Metformin, a synthetic biguanide, is widely used to manage type 2 diabetes, and is commonly prescribed in polycystic ovary syndrome (PCOS) to address insulin resistance and associated metabolic and reproductive disturbances. PCOS is characterised by hormonal imbalances such as hyperandrogenism and anovulation, metabolic abnormalities including insulin resistance and increased cardiometabolic risk, and higher rates of pregnancy complications. However, the role of metformin in the multifaceted nature of PCOS remains debated. This review synthesises the mechanisms of action of metformin and its effects on metabolic, hormonal, reproductive, and pregnancy‐related outcomes in PCOS. In non‐pregnant women, metformin improves insulin resistance, menstrual regularity, and androgen levels, particularly in those with obesity or insulin resistance, and may enhance fertility when combined with other treatments. However, it is not effective as a first‐line therapy for weight loss, ovulation induction, or treatment of clinical hyperandrogenic features, including hirsutism or acne. In pregnancy, metformin may reduce early pregnancy loss, miscarriage, and preterm birth, though findings for gestational diabetes and preeclampsia are inconsistent. Evidence is limited by study heterogeneity, varying diagnostic criteria, and the use of aggregate data in meta‐analyses, all of which make interpretation challenging. Future research should prioritise well‐powered clinical trials, individual patient data meta‐analyses, and longer‐term follow‐up studies, particularly in pregnancy, to better define the populations most likely to benefit from metformin use across the PCOS spectrum. Plain Language Summary: Polycystic ovary syndrome (PCOS) is a common condition that affects up to 1 in 10 women of reproductive age. It is characterised by irregular or absent periods, signs of elevated male hormones (high androgens or excess hair growth), and/or polycystic ovaries seen on ultrasound. These features can lead to fertility problems, acne, psychological distress, and an increased risk of various disorders such as depression, type 2 diabetes and heart disease. Many women with PCOS also experience challenges during pregnancy, including a higher risk of miscarriage, preterm birth, and gestational diabetes. Metformin is a medication most often used to manage diabetes. In women with PCOS, it can help improve how the body responds to insulin, which may also reduce male hormone levels, improve menstrual cycles, and support fertility. This review examines the role of metformin in treating PCOS—both before and during pregnancy—by summarising key findings from the available evidence. In women who are not pregnant, metformin can help improve insulin resistance, hormone levels, and menstrual regularity, particularly among those who are overweight or have signs of insulin resistance. However, metformin alone is not a first‐choice treatment for weight loss, ovulation problems, or symptoms such as acne and unwanted hair growth. When combined with other treatments, such as hormone therapy or fertility medications, it may offer additional benefits. During pregnancy, metformin is considered safe for use in women with PCOS and may lower the risk of early pregnancy loss and preterm birth. However, its effects on preventing gestational diabetes or high blood pressure are less clear, with mixed results across studies. Some research suggests that babies exposed to metformin in the womb may have slightly larger head sizes or a higher risk of being overweight in early childhood, but the long‐term health effects remain unknown. Overall, metformin can be a helpful part of treatment for some women with PCOS, especially those with insulin resistance or certain pregnancy risks. Still, it is not a one‐size‐fits‐all solution. More high‐quality research is needed to better understand which women benefit most and to assess any long‐term effects on children exposed to metformin during pregnancy.

Cardiovascular disease (CVD) is the leading cause of death in patients with non-alcoholic fatty liver disease (NAFLD). Curcumin has been shown to exert glucose-lowering and anti-atherosclerotic effects in type 2 diabetes. Hence, we investigated curcumin’s effects on atherogenesis markers, fatty liver, insulin resistance, and adipose tissue-related indicators in patients with NAFLD. In this secondary analysis of a 12-week randomized controlled trial, fifty-two patients with NAFLD received lifestyle modification. In addition, they were randomly allocated to either the curcumin group (1.5 g/day) or the matching placebo. Outcome variables (assessed before and after the study) were: the fatty liver index (FLI), hepatic steatosis index (HSI), fatty liver score (FLS), BMI, age, ALT, TG score (BAAT), triglyceride glucose (TyG) index, Castelli risk index-I (CRI-I), Castelli risk index-II (CRI-II), TG/HDL–C ratio, atherogenic coefficient (AC), atherogenic index of plasma (AIP), lipoprotein combine index (LCI), cholesterol index (CHOLINDEX), lipid accumulation product (LAP), body adiposity index (BAI), visceral adiposity index (VAI), metabolic score for visceral fat (METS-VF), visceral adipose tissue (VAT), and waist-to-height ratio (WHtR) values. The TyG index decreased in the curcumin group and increased in the placebo group, with a significant difference between the groups (p = 0.029). However, a between-group change was not significant after adjustment for multiple testing. Other indices were not significantly different between the groups either before or after multiple test correction. After the intervention, there was a lower number of patients with severe fatty liver (FLI ≥ 60) and metabolic syndrome in the curcumin group compared to the placebo (p = 0.021 and p = 0.012, respectively). In conclusion, curcumin offers no additional cardiometabolic benefits to lifestyle intervention in patients with NAFLD.

Metformin is widely prescribed for the management of type 2 diabetes mellitus, polycystic ovary syndrome, and gestational diabetes mellitus in pregnancy. Its use is driven by factors including oral administration, lower patient and health system burden and cost, and benefits including lower risk of excess gestational weight gain and hypoglycemia compared with insulin. Metformin use appears safe in pregnancy; however, there remain concerns regarding long‐term effects of intrauterine metformin exposure on offspring health. Randomized controlled trial follow‐up studies suggest that metformin‐exposed offspring may have altered postnatal growth trajectories and increased adiposity in childhood, although data are limited. Whether this is a transient adaptation or a precursor to long‐term metabolic dysfunction is unclear, as data on cardiometabolic and neurodevelopmental parameters, including glucose homeostasis, lipid metabolism, and cognitive function, are sparse and inconsistent. Methodological challenges include heterogeneous study designs, high attrition rates, and inadequate control for confounding variables. Given these uncertainties, further well‐powered, long‐term prospective studies and individual patient data meta‐analyses, harmonizing data and adjusting for confounders, are needed to clarify risks and benefits of metformin use in pregnancy. Until such data are available, clinicians must weigh the benefits and advantages of metformin use in pregnancy against the unknowns regarding potential long‐term impact on offspring health. Plain Language Summary: Metformin is a medicine often used during pregnancy to help manage conditions such as type 2 diabetes, gestational diabetes, and polycystic ovary syndrome (PCOS). It is commonly chosen because it is taken as a tablet rather than by injection, has a lower risk of causing low blood sugar, and is generally easier and less expensive to use than insulin. Research has shown that metformin is safe for use during pregnancy in the short term. However, there are still questions about whether it has any lasting effects on children who were exposed to it before birth. This review explores this topic in detail. Some studies have found that children exposed to metformin during pregnancy may have slightly different growth patterns, such as having more body fat or being heavier in early childhood. However, these results are inconsistent and most studies show no clear differences in overall health outcomes, including in heart health, metabolism, or brain development. The results are mixed, and many studies are small or have design limitations, which makes it difficult to draw strong conclusions. At this stage, there is no clear evidence that metformin causes harm to children in the long term. However, because some studies suggest there may be effects on childhood growth and development, researchers emphasize the need for further long‐term research. These future studies should follow children into adolescence and adulthood to better understand any lasting impacts. Until more is known, doctors and patients will need to carefully consider the known benefits of metformin in pregnancy alongside the current uncertainties about long‐term effects on child health.

Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of morbidity and mortality in patients with prediabetes and type 2 diabetes mellitus (T2DM). Carnosine has been suggested as a potential approach to reduce ASCVD risk factors. However, there is a paucity of human data. Hence, we performed a 14-week double-blind randomized placebo-controlled trial to determine whether carnosine compared with placebo improves vascular and metabolic outcomes in individuals with prediabetes and T2DM. In total, 49 patients with prediabetes and T2DM with good glycemic control were randomly assigned either to receive 2 g/day carnosine or matching placebo. We evaluated endothelial dysfunction, arterial stiffness, lipid parameters, blood pressure, heart rate, hepatic and renal outcomes before and after the intervention. Carnosine supplementation had no effect on heart rate, peripheral and central blood pressure, endothelial function (logarithm of reactive hyperemia (LnRHI)), arterial stiffness (carotid femoral pulse wave velocity (CF PWV)), lipid parameters, liver fibroscan indicators, liver transient elastography, liver function tests, and renal outcomes compared to placebo. In conclusion, carnosine supplementation did not improve cardiovascular and cardiometabolic risk factors in adults with prediabetes and T2DM with good glycemic control. Therefore, it is improbable that carnosine supplementation would be a viable approach to mitigating the ASCVD risk in these populations. The trial was registered at clinicaltrials.gov (NCT02917928).

Background/Objectives: In vitro studies suggest that carnosine reduces inflammation by upregulating anti-inflammatory mediators and downregulating pro-inflammatory cytokines. However, human clinical trials examining the effects of carnosine on inflammatory biomarkers are scant. We conducted a secondary analysis of a double-blind randomised controlled trial (RCT) to examine the effects of carnosine supplementation on inflammatory markers and adipokines in participants with prediabetes or well-controlled type 2 diabetes (T2D). Methods: Out of 88 participants who were recruited, 49 adults with prediabetes or well-controlled T2D (HbA1c: 6.6 ± 0.7% [mean ± SD]) who were treated with diet and/or metformin were eligible for inclusion. Participants were randomised to receive 2 g/day of carnosine or a matching placebo for 14 weeks. We measured serum concentrations of monocyte chemoattractant protein-1 (MCP-1), interleukin (IL)-6, IL-10, C-reactive protein (CRP), tumour necrosis factor-α (TNF-α), adiponectin, leptin, adipsin, serpin, and resistin levels at baseline and after 14 weeks. The trial was registered at clinicaltrials.gov (NCT02917928). Results: Forty-one participants (M = 29/F = 12) aged 53 (42.6, 59.3) years [median (IQR)] completed the trial. After 14 weeks of supplementation, changes in pro- and anti-inflammatory cytokine and adipokine levels did not differ between the carnosine and placebo groups (p > 0.05 for all). The results remained unchanged after adjustment for confounders including age, sex, and anthropometric measures (e.g., body fat percentage and visceral adipose tissue). Conclusions: In individuals with prediabetes and well-controlled T2D, carnosine supplementation did not result in any significant changes in inflammatory markers. Larger RCTs with longer follow-up durations are needed to evaluate whether carnosine may be beneficial in individuals with poorly controlled T2D.

Background/Objectives: Type 2 diabetes (T2D) is associated with an increased risk of adverse musculoskeletal outcomes likely due to heightened chronic inflammation, oxidative stress, and advanced glycation end-products (AGE). Carnosine has been shown to have anti-inflammatory, anti-oxidative, and anti-AGE properties. However, no clinical trials have examined the impact of carnosine on musculoskeletal health in adults with prediabetes or T2D. Methods: In a randomized, double-blind clinical trial, 49 participants with prediabetes or T2D and without existing musculoskeletal conditions were assigned to receive either 2 g/day carnosine or matching placebo for 14 weeks. Whole-body dual-energy X-ray absorptiometry (DXA) was used to assess body composition, and peripheral quantitative computed tomography (pQCT) was used to assess bone health at the distal and proximal tibia. Results: Forty-three participants completed this study. Carnosine supplementation had no effect on change in hand grip strength (HGS) or upper-limb relative strength (HGS/lean mass) versus placebo. Change in appendicular lean mass, percentage of body fat, visceral fat area, proximal tibial cortical volumetric bone mineral density (vBMD), distal tibial trabecular vBMD, and stress-strain index did not differ with carnosine compared to placebo. Fourteen weeks of carnosine supplementation did not improve muscle strength, body composition, or bone health in adults with prediabetes or T2D. Conclusions: Carnosine supplementation may not be an effective approach for improving musculoskeletal health in adults with prediabetes and T2D without musculoskeletal conditions. However, appropriately powered trials with longer duration are warranted to confirm our findings. The trial was registered at clinicaltrials.gov (NCT02917928).