One Week Flat delivers a multi strain probiotic blend with a prebiotic fibre that supports gut health and eases everyday digestive discomfort. With a carefully chosen probiotic mix, it’s designed to reach your gut and support normal digestion. This is part of OptiBac's long standing focus on gut friendly formulas that are gluten free and vegan.

Available Sizes & Variants:

28 sachets – convenient weekly probiotic course that you can repeat as needed

Benefits & Features:

• Supports gut health and everyday comfort, helping you feel more settled after meals.
• Designed to reach the gut alive and deliver live cultures where they matter, this probiotic blend also includes a prebiotic fibre that helps feed friendly bacteria for a healthier balance.
• Gluten free and vegan, ideal for daily use.
• No added sugars or artificial flavours, making it kinder to sensitive stomachs.
• Gentle enough for daily use, and easy to incorporate into breakfast.

OptiBac One Week Flat sits within our trusted range of probiotics for gut health supplements, built on years of UK expertise. It’s a flavourless powder in convenient vegan sachets, so you can mix it with breakfast or a drink without fuss. The strains are chosen for their ability to reach the gut alive and support digestive health, while a prebiotic fibre nourishes friendly bacteria. Plus, Vegetarian Society Approved status reinforces its accessibility for vegetarians and beyond.

Live cultures: Bifidobacterium bifidum Rosell-71, Lactobacillus casei Rosell-215, Lactococcus lactis Rosell-1058 and Lactobacillus acidophilus/helveticus Rosell-52
Each sachet guarantees 5 billion live cultures + 0.3g FOS fibres.
Other: Maltodextrin (natural source)
Fructooligosaccharides (FOS 0.3g)

• GTIN: 5060086610710
• Manufacturer: OptiBac
• Categories: New ArrivalsOptiBacProbiotic Tablets, Capsules & Liquids
• Best buy: 6 - 24 months+

United Kingdom Shipping:

Orders placed by 2pm (Monday to Friday) are dispatched the same day. Orders placed after 2pm will be dispatched the next working day.

Free shipping on orders over £50 to the UK.

Returns: Our products are meant to make you feel healthy and at your best. If you need to return your item, you can do so free of charge within 30 days in the same original and unopened packaging. Subject to T&C's.

This natural food supplement is suitable for adults and children aged 4 and older. Recommended use:

- Take one sachet daily for seven consecutive days, preferably with breakfast.
- Pour a small amount of water into a tall glass, leaving room to swirl.
- Shake the sachet, then gently sprinkle the powder into the glass.
- Swirl vigorously to dissolve the powder completely.

For best results, we suggest using One Week Flat for a full seven-day course. Many consumers choose to repeat this monthly, though it can be used continuously or as preferred. Six capsules daily or as directed by a healthcare professional.

Please consult the product packaging for accurate instructions on how to use the product.

The Active Ingredient Is: Probiotic Strains (Multi-strain Lactococcus lactis Rosell-1058, Lactobacillus casei Rosell-215, Lactobacillus acidophilus Rosell-52, Bifidobacterium bifidum Rosell-71)

Probiotic strains are live microbes that help gut function stay on track by contributing to a balanced intestinal microbiota.

This formula comes as a flavourless, gluten-free, vegan powder in sachets and includes a prebiotic fibre (FOS) to help the probiotic cultures work and keep digestion comfy.

What Do Probiotic Strains Do?

These strains are picked for their ability to reach the gut alive and help maintain a healthy digestive environment. They also help in the production of digestive enzymes that break down lactose and starch, while the prebiotic FOS nourishes good gut bacteria.

The mix supports everyday digestion and gut balance as outlined in EFSA/UK guidance, with guidance on the role of live cultures and prebiotics in gut health.

*This product is not intended to diagnose, treat, cure, or prevent any disease.

OptiBac really stands out with its science-led approach to probiotic formulation and its well established reputation in the UK and Ireland. This brand's focus on carefully chosen strains that are proven to survive stomach acidity lines up with our commitment to scientifically informed picks.

What gives OptiBac its edge is its focus on multi-strain blends and prebiotic components, built to support gut health with a simple, consumer friendly delivery format. This focus on targeted strain science and easy-to-digest formulations mirrors our standards for product integrity, and it explains why OptiBac was chosen as our trusted partner for this supplement. Our decision was reinforced by the brand's long-standing recognition in the probiotic space, along with a philosophy that prioritises product simplicity and consumer suitability.

Welzo's team of experts evaluated OptiBac in line with our tough brand criteria, looking at manufacturing philosophy, quality control processes, and alignment with our our ingredient quality and purity standards. This choice is backed by the expertise of Welzo's healthcare professionals, ensuring alignment with our consumer protection and safety standards.