Diabetes

Serotonin (5-hydroxytryptamine or 5-HT) is a neurotransmitter and hormone that plays a crucial role in blood sugar regulation, insulin sensitivity, and gut function. There is growing evidence linking serotonin imbalance to both Type 1 and Type 2 diabetes, insulin resistance, and metabolic disorders like PCOS.

How does Serotonin Affect Blood Sugar and Insulin?

• Serotonin influences blood glucose control in three major ways:

• Regulating Insulin Secretion from the Pancreas

• Beta cells (in the pancreas) produce insulin, which helps lower blood sugar.

• Serotonin is stored inside beta cells and plays a role in insulin release.

• Low serotonin = Reduced insulin secretion, leading to high blood sugar and insulin resistance.

Controlling Insulin Sensitivity in the Muscles & Liver

• • Serotonin improves insulin sensitivity, meaning cells can use glucose efficiently.

• • If serotonin is low, insulin resistance develops, making blood sugar levels harder to control.

Appetite and Cravings Regulation

• Serotonin regulates hunger and sugar cravings through the brain’s hypothalamus.

• Low serotonin leads to cravings for sugary and high-carb foods, worsening blood sugar spikes.

• People with PCOS, insulin resistance, or diabetes often experience serotonin imbalances, leading to poor appetite control.

Condition	Serotonin Effect	Impact on Blood Sugar
Low Serotonin	Poor insulin secretion, increased stress, cravings for sugar	Higher blood sugar, increased insulin resistance
High Serotonin	Increased insulin sensitivity, improved gut function	Lower blood sugar (but excessive serotonin may cause hypoglycemia)
Fluctuating Serotonin	Irregular appetite and energy metabolism	Unstable blood sugar, increased diabetes risk

People with diabetes or prediabetes tend to have low or unstable serotonin levels, which worsen blood sugar control.

The Gut-Serotonin-Blood Sugar Connection

• Since 95% of serotonin is made in the gut, gut health plays a huge role in managing blood sugar and insulin resistance.

Dysbiosis (Imbalance in Gut Bacteria) and Diabetes

• Unhealthy gut bacteria lower serotonin levels, increasing insulin resistance.

• Inflammation in the gut disrupts serotonin production, leading to metabolic issues.

Serotonin and GLP-1 (Glucagon-Like Peptide-1)

• GLP-1 is a gut hormone that regulates blood sugar and insulin sensitivity.

• Serotonin enhances GLP-1 secretion, improving glucose control.

• Diabetes medications like Ozempic and Trulicity mimic GLP-1, showing how serotonin pathways affect blood sugar.

Medications and Their Effect on Serotonin & Blood Sugar

• SSRIs (Selective Serotonin Reuptake Inhibitors) and Blood Sugar

• Some antidepressants (SSRIs like fluoxetine, sertraline) improve insulin sensitivity and lower blood sugar.

• However, in some cases, SSRIs may increase cravings for carbs, leading to unstable blood sugar.

Metformin and Serotonin

• Metformin (a common diabetes drug) increases serotonin receptor sensitivity.

• This may help reduce cravings and stabilize mood, improving blood sugar control.

Insulin Therapy & Serotonin Interactions

• Insulin increases tryptophan uptake, which helps serotonin production.

• However, excessive insulin levels (from insulin resistance) may disrupt serotonin signaling.

Diabetes

diabetes (especially type 2 diabetes) and noradrenaline (norepinephrine) is strongly intertwined, as noradrenaline affects insulin secretion, glucose metabolism, vascular tone, and even inflammation — all of which are key players in diabetes development and complications.

Let’s dive into how noradrenaline both influences and is influenced by diabetes in a complete, science-backed way.

Noradrenaline & Diabetes: A Deep Connection

Noradrenaline & Insulin Secretion

• Noradrenaline acts on alpha-2 adrenergic receptors in pancreatic β-cells, where it:

• Inhibits insulin secretion

• This is part of the "fight-or-flight" response: your body wants to raise blood sugar to fuel muscles quickly.

• In diabetes, especially type 2:

• Chronic noradrenaline overactivity (due to stress or sympathetic overdrive) can suppress insulin, worsen hyperglycemia, and promote insulin resistance.

2. Noradrenaline & Insulin Resistance

• Noradrenaline increases glucose output from the liver via gluconeogenesis and glycogenolysis.

• It also reduces glucose uptake in skeletal muscle and promotes lipolysis, which raises free fatty acids (FFA)—a major contributor to insulin resistance.

End result: Persistent high noradrenaline = insulin resistance = elevated blood sugar.

Autonomic Nervous System (ANS) Dysfunction in Diabetes

• Many diabetics (especially long-term type 2 or type 1) develop diabetic autonomic neuropathy.

• Reduced sympathetic and parasympathetic tone

• Blunted noradrenaline release, especially in response to low blood sugar (hypoglycemia)

This makes them less responsive to hypoglycemia, increasing the risk of dangerous lows—called hypoglycemia unawareness.

• Diabetes is associated with chronic stress, which:

• Activates the hypothalamic-pituitary-adrenal (HPA) axis

• Activates the hypothalamic-pituitary-adrenal (HPA) axis

• Promotes central obesity, inflammation, and insulin resistance

o Promotes central obesity, inflammation, and insulin resistance

• Noradrenaline contributes to low-grade inflammation by stimulating the production of pro-inflammatory cytokines like IL-6 and TNF-α.

• Chronic inflammation worsens beta-cell function and insulin signaling, both central to type 2 diabetes.

Diabetes, especially type 2, is not just about sugar—it's about hormonal miscommunication within the body. Several key hormones, including Adrenaline, GABA, DHEA, and Cortisol, significantly influence blood sugar regulation, insulin sensitivity, and metabolic balance. When these hormones are disrupted, they can drive the development or worsening of insulin resistance and diabetes.

Adrenaline

Adrenaline, the body’s acute stress hormone, triggers a rise in blood sugar by stimulating glucose release from the liver. While helpful in emergencies, chronic adrenaline surges—from ongoing stress, lack of sleep, or anxiety—lead to persistent high blood sugar levels, worsening insulin resistance and making diabetes harder to control.

GABA (Gamma-aminobutyric acid)

GABA is a calming neurotransmitter that also plays a role in insulin secretion. Low GABA levels are linked to reduced pancreatic function, impaired insulin release, and increased blood sugar variability. GABA also supports emotional regulation, and low levels often lead to stress eating or poor dietary habits that worsen diabetic symptoms.

DHEA (Dehydroepiandrosterone)

DHEA helps counteract the effects of cortisol and supports insulin sensitivity. Low DHEA levels are associated with increased visceral fat, inflammation, and impaired glucose metabolism—all of which are core drivers of insulin resistance. Optimizing DHEA can support better metabolic function and blood sugar control.

Cortisol

Cortisol, your body’s main stress hormone, has a powerful impact on blood sugar. When cortisol is consistently high—due to emotional stress, sleep disruption, or overexercising—it signals the liver to release more glucose. Over time, this leads to chronically elevated blood sugar and insulin resistance, both hallmarks of diabetes.