The term “post-biotics” refers to non-viable probiotics or inactivated probiotics that provide benefits to the host. An increasing body of scientific literature demonstrates that specific, clinically-tested, post-biotic strains confer benefits to the immune system.

Lactobacillus paracasei is part of the Lactobacillus casei group of probiotics and is one of the most widely researched and applied species of lactobacilli.

Several studies have shown statistically significant results indicating that oral intake of non-viable microbial cells, such as heat-killed probiotics — including LAC-Shield™, a strain of heat-killed L. paracasei — can have powerful immune supportive effects.*

LAC-Shield was selected among thousands of probiotic cultures as a promising immuno-stimulator. In fact, research has shown that this strain stimulates promoter cells to produce antibodies, such as IL-12, thereby supporting gut health and both innate and adaptive immunity.* LAC-Shield greatly surpasses many other lactic-acid bacteria in immune activity.*

A recent placebo-controlled human clinical study of 241 participants[i], which followed subjects for 12 weeks in the winter season, showed that LAC-Shield:

  • Supported the body's adaptive immune response.
  • Helped maintain a positive mood state, even under stressful conditions*

LAC-Shield is highly stable and very tolerant to heat and pH, making it easy to incorporate into supplements, foods and beverages.




LAC-Shield acts on the immunocytes in the small intestine Peyer’s patch to produce immunologically active proteins.

Clinical data indicates that LAC-Shield has the potential to improve immune resistance and help maintain a positive mood state, even under stressful conditions.*[i]


L. paracasei species have been granted presumption of safety by the European Food Safety Authority (EFSA). In addition, LAC-Shield is Self-Affirmed GRAS (Generally Recognized As Safe) in the U.S., made in a cGMP-compliant environment that complies with FSCC 22000 Food Safety Management Systems, and has had a history of safe use since 2014.

[i] Murata M, Kondo J, Iwabuchi N, Takahashi S, Yamauchi K, Abe F, Miura K. Effects of paraprobiotic Lactobacillus paracasei MCC1849 supplementation on symptoms of the common cold and mood states in healthy adults. Benef Microbes. 2018 Dec 7;9(6):855–864.