Some links on this site are affiliate links. If you purchase through them, we may earn a small commission at no extra cost to you. We only recommend products we believe in.
BioGaia is one of the few probiotic brands I trust on the manufacturing side because they actually publish the strain code and the trial data behind it. The testosterone hypothesis on ATCC PTA 6475 is rodent-heavy, so I take that with caution, but the gut-barrier and immune data is solid.
The probiotic market is full of products competing on the same metrics: highest CFU count, most strains, biggest capsule, most impressive packaging. Almost none of this correlates with clinical efficacy.
BioGaia operates on a completely different basis. Their products contain relatively few strains - often just one - at modest CFU counts, and they have decades of human clinical trial data behind specific strains. For men who think seriously about what they put in their bodies, this is a meaningful distinction.
Why Strain Specificity Matters
Probiotics are not interchangeable. A Lactobacillus acidophilus strain from one manufacturer is a different biological entity from Lactobacillus acidophilus from another manufacturer - it may have been isolated from different hosts, maintained on different media, and may have completely different colonisation, survival, and activity profiles in the human gut.
More importantly, the effects of probiotics are strain-specific, not species-generic. Evidence that Lactobacillus reuteri DSM 17938 improves infant colic does not mean that any Lactobacillus reuteri product works. The evidence is tied to the specific strain at the specific dose used in the specific trial.
This is the fundamental flaw in most probiotic marketing: citing generic benefits attributed to a species and applying them to a specific product that may or may not contain a clinically validated strain.
BioGaia has built its entire product range around strains with extensive clinical documentation.
BioGaia's Key Strains
Lactobacillus reuteri DSM 17938
This is BioGaia's most extensively studied strain, with over 200 human clinical studies behind it. Established evidence includes:
- Significant reduction of infant colic symptoms (the primary indication BioGaia has studied most)
- Improved gut barrier integrity (reducing intestinal permeability)
- Immune modulation - increased regulatory T cells, reduced pro-inflammatory cytokines
- H. pylori eradication support when used alongside antibiotic therapy
- Reduced incidence and duration of traveller's diarrhoea
Lactobacillus reuteri ATCC PTA 6475
This strain has a different, and for men over 40, particularly interesting evidence profile:
- Bone density: A 2014 RCT (Journal of Internal Medicine) found that L. reuteri ATCC PTA 6475 significantly reduced bone loss in older women versus placebo over 12 months. The mechanism involves reduced intestinal inflammation reducing osteoclast (bone-resorbing) activity.
- Testosterone and testicular function: Animal research has found that L. reuteri ATCC PTA 6475 significantly increased testosterone levels, testicular size, and sperm quality compared to controls. The mechanism is partly through reduced systemic inflammation (LPS reduction) and partly through direct signalling via the gut-testes axis. Human trials specifically on testosterone are ongoing.
- Immune modulation: Similar anti-inflammatory effects to DSM 17938 with some differences in specific cytokine profiles.
BioGaia Gastrus contains both DSM 17938 and ATCC PTA 6475 in combination, making it the most comprehensive product for adults seeking both strains.
The Manufacturing Difference
BioGaia patents both the strains and the manufacturing processes. Their strains are microencapsulated for stability - meaning they survive stomach acid and reach the small intestine and colon alive.
Many probiotic products either don't survive the stomach acid sufficiently, or contain strains that aren't live by the time the product reaches the consumer (poor storage conditions, heat during shipping, inadequate encapsulation). BioGaia's manufacturing quality is consistently demonstrated in trial protocols - they can run clinical trials with reliable outcomes because their product reliably delivers live bacteria to the gut.
The CFU Question
BioGaia products typically deliver 100 million CFU (10^8) - a relatively modest number compared to competitors claiming 50 billion or 100 billion CFU.
This reflects the clinical evidence. The trials showing therapeutic effects from L. reuteri DSM 17938 and ATCC PTA 6475 used doses in the 10^8 range. More is not necessarily better - probiotic effects are not simply dose-linear. Colonisation, competitive exclusion of other bacteria, and immune interaction are what matter, and these depend on strain characteristics more than raw cell count.
How to Use BioGaia Products
BioGaia makes products in drops (for infants) and tablets/lozenges for adults.
BioGaia Gastrus (adults, gut health): Two chewable tablets daily, either with food or between meals. Contains DSM 17938 + ATCC PTA 6475. Best taken at a consistent time each day.
BioGaia ProTectis (gut health, immunity): Same DSM 17938 strain in drops or tablets.
Duration: Probiotic effects require consistent use. Effects accumulate over weeks. Most trial protocols run 4–12 weeks. If you stop, the colonisation effects gradually diminish over days to weeks (depending on gut environment).
With antibiotics: If taking antibiotics, take probiotics at the furthest interval possible (2+ hours away from antibiotic doses). BioGaia's strains have documented resistance to many common antibiotics, meaning they partially survive antibiotic treatment better than many probiotics.
Who Benefits Most
For men over 40, the strongest case for BioGaia is:
- Anyone with gut symptoms (bloating, irregular bowel habits, food sensitivities)
- Men who've taken antibiotics recently and want to restore microbiome diversity
- Men with elevated inflammatory markers (hsCRP above 1.0 mg/L) where gut dysbiosis may be contributing
- Men interested in the testosterone-adjacent animal evidence on L. reuteri ATCC PTA 6475
For BioGaia specifically, take Gastrus daily for at least 8 weeks before judging. Strain codes (DSM 17938, ATCC PTA 6475) and microencapsulation are what you're paying for — the modest CFU count is by design, not a flaw.
This article is for educational purposes. Probiotic supplements should be discussed with a GP if you have significant gastrointestinal disease or are immunocompromised.
