Lactobacillus rhamnosus HN001

Originally isolated from dairy foods in New Zealand, Lactobacillus rhamnosus HN001 is a naturally occurring friendly bacterium that has been the subject of high-quality clinical research for over two decades. Think of HN001 as a tiny immune tutor that moves into your gut (or your baby's gut) and gently teaches the body's defence system to stay calm around harmless things — like pollen, pet dander, or certain foods — rather than overreacting and triggering itchy skin or a runny nose. It does this partly by helping the gut lining stay tight and strong, and partly by nudging the immune system toward a more balanced, less hair-trigger response. When given to mothers from mid-pregnancy onward and then to infants from birth, HN001 appears to send signals that shape the very foundation of a baby's immune programming during the most critical window of development.

The research on HN001 and childhood allergy is striking. In long-running clinical trials following high-risk infants from birth, those whose mothers took HN001 during pregnancy — and who continued taking it themselves in their first two years of life — had roughly half the rate of eczema compared to babies in the placebo group. Most remarkably, this protective effect didn't fade when supplementation stopped; children still showed significantly lower rates of eczema and even hay fever-like symptoms when researchers checked in at age four and again at age six. For parents who have lived with the sleepless nights and constant scratching that come with a baby suffering from eczema, that kind of lasting protection is genuinely life-changing. Beyond skin health, HN001 has also shown promise for mothers' own wellbeing: women who took it throughout pregnancy and during breastfeeding reported meaningfully lower feelings of depression and anxiety in the postpartum period — a particularly meaningful finding given how common and under-treated postnatal mental health struggles can be. Research has also explored its role in supporting healthy blood sugar levels during pregnancy, with some evidence suggesting it may help reduce the risk of gestational diabetes, especially in women aged 35 and over.

HN001 has an excellent safety profile with decades of use in both pregnant women and newborns — two of the most sensitive populations there are — with no significant adverse effects reported in clinical trials. It is generally well-tolerated even from the earliest weeks of life. The strain is most commonly taken as a capsule or powder sachet, and the dose used in the landmark eczema-prevention studies was around 6 billion CFU per day. Pregnant women typically start it around 14–16 weeks of gestation and continue through breastfeeding; infants are often given it from birth until around two years of age. Beyond its headline allergy and mood benefits, HN001 also demonstrates broad immune-supporting properties, has been studied for its role in gut barrier health, and may provide additional benefits for gut comfort and bowel regularity. As always, particularly during pregnancy, it's worth having a quick conversation with your midwife or doctor before starting any new supplement, just to make sure it fits your individual health picture.