There is an increased focus on the outcomes of Health Science PhD-education, particularly if PhD-graduates remain active in research. There is a gap in our knowledge about the extent the investment in Health Science PhDs is moving science forward and no definition of expected investment return from PhD exists. We explore the research production of Danish Health Science PhDs, 5-9 years post PhD-defence, to find the fraction of PhD-graduates that are still actively publishing internationally. Secondary endpoints include analyses of the number of publications over time, identification of consecutive publishers, gender differences, and differences between medical doctors with a PhD (MDs) and non-MDs with a PhD. PhD-theses defended in 2005 and 2006 were identified and collected using the Danish National Research Database and via the four Danish universities offering Health Science PhD-programmes. Publication data were collected from Years 5 to 9 post PhD-defence to allow publications produced during the PhD-period to be washed out. Total 532 unique PhD-graduates (300 female and 232 male) produced a total of 4,530 PubMed-indexed publications. Results show zero publishers represented 31.2% (n = 166), while 25.8% (n = 137) of PhD-graduates published 10 or more publications during the 5-year observation window. Overall publication count increased from post PhD Years 5-9 with 68% (from 720 to 1,049). Number of publications did not differ between MDs and non-MDs. Our results evidence that not all graduates continue in research. Consequently, we need to identify early factors that make graduates remain in research, to identify future PhD-candidates that will continue publication post PhD.