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Acidophilus lactobacillus: benefits, dosage, side-effects

23 Nov 2022 • 4 min read


Find out all about acidophilus, including what it does, the top 10 benefits to taking it and how much you might need.

What is acidophilus lactobacillus?

Acidophilus is a type of ‘friendly’ bacteria in the lactobacillus family that helps ferment carbohydrates in foods and in particular lactose, the sugar found in milk.1

You may see it listed as L. acidophilus or simply acidophilus, and can find it in yoghurt, other fermented foods and supplements.

Is acidophilus a probiotic?

Yes, lactobacillus acidophilus is one of the most common types of probiotics.

Probiotics are defined as ‘live micro-organisms, when administered in adequate amounts, confer a benefit on the host’ by The World Health Organization (WHO).2

Like most probiotics, you can find lactobacillus acidophilus in supplement form, e.g., tablets and drinks.

And unlike some so-called probiotic bacteria strains that food manufacturers use that simply don’t have health benefits; lactobacillus acidophilus has shown that it may provide several health benefits.3

You can also find it naturally in fermented foods like miso, tempeh and sauerkraut.

What does acidophilus do?

Acidophilus lives in the gut, mouth and vagina. Sometimes, the natural balance of friendly bacteria in your body can be affected by illness or medication.

However, plenty of studies report that taking acidophilus, or another type of ‘good’ bacteria, may help restore the body’s natural equilibrium.4

Acidophilus is available as a capsule, tablet, powder or vaginal suppository, and is also found in certain fermented foods such as live yogurt and kefir.


  • Lactobacillus acidophilus is a probiotic that helps keep the bacteria in your body balanced
  • It can be found in fermented foods and drinks like yoghurt, as well as in capsules, tablets, vaginal suppositories and powders

What is acidophilus used for?

Acidophilus is used to make certain fermented foods and drinks like yoghurt and is also made into supplements for a range of health benefits.

Benefits of acidophilus

Friendly bacteria, such as acidophilus, have been shown to help restore the balance of gut flora in a number of different ways.5

  • Preventing ‘bad’ bacteria, like E-coli, from sticking to the gut lining
  • Secreting acids that decrease the pH of the gut, preventing the growth of unfriendly bacteria
  • Reducing inflammation triggered by unwelcome bacteria

10 acidophilus benefits

At the moment, the science shows these actions may help the body in the following ways:

  1. It may restore the natural balance of bacteria in the vagina

Lactobacilli are the most common bacterial family inhabiting the vagina in healthy women, which includes lactobacillus acidophilus.

A healthy vaginal microbiota (bacteria) can change rapidly, for reasons that aren’t entirely clear – but very annoying none the less!

When the bad bacteria tips the good bacteria out of balance, women can develop infections like bacterial vaginosis (BV), thrush and urinary tract infections (UTIs).6

Evidence shows that maintaining adequate lactobacilli colonies in the body can help to retain a harmonious balance to help prevent the occurrence of infections.

A 2014 Iranian study reported that friendly bacteria taken orally or as a pessary released acids inside the vagina that help maintain the pH at a healthy level, suppressing the growth of bacteria that can cause problems such as thrush and UTIs.7

  1. Could help reduce the risk of infections during the menopause

As women go through the menopause, their hormonal changes can trigger changes in the vagina microbiota.

When women go through the menopause, their bodies are reacting to a decrease in estrogen levels, amongst other changes. A drop in estrogen levels can affect the ability of lactobacilli to colonise the vagina and help prevent infections occurring.

This is one of the reasons why postmenopausal women are more susceptible to urogenital infections, which supports the theory that vaginal lactobacilli could protect us from these pathogens.8,9

One review of studies focusing on the influence of probiotic supplementation on symptoms of the menopause found a positive link.

They stated that recent studies suggested that the intervention on probiotics could help improve the health status of menopausal women.10

  1. It may help lower cholesterol

Cholesterol is an essential compound made in our livers that helps maintain cell membranes, make vitamin D and even help make steroid hormones, like oestrogen and testosterone.

And it turns out that probiotics such as lactobacillus acidophilus could help keep levels in check.

High cholesterol happens when you have high levels of LDL (bad cholesterol).

This can cause plaque to build up and narrow arteries, making it hard to oxygen and other essential nutrients to travel around the body.

Studies have suggested that some probiotics can help reduce cholesterol levels, lactobacillus acidophilus being one of the most effective – especially when combined with other probiotics.

One study found that taking lactobacillus acidophilus along with another probiotic for 6 weeks experienced a significant lowering of cholesterol levels – total cholesterol, LDL cholesterol and also HDL cholesterol.11

Several other studies have found that yoghurts supplemented with lactobacillus acidophilus lowered cholesterol levels by up to 7% compared with ordinary yoghurt.12,13,14,15

  1. It can curb an over-active immune system

An over-active immune system can damage the body’s own cells and tissues and is linked to a raised risk of allergic conditions such as childhood eczema.

It’s thought to be caused by an imbalance in gut bacteria; a 2014 study by Canada’s McGill University reported that friendly bacteria may help rebalance and regulate the immune system’s over-activity, although more research is needed.16

  1. It can ease diarrhoea

Diarrhoea is very common and has many causes, including bacterial infections. It’s not fun and can be dangerous if it lasts for a long time, sometimes causing dehydration.

Various studies have looked at the benefits of taking friendly bacteria, such as acidophilus, to help diarrhoea.

A 2016 review from the Cochrane Collaboration analysed 63 studies involving 8000 participants, and reported that the friendly bacteria worked in the gut to:

  • Suppress the germs causing diarrhoea
  • Help the body fight the infection

Scientists found a friendly bacteria, like one from the lactobacilli family, could shorten the length of a bout of diarrhoea by one day, although they called for more research into this effect.17

Lactobacillus acidophilus has even been recommended for traveller’s diarrohea – named so due to the prevalence of diarrohea in travelers when they are exposed to different countries, foods and environments.

A review of 12 studies found that probiotics can help prevent traveller’s diarrohea, and that combining lactobacillus acidophilus with other probiotics was most effective at keeping those ‘Delhi bellies’ at bay!

  1. It could help ease symptoms of IBS

Irritable bowel syndrome (IBS) is a common digestive system condition, which can cause side effect like bloating, stomach pain and irregular bowl movements.19

The cause of IBS is still very much a mystery, but there is a theory that it could be something to do with certain types of bacteria in the intestines.

Which prompts the question: could probiotics be used to help ease the symptoms?

A study involving 60 participants with functional bowel disorders, including IBS, tested the effectiveness of lactobacillus acidophilus on symptoms. They took the probiotic for 1-2 months and found a reduction in bloating.20

Similar research found that taking just lactobacillus acidophilus reduced stomach pain in those with IBS.21

  1. May help support the immune system

A healthy gut is essential for a healthy immune system, which we need to help reduce the risk of viral infections, like the common cold.

Some studies have shown that probiotics could help improve or prevent symptoms of the common cold.22,23

One study followed 326 children taking lactobacillus acidophilus daily for 6 months. They found that it reduced fever by 53%, coughing by 41% and days off sick from school by 32%.24

  1. May help reduce or prevent eczema symptoms

Eczema is one of the most common skin conditions out there, with around 1 in 5 children and 1 in 20 adults having the condition.25

Research suggests that probiotics could help reduce the symptoms of eczema in both children and adults.

One study found that supplementing lactobacillus acidophilus in conjunction with traditional medical therapy vastly improved dermatitis symptoms in children.26

Another similar study found that giving pregnant women and their babies (from birth to 3 months) a mix of lactobacillus acidophilus and other probiotics reduced the prevalence of eczema by an impressive 22% by the time they got to 1 year’s old.27

  1. Could help reduce or prevent allergy symptoms

Common allergies are known for their annoying symptoms like itchy eyes and a runny nose, but thankfully, some research suggests that probiotics could help ease some of them.28

A large study of 47 children found that when they took a combination of lactobacillus acidophilus and other probiotics reduced the nasal blocking, runny nose and some other symptoms of a pollen allergy.29

Another study found that taking lactobacillus acidophilus for 4 months reduced some of the hay fever-like symptoms in children with perennial allergic rhinitis, including nasal swelling.30

  1. Supports overall gut health

Gut bacteria is incredibly diverse, with trillions of different types of bacteria playing a part in your overall health.

Like all lactobacilli, lactobacillus acidophilus is generally very good for gut health for a number of reasons, including the production of lactic acid.

This acid helps to prevent harmful bacteria from growing in the intestines and can also help support intestinal lining.31

Lactobacillus acidophilus has also been seen to help increase numbers of other healthy gut bacteria like lactobacilli and bifidobacteria.23


  • There are lots of potential benefits to making sure your body gets enough of lactobacillus acidophilus, including vaginal health and supporting normal immune function


Wondering how much acidophilus you should be taking? We've got the answers here, including how to take it and how often.

How to take lactobacillus acidophilus

Lactobacillus acidophilus can already be found in healthy digestive systems and other parts of the body.

However, you can top up or maintain your levels by eating foods that contain it or by taking a supplement.

Some of the best food sources of lactobacillus acidophilus include:

  • Kefir: this drink is made of bacteria and yeast ‘grains’ which are added to milk or water to make the famous fermented drink. It commonly contains lactobacillus acidophilus, amongst other probiotics
  • Yoghurt: bacteria is essential for making yoghurt, and lactobacillus acidophilus is perfect for the job!
  • Miso: this paste is made using fermented soybeans and comes from Japan. Lactobacillus acidophilus is sometimes used to make it.
  • Cheese: lactobacillus acidophilus is not often used in the cheese making process, but is sometimes added as a probiotic
  • Tempeh: another product make from fermented soybeans, tempeh is an Indonesian dish that commonly contains lactobacillus acidophilus
  • Sauerkraut: this fermented cabbage dish commonly contains lactobacillus, including lactobacillus acidophilus

As well as lactobacillus acidophilus-rich foods, you can also turn to taking probiotic supplements. You can take it on its own or take a product with multiple strains of probiotics.

We suggest always starting slow with probiotics in any form and increasing your dose little by little to help ‘ease you in’.

How much acidophilus is safe to take?

Read the label carefully, as different products may contain different compositions and different amounts of acidophilus.

But in general, taking too much friendly bacteria doesn’t appear to cause unwanted symptoms in most people.33

Keep reading to find out who should be cautious with acidophilus.

Is acidophilus safe for everyone?

Acidophilus may not be safe for some groups of people.

Talk to your doctor before taking acidophilus if:

  • Your immune system is compromised – for example by HIV or medications such as corticosteroids or chemotherapy34
  • You have a lactose intolerance – some acidophilus products may contain lactose35

Is it ok to take acidophilus daily?

Most probiotics are designed to be taken daily, but always check the label and usage instructions as formulations will differ.

How long does acidophilus take to work?

Probiotics take at least a few weeks to start taking effect, but this will vary from person to person.

Don’t be too speedy to discount them before they’ve been given enough time to work and try taking them for at least a few months and monitor any effects – good or bad.

What are the side-effects of taking acidophilus?

Friendly bacteria is considered safe to take, but possible side-effects may include the following 3 side effects.

3 acidophilus side effects

  • Bloating
  • Gassiness
  • Constipation
  • Increased thirst www.mayoclinic.org/drugs-supplements-acidophilus/art-20361967

The final say

  • Lactobacillus acidophilus is one of the most prevalent bacteria strains found in our bodies, and is commonly found in the intestine and vagina
  • It can help produce lactic acid and support your immune system, as well as help balance vaginal pH
  • Eating fermented foods like kimchi, miso and yoghurt can help increase lactobacillus acidophilus in your gut
  • Taking lactobacillus acidophilus supplements or other mixed probiotic strains can also be beneficial
The advice in this article is for information only and should not replace medical care. Please check with your GP or healthcare professional before trying any supplements, treatments or remedies. Food supplements must not be used as a substitute for a varied and balanced diet and a healthy lifestyle.

Last updated: 7 July 2021



Author: Donia HilalNutritionist

Joined Holland & Barrett: Jan 2018

Bsc in Nutrition, Registered Associate Nutritionist and Certification in Pre and Post Natal Nutrition

Donia started her career as a freelance nutritionist, later she joined Nestle as their Market Nutritionist to help support their healthier product range, before joining the team at Holland & Barrett in January 2018.

Donia has over 6 years experience as a Nutritionist and also works with clients on a one to one basis to support their goals which include weight loss, prenatal and postnatal nutrition and children’s health.

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