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Metformin

Metabolic & Circadian Hormones
GlucophageFortametRiomet

Overview

Metformin is a synthetic biguanide compound primarily used as an oral antihyperglycemic agent. It is not an endogenous hormone but is chemically synthesized and widely used in the management of type 2 diabetes mellitus. Metformin is classified under the biguanide class of compounds and is available under various brand names, including Glucophage, Fortamet, and Riomet. It is not produced naturally in the body and is administered orally. Researchers have extensively studied metformin for its role in glucose metabolism and its potential benefits in other metabolic disorders. The primary physiological role of metformin is to lower blood glucose levels, primarily by reducing hepatic glucose production and improving insulin sensitivity. Research areas include its effects on weight management, cardiovascular health, and potential anti-aging properties. Metformin's mechanism of action involves the activation of the AMP-activated protein kinase (AMPK) pathway, which plays a crucial role in cellular energy homeostasis. By activating AMPK, metformin decreases hepatic glucose production and increases insulin sensitivity in peripheral tissues. Additionally, it may influence the gut microbiota and improve glucose uptake in muscle cells. Metformin has a half-life of approximately 4 to 8.7 hours and is primarily excreted unchanged in the urine. It has a bioavailability of 50-60% when taken orally, with absorption occurring mainly in the small intestine. The drug is not metabolized by the liver, which reduces the risk of hepatic side effects. Clinically, metformin is widely used as a first-line treatment for type 2 diabetes and is approved by regulatory agencies worldwide. It is also being investigated for its potential use in polycystic ovary syndrome (PCOS) and other metabolic conditions. Metformin is generally well-tolerated, with gastrointestinal disturbances being the most common side effects. It is available by prescription and is not classified as a controlled substance.

Mechanism of Action

Metformin acts primarily through the activation of the AMP-activated protein kinase (AMPK) pathway, which leads to decreased hepatic glucose production and increased insulin sensitivity. This activation results in improved glucose uptake in peripheral tissues and reduced intestinal absorption of glucose, contributing to its antihyperglycemic effects.

Molecular Data

FormulaC4H11N5
Molecular Weight129.16 g/mol
CAS Number657-24-9
PubChem CID4091

Half-Life & Pharmacokinetics

OralApproximately 4 to 8.7 hours

Metformin is not metabolized by the liver and is excreted unchanged in the urine. Bioavailability is 50-60% when taken orally.

Storage

Temperature

Store at room temperature (15-30°C)

Light

Protect from light

Form

Tablets and oral solutions

Notes

Keep in a tightly closed container to protect from moisture.

Solubility

Metformin is highly soluble in water, which is relevant for its formulation as an oral solution or tablet.

Legal Status

🇩🇪DE

In Germany, metformin is a prescription-only medication (verschreibungspflichtig) and is not a controlled substance under the BtMG.

🇺🇸US

In the USA, metformin is FDA-approved for the treatment of type 2 diabetes and is available by prescription. It is not a controlled substance.

🇦🇺AU

In Australia, metformin is classified as a Schedule 4 (S4) prescription-only medicine by the TGA.

🇬🇧UK

In the UK, metformin is classified as a prescription-only medicine (POM) by the MHRA.

Legal status information is provided for general reference only and may not reflect the most current regulatory changes. Always verify with official government sources before making any decisions.

10 Research Publications

Update on the therapeutic role of metformin in the management of polycystic ovary syndrome: Effects on pathophysiologic process and fertility outcomes.

Review

Women's health (London, England) · 2025

Researchers observed that metformin can help manage polycystic ovary syndrome (PCOS) by improving insulin resistance, which may enhance ovulation and increase pregnancy rates. They found that combining metformin with clomifene citrate is more effective for women resistant to clomifene alone, while continuing metformin during early pregnancy may reduce miscarriage rates.

  • Metformin improves hormonal balance and increases ovulation in women with PCOS.
  • Combining metformin with clomifene citrate is more effective than either treatment alone.
  • Continuing metformin during early pregnancy may lower miscarriage rates.
PubMed

Zhimu-Huangbai herb-pair ameliorates hepatic steatosis in mice by regulating IRE1α/XBP1s pathway to inhibit SREBP-1c.

Animal

Phytomedicine : international journal of phytotherapy and phytopharmacology · 2024

Researchers observed that the Zhimu-Huangbai herb-pair significantly improved liver health in mice with non-alcoholic fatty liver disease (NAFLD) by reducing fat buildup. This effect was linked to the herb-pair's ability to regulate certain proteins involved in lipid metabolism and stress responses in liver cells.

  • Zhimu-Huangbai reduced liver fat accumulation in mice on a high-fat diet.
  • The herb-pair inhibited the production of a protein called SREBP-1c, which is involved in fat synthesis.
  • The treatment helped relieve stress in liver cells, contributing to its protective effects against NAFLD.
PubMed

Metformin: Is it a drug for all reasons and diseases?

Meta-Analysis

Metabolism: clinical and experimental · 2022

Researchers observed that metformin, originally developed for type 2 diabetes, may have potential benefits for various diseases, including cancer and neurodegenerative conditions. They found that while its primary effects are related to blood sugar control, metformin may also improve overall health and reduce disease risk through other mechanisms.

  • Metformin is primarily effective for type 2 diabetes but shows promise for other diseases.
  • It may help reduce cancer incidence and protect against neurodegenerative diseases.
  • The drug's benefits may extend beyond blood sugar control, enhancing overall health.
PubMed

Benefits of Metformin in Attenuating the Hallmarks of Aging.

Review

Cell metabolism · 2020

Researchers observed that metformin, a drug commonly used for diabetes, may help slow down the aging process by targeting various biological mechanisms associated with aging. This includes improving how cells communicate, protecting against cellular damage, and delaying the aging of stem cells, making it a promising candidate for future studies on aging.

  • Metformin improves nutrient sensing and enhances cell communication.
  • It protects against cellular damage and delays stem cell aging.
  • Metformin shows potential as a treatment to target aging in humans.
PubMed

Metformin: historical overview.

Human

Diabetologia · 2017

Researchers observed that metformin, originally derived from a traditional herbal medicine, has become the preferred treatment for type 2 diabetes due to its ability to lower blood sugar without causing weight gain or hypoglycemia. Its long-term cardiovascular benefits were recognized in the late 1990s, solidifying its role as a first-line therapy.

  • Metformin was rediscovered in the 1940s and first used for diabetes in 1957.
  • It gained popularity after being shown to have cardiovascular benefits in the UK Prospective Diabetes Study.
  • Metformin is now the most prescribed glucose-lowering medication worldwide.
PubMed

Metformin alters the gut microbiome of individuals with treatment-naive type 2 diabetes, contributing to the therapeutic effects of the drug.

Human

Nature medicine · 2017

Researchers found that metformin, a common medication for type 2 diabetes, significantly changes the gut microbiome of patients. These changes may help improve blood sugar control, as shown in experiments with mice receiving fecal samples from metformin-treated individuals. The study highlights the important role of gut bacteria in the drug's effectiveness.

  • Metformin alters the gut microbiome in individuals with type 2 diabetes.
  • These microbiome changes are linked to improved blood sugar control.
  • Experiments with mice suggest that the altered gut bacteria contribute to metformin's effects.
PubMed

Understanding and overcoming metformin gastrointestinal intolerance.

Review

Diabetes, obesity & metabolism · 2017

Researchers found that many patients with type 2 diabetes struggle to tolerate metformin due to gastrointestinal issues like diarrhea and nausea. They observed that while adjusting the dosage and exploring different formulations can help, some patients may still need alternative treatments if they cannot tolerate metformin at all.

  • Gastrointestinal side effects are common with metformin, affecting patient adherence.
  • Starting with a low dose and increasing slowly may reduce side effects.
  • Alternative therapies should be considered if metformin is not tolerated.
PubMed

Initial Combination of Empagliflozin and Metformin in Patients With Type 2 Diabetes.

Human

Diabetes care · 2016

Researchers observed that combining empagliflozin and metformin significantly lowered blood sugar levels in patients with type 2 diabetes compared to using either medication alone. They also found that this combination led to greater weight loss without increasing the risk of low blood sugar episodes. Overall, the treatment was well tolerated by participants.

  • Combination therapy reduced blood sugar levels more effectively than monotherapy.
  • Patients experienced greater weight loss with the combination treatment.
  • The treatment was well tolerated with no increased risk of hypoglycemia.
PubMed

Metformin and the gastrointestinal tract.

Review

Diabetologia · 2016

Researchers observed that metformin, a common medication for type 2 diabetes, has significant effects on the gastrointestinal tract, influencing glucose uptake and gut bacteria. They found that a new delayed-release version of metformin may improve blood sugar control with fewer side effects, suggesting that the gut plays a crucial role in how well metformin works for individuals.

  • Metformin affects glucose uptake and lactate production in the gut.
  • A new delayed-release formulation shows similar effectiveness with fewer side effects.
  • The gut's role is important in how individuals respond to metformin.
PubMed

Rosiglitazone/Metformin.

Review

Drugs · 2005

Researchers found that combining rosiglitazone and metformin is more effective at controlling blood sugar levels in people with type 2 diabetes than using metformin alone. This combination therapy was well tolerated by patients, with only a small percentage experiencing mild hypoglycemia.

  • Rosiglitazone increases insulin sensitivity, while metformin reduces glucose production in the liver.
  • The fixed-dose combination of rosiglitazone and metformin significantly lowered HbA1c and fasting plasma glucose levels compared to metformin alone.
  • The combination therapy had a similar safety profile to metformin monotherapy.
PubMed

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This page is for informational and research purposes only. All information is based on published scientific literature. Nothing on this page constitutes medical advice or replaces consultation with a qualified healthcare professional.