74 articles (72%) used subcutaneous administration, with 27 (26%) using intraperitoneal, oral in 1 (1%), and was not stated in 1 study (1%). We categorised the dose of d-galactose into 4 groups: 0–60 mg/kg (17%). 100–125 mg/kg (35%), 150–250 mg/kg (27%) and 300–1250 mg/kg (20%). We categorized the duration of d-galactose exposure used to induce ageing as 7–40 days (10%), 42 days (22%), 49–56 days (45%) and 60–112 days (23%).