Lacticaseibacillus paracasei NB23 improved multiple markers of metabolic and muscle health in healthy participants, according to a study published in Probiotics and Antimicrobial Proteins.
The 12-week trial randomized 51 adults to receive a daily NB23 supplement or placebo. The results suggested that muscle mass, lower limb strength, and insulin-like growth factor-1 (IGF-1) increased, and showed significant improvements in cardiometabolic markers.
"These findings support its potential as a functional food component for cardiometabolic resilience and muscle maintenance", wrote researchers from Hungkuang University and Kuang-Tien General Hospital in Taiwan.
They suggested that the observed effects can be categorized into three main domains: metabolic health improvements, enhanced muscle strength and mass, and activation of IGF-1 signaling pathways.
IGF-1 promotes the synthesis of muscle cells and enhances muscle mass, strength, growth, repair, and function. Increased IGF-1 levels may enhance insulin sensitivity and help to prevent insulin resistance. Therefore, IGF-1 plays a key role in maintaining metabolic health and preventing sarcopenia, which can induce insulin resistance.
They noted that their results align with known probiotic mechanisms such as modulating the microbiota, reducing inflammation, and increasing short-chain fatty acids. Additionally, the observed improvements in blood pressure and lipid markers suggest "a beneficial impact on vascular tone and lipid homeostasis."
The current research adds evidence to support the metabolic and muscle-enhancing benefits of L. paracasei strains that have been suggested in previous studies.
All the participants, who had no regular exercise habits, were randomized to receive either NB23 containing 50 billion CFU or placebo twice daily.
Researchers analyzed the participants' anthropometrics, muscle strength, inflammatory and cholesterol markers, lipid profiles, blood pressure, insulin resistance (HOMA-IR), and IGF-1 pathway markers (PI3K, Akt, p-mTOR)
The results suggested that NB23 supplementation improved systolic and diastolic blood pressure, waist circumference, triglycerides, LDL, and LDL/HDL ratios and increased HDL and serum calcium. There were also significant improvements in HOMA-IR and inflammatory cytokines.
"These effects were observed despite increased caloric intake, suggesting a potential protective effect against dietary metabolic stress," the researchers wrote. "Muscle mass and lower-limb strength increased, along with elevated IGF-1 and downstream signaling pathway activation."
The researchers noted that the reductions in blood pressure may have meaningful cardiovascular implications, "given that a 10 mmHg rise in systolic blood pressure increases the risk of coronary artery disease by approximately 16%".
Despite the promising findings, the researchers acknowledged the study limitations and cautioned against generalizing the results to clinical populations, while recommending further studies to validate the results.
Source: Probiotics & Antimicro. Prot. (2025). https://doi.org/10.1007/s12602-025-10604-4 "The Effects of Lactobacillus paracasei NB23 on IGF-1, Muscle Function, and Cardiometabolic Risk Factors in Healthy Individuals: A Randomized Controlled Trial." Authors: S. Lin et al.