How Green Juju’s Soil Probiotic Improved Dog Gut Health: New Study Results with Innovative Pet Lab

I'll be the first to tell you that I've fallen off of the probiotic bandwagon. I just wasn't seeing the results consistently with the product availability on the market. Sure, some dogs would benefit, especially ones who did not get fed a species appropriate diet, and some with more sever gut issues, but overall, I had stopped recommending probiotics to every client no matter what. They weren't getting us anywhere. Instead, I opted for food based probiotics like raw goats milk. Even today, raw goats milk is a staple in my dogs diet. 

Then something changed. Billy Hoekman, Vice President of Nutrition and Communication at Green Juju introduced us to 3 new probiotics - something never seen before in the human or pet space. These 3 probiotics are grown on food: Soil is grown on Green Juju's Bailey's Blend, Farm is grown on raw goats milk, and Leaf is grown on Billy's kombucha scoby. They ferment and grow bacteria, then the lab removes the food, leaving us with a huge array of diverse bacteria. 

I tried them wit my pets, myself, and my clients pets and have been impressed. Then something really cool happened: Green Juju teamed up with Innovative Pet Lab to run a study on the effectiveness of their Soil probiotic. You can read their study break-down here. 

In this post, we will discuss the study and the results so that you can decide for yourself if giving these innovative new products a try is right for your pets. 

What the study actually looked at

Forty-seven dogs completed the full protocol: baseline testing, a run on Soil, and final testing. Owners logged symptoms — infections, GI issues, coat and skin, behavior — and a lab panel tracked six biomarkers tied to gut health: beta-glucuronidase, calprotectin, zonulin, secretory IgA, elastase, and antigliadin antibodies. That combination matters. Owner-reported symptoms tell you how the dog seems. The biomarkers tell you what's actually happening in the gut, whether or not it's visible yet. 

One thing worth saying up front, because I'd rather you hear it from me than notice it yourself and wonder why I didn't mention it: this was an open-label study, run with the brand, no placebo group. That doesn't mean the data's worthless — the biomarker shifts are lab values, not owner opinion, and those don't respond to a placebo effect. But it does mean "correlation" is the honest word here, not "proof." Keep that in your back pocket as you read the rest of this.

The symptom side

Frequent infections dropping 91% is the standout, and it's not a fluke sitting alone — it lines up with what happened underneath, in the biomarkers. Anxiety moved the least of anything on this list, which tracks with something the report itself points out: physical markers shifted faster than behavior did. Gut chemistry can turn around in weeks. A dog's nervous system, understandably, takes longer to believe it's safe.

What was actually happening in the gut

Beta-glucuronidase was the clearest mover, and also the one with an actual mechanism behind it, not just a number going down. This enzyme gets produced by opportunistic bacteria — the ones you don't want dominating — and elevated levels are tied to toxin recirculation in the gut. 70% of the dogs started in the normal range; 98% ended there. Of the dogs that started high or borderline, all but one landed in normal range by the end. The working theory in the report is that Soil is feeding the commensal bacteria enough that they're crowding out the opportunistic strains making the enzyme in the first place — which, if true, is the mechanism doing the heavy lifting for a lot of the symptom improvement above, especially the infection and GI numbers.

Calprotectin is where the data gets honest in a way I actually respect. Individually, 55% of dogs saw their calprotectin drop — real signal, real reduction in intestinal inflammation. But the group average went up, because one dog (an outlier with a specific intestinal issue at the final test) pulled the mean way off center. Take that one dog out, and the average calprotectin actually fell 28%. The report didn't bury that outlier in a footnote, they showed the chart with and without it. That's the kind of study I'll actually cite.

Zonulin is the one number I want to flag directly, because it's the one place symptoms and biomarkers disagreed. Zonulin regulates gut barrier permeability — "leaky gut," in the shorthand everyone uses — and the group average rose 71% even while GI symptoms improved by half. A few individual dogs (Eeyore, Gibbs) saw real spikes tied to ongoing behavioral issues, while others improved right alongside their symptoms. My read: outward symptoms can stabilize well before the gut lining itself finishes repairing. Stool consistency is a faster signal than barrier integrity. If you're using Soil for a dog with confirmed leaky gut, I wouldn't declare victory off symptoms alone — recheck the marker.

Secretory IgA, elastase, and antigliadin all moved in the right direction but modestly — 4.5%, 4.7%, and 11.2% respectively. The elastase number undersells itself a little: every single dog that started borderline-low on digestive enzyme output normalized by the end. And SIgA had one dramatic case — a dog named Blue went from 10.14 to 212.32, alongside his lethargy and skin issues clearing up — which is a good reminder that group averages flatten out the dogs for whom this did something significant.

Size seemed to matter

Large dogs (61+ lbs) saw the steepest overall improvement, at 62%, with the biggest drops in panting and lethargy. Medium dogs had the most consistent GI wins, flatulence and diarrhea both down over half. Small dogs improved plenty but held onto the highest final scores for anxiety and licking — worth knowing if you've got a small anxious dog and you're calibrating your expectations for timeline.

Where I land on this

I stopped recommending blanket probiotics because most of them were doing nothing measurable for most dogs. This is the first one in a while where I've seen both self-reported improvement and lab markers moving the same direction, with the study honest enough to show me the marker that didn't cooperate. That's rare, and it's the reason I'm back in the probiotic conversation after being out of it for a while.

This fits squarely into the ReWilding approach: feed the microbiome real, whole-food-grown bacteria instead of managing symptoms with another pill, and let the gut do what it's actually built to do. If your dog's dealing with recurring infections, GI flare-ups, or coat issues that never quite resolve on diet changes alone, Soil is worth a look — just go in with real expectations, not a miracle-cure story. The data doesn't need the hype. It's solid on its own.

Listen to Billy talk about the Green Juju probiotic study on The Pet Parenting Reset podcast.