Premature ovarian insufficiency (POI) is defined as a cessation of ovarian function before the age of 40. Such early deprivation of estrogens in women may be associated with several adverse cardiovascular and metabolic consequences. The aim of this retrospective study was to investigate whether women with POI and a serum follicle-stimulating hormone (FSH) level of 25–40 I/U (Group A) have the same metabolic profile as women with POI and a serum FSH level of >40 I/U (Group B). One hundred twenty-three women were included in the study group (Group A; n = 41; Group B; n = 82). The control group comprised 77 healthy women with regular menstruation. In the age- and BMI-adjusted model, no differences were found between the groups with respect to total cholesterol, high-density lipoproteins, triglycerides, HOMA-IR, glucose, and insulin. The only significant difference was found in terms of low-density lipoprotein cholesterol (LDL-C). The highest serum concentration was found in Group B, the second highest was found in Group A, and the lowest was in the controls. In conclusion, changing the threshold of FSH required to establish a POI diagnosis may have an impact on the level of serum LDL-C.