Probiotics are live organisms that beneficially effect the health of the host by improving the microbial balance. Lactobacillus is one of the most widely studied probiotics species with many beneficial properties including gastro-intestinal health, inflammation, microbial balance, and even mood and hormones. One study in rodent models showed increased levels of testosterone due to the anti-inflammatory properties of the species tested. Based on these findings the objective of this study was to investigate the potential daily effect probiotic administration on hormones and other relevant markers, i.e. lipid profile. Twenty participants were divided in three groups with group A and group B consuming different strains of Lactobacillus and the control group consuming placebo tablets. All participants received placebo tablets for the first two weeks and then continued with the actual treatment for six weeks according to their assigned group. Blood samples and a questionnaire were taken at baseline, 2 weeks and 6 weeks. After 6 weeks of administration, although no significant change was observed for the level of testosterone, the placebo group had higher decrease in the level of testosterone compared to group A and B. The lipid profile did not significantly change throughout the study, however HDL levels significantly decreased in the placebo group compared to probiotic groups. Only Group B had a decreased ratio of chol/HDL after treatment. TSH levels increased for both probiotic groups but decreased in the placebo group. The results from the questionnaire showed improvements in both physical and psychological aspect but all three groups showed improvement. In conclusion, it is difficult to determine the effect of the probiotics, which is partly due to the COVID-19 pandemic as the participants are not able to maintain their lifestyle throughout the study. Further conclusions are presented in the thesis.