Your gut does more than digest food. Total Gut Health is built for the whole picture.

The gut microbiome has become one of the most actively researched areas in modern medicine - and for good reason. The microorganisms living in your digestive tract influence immune function, nutrient absorption, energy metabolism and, increasingly, brain function via the gut-brain axis. Total Gut Health from Onnit is one of the few supplements on the market that addresses all four key aspects of gut function in a single formula: digestive enzymes, stomach acid support, probiotic yeast, and a multi-strain probiotic blend.

What's in it and why

DigesTeach Enzyme Blend — a full-spectrum digestive enzyme complex covering the major food groups. Lipase for fats, lactase for dairy, amylase for carbohydrates, protease for protein, and cellulase for plant fibre. The practical upside: taking it with your largest meal means your digestive system gets support across everything on the plate, not just one macronutrient.

Betaine HCl — betaine hydrochloride is a compound that supports the stomach's natural acid environment. Adequate stomach acid is the first step in protein digestion and is also the body's primary barrier against pathogens entering the gut. Many adults, particularly those over 40, produce less stomach acid than optimal - betaine HCl is a well-established way to support this.

Saccharomyces boulardii — a non-pathogenic probiotic yeast that's unusually resistant to stomach acid, meaning it survives the journey through the stomach and reaches the small intestine intact. Unlike bacterial probiotics, it also survives antibiotic courses. A randomised, double-blind, placebo-controlled trial found that Saccharomyces boulardii supplementation in adults with diarrhea-dominant IBS improved the cytokine profile, gut histology, and quality of life scores compared to placebo.

Five acid-resistant probiotic strains — selected specifically for their ability to survive the stomach's acidic environment and reach the lower gut where they're needed. The strains included are L. acidophilus DDS-1, L. plantarum, L. rhamnosus, B. infantis, and B. lactis. A clinical trial examining Lactobacillus plantarum found meaningful improvements in IBS symptom scores, with the strain showing a good tolerability profile. Strain selection matters significantly with probiotics - not all strains do the same thing, and the five here were chosen for complementary effects on gut flora balance.

The gut-brain connection

One of the more interesting recent developments in gut research is the growing understanding of how gut microbiome composition influences mood, cognition and stress response - the gut-brain axis. Roughly 90% of the body's serotonin is produced in the gut, not the brain. The microbiome plays a direct role in this production. We're not making claims about mental health outcomes here - but it's worth understanding why gut health matters beyond digestion alone.

How to take it

Four capsules once daily, taken with your largest meal. At 4 capsules per serving, the 60-capsule bottle is a 15-day supply.

Why Onnit?

Onnit is a US performance nutrition brand best known for Alpha Brain, and one of the few supplement companies to invest consistently in third-party testing and published research on their own products. Total Gut Health reflects the same "whole system" philosophy that runs through their range - addressing the mechanism rather than just the symptom.