Many women, and even a number of clinicians, believe that taking combined oral contraceptives (i.e., contraceptives that contain 2 ingredients, estrogen and progestin) will cause weight gain. This belief often leads to a significant number of women (especially younger women) being reluctant to use this highly effective method of contraception, and many women who are already using this method of contraception discontinuing it or switching to another method during the course of its use. However, is there indeed a correlation between the use of compounded oral contraceptives and weight gain? In 2014, Gallo and other experts conducted a study on the topic of whether or not compounded oral contraceptives have an effect on weight. They searched all studies on compounded oral contraceptives in repositories such as CENTRAL, MEDLINE, POPLINE, EMBASE, LILACS, Clinicaltrial.com, and ICTRP prior to November 2013, and also contacted known researchers and pharmaceutical companies for unsearched published and unpublished information and data from clinical trials. Randomized controlled trials of combined oral contraceptives with placebo or blank controls, or of one combined oral contraceptive with another (differing in formulation, dosage, method of administration, or duration of study), written in English and applied for more than 3 cycles, were included for further in-depth analysis. Data from these profiles were analyzed and processed using RevMan software; information screened into the study and processed data were verified by another researcher. For continuous data, fixed-effects models were used to calculate the mean difference (MD) and 95% confidence interval (CI) for the change in baseline weight and the change in weight that occurred after taking the pill (or placebo, blank control). For count data, such as the proportion of people who gained or lost weight up to a particular value, the ratio (Peto OR, or OR) and 95% CI were calculated. A total of 49 clinical trials were eligible for in-depth analysis of the study. These clinical trials included 52 randomized, controlled, comparisons of different pairs of contraceptives (or placebo); the results of 4 randomized, controlled comparisons of contraceptives with placebo (or blank controls) did not support a causal relationship between the use of combined oral contraceptives or combined contraceptive skin patches (combined contraceptive patches) and weight change. Most of the comparisons between different combined oral contraceptives did not show substantial weight changes. In addition, there was no difference in discontinuation of oral contraceptives due to weight change between groups, i.e., there was no observed increase in discontinuation of the combination pill or the combination patch in women due to weight change. Based on these findings, Gallo et al. concluded that although the available evidence is not yet sufficient to establish that compounded oral contraceptives have no effect at all on body weight, it is safe to assume that the evidence that compounded oral contraceptives do not have a significant effect on body weight is still sufficient. Clinical trials evaluating the relationship between compounded oral contraceptives and changes in body weight will need to establish control groups of placebo or non-hormonal contraceptive methods to control for other factors affecting body weight, such as the effect of time on body weight.