Browse evidence-based analysis of health-related claims and assertions
Turning off insulin signals in the back part of the liver cuts fat without making the body pump out more insulin.
Descriptive
The liver isn’t the same all the way through—different parts react differently when insulin stops working, leading to very different outcomes for fat and sugar.
When the front part of the liver can't respond to insulin, blood sugar goes up—even if the liver makes less fat.
When the front part of the liver doesn’t respond to insulin, the body makes more insulin to try to compensate.
Turning off insulin signals in the back part of the liver doesn’t make blood sugar go up, even when the mouse eats a high-fat diet.
The front part of the liver needs insulin to make fat when the mouse eats a lot of fat—without it, fat production drops.
Mechanistic
When insulin doesn't work in the back part of the liver, the muscles start using more sugar instead, which helps keep blood sugar levels normal.
Blocking insulin signals in the other part of the liver (pericentral zone) cuts down fat buildup in that area without raising blood sugar, even when the mouse eats a high-fat diet.
When the part of the liver that usually responds to insulin is blocked, the liver makes less fat even when the mouse eats a high-fat diet—but its blood sugar and insulin go up instead.
Combinatorial targeting of adipose tissue mobilization (via GHRH/IGF-1) and mitochondrial fuel utilization (via AMPK) produces synergistic metabolic benefits beyond additive effects.
Assertion
MOTS-c activates AMP-activated protein kinase (AMPK), leading to improved glucose uptake, insulin sensitivity, and metabolic efficiency independent of growth hormone signaling.
Tesamorelin upregulates nuclear-encoded genes involved in mitochondrial oxidative phosphorylation and fatty acid β-oxidation.
Increased IGF-1 levels are associated with enhanced mitochondrial oxidative capacity, as measured by phosphocreatine recovery kinetics following exercise.
Tesamorelin increases cross-sectional area and density of trunk skeletal muscles while reducing intramyocellular lipid infiltration.
Reduction in adipose tissue volume is accompanied by increased adipocyte density, reflecting smaller adipocyte size, improved vascularization, reduced hypoxia, and decreased local inflammation.
Hepatic lipid accumulation impairs insulin signaling and glucose metabolism, acting as a primary driver of systemic insulin resistance.
Administration of tesamorelin results in a statistically significant reduction in visceral adipose tissue volume compared to placebo, with a mean reduction of approximately 11% after 6 months of treatment.
Quantitative
Tesamorelin, a growth hormone-releasing hormone (GHRH) analog, stimulates endogenous growth hormone secretion from the pituitary gland in a pulsatile, physiologically regulated manner.
Visceral adipose tissue is metabolically active and secretes pro-inflammatory cytokines that impair insulin signaling in liver, muscle, and brain tissues.
Instead of just saying ‘obese’ or ‘not obese,’ the study looked at how even small increases in belly fat measures were linked to higher depression risk — giving a more detailed picture.
There could be other hidden factors — like diet, stress, or sleep — that make both belly fat and depression more likely, so we can’t be sure the fat itself is causing the mental health issues.
Because everyone in the study was Taiwanese, we can’t be sure these results apply to people from other countries or cultures — especially since body shape and how people talk about mental health can be very different.
We can’t tell if belly fat leads to depression, depression leads to weight gain, or if both happen together — because this study only looked at people at one point in time.
Even after accounting for age, smoking, exercise, and other health problems, belly fat still links to depression and anxiety — meaning the connection isn’t just because of other health issues.
Correlational