Immunity
Probiotics Studied For Recurrent Respiratory Infections
If it feels like you catch every cold that goes around the office or the classroom, your body's defence system may simply need a little backup. Your immune system works like a well-trained security team — the sharper and better-coordinated it is, the quicker it spots and handles invading germs before they take hold. When that team is run-down or out of sync, the same coughs, colds, and sore throats keep slipping past the gates and knocking you out for days.
Because so much of your immune training happens in the gut, nurturing your microbiome is one of the most underrated ways to support your defences. Specific probiotic strains help promote a well-regulated immune response and support the body's natural resilience against everyday respiratory bugs, which may translate into fewer and milder episodes. Some strains even set up shop in the mouth and throat — your body's front door — helping to keep that first line of defence strong.
Clinical Evidence
Associated Strains
Bifidobacterium · BB-12 (DSM 15954)
Bifidobacterium lactis BB-12
Immune Support and Constipation Relief from a Well-Researched Probiotic
BB-12 is quite possibly the most studied Bifidobacterium on the planet, with over 130 human clinical trials backing it up. It's the go-to strain for people who want to move things along in the bathroom and build a stronger immune defense — all from one tiny capsule. Whether you're fighting off winter sniffles or just trying to feel more comfortable after meals, BB-12 has the science to support you.
Read Full ProfileLactobacillus · YIT 9029 (Shirota)
Lactobacillus casei Shirota
The Probiotic Strain Behind Yakult, Studied for Digestion and Immunity
One of the most extensively researched probiotic strains on the planet, Lactobacillus casei Shirota has been clinically studied for its remarkable ability to get sluggish bowels moving again and strengthen the body's everyday immune defenses. Originally cultivated in Japan almost a century ago, it works by replenishing the good bacteria in your gut — and its benefits have been felt by millions of people worldwide. Whether you're dealing with uncomfortable constipation or simply want to stay well during cold-and-flu season, this strain has some of the deepest science behind it.
Read Full ProfileStreptococcus · K12 (BLIS K12)
Streptococcus salivarius K12
Bad Breath and Sore Throat Relief from an Oral Probiotic
Streptococcus salivarius K12 is the original oral probiotic — a friendly bacteria that lives naturally in healthy mouths and fights off the germs behind sore throats, bad breath, and ear infections. Think of it as placing a team of bodyguards directly in your mouth, crowding out the troublemakers before they can cause problems. It's one of the most well-researched oral health strains in the world and is especially popular with parents looking for a natural way to keep their kids' throats healthy all winter long.
Read Full ProfileLactobacillus · CECT5716 (Lc40)
Lactobacillus fermentum CECT5716
Breast Milk-Derived Probiotic Support for Nursing Mothers and Infant Immunity
Discovered inside human breast milk itself, Lactobacillus fermentum CECT5716 is nature's own gift from mother to baby — a probiotic that was literally born to support the nursing journey. Clinical studies show it helps protect breastfeeding mothers from painful breast infections while simultaneously passing immune-boosting benefits on to their infants. If you're a nursing mom looking for a science-backed way to keep both you and your baby healthier, this strain deserves a spot in your routine.
Read Full ProfileMedical Disclaimer
The information provided on probioticstrains.com is intended for educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Strain profiles and clinical summaries are compiled from published peer-reviewed literature. While we may evaluate or highlight specific commercial formulations, our insights are always grounded in available scientific evidence. Always consult a qualified healthcare provider before starting, changing, or stopping any supplement or health regimen.