L. reuteri ATCC PTA 6475,
does it really help with Increased testosterone and vitality in middle-aged men?
research showsMouse findings of larger testes and higher circulating testosterone were expanded to humans, but a double-blind placebo-controlled trial in healthy men aged 50 to 65 found that neither the low nor high dose increased testosterone. Aging Males' Symptoms scores also did not improve significantly, resulting in D. This is a strain-and-claim-specific verdict unrelated to the infant-colic evidence for DSM 17938.
ads claimMarketing and biohacking content turns larger testes and higher testosterone in mice into increased human libido, muscle, energy, and 'masculinity.' L. reuteri without a strain identifier, DSM 17938, mixed-strain products, and home-fermented yogurt are not the ATCC PTA 6475 study product.
Useful facts when choosing a product
- Official BioGaia distribution in South Korea centers mainly on DSM 17938 products; regular domestic distribution of the high-dose ATCC PTA 6475-only Osfortis product was not confirmed, so consumers are more likely to encounter cross-border products.
- Gastrus combines ATCC PTA 6475 with DSM 17938 and provides 2×10^8 total CFU per serving, whereas the testosterone trial used ATCC PTA 6475 alone at 1×10^9 or 1×10^10 CFU/day.
- The viable count, strain identity, and storage conditions of home-fermented yogurt are unvalidated, and its dose is not evidence that bypasses the trial result.
- No clear serious-harm signal appeared in healthy adults, but live probiotics warrant clinical judgment in people who are immunocompromised or have central venous catheters.
What the research actually shows
Poutahidis 2014 reported larger testes, more Leydig cells, and higher circulating testosterone in mice fed ATCC PTA 6475. The translational trial by Ljunggren in 2024 randomized 57 healthy men aged 50 to 65 to low dose, high dose, or placebo, with 49 included in the intention-to-treat population. At 12 weeks, neither dose increased testosterone and AMS scores did not change significantly. BioGaia sponsored the trial and one author was a company employee.
Why this is classified as D (30)
The pivotal human RCT was null for its primary testosterone endpoint and AMS score, and positive evidence is preclinical only, resulting in D with 30 points. Safety and strain or product variation were assessed separately from efficacy.
Counterpoint. A sufficiently powered strain-specific RCT in men with low testosterone is still needed, but current evidence does not support increased hormones or vitality in healthy middle-aged men.
Rejudgment record. New verdict — A strain-specific double-blind RCT found no testosterone or AMS benefit at either dose, while positive evidence is limited to mice
Sub-claim grades by effect
This ingredient is marketed for several effects. A single overall grade blends strong and weak claims together, so each effect is graded separately here. The overall grade reflects the strongest disconfirming or core claim.
| Effect (sub-claim) | Grade | Basis |
|---|---|---|
| Increased testosterone in middle-aged men | D | Both high and low doses were null in a strain-specific double-blind RCT. |
| Increased vitality in middle-aged men | D | Total and component AMS scores did not improve significantly in the same trial. |
Cross-check — Codex and Claude
Evidence Table
| Study | Design | Sample | Funding | Endpoint | Result | Weight |
|---|---|---|---|---|---|---|
| Ljunggren L et al. 2024 | Randomized double-blind three-arm placebo-controlled trial | 65 | Sponsored by BioGaia with a company employee among the authors | Total testosterone, related hormones, and AMS questionnaire | Neither 1×10^9 nor 1×10^10 CFU/day increased testosterone, and AMS changes were not significant. | Key opposing |
| Poutahidis T et al. 2014 | Preclinical mouse study | Public research funding | Testicular weight, Leydig cells, and circulating testosterone | Reported testicular and testosterone signals with ATCC PTA 6475, but this is not human efficacy. | Preclinical |
Receipt — 2 References
All 2 cited sources were verified for existence at the original page (as of 2026-07-18).
Reviewed and approved: Chamgap Editorial Team · Approval date: 2026-07-18 · Corrections: none
Cite this verdict
[Chamgap] L. reuteri ATCC PTA 6475 x increased testosterone and vitality in middle-aged men — Evidence Grade D·30. 2 cited sources checked. Source: https://chamgap.com/en/verdicts/mens/limosilactobacillus-reuteri-atcc-pta-6475-testosterone-vitality/ · CC BY 4.0CC BY 4.0 — free to use with attribution; do not distort grades, numbers, or verdict meaning.
What this document does and does not do
Chamgap is an information source. It reports what research has and has not confirmed; it does not tell readers what to take or buy. That decision belongs to readers and, when needed, medical or legal professionals. This verdict reflects literature available up to the search date and may change as new research appears. Nothing here is medical advice.