One week flat

28 sachets


(ex. tax)
4.2/5 (81 reviews) Read the product reviews

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Suitable for



Gluten free

Gluten free

During pregnancy

During pregnancy

During breastfeeding

During breastfeeding


OptiBac Probiotics 'One week flat' is an easy-to-take 7-day course of live cultures and prebiotics, containing 5 billion friendly bacteria and 0.3g prebiotic FOS fibres per sachet.

This 4-strain live cultures combination, including the world renowned Lactobacillus acidophilus Rosell-52, supports digestive health, including occasional bloating*. 

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Probiotic Strains

  • Lactococcus lactis Rosell-1058
  • Lactobacillus casei Rosell-215
  • Lactobacillus acidophilus Rosell-52
  • Bifidobacterium bifidum Rosell-71
  • Product Description

  • How To Use

  • Ingredients

  • Help & Advice

  • Reviews

  • Delivery & Returns

  • Product Description

    Friendly bacteria expert Jen (Complementary Therapy BSc Hons) explains OptiBac 'One week flat'

    Who is 'OptiBac Probiotics One week flat' for​?

    For those with occasional bloating, especially designed to be taken for one week. 

    Key benefits

    • Each sachet provides 5 billion live cultures + 0.3g Fructooligosaccharides (FOS) - the billions count is guaranteed until end of expiry.
    • Contains 4 high quality friendly bacteria strains from the world's leading probiotic laboratories, all scientifically proven to survive stomach acidity and reach the gut alive. 
    • Complements your natural gut bacteria.
    • Includes one of the world's best probiotic strains, Lactobacillus acidophilus Rosell-52, which has been shown to support digestion and ease the discomfort associated with occasional bloating*. 
    • Easy to take on the go – no refrigeration required.
    • Suitable for all from 4 years, including pregnant and breastfeeding women, vegetarians, and coeliacs.
    • Free from artificial flavourings or colourings often found in other food & drinks containing probiotics.
    • Take for 7 consecutive days (1 sachet per day) or as professionally directed.
    • Can be taken once a month, or as frequently as desired.
    • Available to order in two pack sizes of 7 or 28 sachets.
    • From the UK’s most trusted & recommended brand of friendly bacteria supplements. As determined in an independent survey of 1000 British women+

    Please note: This is a food supplement and is not intended to prevent, treat or diagnose any medical conditions.



    Customer feedback collected via independent review platform Trustpilot. See 'Reviews' tab for more customer opinions collected via our own website.

  • How To Use

    Instructions for use 

    Natural food supplement suitable for adults and children (from 4 year onwards) with the following recommendations:

    • Take 1 sachet daily with breakfast for a 7-day course, or as professionally directed.
    • Pour an inch of water into a tall glass, leaving plenty of room for swirling.
    • Shake the sachet well before gently sprinkling the powder into the glass.
    • Vigorously swirl the water around in the glass making sure the powder is dissolved.
    • Drink, wait and enjoy the benefits.

    We highly recommend you take 'One week flat' for 7 consecutive days. Most consumers take this course once a month. However, it can be taken as often as desired.

    Food supplements should not be used as a substitute for a healthy diet and lifestyle. Those with serious medical conditions should consult their doctor before use. The OptiBac Probiotics range will not cause dependency, and may be used on an ongoing basis.


    Like the rest of the OptiBac Probiotics range, 'One week flat' does not require refrigeration. Store in a cool, dry place below 25°C and out of direct sunlight.


    Live cultures 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, infants with short bowel syndrome, or patients with open wounds following major surgery; unless under a doctor's care.

  • Ingredients

    Ingredients one week flat supplement fact panel

    • Stabiliser: maltodextrin (natural source)
    • Fructooligosaccharides (FOS)
    • Live cultures: Lactococcus lactis Rosell-1058, Lactobacillus casei Rosell-215, Lactobacillus acidophilus Rosell-52 and Bifidobacterium bifidum Rosell-71

    Each sachet guarantees 5 billion good bacteria + 0.3g FOS fibres.

    Suitable for vegetarian and gluten-free diets.

    Following the taxonomic updates by a global team of scientists and published in April 2020, a reclassification has been advised for the L. casei species. The casei strain in the OptiBac Probiotics 'One week flat' product is now also known as Lacticaseibacillus casei Rosell-215.



    Customer feedback collected via independent review platform Trustpilot. See 'Reviews' tab for more customer opinions collected via our own website.

  • 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 have used these on and off when required for years now they are a holy grail supplement when it comes to debloating my awful endometriosis belly! If ever I have a an event like a wedding / or holiday ( or if I am having a bad month with my endo) I take for a week before and it works everytime my bloat is massively reduced alongside that horrible uncomfortable bloated feeling. I 100% reccomend :)

      Georgie - 10th April 2021

    • Find they are very difficult to dissolve, no matter how much you vigorously swirl

      Lorna - 6th April 2021

    • I started taking the 28 course for my wedding and did not think I was very bloated but apparently so. I feel so much more comfortable when using these, my periods are less bloaty and after a big or heavy meal the bloating is also controlled and my trousers fit so much better. Does not taste of anything and I drink lots of water so this product is nice and easy for me. I found it cheaper on Medino website - hence the one less star.

      Emily - 22nd October 2020

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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 therefor 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 delivered within 4-10 working days.
    Free standard shipping on orders over $100.

    USA express shipping: $6.99

    We use DHL and orders are typically delivered within 1-3 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.

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