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Head-to-head evidence comparison — which supplement is right for you?
Probiotics wins 3 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Likely helps
30 of 39 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
12 of 15 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both Probiotics and Vitamin K2 have evidence — compare verdict strength side-by-side.
10-20 billion CFU
With or without food (strain-dependent), Same time daily for consistency
Capsules with multiple strains
100-200mcg (MK-7)
With a meal containing fat
MK-7 (menaquinone-7)
2-4 weeks
4-8 weeks
4-8 weeks
First 1-2 weeks
6-12 months
1-3 years
Preventive Effect of Probiotics on Oral Mucositis Induced by Cancer Treatment: A Systematic Review and Meta-Analysis
International journal of molecular sciences (2022) · Meta analysis · n=708
Three trials using Lactobacilli-based probiotics reported that the incidence of oral mucositis in the probiotic group was significantly low (risk ratio [RR] = 0.84, 95% confidence interval [CI] = 0.77−0.93, p = 0.0004).
Probiotics for treating acute infectious diarrhoea
The Cochrane database of systematic reviews (2020) · Meta analysis · n=12127
Effect size was similar in the sensitivity analysis and marked heterogeneity persisted.
Probiotics for the prevention of Clostridium difficile-associated diarrhea in adults and children
The Cochrane database of systematic reviews (2017) · Meta analysis · n=9955
A complete case analysis (i.e. participants who completed the study) among trials investigating CDAD (31 trials, 8672 participants) suggests that probiotics reduce the risk of CDAD by 60%.
Vitamins K2 and D3 Improve Long COVID, Fungal Translocation, and Inflammation: Randomized Controlled Trial
Nutrients (2025) · Rct · n=151
The median age was 46 years; 71% were female and 29% were non-white.
The effect of vitamin K2 supplementation on bone turnover biochemical markers in postmenopausal osteoporosis patients: a systematic review and meta-analysis
Frontiers in endocrinology (2025) · Meta analysis · n=2570
Vitamin K2 (VK2) increased osteocalcin (OC; MD 1.86, 95% CI 1.17-2.56) and bone-specific alkaline phosphatase (BAP; MD 1.49, 95% CI 0.98-2.00).
Vitamin K2 in Managing Nocturnal Leg Cramps: A Randomized Clinical Trial
JAMA internal medicine (2024) · Rct · n=310
Of the 199 enrolled individuals, 108 (54.3%) were female, and the mean (SD) age was 72.3 (5.5) years.
Based on meta-analyses showing benefits for IBS and digestive symptoms. Effect sizes varied considerably between studies with low to very low certainty of evidence. Initial GI symptoms common when starting but typically resolve within 1-2 weeks.
Based on meta-analyses showing 2.17% WMD improvement in lumbar BMD. Effects primarily demonstrated with MK-7 form in postmenopausal women. Combination with vitamin D3 may enhance effects.
AI-estimated from published studies. Interpret as directional guidance.
Probiotics has a higher evidence score (9/10 vs 6/10) and wins in 3 of 3 categories.
For reduce inflammation, Probiotics has a higher relevance score (95 vs 70).
No known interactions between Probiotics and Vitamin K2 have been documented in our database. However, always consult a healthcare provider before combining supplements.