Although studies had suggested that monosodium glutamate (MSG) may serve as a salt substitute in processed foods, its market impact remains unclear. This study was aimed to: (1) identify MSG in ingredient lists, (2) compare sodium levels in products with and without MSG, (3) examine the association between MSG and other umami enhancers, and (4) assess manufacturers’ adherence to the Food Regulation 1985 for MSG declaration. An observational cross-sectional market survey was conducted during the Movement Control Order (June to September 2021) on 1076 processed foods from selected Malaysian hypermarkets, that were located within 10 km of the researcher’s residence to ensure accessibility amid the COVID-19 pandemic movement restrictions. Additionally, online platforms were used to supplement any missing data. Nutritional and ingredient information were collected from packaging, and foods were classified by using the FAO/WHO Food Standards CODEX Alimentarius. Over half (50.8%) of the surveyed products contained MSG. Results found that MSG-containing products had a significantly higher sodium levels (2812.2 ± 5191.4 mg/100 g) than those without (1372.2 ± 1541.4 mg/100 g) (p < 0.001). Additionally, 14.4% of MSG-free products were labelled as ‘No Added MSG’, while products with MSG were more likely to contain other umami enhancers (p < 0.001). Compliance with MSG declaration regulations was 61%. In conclusion, MSG was present in half of the surveyed products. MSG-containing products were more likely to have higher sodium content and include other flavour enhancers. Future research should analyse the actual MSG as well as sodium content and explore alternative sodium reduction strategies.