Browse the evidence

Uncarboxylated osteocalcin (un-OC) acts as an endocrine hormone that regulates energy metabolism by stimulating pancreatic beta-cell proliferation, insulin secretion, and adiponectin production, thereby improving glucose tolerance and reducing fat mass.

Current research suggests that bone health and metabolic health are linked via osteocalcin. While you cannot directly supplement osteocalcin effectively based on this text, maintaining bone health through resistance training and adequate Vitamin K intake may support this hormonal pathway. However, human causal evidence is still pending, so prioritize standard metabolic interventions (diet/exercise) first.

Daily vitamin D supplementation (3,332 IU) for one year significantly increases total, bioactive, and free testosterone levels in overweight men with baseline vitamin D deficiency.

If you are overweight and have low Vitamin D levels, supplementing with 3,332 IU of Vitamin D daily for a year may significantly boost your testosterone levels. This effect was observed in men who were also losing weight, suggesting that correcting this specific deficiency is a valuable step for hormonal optimization in this demographic.

BCAA supplementation can enhance the anabolic effect of intact protein meals (e.g., whey) by potentially overcoming rate-limiting steps or activating initiation factors, though this is distinct from the effect of BCAAs alone.

If you are consuming protein, adding BCAAs might boost the muscle-building response, potentially allowing you to get more benefit from a smaller amount of protein. However, this benefit is only seen when BCAAs are mixed with complete protein, not when taken alone.

Specific probiotic and synbiotic interventions improve insulin sensitivity, fasting blood glucose, and lipid profiles in patients with Type 2 Diabetes (T2D) and Insulin Resistance Syndrome (IRS).

If you have T2D or IRS, adding specific probiotics (like L. plantarum A7 or synbiotics with L. casei/rhamnosus) to your daily routine for several weeks may help lower blood sugar and improve insulin sensitivity. This is a supportive strategy, not a replacement for prescribed medication.

Specific probiotic and synbiotic interventions improve liver function markers (ALT, AST) and reduce liver fat in patients with Non-Alcoholic Fatty Liver Disease (NAFLD) and NASH.

If you have NAFLD or NASH, specific probiotics (like L. bulgaris/S. thermophilus or synbiotics with L. plantarum) taken daily for 8-30 weeks may help improve liver enzyme levels and reduce liver fat. This is a supportive strategy alongside lifestyle changes.

Combining metformin with lifestyle modification (diet and exercise) results in significantly greater reductions in BMI and subcutaneous adipose tissue, and increases menstrual cycle frequency, compared to lifestyle modification alone in women with PCOS over 6 months.

If you have PCOS, combining metformin with lifestyle changes (diet and exercise) leads to better weight loss and more regular periods than lifestyle changes alone. However, metformin by itself does not help with weight loss compared to lifestyle changes. The benefit of adding metformin is primarily seen in weight management and menstrual regulation, not necessarily in improving blood sugar or lipid markers beyond what lifestyle changes achieve.

Prior resistance exercise-induced hypertrophy creates an epigenetic memory in human skeletal muscle, evidenced by sustained DNA hypomethylation of specific genes (e.g., AXIN1, GRIK2, UBR5) during detraining, which facilitates a significantly greater hypertrophic response upon subsequent reloading compared to the initial training phase.

If you have trained before, stopped, and are starting again, your muscles may respond faster than when you first started. This is due to epigenetic changes (DNA methylation) that persist even after muscle mass returns to baseline. To leverage this, ensure your initial training phase was substantial enough to induce hypertrophy, as this creates the 'memory' that accelerates reloading gains.

Two nights of partial sleep deprivation (approx. 4 hours sleep opportunity) significantly decreases fasting and postprandial insulin sensitivity in normal-weight young men, while simultaneously altering gut microbiota composition by increasing the Firmicutes:Bacteroidetes ratio and the abundance of Coriobacteriaceae and Erysipelotrichaceae.

If you are a healthy young adult, restricting your sleep to ~4 hours for two consecutive nights will likely impair your body's ability to handle glucose (insulin sensitivity) and shift your gut bacteria towards profiles often seen in metabolic disorders. While the gut changes might not directly cause the insulin resistance, the metabolic risk is real. Prioritize getting 7-9 hours of sleep to maintain metabolic health.

Dietary prebiotics (non-digestible carbohydrates) improve leptin sensitivity and reduce food intake in diet-induced obesity by modulating gut microbiota to increase short-chain fatty acid (SCFA) production, which activates GPR41/43 receptors and reduces low-grade inflammation.

If you are struggling with leptin resistance (common in obesity), consider increasing your intake of prebiotic fibers (like inulin-type fructans or resistant starch). These feed gut bacteria to produce SCFAs, which help restore your body's sensitivity to leptin, potentially reducing hunger and improving metabolic health. This is a dietary strategy to reset hormonal signaling rather than just adding bulk.

Gut microbiota-derived short-chain fatty acids (SCFAs), specifically propionate, improve insulin sensitivity and glucose homeostasis by stimulating intestinal gluconeogenesis via the GPR43 receptor and a gut-brain neural circuit.

Consuming prebiotic fibers that generate propionate (a type of SCFA) can help improve your body's ability to manage blood sugar. This happens through a communication pathway between your gut and brain. Focus on foods rich in resistant starches and inulin to support this natural glucose-regulating mechanism.

Gut microbiota composition influences the secretion of anorexigenic gut peptides (GLP-1 and PYY) and reduces orexigenic ghrelin, thereby reducing food intake and body weight, mediated by microbial fermentation of non-digestible carbohydrates.

To naturally reduce hunger, incorporate prebiotic fibers (like those in onions, garlic, bananas, or supplements like inulin) into your diet. These fibers feed gut bacteria that produce SCFAs, which in turn stimulate the release of satiety hormones (GLP-1, PYY) and reduce hunger hormones (ghrelin), helping you feel full longer.

Dietary fiber intake modulates gastrointestinal transit time, which serves as a key mechanism for improving glucose homeostasis and reducing the risk of metabolic diseases like obesity and type 2 diabetes.

Increase your intake of dietary fibers from various plant sources (whole grains, vegetables, legumes) to support healthy gastrointestinal transit. This can help regulate blood sugar levels and may reduce the risk of metabolic diseases. Start gradually to minimize digestive discomfort.

Viscous soluble fibers (e.g., beta-glucans, pectin, psyllium) delay gastric emptying, which contributes to reduced postprandial glucose concentrations and improved insulin sensitivity.

Incorporate viscous soluble fibers like beta-glucans (oats), pectin (apples), or psyllium into your meals. These can help slow down digestion, leading to more stable blood sugar levels after eating. Ensure adequate water intake when consuming these fibers.

Women with PCOS should be assessed for cardiovascular disease risk factors, including lipid profiles and blood pressure, regardless of age or BMI, due to increased risk of cardiovascular disease and mortality.

If you have PCOS, get your cholesterol and blood pressure checked at diagnosis and annually thereafter, even if you are young and have a healthy weight. This is standard care for PCOS, not optional.

Curcumin administration improves metabolic health in obese/diabetic models by modulating gut microbiota to reduce inflammation and improve intestinal barrier function.

If you consider curcumin, understand that its benefit may come more from its interaction with your gut bacteria than direct absorption. It may help with insulin sensitivity and gut barrier integrity, especially if you have metabolic issues. Formulations that enhance bioavailability (like with piperine or lipids) may be more effective.

Quercetin supplementation reduces inflammation and improves metabolic parameters (glucose, lipids) by modulating gut microbiota composition, specifically by increasing beneficial bacteria and reducing pathogenic ones.

Quercetin, found in onions, apples, and tea, may help manage blood sugar and lipids by supporting healthy gut bacteria. Regular dietary intake is a practical way to leverage these effects.

Administration of probiotics, prebiotics, or synbiotics can improve insulin sensitivity and glucose metabolism in humans, primarily through mechanisms involving short-chain fatty acid (SCFA) production, modulation of gut microbiota composition, and reduction of systemic inflammation.

If you have insulin resistance or type 2 diabetes, consuming specific probiotic strains (like Lactobacillus and Bifidobacterium combinations) or prebiotics (like inulin or FOS) may help improve your blood sugar control. However, results are not guaranteed and depend heavily on the specific strain and dose used. It is not a substitute for standard medical care but may be a useful adjunct.

Probiotic supplementation can reduce systemic inflammation and oxidative stress, which are contributors to insulin resistance, by lowering pro-inflammatory cytokines and increasing antioxidant enzyme activity.

Some probiotic supplements may help lower chronic inflammation and oxidative stress in people with diabetes, which can indirectly support better insulin sensitivity.

Omega-3 PUFAs reduce intestinal inflammation and immune response by inhibiting pro-inflammatory signaling pathways (NF-κB, MAPK) and promoting anti-inflammatory mediators (IL-10, SCFAs like butyrate).

If you suffer from inflammation or gut issues, omega-3s (EPA/DHA) can help by directly reducing inflammatory signaling in the gut. This is achieved by blocking pro-inflammatory pathways and boosting anti-inflammatory factors. This benefit is most pronounced when using direct sources of EPA/DHA rather than just plant-based ALA.

Testosterone therapy in transgender men is associated with virilization (deepening voice, increased muscle mass, cessation of menses) and is considered safe regarding cardiovascular and oncological disease in the short- to mid-term.

Testosterone therapy for transgender men causes virilization, including voice deepening (which is permanent), increased muscle mass, facial/body hair growth, and cessation of menses. It is considered safe for cardiovascular and cancer risk in the short to mid-term, though long-term data is still being gathered.

Low-Glycemic Index (GI) diets promote greater weight loss, better insulin regulation, and lower weight regain compared to high-GI or conventional diets, primarily by enhancing satiety and minimizing postprandial insulin secretion.

Choose carbohydrates that digest slowly (low GI), such as vegetables, legumes, and whole grains, rather than refined grains and sugars. This helps control hunger and insulin levels, leading to better weight loss and maintenance.

Sleep deprivation causes a muted immune response to vaccination, specifically demonstrated by a reduced immune response to flu vaccination.

Ensure adequate sleep when receiving vaccinations, as sleep deprivation may reduce the effectiveness of the immune response.

Exercise-induced irisin promotes the browning of white adipose tissue and increases energy expenditure, offering a potential therapeutic mechanism for managing obesity and metabolic syndrome.

Exercise is beneficial for metabolic health, partly through mechanisms involving irisin and fat browning, but you cannot currently rely on blood tests for irisin to track progress or prescribe specific doses. Focus on consistent physical activity, particularly resistance training, which may influence irisin pathways, rather than seeking 'irisin-boosting' supplements which lack robust human validation.

Irisin acts as an insulin-sensitizing hormone that facilitates glucose uptake in skeletal muscle and improves hepatic glucose metabolism, potentially reducing the risk of type 2 diabetes.

Exercise improves glucose metabolism through multiple pathways, including irisin-mediated effects. Do not expect irisin supplementation to cure diabetes. Focus on resistance and aerobic exercise to naturally support insulin sensitivity and glucose uptake.