The Health Benefits of Lactobacillus Acidophilus

Found naturally in your intestines, Lactobacillus acidophilus is one of the best-known probiotics—beneficial microorganisms that may promote health and protect against infections.

Also known as L. acidophilus or acidophilus, it belongs to the Lactobacillus family of bacteria. Lactic acid bacteria (or L) converts sugars into lactic acid and hydrogen peroxide, substances that inhibit the growth of undesirable bacteria in the intestines.

Commonly found in yogurt and other fermented foods, acidophilus may help to balance potentially harmful bacteria that can otherwise flourish in the gut due to illness or antibiotics. Acidophilus may also help to balance the flora in the vagina, helping to prevent yeast infections.

In alternative medicine, acidophilus is sometimes used to prevent or treat several health conditions, including:

Some proponents also claim that acidophilus can promote weight loss and strengthen the immune system.

Sauerkraut, cucumber pickles and yogurt
marekuliasz / Getty Images

Health Benefits

Although acidophilus is one of the more extensively studied probiotics, findings have varied widely due to differences in patient populations, acidophilus strains, and other factors. Here's a look at some findings from the available research:

High Cholesterol

Studies suggest that probiotics may help to cut cholesterol levels, and acidophilus appears to be more effective than other species.

A 2015 literature review published in the Annals of Medicine concluded that probiotic supplements containing L. acidophilus were effective in lowering total cholesterol and LDL cholesterol levels ("bad cholesterol"). The review of 15 studies with 788 subjects also found the probiotic improved factors associated with cardiovascular disease, including body mass index, waist circumference, and inflammatory markers. Compared with other strains, acidophilus was found to be more effective in reducing LDL levels.

These results were confirmed in a review published in the journal Medicine in 2015. Researchers analyzed 30 randomized controlled trials with 1,624 participants and found probiotics lowered total cholesterol and LDL cholesterol by 7.8 mg/dL and 7.3 mg/dL, respectively. The study authors noted, however, many studies showing the strongest connection were funded by supplement companies and more independent research is needed.


Acidophilus has been recommended in alternative medicine as a potential treatment for diarrhea. Research suggests it may help to prevent C. difficile-associated diarrhea, a type of severe diarrhea that often affects older adults in medical care who require broad-spectrum antibiotic treatment.

In a research review published in the Cochrane Database of Systematic Reviews in 2017, scientists analyzed 31 previously published trials on the use of various types of probiotics to prevent C. difficile-associated diarrhea and concluded that the short-term use of probiotics is safe and effective for preventing C. diff-associated diarrhea in people who do not have weakened immune systems or are severely debilitated.

Vaginal Health

L. acidophilus may be helpful in the prevention and treatment of vaginal infections. According to a 2014 review, Lactobacillus (including acidophilus) supplements taken daily may help prevent and treat bacterial vaginosis, a common vaginal infection that results from an imbalance in the types of bacteria in the vagina.

Acidophilus is commonly recommended for prevention of yeast infections while taking antibiotics. Laboratory research shows the probiotic inhibits the growth of Candida albicans in cell cultures, but little research has been done in humans.

A 2015 clinical trial published in the journal Probiotics and Antimicrobial Proteins, found L. acidophilus can help to prevent recurring yeast infections following standard medical treatment. In the study, 436 women with vaginal candidiasis were treated with fenticonazole. Five days later, roughly half the subjects were treated with multiple intravaginal L. acidophilus treatments. Those given the probiotic had a significant reduction in recurring infections.


Emerging research suggests probiotics including L. acidophilus may help to prevent and treat depression. Scientists have found a link between gut health and emotional health, and taking probiotics may improve intestinal health.

A 2016 literature review published in the journal Nutrients found that probiotics were associated with a significant reduction in depression and should be studied further as a potential preventive strategy for depression.

Possible Side Effects

Common side effects include digestive complaints, such as gas, bloating, upset stomach, or diarrhea. Although most digestive side effects decrease with use, if they do not improve or worsen, you should discontinue use and consult your healthcare provider.

Serious side effects are rare. However, if you experience hives, skin rash, itching, difficulty breathing, vomiting, or swelling of your face, lips, tongue, or throat, discontinue use and seek immediate medical attention.

People with a weak or impaired immune system due to a medical condition or immune-suppressing treatment or medication, should not take acidophilus.

People with milk allergies or lactose intolerant should be cautious when buying acidophilus as there may be milk allergens or traces of lactose in dairy-derived acidophilus products. Check the label to confirm it is dairy-free.

There's some concern that acidophilus can raise the risk of D-lactate toxicity. People who have short bowel syndrome, small intestine bacterial overgrowth, thiamine deficiency, kidney failure, diabetes, or have had gastric bypass surgery may be at greater risk. 

Avoid acidophilus if you have a condition resulting in intestinal damage, due to the risk that the bacteria could escape into other parts of the body and potentially cause serious complications such as bacteremia or sepsis. There have been reports of other Lactobacillus species being involved in infections, such as abscess and meningitis.

You shouldn't take acidophilus if you have an artificial heart valve, heart valve disorder, or central venous catheter due to the risk of infection.

Acidophilus may weaken tooth enamel over time when exposed to teeth.

If you are pregnant or breastfeeding, speak to your doctor before taking acidophilus. You should consult your pediatrician before giving acidophilus to children, babies, or infants. Children who are ill, premature infants, and children with weakened immune systems are at a greater risk for adverse events and complications.

Unlike prescription and over-the-counter drugs, the U.S. Food and Drug Administration (FDA) doesn't regulate probiotics or test them for safety. Some products may contain fewer than the stated number of live organisms. Other products may be contaminated with other bacterial strains or ingredients.

Dosage and Preparation

Acidophilus supplements are sold as capsules, tablets, drink, pearls, powder, chewable wafers, liquid, and suppositories. The typical adult dose is 1 to 10 billion living organisms taken in up to four divided doses. Follow the directions on the packaging or speak to your doctor about the appropriate dose for you.

For children, check with the pediatrician for the appropriate dose or purchase a brand formulated for children and follow the directions on the packaging.

While you may find shelf-stable acidophilus tablet available in stores, refrigerated probiotics are usually of better quality. Store probiotics in an airtight container in the refrigerator.

What to Look For

Acidophilus is available at health-food stores, supermarkets, drug-stores, and online. When purchasing acidophilus, look for ones stored in the refrigerated section.

Acidophilus supplements come in many forms. Some contain a single strain, while others contain a number of different strains or species of bacteria. There are many different strains of probiotics that have similar health benefits as acidophilus. Look for a broad-spectrum probiotic that includes L. acidophilus.

Some probiotic supplements may contain dairy. If you are allergic to milk proteins or lactose intolerant look for a dairy-free acidophilus formulation.

Some acidophilus supplements contain pectin, a soluble fiber found in citrus and other fruit. Proponents claim that the pectin is a prebiotic (a substance that promotes the growth of probiotic bacteria).

Supplements are not regulated by the U.S. Food & Drug Administration. To ensure you are getting a quality product, look for a trusted independent, third-party seal on the label, such as U.S. Pharmacopeia, NSF International, or ConsumerLab, etc.

Food Sources

Lactic acid bacteria are used in the making of many foods, including yogurt, kefir, and buttermilk. Acidophilus, in particular, can be found in yogurt that is made with live acidophilus cultures, other fermented milk products such as kefir.

Other sources of acidophilus include kimchi (a traditional Korean fermented cabbage dish), sour pickles, sauerkraut, sourdough bread, and fermented soy products such as miso and tempeh.

The number of live organisms varies greatly from product to product due to differences in processing methods. Look for products sold in the refrigerated section of the grocery store, which are more likely to contain live cultures than jars or packaging stored at room temperature.

Other Questions

Can acidophilus help me lose weight?

Some probiotic proponents claim that supplementing with probiotics like L. acidophilus can promote weight loss, but the research is conflicting. While it shows promise in animal trials, human trials have inconclusive results.

The best researched and seemingly effective probiotic strain for weight loss is Lactobacillus gasseri. In a 2013 study published in The British Journal of Nutrition, 210 adults with abdominal fat were assigned to drink 7 ounces of fermented milk with either 1 billion, 10 billion, or 0 colony-forming units of L. gasseri a day for 12 weeks.

At the end of the study, abdominal fat was reduced by more than 8% in the probiotic groups compared to the control group. Additional measures, such as body mass index, waist-to-hip ratio, and total body fat, were also significantly reduced in those drinking fermented milk with L. gasseri.

Does acidophilus boost immunity?

Possibly. Acidophilus has antimicrobial and antiviral properties and may help to prevent colds, viruses, and even allergies. There is research to suggest probiotics, including acidophilus, may reduce cold symptoms in children.

A 2009 study published in in the journal Pediatrics found six months of daily L. acidophilus probiotics reduced fever by 53%, coughing by 41%, antibiotic use by 68% and days absent from school by 32%. Combining acidophilus with a broad spectrum of probiotics was found to be even more effective.

Can acidophilus supplements treat diabetes?

Various probiotics are being studied for their potential to reduce blood sugar in people with diabetes. It is believed that the beneficial bacteria may improve carbohydrate metabolism.

A 2016 review of seven published studies of people with type 2 diabetes found those who took probiotics for at least 8 weeks decreased fasting blood sugar by 16 mg/dl and A1C levels by 0.53 percentage points compared to the placebo group. Subjects taking a broad spectrum of probiotics experienced a 35 mg/dl drop in fasting glucose levels.

The research focused on various probiotics and it is unclear if acidophilus alone is beneficial for blood sugar management.

A Word From Verywell

While acidophilus may seem harmless because it is found naturally in the body and in many common foods, it isn't right for everyone. If you're considering taking acidophilus for any condition, it's a good idea to consult your health-care provider first to confirm if it's appropriate and safe for you.

The current research on acidophilus is inconclusive as most studies have used a unique combination of probiotics or different doses, making it difficult to determine its effectiveness and standardized dosing.

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