I’ve been to four conferences in the past couple of weeks, plus an evening event. At every one, there’s been a ton of discussion about the gut.

I’ve tried Jona and Tiny Health Pro myself, both using the latest technology for detecting what's in the microbiome of the gut.

Getting my poop tested was pretty easy. But what do we do with all the results?

Let's do a rundown on the latest and greatest in this somewhat stinky but important part of health and longevity!

This issue is not for the faint of heart. If you do not like discussion of poo, just skip this one!

My Tiny Health Pro kit and collection setup, October 2.

I’m friends with the founders and teams at both Jona and Tiny Health. I have no commercial relationship with either.

The new kits on the market are pretty clever. You tape a little pocket to your toilet, poop into it, and collect your sample.

You’re not supposed to mix in urine. If you’re a woman, you know what I mean when I say this can be...challenging. A lot of poop, or really wet poop, can make things sloppier. You might end up needing to perform acrobatic maneuvers to rescue it before it drops into the toilet, because toilet water is off-limits too.

I know this is kind of gross.

The swab itself is easy. For more in-depth testing, though, there’s some scooping. The nicest way I can put it is that it’s like scooping into a little bucket of ice cream.

Just much stinkier.

My report suggested more polyphenols, with examples like apples, blueberries, and cloves. And this was just the start of a long list of supplement, food, and probiotic recommendations.

I don’t even cook. I pay a service to prepare my meals, and my snacks are basically protein in various forms. So I fully admit that I’ve had a hard time making these dietary changes.

So what do I make of all this?

I practice precision medicine, and I like these tests for people who have symptoms they're concerned about and are interested in probiotics or other gut interventions. We still need good data and ongoing measurement.

I’d track symptoms (holistically, from energy levels to sleep and, of course, bowel habits) alongside the lab results. For repeat microbiome testing, I’d use the same lab and method where possible, check whether its analysis changed, and note changes in diet, medicines, or antibiotics.

For probiotics, the evidence depends on the strain, dose, and problem we’re treating. A low level of one bacterium doesn’t, by itself, tell us which probiotic to take. Most probiotics on the market are fairly random guesses at what might be good for you, so I don't typically recommend them. Those with evidence for the specific strain and symptom can be helpful.

So if you have ever looked at what's out there for gut microbiome testing, you're probably intensely overwhelmed.

If nothing else, just remember there are old ways and new ways to look at the DNA of the microbiome. Jona and Tiny Health use the latest technology - shotgun DNA sequencing - to profile microbes and their genes.

For those paying close attention: those genes suggest what the microbes might do; they don’t directly measure how much of a substance the microbes produce inside you. Which is a convoluted way of saying - we still don't really understand how any of this matters.

But it is a good place to start if you're worried about something being wrong with your body.

Tiny Health Pro also measures stool markers, including calprotectin for inflammation and pancreatic elastase for digestion. That’s different information from a microbial DNA profile and often helpful context in conjunction with the microbiome result.

Jona uses AI to connect findings with research and suggest foods or supplements. I like being able to look at the studies behind a suggestion, so this feature is nice, although I still think the state of the research is quite early.

If you have an ongoing symptom or chronic condition and no clear answer, the gut is one of the places I’d look. Sometimes a targeted test for infection, inflammation, or poor digestion answers the question. Sometimes a broader microbial profile might add something.

Both companies have told me about impressive improvements among their users. These are mostly case reports, although Tiny has some real research ongoing.

Tiny Health has a small randomized study in infants born by C-section. Babies in a program combining reports, coaching, education, diet advice, and probiotic recommendations had less parent-reported eczema. The study wasn't perfect, but it is an important question we've all been wondering about: whether intervening on gut microbiome findings can actually improve health in a specific way.

One thing that worries me is how unreliable stool testing can be. In a 2026 NIST study, seven consumer services (anonymized) tested portions of the same homogenized stool sample. Reports differed, and repeatability within a service varied too.

An international consensus statement still finds too little evidence for routine clinical microbiome testing.

So I typically will only recommend testing one's gut microbiome if we're dealing with a tough symptom and want clues to understand what general direction to go in.

“Gut test” can mean very different things. A few examples:

My gut-testing guide has the full comparison: microbiome kits, broader stool panels, and tests for specific GI problems, with methods, access rules, and limits.

Fun side note: One of my earliest startup ideas was GutSavvy, a gut test for colon-cancer screening. Too early! This was the actual kit, and yes, I put chocolates in it.

The actual GutSavvy kit, chocolates included.

I’m eager to get my Tiny Health Pro results. In the meantime, I’m still working on what to do with Jona’s.

If you’ve tried a gut test, I’d love to know what you actually changed, and whether it helped.

Longevity is about knowing more and having more choices, after all.

Hillary Lin, MD

More years. More choices.

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