The aim of this paper is to evaluate and compare the readability level of the stem cell companies’ websites content and scientific articles devoted to this topic. Eight readability formulas were utilised to assess the readability of the information available on the 2020 top ten stem cell companies’ websites and of 24 scientific articles (12 research articles and 12 reviews) published in npj Regenerative Medicine between 2018 and 2020, selected on the basis of the search term “stem cell therapy human”. The average Flesch Reading Ease Score was 32.6 (difficult) for website pages, 35.8 (difficult) for original articles, and 22.4 (very difficult) for reviews. Based on the other seven readability algorithms applied here, none of the examined texts was written beyond the sixth-grade level of readability, indicating that neither scientific articles nor commercial materials from the companies’ websites delivered information on stem cell-based therapies that would be easily readable for an average adult.