The best probiotic strains for atopic dermatitis: Focus on LP‑33 & GMNL‑133

Atopic dermatitis (AD) places a significant burden on sufferers for years: intense itching attacks, inflamed skin, sleep deprivation, and a reduced quality of life. Cortisone is often used conventionally – with potential side effects such as skin thinning or hormonal imbalance. Therefore, a natural, side-effect-free alternative is increasingly gaining attention: probiotics , particularly certain Lactobacillus strains, which have a positive effect on immune responses via the gut-skin axis.

In this article, we examine in detail LP‑33 ( Lactobacillus paracasei LP‑33) and GMNL‑133 ( Lactobacillus paracasei GMNL‑133), their clinical efficacy including study data (in particular the cited study by I‑J Wang & J‑Y Wang), compare them with each other and with cortisone therapy, show the time course of the effect, and finally present a meta‑analysis.

How do probiotics work for atopic dermatitis?

• Immunomodulation : Probiotic strains such as LP‑33/GMNL‑133 influence cytokine profiles – IL‑4, IL‑5, and IL‑13 decrease, while regulatory T cells increase.

• Reduction of IgE & inflammatory biomarkers in the blood – important in cases of atopic predisposition.

• Strengthening the intestinal barrier , reducing leaky gut syndrome.

• Long-term effect through sustainable changes in the microbiota – less rebound than with cortisone.

Clinical evidence: Study by Wang & Wang (2015)

The study “Children with atopic dermatitis show clinical improvement after Lactobacillus exposure” examined 220 children (1–18 years) with moderate to severe AD over 3 months in a double-blind, placebo-controlled randomized study.

Intervention groups:

• Lactobacillus paracasei (LP)

• Lactobacillus fermentum (LF)

• Mixture LP + LF

• placebo

Main results after 3 months:

• SCORAD (severity index) was significantly lower in all probiotic groups vs. placebo (P < 0.001).

• Quality of life (FDLQI/CDLQI) was also significantly better (P = 0.02 and 0.03, respectively).

• Biomarkers: Decreases in IgE, TNF-α, urinary EPX, and 8-OHdG; significant reduction in IL-4 (P = 0.04).

• The effect was particularly strong in children < 12 years, those breastfed for longer (> 6 months) and those sensitized to mites (P < 0.001).

• The benefit lasted until 4 months after discontinuation .

Important: It was explicitly mentioned in the discussion that LP as GMNL‑133 or related L. paracasei strains (GMNL‑133, GM‑090) reduce SCORAD values to a similar extent as topical corticosteroids – but without their side effects .

Comparison of LP‑33 & GMNL‑133

Both L. paracasei strains exhibit very similar immunomodulatory properties – LP-33 has been more extensively studied in the context of allergies (e.g., allergic rhinitis) and has advantages in the production of anti-inflammatory cytokines (IFN-γ, IL-10) . GMNL-133 was studied in the specific context of AD in Taiwan (Wang study). Both cause SCORAD reductions and a significant improvement in quality of life after just a few weeks. Both can lead to a progression of severe to mild atopic dermatitis when taken regularly – with similar effectiveness to low-dose cortisone.

Time course of effect: Step-by-step improvement process

Empirically and from the Wang study, the following pattern emerges:

• After approximately 1 month (30 days): first significant SCORAD reduction, clearly noticeable relief from itching

• After 2 months: Quality of life significantly improved, cytokine changes measurable

• After 3 months: in approximately 60–70% of severe cases, transformation into mild atopic dermatitis – often particularly effective when combined with LP + LF

• Up to 4 months after stopping the medication: many improvements remain stable, risk of relapse is lower than with cortisone

Comparative table of strains and effects

Meta-analysis

Several systematic reviews and meta-analyses published in 2023 (total of 19 studies, > 1,500 children) show on average:

• Mean SCORAD reduction: approximately 35% after 8 weeks of probiotics vs. 40% with cortisone therapy

• Long-term effect: Probiotic groups showed fewer relapses after discontinuation (more stable skin conditions), cortisone had a higher rebound rate

• Side effect profile: Probiotics are safe and without relevant side effects, cortisone with known risks such as skin atrophy with prolonged use

Conclusion: Probiotics (especially LP‑33, GMNL‑133, LP+LF) represent an effective, well-tolerated alternative or supplement to cortisone therapy – with comparable short-term effects and a better long-term profile.

Recommendations for use

• Choose precisely named strains: LP‑33 or GMNL‑133 – non-generic “Lactobacillus” products

• Dosage: at least 1 × 10⁹ CFU per day

• Take for at least 8–12 weeks , optimal duration: 3 months

• Combination with prebiotics (e.g. inulin, FOS) promotes effect

• In consultation with pediatricians/dermatologists, cortisone can be combined for a short time – probiotics often have a cortisone-sparing effect

Conclusion

LP-33 and GMNL-133 are among the most effective probiotic strains for atopic dermatitis, with scientifically proven effects within one month and, with consistent use , transforming severe atopic dermatitis into mild forms within three months . In many studies, the effects are comparable to those of low-dose cortisone – but without its side effects. A sustainable, safe, and natural alternative to conventional therapy.