Active substance: Metformin Hydrochloride
Active life: ~6–12 hours (extended-release formulations may last up to 24 hours)
Detection time: Not commonly tested in standard anti-doping screenings; generally undetectable in performance-enhancing drug panels.

Metformin Hydrochloride is a widely used oral antidiabetic drug, primarily prescribed to manage type 2 diabetes by improving insulin sensitivity and reducing hepatic glucose production. In the bodybuilding and performance-enhancement context, it has gained attention for its potential benefits in improving nutrient partitioning, reducing fat gain during bulking phases, and enhancing metabolic efficiency.

Although not anabolic, Metformin can indirectly support physique goals by enhancing insulin sensitivity, which facilitates better glucose uptake into muscle cells and reduces the likelihood of excess carbohydrate storage as fat. This makes it particularly appealing for athletes undergoing high-calorie bulking cycles or using insulin and growth hormone (GH) to maximize muscle gain.

Some bodybuilders also incorporate it during cutting phases to assist with fat loss, as Metformin may help lower insulin levels, promote lipolysis, and improve overall metabolic flexibility. Additionally, the drug’s activation of AMPK can provide benefits related to mitochondrial health, endurance, and even potential longevity effects.

How to use:

Metformin Hydrochloride is commonly used during bulking cycles to reduce fat accumulation or during cutting cycles to aid in fat loss and improve insulin control. It is also sometimes paired with exogenous insulin or GH to modulate their metabolic effects more favorably.

Common dosage:
500 mg to 1,500 mg per day, typically split into two or three doses to improve gastrointestinal tolerance. Starting at a low dose (e.g., 500 mg/day) is advised to assess individual response and minimize gastrointestinal discomfort.

Important considerations:

• Should be taken with meals to reduce gastrointestinal side effects (nausea, bloating, diarrhea).

• Extended-release (XR) versions may improve tolerability and provide a more steady effect.

• Long-term use may reduce Vitamin B12 absorption — periodic monitoring or supplementation is recommended.

• Not suitable for individuals with impaired kidney function due to the risk of lactic acidosis.

Metformin Hydrochloride is not a fat burner or stimulant, but rather a metabolic regulator. Its role is to improve insulin sensitivity, which, when paired with a balanced diet and training, can help optimize body composition.