Probiotics are one of the most popular supplements in the US, and one of the most misunderstood. They will not fix everything, and most healthy people do not strictly need one. But for a number of everyday goals, from digestion to cold season, there is solid research behind specific probiotic strains. Here are ten evidence-based reasons to consider adding one to your routine, and who should check with a doctor first.
What is a probiotic, exactly?
Scientists define probiotics as live microorganisms that, when taken in adequate amounts, give the person taking them a health benefit. That definition matters: a benefit seen with one strain does not automatically carry over to another, and different types of probiotics may have different effects. The most common probiotics belong to two groups, Lactobacillus and Bifidobacterium. Our primer on what probiotics are and what to look for covers the basics in more detail.
Reasons to take a probiotic for digestion
1. Support during and after a course of antibiotics
Antibiotics clear out helpful bacteria along with harmful ones, and loose stools are a common result. A 2021 review of 42 trials in more than 11,000 adults found that taking probiotics alongside antibiotics lowered the risk of antibiotic-associated diarrhea by 37%, with the clearest benefit from Lactobacillus and Bifidobacterium species. See our guide to supporting your gut after antibiotics for the rest of the picture.
2. More regular bathroom habits
In a meta-analysis of 14 trials in adults with functional constipation, probiotics added about 1.3 bowel movements a week and shortened gut transit time, with Bifidobacterium lactis showing the most consistent effect. The authors noted the studies varied a lot, so results differ from person to person.
3. Support for occasional bloating and digestive comfort
Bloating is one of the most common reasons people try a probiotic. For people with irritable bowel syndrome (IBS), a 2026 analysis of 40 trials found that probiotics improved overall symptom scores, though the certainty of the evidence was low. For everyday digestive comfort, Trust Your Gut is formulated to help support occasional bloating alongside a fiber-rich diet. If you have ongoing gut symptoms, it is worth getting them checked rather than self-treating.
4. Easier lactose digestion
Many probiotic bacteria make their own lactase, the enzyme that breaks down milk sugar. A systematic review of 15 randomized trials found an overall positive relationship between probiotics and lactose intolerance symptoms, though results varied by strain. More on that in our article on lactose intolerance and gut health.
Reasons to take a probiotic for immune support
5. Fewer and shorter colds
A 2022 Cochrane review of 23 trials and nearly 7,000 people found that probiotics may reduce the number of people who catch a cold or other upper respiratory infection by about a quarter, and may shorten an episode by about a day. The evidence is rated low certainty, but the direction is consistent. Our article on probiotics and the immune system goes deeper.
6. A healthy gut lining, where much of your immune system lives
The gut-associated lymphoid tissue makes up almost 70% of the entire immune system. Probiotics are thought to work partly by interacting with immune cells in the gut lining and influencing how they respond, which is one reason gut health and immune health are so closely linked.
Reasons beyond the gut
7. Support for mood through the gut-brain axis
The gut and brain talk to each other constantly. In a meta-analysis of 34 controlled trials, probiotics had small but significant effects on symptoms of depression and anxiety, with larger effects in clinical groups. That makes probiotics a promising add-on, not a replacement for care. Read more in Can Probiotics Improve Your Mood?
8. Help maintaining healthy cholesterol levels
Across 40 randomized trials in people with cardiometabolic risk factors, probiotic and synbiotic supplements lowered LDL cholesterol by about 5 mg/dL and triglycerides by about 12 mg/dL. The effect is modest, so think of it as one small piece of heart-healthy habits alongside diet and exercise.
Reasons a supplement can be more practical than food alone
9. Fermented foods vary a lot
Yogurt, kefir, sauerkraut, kimchi and miso are great foods, and we encourage them. But the number of live bacteria in fermented foods varies widely depending on how they are made, processed and stored, and many are pasteurized after fermentation. A supplement gives you named strains at a known dose every day.
10. Pairing probiotics with prebiotics
Prebiotics are substrates selectively used by your gut microbes to confer a health benefit, mostly types of fiber. A product that combines the two is called a synbiotic. Both vegan Trust Your Gut Probiotic + Prebiotic Daily Essential (16 billion CFU from 6 acid-resistant strains) and Trust Your Gut powder (20 billion CFU from 7 clinically studied strains) include organic prebiotics. Learn more in What Are Prebiotics?
Who should talk to a doctor before taking probiotics?
Probiotics have a long record of safe use in healthy people. Still, theoretical risks include infections in susceptible people, and the risk of harmful effects is greater in people with severe illnesses or compromised immune systems. Check with your doctor first if you are immunocompromised, seriously ill, pregnant, or caring for a premature infant.
It is also worth knowing what probiotics will not do. Claims that they speed up the thyroid, melt away weight, prevent cancer or clear up skin conditions on their own are not supported by good evidence. Choose a product with well-studied strains, take it consistently (our guide covers how and when to take your probiotic), and give it a few weeks.
