Browse the evidence

Anabolic steroids exert their effects through multiple mechanisms including androgen receptor modulation, anticatabolic effects via glucocorticoid receptor interference, and non-genomic pathways.

Anabolic steroids work through complex hormonal pathways, including receptor modulation and anticatabolic effects, which contribute to muscle growth and training motivation.

Overexpression of the short p53 isoform (p44) in mice accelerates aging and reduces lifespan by hyperactivating the IGF signaling axis, which triggers a kinase cascade that clamps cell proliferation via p21Cip1 induction.

This research highlights the complexity of the p53 pathway in aging. While reducing IGF signaling is often associated with longevity, this study shows that hyperactivating it via specific p53 isoforms can accelerate aging. This suggests that maintaining a balance between p53 isoforms is crucial for longevity, rather than simply maximizing or minimizing p53 activity.

Pharmacological inhibition or genetic ablation of enzymes controlling sphingolipid synthesis (specifically Serine Palmitoyltransferase and Dihydroceramide Desaturase 1) ameliorates insulin resistance, atherosclerosis, and cardiomyopathy in rodent models.

This research suggests that the type of fat you consume matters more than just the total amount, specifically regarding how it affects your body's insulin sensitivity. Saturated fats appear to trigger the production of specific lipids (ceramides) that block insulin action, contributing to metabolic disease. While this is proven in animals, it implies that dietary quality, particularly the ratio of saturated to unsaturated fats, is a critical lever for metabolic health.

In vivo expression of p16INK4A in human skin significantly increases with chronological age, serving as a robust biomarker for intrinsic cellular aging.

This research confirms that cellular aging in skin is a measurable biological process, not just wear and tear. The accumulation of p16INK4A-positive cells is a key indicator of this process. While this paper identifies the marker, it does not offer a direct treatment. However, it validates the importance of monitoring cellular health and suggests that interventions targeting senescence (senolytics) or gene regulation (like BMI1) may be relevant for longevity strategies.

Circulating levels of miR-122 are significantly elevated in patients with non-alcoholic steatohepatitis (NASH) compared to healthy controls and those with simple steatosis, serving as a biomarker for disease severity.

For individuals with fatty liver, elevated circulating miR-122 levels may indicate a progression to more serious liver inflammation (NASH). While not yet a standard clinical tool, this biomarker shows promise as a non-invasive alternative or complement to liver enzymes for assessing disease severity, potentially reducing the need for invasive biopsies in some cases.

Rapid catch-up weight gain during infancy (birth to 2 years) in small-for-gestational-age (SGA) children drives the subsequent development of central adiposity and insulin resistance between ages 2 and 4, despite normal overall weight and BMI trajectories.

For parents of small-for-gestational-age (SGA) infants, the rate of weight gain in the first two years of life is a critical predictor of future metabolic health. Rapid catch-up growth during this infancy period is strongly associated with increased abdominal fat and insulin resistance by age 4, even if the child's overall weight appears normal. Caregivers should monitor growth velocity and body composition during infancy, as this is the primary window for preventing adverse metabolic outcomes, rather than focusing solely on weight gain after age 2.

GLP-1 receptor activation inhibits beta-cell apoptosis through cAMP/PKA and PI3K/Akt signaling pathways, protecting beta-cells from cytokine and fatty acid-induced death.

GLP-1 helps beta-cells survive stress by activating survival pathways (Akt and CREB). This protection may help maintain insulin production in the face of metabolic stress.

GLP-2 administration promotes intestinal epithelial proliferation and regeneration, reducing apoptosis and improving outcomes in models of intestinal injury such as enteritis and mucositis.

GLP-2 helps the gut lining grow back and repair itself after injury from drugs or disease. This suggests potential utility in treating inflammatory bowel disease or chemotherapy-induced gut damage.

Genetic manipulations that interfere with dietary restriction-mediated lifespan extension (DR-essential genes) identify key pathways where DR acts, and some genes act as genetic DR mimetics by extending lifespan even without DR.

Research into DR-essential genes and genetic mimetics (like the growth hormone receptor) offers potential targets for pharmacological interventions that mimic the benefits of caloric restriction without the need for severe dietary restriction. This suggests future drugs could target these pathways to extend healthspan.

Genetic deletion of the insulin receptor substrate 1 (Irs1) gene extends median lifespan by 18% in female mice and delays multiple age-related biomarkers, including motor decline, immune senescence, and bone loss, despite the presence of lifelong insulin resistance.

This research identifies IRS1 signaling as a critical regulator of aging in mammals. While direct genetic manipulation is not possible for humans, it suggests that modulating this specific intracellular pathway could be a target for therapies to delay aging and age-related diseases, independent of improving insulin sensitivity.

Rapamycin extends mean and maximum life spans in genetically heterogeneous mice when administered in mid-to-late life, making it the most strongly supported mammalian longevity therapeutic.

Rapamycin is currently the most effective known drug for extending lifespan in animal models, working by inhibiting the mTOR growth pathway. However, it carries significant risks in humans, including immune suppression, metabolic disturbances, and wound healing issues. It is not currently recommended for healthy individuals seeking longevity, but research into safer analogs (rapalogs) or intermittent dosing strategies is ongoing.

HOMA-IR loses diagnostic accuracy for metabolic syndrome in non-diabetic women over 70 years of age, rendering it an unreliable screening tool for this specific subgroup.

If you are a non-diabetic woman over 70, a HOMA-IR test may not accurately reflect your metabolic risk. The study suggests this test becomes unreliable in this age group. Focus on direct measures of metabolic health: monitor blood pressure, lipid profiles, waist circumference, and blood glucose directly, as these are more robust indicators for your demographic.

In nonalcoholic fatty liver disease (NAFLD), hepatic de novo fatty acid synthesis and uptake are up-regulated (increased ACC1, FAS, SREBP-1c, ADRP) despite existing fatty acid accumulation, driven by a failure of negative feedback regulation.

In NAFLD, the body's normal ability to shut down fat production when fat stores are high is broken. Instead of turning off synthesis, the liver continues to produce and take up fatty acids actively. This suggests that simply reducing dietary fat may not be sufficient if the underlying hormonal regulation (insulin/SREBP-1c) is not addressed.

Silencing estrogen receptor alpha (ERα) specifically in the ventromedial nucleus of the hypothalamus (VMN) causes metabolic syndrome in female mice and rats, characterized by obesity, hyperphagia, glucose intolerance, and reduced energy expenditure.

This research highlights the critical role of estrogen receptor alpha (ERα) in the ventromedial nucleus of the hypothalamus (VMN) in regulating energy balance. Silencing this receptor leads to metabolic syndrome, including obesity, hyperphagia, and reduced energy expenditure. While this is a preclinical study using viral vectors, it underscores the importance of hormonal signaling in the brain for maintaining healthy body weight and metabolism.

Estrogen (E2) reduces adiposity and adipocyte size independently of energy intake by down-regulating lipogenic genes (SREBP-1c, FAS, ACC-1) and up-regulating lipid oxidation pathways (PPAR-alpha, AMPK) in skeletal muscle and adipose tissue.

If you are post-menopausal or have low estrogen, you may experience increased abdominal fat storage due to metabolic changes, not just eating more. Estrogen replacement therapy can help maintain leanness by shifting your body to burn fat rather than store it, acting directly on your muscles and fat cells.

Fibrosis and inflammation significantly confound steatosis biomarkers, causing them to yield higher values in patients with advanced fibrosis or NASH even when the amount of liver fat is similar.

If your steatosis biomarker score is high, do not assume you have severe fatty liver. It may be elevated due to liver inflammation or scarring (fibrosis). These markers are not specific to fat alone.

Postdevelopmental inactivation of evolutionarily conserved essential genes (via RNAi) extends adult lifespan in C. elegans, with some inactivations extending lifespan as robustly as the strongest known regulators like daf-2.

This study in worms shows that turning down certain essential genes after adulthood can significantly extend lifespan, often through insulin-like signaling pathways. While direct application to humans is not possible, it highlights that aging is a regulated biological process influenced by conserved genetic pathways, suggesting that interventions targeting these pathways (like insulin signaling) might be viable strategies for longevity.

Colonization of germfree mice with a human-derived microbiome (HBF) significantly alters host lipid metabolism by increasing ileal tauro-conjugated bile acids, which leads to reduced plasma lipoproteins but increased hepatic triglyceride storage and glutathione depletion.

Your gut bacteria directly influence how your body handles fats. Introducing specific microbial communities can shift your bile acid profile, which in turn affects how much fat is stored in your liver versus circulating in your blood. While this study used mice, it highlights that microbiome composition is a key driver of lipid metabolism, not just diet alone.

In Type 1 Diabetes (T1D), functional impairment of beta cells occurs early in the prediabetic phase, whereas a substantial decrease in beta cell mass occurs late, close to clinical manifestation.

For T1D, preserving existing beta cell function early is as critical as replacing mass later. Treatments aiming to restore function (like those inducing the 'honeymoon phase') may be more effective if applied early, before massive cell death occurs.

Peripheral leptin action (on pancreas, muscle, liver) is not required for normal energy balance or body weight regulation in mice, as peripheral LEPRb deletion does not alter these metrics.

While leptin affects organs like the liver and muscle, its main job for weight control is signaling to the brain. Peripheral effects are secondary to the central nervous system's regulation.

Endogenous levels of DHEAS (dehydroepiandrosterone sulfate) are not clearly associated with the presence of severe aortic atherosclerosis in either elderly men or women.

For men and women over 55, your natural DHEAS levels are not a reliable indicator of whether you have severe aortic atherosclerosis. Unlike testosterone, DHEAS does not show a clear protective association with the presence of the disease. Focus on proven risk factors like blood pressure, cholesterol, and smoking status.

Differentiation of white adipocytes involves a 20- to 30-fold increase in mitochondrial protein concentration and density, indicating that mitochondrial biogenesis is a fundamental aspect of white adipose cell differentiation.

This research highlights that white fat cells are metabolically active and build significant mitochondrial capacity during differentiation. While this is a cellular mechanism rather than a direct human intervention, it suggests that promoting healthy adipose tissue differentiation may support overall metabolic health and insulin sensitivity.

Treatment with the PPAR-gamma agonist rosiglitazone increases mitochondrial density and alters mitochondrial morphology (shorter, denser profiles with lamellar cristae) in differentiated white adipocytes.

Rosiglitazone, a PPAR-gamma agonist, increases mitochondrial density and changes their structure in fat cells. This cellular remodeling may contribute to the drug's ability to improve insulin sensitivity, although its clinical use is limited by safety profiles.

Nordihydroguaiaretic acid (NDGA) extends median lifespan in male mice across multiple doses, but has no effect on female lifespan even when blood levels are matched to males.

NDGA extends the lifespan of male mice in a dose-dependent manner, but has no effect on female lifespan, even when blood levels are matched to those of males. This indicates a fundamental sex-specific difference in how NDGA affects longevity.