Probiotic strains
Probiotic strains, by the human evidence
A probiotic's results belong to its exact strain, the code after the species name. These are the named strains with human trials behind them, A to Z. Each links to the one page on this site that covers it.
- Akkermansia muciniphila
A small 3-month RCT in overweight/insulin-resistant adults found pasteurized Akkermansia improved insulin sensitivity and some metabolic markers. One short, single trial.
Studied for: blood sugar / metabolic
- B. lactis DN-173 010
2 human trials · DN-173 010 is the strain used in Activia-style fermented milk.
Studied for: constipation / regularity
- B. lactis HN019
3 human trials · HN019 is the probiotic strain most often sold for constipation and slow digestion.
Studied for: bloating / gas · constipation / regularity
- Bifidobacterium lactis B420
In a 6-month RCT, B420 modestly reduced body-fat mass versus placebo; metabolic read-throughs were secondary and smaller.
Studied for: blood sugar / metabolic · weight / body fat
- Clostridium butyricum CBM588
A butyrate-producing strain with mechanistic and early human data relevant to metabolism; direct metabolic-endpoint RCTs in this context are limited.
Studied for: blood sugar / metabolic · bloating / gas
- Hafnia alvei HA4597
An “appetite” strain built on a ClpB / α-MSH mimicry mechanism, with one small weight-management RCT. Intriguing but early.
Studied for: weight / body fat
- Lactobacillus gasseri SBT2055
A 12-week RCT in adults with an obese tendency reported a small reduction in abdominal (visceral) fat that partly rebounded after stopping.
Studied for: weight / body fat
- Lactobacillus rhamnosus GG (LGG)
12 human trials · LGG is one of the most-studied probiotic strains.
Studied for: post-antibiotic recovery
- Saccharomyces boulardii
21 human trials · Saccharomyces boulardii is a probiotic yeast with some of the strongest evidence of any probiotic for one job: lowering the chance of diarrhea while you take antibiotics.
Studied for: post-antibiotic recovery
Blends, categories and diet
Bifidobacterium & Lactobacillus blends · Dietary fiber + fermented foods (first line) · Multi-strain blends (for GLP-1 GI upset) · Multi-strain blends (meta-analytic) · Probiotics in general (meta-analytic) · Spore-based (Bacillus) probiotics · Whole-diet fiber + fermented foods (not a pill). These aren't single strains, so they live in the strain-to-evidence lookup instead, graded goal by goal.