Research

Hormonal

High serum leptin levels (>25-30 ng/mL) saturate the blood-brain barrier transport system, preventing leptin from entering the brain and thereby contributing to leptin resistance.

In obesity, the body produces so much leptin that it clogs the 'door' (blood-brain barrier) through which the hormone enters the brain. This saturation point means the brain stops receiving the 'full' signal, perpetuating hunger and weight gain. Reducing body fat may help lower leptin levels, potentially restoring the efficiency of this transport system.

GoodSupportsHIGH confidence
At serum leptin levels above the range of 25–30 ng/mL, the concentration of leptin in brain tissues and cerebrospinal fluid does not increase. This phenomenon likely plays a role in the development of leptin resistance and obesity, where excessive levels of leptin in the blood result in decreased BBB permeability.
О. В. Груздева et al. · Diabetes Metabolic Syndrome and Obesity · 2019

Why this rating

Cites specific studies on BBB transport saturation in obese individuals.

Source

<p>Leptin resistance: underlying mechanisms and diagnosis</p>

О. В. Груздева et al. · Diabetes Metabolic Syndrome and Obesity · 2019

DOI 10.2147/dmso.s182406

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DOI resolved against Crossref · corpus check 2026-06-10

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