Lactulose is form of sugar that is used medically in the digestive tract and vagina to feed good bacteria, considered a prebiotic. Lactulose is not absorbed in the insteine like other forms of sugar, which means it can travel through the digestive tract to the large intestine. When it gets to the bowel, it provides a food source for bacteria there, but also draws water to the intestine and stimulates diarrhoea as a laxative.
Lactulose can be used in the vagina to effectively feed lactobacilli. Research has demonstrated that lactulose does not feed yeasts or bacterial vaginosis/vaginal dysbiosis-related microbes, making it an effective way to increase vaginal lactobacilli counts. In fact, lactulose limits the growth of Candida albicans and Atopobium vaginae, and does not affect the growth of Gardnerella vaginalis, Prevotella bivia, or Mobiluncus curtisii.
Our top vaginal warriors, Lactobacillus crispatus, L. gasseri and L. jensenii had growth broadly and easily stimulated by lactulose, and lactulose was preferred over other sugars.
Lactulose can also lower vaginal pH, getting the vagina back to a healthy pH of between 3.5 and 4.5. This is likely due to the extra activity of lactic-acid-producing bacteria, lactobacilli.
What is lactulose?
Lactulose is made from milk sugar, lactose. Raw milk does not contain lactulose, but is created in milk during the heating process (pasteurisation). The higher the heat, the more lactulose is produced. Lactulose is an isomer of lactose, created by one molecule of fructose and galactose, making it a disaccharide.
Where to buy lactulose
Lactulose is available over the counter in some areas, at pharmacies and supermarkets (ask for it by name if you can’t see it), however some jurisdictions may require medical advice prior to the product being made available. Seek out the liquid form of lactulose, without added ingredients.
Lactulose may require a prescription or medical advice in some countries, when using orally for treating diarrhoea or as a laxative. Lactulose may contribute to health problems if it is used too much or used incorrectly, so unless you are advised to by a medical practitioner, do not use orally.
When used vaginally, these cautions do not apply, since the liquid is not entering the digestive tract and is not absorbed into the bloodstream.
How does lactulose work?
Lactulose is not broken down by enzymes in the human digestive system or vagina and therefore remains as a source of food for bacteria and microbes that can use it. This includes lactobacilli, the friendly vaginal bacteria that you want to keep around.
Lactulose safety and effectiveness
Lactulose has been used medically since the 1950s and is considered by the World Health Organisation as an essential medicine. There have been no reports of harm from using during pregnancy and is considered safe to use during breastfeeding.