Immune Support Probiotics

30 capsules


(ex. tax)
4.6/5 (25 reviews) Read verified product reviews

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Suitable for



Gluten free

Gluten free

During pregnancy

During pregnancy

Dairy free

Dairy free

GMO free

GMO free

During breastfeeding

During breastfeeding

See full ingredients list


Formulated for optimum immune health support*, Optibac Probiotics Immune Support is a high-quality, extensively researched probiotic supplement with vitamin C to help maintain a healthy immune system and digestion*.

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Probiotic Strains

  • Lactobacillus paracasei CASEI 431®

Added nutrients

  • Vitamin C
  • Product Description

  • How To Use

  • Ingredients

  • Help & Advice

  • Reviews

  • Delivery & Returns

  • Product Description

    Who is Optibac Probiotics Immune Support for​?

    For anyone who tends to suffer from poor immune health, and who is looking for a daily probiotic supplement with vitamin C to help support immune function and digestive health*.

    Key benefits

    • Probiotics for immune system support – Optibac Probiotics Immune Support contains 5 billion live cultures of the strain L. paracasei CASEI 431®, which helps to support immune health
    • Extensively researched – L. paracasei CASEI 431® has been studied in over 20 clinical trials where it was shown to stimulate immune responses and increase immune cell activity
    • With Vitamin C for immune function – with 80mg of Vitamin C per capsule, to help maintain normal function of the immune system, contribute to our resistance to infection, and reduce tiredness and fatigue
    • Also aids digestion - L. paracasei CASEI 431® has also been shown to support gut health and complement the natural gut bacteria
    • Scientifically proven – shown to survive stomach acidity and reach the gut alive, where over 70% of the body’s immune cells reside
    • For daily use – high-quality, daily immune support in just one easy-to-swallow capsule
    • Natural and vegan – vegan, dairy free and gluten free, with absolutely no artificial flavorings or colorings
    • Highly recommended - from the UK’s most trusted & recommended brand of probiotic supplements, as determined in an independent survey of 1000 British women+

    Available in a pack size of 30 capsules – serving size 1 capsule per day.


    Product reviews


    Customer feedback collected via independent review platform Trustpilot. See more Immune Support reviews for more customer opinions collected via our own website.

  • How To Use

    Recommended use

    Immune Support can be given to adults and children, from 1 year onwards, with the following recommendations:

    • Take 1 capsule daily, preferably with breakfast, or as professionally directed.
    • For those  unable to swallow capsules, open and mix contents with cool drink/food .
    • May be used on an ongoing basis

    Storage instructions

    • For best results, do not remove desiccant sachet from the glass jar and close lid firmly after each use.
    • Store in a cool, dry place below 25°C and out of direct sunlight. For maximum potency, can be refrigerated after opening.

    Customer Questions

    All questions answered by probiotic experts Dr Kate Stephens PhD (Food and Microbial Sciences) BSc(Hons) Medical Microbiology and Kerry Beeson BSc (Nut. Med.) Nutritional Therapist.

    Can probiotics be taken every day?

    The simple answer is yes! Probiotics have been researched for decades and the growing weight of evidence suggests that daily use is both safe and recommended.1,2 There’s no known risk of dependency or overdose: the human gut naturally contains trillions of micro-organisms, so the numbers found in supplements are modest by comparison. Probiotic bacteria are found naturally in our diets, but not all probiotic strains do the same thing, therefore, many people like to use a supplement containing probiotic strains which have been shown to support a specific area of health, such as immune function.4

    How can I boost my immune system?

    Various factors affect the health of our immune system: some of these we can’t control, such as cold, damp weather or stressful events, but there are many things we can easily do to help our immune systems fight off cold, viruses and infections. Include plenty of fruits and vegetables in your diet, limit alcohol intake, get a good night’s sleep, exercise daily, and wash your hands properly.

    Many people also like to use supplements designed specifically to support the immune system, especially during winter months when coughs, colds and flu are especially common. As 70% of our immune system is in the gut, it’s important to consider gut health as part of your immune-boosting health regime. Optibac Immune Support offers all-round gut and immune support.

    Which probiotic supplements are best for the immune system?

    It’s best to choose supplements containing probiotics and other ingredients which have been extensively researched and found to support the immune system. Optibac Immune Support contains one of the world’s most clinically researched bacterial strains, Lactobacillus paracasei CASEI 431®, which has been tested in thousands of people in numerous clinical trials and found to support immune health4. To further support immune function, this high-quality probiotic strain is combined with vitamin C, which also helps to support a healthy immune system and your body’s resistance to infection*.

    Who should not take probiotics for immune support?

    Older people can be more vulnerable to colds and flu so may choose to take a supplement for extra support, but often have concerns about whether it’s safe for them to take probiotics. However, friendly bacteria supplements are safe to be taken by everyone from birth into old age 1,2. There are only a few circumstances when probiotics may not be appropriate, such as for adults or children who are immune-compromised – please see our safety information for more details. If you have a serious health condition, you should always speak to your doctor before taking any supplement.


    1. Jacobsen et al. (1999). 'Screening of probiotic activities of 47 strains of Lactobacillus spp. by in vitro techniques and evaluation of the colonisation ability of 5 selected strains in humans'. Applied and Environmental Microbiology; 65(11): 4949-4956
    2. Doron, S., & Snydman, D. R. (2015). Risk and safety of probiotics. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America60 Suppl 2(Suppl 2), S129–S134.
    3. Tomasz, B. et al, (2014). Long-term use of probiotics Lactobacillus and Bifidobacterium has a prophylactic effect on the occurrence and severity of pouchitis: a randomized prospective study. BioMed research international2014, 208064.
    4. Jespersen L. et al., (2015), ‘Effect of Lactobacillus paracasei subsp. paracasei, L. casei 431® on immune response to influenza vaccination and upper respiratory tract infections in healthy adult volunteers: a randomized, double- blind, placebo-controlled, parallel-group study’. Am.J.Clin.Nutr., 101:1188-1196.


    Probiotics are not recommended for those with serious medical conditions e.g. those who are severely immunosuppressed, have pancreatitis, are in the ICU, have melaena, have a central venous catheter, short bowel syndrome, or patients with open wounds following major surgery; unless under a doctor's care. Keep out of reach of children.

    This is a dietary supplement and is not intended to prevent, treat or diagnose any medical conditions. Probiotic supplements should not be used as a substitute for a healthy diet and lifestyle. If you are taking any medications or have a serious medical condition, consult a doctor before use. Optibac supplements will not cause dependency and may be used on an ongoing basis.

  • Ingredients

    Ingredients Optibac Immune Support Supplement fact panel

    Vitamin C (80mg); Probiotic cultures: Lactobacillus paracasei CASEI 431®; maltodextrin, hydroxypropyl methylcellulose, vegetable magnesium stearate

    Each capsule contains 5 billion CFU.


    • Vegan
    • Vegetarian
    • Dairy free
    • Gluten free
    • No added sugars
    • GMO free
    • Yeast free
    • Free from artificial flavorings, colorings and preservatives
    • No chemicals or parabens
    • Suitable during pregnancy
    • Suitable during breastfeeding

    Following the taxonomic updates published in April 2020 which are intended to be adopted globally, this strain may now also be referred to as Lacticaseibacillus paracasei subsp. paracasei CASEI-431.

  • Help & Advice

    Talk to our experts

    If you have a specific question or need some advice on which product to choose please email or click on the link below for our contact form

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  • Reviews

    Customer reviews

    • I genuinely feel my stomach is more settled and less bloated after about 2 weeks. I’m guessing if my gut feels fine something is right which will lead to better health.

      Andy C - 17th April 2022

    • A huge thank you to OptiBac Advisor and Nutritionist Claire Foss for all her support and guidance around my digestive health and OptiBac products. Very happy to say that the gentleness of OptiBac Immunity is working well after a few weeks after many other brands did not agree my digestive system. The secret is trying different products, give them a few weeks each. I know you're eager to reduce your symptoms, but issues like this can take some time to resolve... keep going, and thanks again to Claire for her help.

      Joe - 25th May 2021

    • My wife bought this for us last year and we've both been taking it ever since. So far so good - we're feeling well, good energy and regular in the gut health department!

      Will B. - 4th January 2021

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  • Delivery & Returns

    USA Shipping

    Coronavirus Update

    We ship all USA orders from our warehouse in Hampshire in the UK. Due to the ongoing global pandemic many US, European and Worldwide postal routes are seeing increased transit times. Delivery times provided on this site are therefore a guide and not a guarantee. Express Services largely remain unaffected however these routes are typically subject to local tax and duties at customs.

    USA standard shipping: $4.99

    International postal order - typically deatched and delivered within 5-10 working days.
    Free standard shipping on orders over $100.

    USA express shipping: $6.99

    We use DHL and orders are typically dispatched and delivered within 2-5 working days.



    Good to know

    • We'll send you an email to confirm once your parcel has been dispatched.
    • For delivery queries, please email
    • We are unable to ship orders to PO boxes.
    • Product prices on this website are always shown in US dollars (USD $) and exclude tax - tax is not applicable as orders are fulfilled from the UK.

    Worldwide Delivery

    • We deliver to more than 50 countries.
    • Shipping is charged at cost - please note that duties may apply.
    • Please allow 3-7 working days for delivery within Europe and 5-12 days to all other destinations. Includes order tracking.  
    • If you are located within the United Kingdom or Europe, we recommended switching to our UK website.
    • International deliveries might currently take a little longer due to the global coronavirus situation. Please refer to the webpage of our international delivery provider DHL to confirm the number of days it takes to receive your order and whether they currently ship to your country.
    • Most international delivery prices are dependent on the size and weight of your order and where it is being sent. You'll be shown the final price of shipping in the checkout, before payment, once we have your address and order details.
    • Long distance shipping and short-term exposure to high temperatures will not compromise the viability of our products. Customers living in very hot countries should store the products out of direct sunlight and refrigerate if the option is available.

    For more details regarding international orders, currency conversion and applicable tax for orders outside the USA, please take a look at our delivery FAQ.