Background: A significant growth in dietary supplement usage has occurred and this trend is particularly evident among females. This underlines the need to establish current knowledge levels among a female participant cohort based in the Aseer Region of the Kingdom of Saudi Arabia (KSA), along with determining the types of products being used and the typical reasons cited for their consumption. Methods: A total of 173 participants drawn from various age groups took part in this descriptive cross-sectional survey design. The survey was conducted over a three-month period from September to November 2019, using a structured online questionnaire. Results: The results of this research show that dietary supplement usage was highly prevalent among study participants. Young females (18–24 years) demonstrated significantly higher knowledge levels as compared to all other age groups (p<0.001 vs. other participants). Conclusion: This study has clearly shown that the participants in fact have a very varied range of knowledge, very often according to age, about the use of dietary supplements. 18–24-year-olds demonstrated higher levels of dietary supplement knowledge compared to the other age groups.