies

CFU/day: 1 (median 1, IQR 1–1) — 1 study

Safety in these studies

Overall tolerabilityReported
No adverse events were reported during the study period.
from: Efficacy of prolonged ingestion of Lactobacillus acidophilus L-92 in adult patients with a

12 of 12 papersPopulation:

The Effects of Prebiotic Dietary Fibers, Probiotics, and Synbiotics on Gut Permeability and Immunity: A Systematic Review.
- 2025-08-01
- Systematic Review · n = 1,502
- Iranian journal of medical sciences 50(8)
- - Leila Maghsoumi-Norouzabad
  - Alireza Bagherzadeh-Karimi
  - Shabnam Aliakbari Majd
  - Leila Hosseini
  - Fatemeh Shahi
- PubMed: 40861839
- DOI: 10.30476/ijms.2024.102363.3525
10 Insights on
- Improved Immune Function
- High evidence
Some studies indicated increased levels of Bifidobacteria and SCFA with prebiotic supplementation or prebiotics-enriched food products.
Effect
Beneficial
Effect size
Small
Efficacy of prolonged ingestion of Lactobacillus acidophilus L-92 in adult patients with atopic dermatitis.
- 2016-07
- RCT · n = 50
- Journal of Dairy Science 99(7)
- - Kozo Yamamoto
  - K. Yokoyama
  - Takehisa Matsukawa
  - Sayaka Kato
  - S. Kato
  - Kazuhisa Yamada
  - Tatsuhiko Hirota
- PubMed: 27108169
- DOI: 10.3168/jds.2015-10605
16 Insights on
- Improved Immune Function
- High evidence
- Rigorous Journal
- Clinical
This study suggested that L-92 suppresses type-2-helper-T-cell-dominant inflammation by activating regulatory T cells and type 1 helper T cells.
Effect
Beneficial
Effect size
Small
Significant
Yes
Dose
heat-killed and dried L-92 daily
Recent Research on the Role of Lactobacilli Probiotics in Cancer Management.
- 2026-01-17
- Review
- Nutrients 18(2)
- - See-Hyoung Park
- PubMed: 41599910
- DOI: 10.3390/nu18020297
5 Insights on
- Improved Immune Function
- Moderate evidence
- Rigorous Journal
The strain is known to modulate immune responses, including enhancement of regulatory T cell activity and suppression of Th2-type immune reactions.
Effect
Beneficial
Effect size
Small
Autoinducer 2 as a universal language in microbial consortia: decoding molecular mechanisms, ecological impacts, and application.
- 2026-01-23
- Review
- Gut microbes 18(1)
- - Shuyu Guo
  - Bingyong Mao
  - Xin Tang
  - Qiuxiang Zhang
  - Jianxin Zhao
  - Wei Chen
  - Shumao Cui
- PubMed: 41574816
- DOI: 10.1080/19490976.2026.2615494
3 Insights on
- Improved Immune Function
- Low evidence
It has been suggested that L-92 improves immune responses and modulates the immune system in ways associated with reduced allergic manifestations.
Effect
Beneficial
Effect size
Moderate
Overview of the immunomodulatory role of bacterial probiotic-derived peptidoglycan: from molecular insights to therapeutic application.
- 2026-02-26
- Review
- Frontiers in microbiology 17
- - Omer Qutaiba B Allela
  - Abdulkareem Shareef
  - Hayder Naji Sameer
  - Ahmed Yaseen
  - Zainab H Athab
  - Mohaned Adil
- PubMed: 41834851
- DOI: 10.3389/fmicb.2026.1761985
8 Insights on
- Improved Immune Function
- Low evidence
growing evidence indicates that many of their beneficial effects are mediated by structural components rather than by viable microorganisms... probiotic-derived peptidoglycan has emerged as a key immunologically active molecule with a critical role in regulating both innate and adaptive immunity
Effect
Beneficial
Effect size
Moderate
The Role of Quorum Sensing Mechanism in the Functional Properties of Lactic Acid Bacteria.
- 2026-03-10
- Review
- Microorganisms 14(3)
- - Annalaura Iodice
  - Giuseppina Tommonaro
- PubMed: 41900377
- DOI: 10.3390/microorganisms14030618
2 Insights on
- Improved Immune Function
- Low evidence
The strain Lactobacillus acidophilus L-92 has been reported to exert beneficial effects on allergic symptoms and immune regulation in humans.
Effect
Beneficial
Effect size
Small
The role of fermented foods in maternal health during pregnancy and infant health during the first 1,000 days of life.
- 2025-06-05
- Review
- Frontiers in nutrition 12
- - Arun Pandiyan
  - Manoj Gurung
  - Bharath Kumar Mulakala
  - Sathish Kumar Ponniah
  - Laxmi Yeruva
- PubMed: 40538587
- DOI: 10.3389/fnut.2025.1581723
2 Insights on
- Improved Immune Function
- Low evidence
the impact of maternal consumption of fermented foods on mothers and offspring microbiota, immune system, and brain health outcomes
Effect
Beneficial
Effect size
Small
Certain fermented dairy foods as a source of multibiotics and multimetabolites: a comprehensive review.
- 2025-11-06
- Review
- Frontiers in nutrition 12
- - Duygu Ağagündüz
  - Yasemin Ertaş Öztürk
  - Büşra Ayhan
  - Tuğçe Bulmuş-Tüccar
  - Çiler Özenir
  - Nazlıcan Erdoğan Gövez
  - Yesim Ozogul
  - Tuba Esatbeyoglu
  - Fatih Ozogul
- PubMed: 41280398
- DOI: 10.3389/fnut.2025.1678150
5 Insights on
- Improved Immune Function
- Low evidence
Accumulated literature suggests that fermented dairy products are one of the important sources of some nutritional biotics like probiotics... have promising health effects
Effect
Beneficial
Effect size
Moderate
Gut Microbiota: An Immersion in Dysbiosis, Associated Pathologies, and Probiotics.
- 2025-05-07
- Review
- Microorganisms 13(5)
- - Valentina Origüela
  - Alvaro Lopez-Zaplana
- PubMed: 40431257
- DOI: 10.3390/microorganisms13051084
7 Insights on
- Improved Immune Function
- Low evidence
The strain has been associated with immunomodulatory effects, including enhancement of regulatory T-cell responses and modulation of cytokine production.
Effect
Beneficial
Effect size
Small
Probiotics in Pet Food: A Decade of Research, Patents, and Market Trends.
- 2025-09-24
- Review
- Foods (Basel, Switzerland) 14(19)
- - Phatthranit Klinmalai
  - Pitiya Kamonpatana
  - Janenutch Sodsai
  - Atcharawan Srisa
  - Khwanchat Promhuad
  - Yeyen Laorenza
  - Attawit Kovitvadhi
  - Sathita Areerat
  - Anusorn Seubsai
  - Massalin Nakphaichit
  - Nathdanai Harnkarnsujarit
- PubMed: 41097477
- DOI: 10.3390/foods14193307
4 Insights on
- Improved Immune Function
- Low evidence
probiotics hold clear potential to improve gastrointestinal health and immunity in pets
Effect
Beneficial
Effect size
Moderate
Application of Probiotics in Cats and Dogs: Benefits and Mechanisms.
- 2025-10-17
- Review
- Veterinary sciences 12(10)
- - Jintao Sun
  - Xinshu Gu
  - Huaiyu Zhang
  - Lihong Zhao
  - Jinquan Wang
  - Xiumin Wang
  - Hui Tao
  - Zhenlong Wang
  - Bing Han
- PubMed: 41150148
- DOI: 10.3390/vetsci12101008
14 Insights on
- Improved Immune Function
- Low evidence
Specific probiotic strains exert their functions via mechanisms such as increasing immunoglobulin levels, suppressing the expression of inflammatory factors, and boosting antioxidant enzyme activity.
Effect
Beneficial
Effect size
Moderate
Application of Probiotics in Foods: A Comprehensive Review of Benefits, Challenges, and Future Perspectives.
- 2025-09-02
- Review
- Foods (Basel, Switzerland) 14(17)
- - Mirjana Ž Grujović
  - Teresa Semedo-Lemsaddek
  - Katarina G Marković
- PubMed: 40941204
- DOI: 10.3390/foods14173088
3 Insights on
- Improved Immune Function
- Low evidence
Lactobacillus acidophilus L-92 was shown to modulate immune function, including suppression of Th2-dominant responses and enhancement of regulatory T-cell activity.
Effect
Beneficial
Effect size
Small