The composition of phytosterol (PS) formulations used to enrich food and supplements are typically different due to varying natural sources. Sitosterol and it's hydrogenated form: sitostanol are the major PSs in most of these formulations. This review aimed to investigate whether the proportion of sitosterol plus sitostanol in a PS formulation is a determinant of the hypocholesterolaemic effect of PS products. If the amount of sitosterol plus sitostanol in a PS composition is ≥80%, the product is considered to be high in sitosterol plus sitostanol, otherwise the product is considered to be low in sitosterol plus sitostanol. We conducted a meta-analysis on the cholesterol-lowering potential of PS products that were high or low in sitosterol plus sitostanol. Databases including PubMed, EMBASE, and Cochrane Library were searched, and published RCTs investigating the efficacy of dietary PSs intervention (≥1.5 g/d) on blood lipid profile improvement were selected. After strict screening and quality assessment, a total of 51 RCTs were included. As expected, PSs with all compositions significantly reduced LDL-C (p < 0.00001), while the LDL-C lowering effect associated with the high sitosterol plus sitostanol group was significantly greater than that of the low sitosterol plus sitostanol group (p = 0.002). PSs also significantly reduced TG (p = 0.009) without affecting HDL-C. Thus, the composition might affect the hypocholesterolaemic effect of PS products. PS products with higher sitosterol plus sitostanol proportions might have superior cholesterol-lowering potential than those with lower sitosterol plus sitostanol proportions.