Lactobacillus salivarius UCC118: Effects on C-Peptide and Health Markers

This conversation examines the evidence for Lactobacillus salivarius UCC118's effect on C-peptide levels, finding no significant impact. It also reviews other health outcomes, including improved insulin sensitivity, reduced inflammation, lower gestational diabetes risk, and benefits for glucose metabolism and gut health.

Jun 19, 2026

Does taking Lactobacillus salivarius UCC118 help lower C-peptide levels, and is there any evidence it affects other health markers?

Lactobacillus salivarius UCC118 and C-Peptide Levels

Based on data from Pillser's research database, there is no strong evidence that Lactobacillus salivarius UCC118 significantly lowers C-peptide levels. One randomized controlled trial (2015, n=149) investigated this in women with gestational diabetes mellitus and found a neutral, small, non-significant effect on C-peptide levels¹.

Other Health Markers — What the Evidence Shows

Pillser's database tracks 10 studied health outcomes for this specific probiotic strain. Here's what the research indicates:

✅ Outcomes with Stronger Evidence

Health Outcome	Studies	Effect	Details
Improved Insulin Sensitivity	6 studies	✅ Beneficial (moderate)	All 6 studies reported benefits, with several reaching statistical significance. Best evidenced in pregnant women and those with gestational diabetes².
Reduced Inflammation	8 studies	✅ Beneficial (moderate)	A large meta-analysis (n=896) in women with gestational diabetes showed significant reduction in C-reactive protein (CRP), a key inflammatory marker³.
Reduced Prevalence of Gestational Diabetes Mellitus (GDM)	4 studies	✅ Beneficial (moderate)	One meta-analysis reported a 48% lower risk (RR 0.52, p=0.003) and another a 29% lower risk (RR 0.71, p=0.03)⁴.

✅ Outcomes with Moderate-to-Lower Evidence

Improved Glucose Metabolism — 4 studies, all beneficial with moderate effect sizes, primarily in pregnant women with GDM⁵.
Reduced Insulin Levels — 3 studies (2 beneficial, 1 neutral), with moderate effect sizes⁶.
Improved Gastrointestinal Health — 10 studies (all reviews), reporting beneficial but small-to-moderate effects⁷.
Reduced Risk of Infection — 3 reviews reporting moderate beneficial effects⁸.
Improved Gut Health — 6 studies (reviews and non-human), small effects⁹.
Improved Immune Function — 5 reviews, small beneficial effects¹⁰.

Summary

To directly answer your question: No — the one available trial on C-peptide showed a neutral (non-significant) result¹. However, this strain has shown more promising effects on insulin sensitivity, inflammation (CRP), glucose metabolism, and GDM risk reduction, particularly in pregnant women and those with gestational diabetes. The strongest body of evidence points toward improvements in insulin sensitivity and reduced inflammation²³.

Pillser research database, Lactobacillus salivarius UCC118 & Reduced C-Peptide Level — 2015 RCT, n=149, neutral effect. ↩ ↩²
Pillser research database, Lactobacillus salivarius UCC118 & Improved Insulin Sensitivity — 6 studies, all beneficial. ↩ ↩²
Pillser research database, Lactobacillus salivarius UCC118 & Reduced Inflammation — 8 studies, all beneficial, including CRP reduction. ↩ ↩²
Pillser research database, Lactobacillus salivarius UCC118 & Reduced Prevalence of GDM — 4 studies, RR reductions of 29–48%. ↩
Pillser research database, Lactobacillus salivarius UCC118 & Improved Glucose Metabolism — 4 studies, all beneficial. ↩
Pillser research database, Lactobacillus salivarius UCC118 & Reduced Insulin Levels — 3 studies, 2 beneficial, 1 neutral. ↩
Pillser research database, Lactobacillus salivarius UCC118 & Improved Gastrointestinal Health — 10 studies. ↩
Pillser research database, Lactobacillus salivarius UCC118 & Reduced Risk of Infection — 3 studies. ↩
Pillser research database, Lactobacillus salivarius UCC118 & Improved Gut Health — 6 studies. ↩
Pillser research database, Lactobacillus salivarius UCC118 & Improved Immune Function — 5 studies. ↩

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