Metformin
Also known as: Glucophage, Met
Classic antidiabetic drug discussed off-label in the biohacking space for its possible effects on insulin sensitivity and longevity.
Substance family
Medications for blood pressure, lipids and glucose. They appear here because these are exactly the markers most anabolic compounds push in the wrong direction.
Effects on
Which outcomes this substance acts on — descriptive, not a recommendation.
Strain profile
Where this substance is most likely to hit — a rough orientation, individually dependent on dose, duration and predisposition.
This substance works against
Dosing & protocols by goal
Rough orientation ranges as reported in harm-reduction literature — not an individual treatment plan. Doses are individual and open-ended; frequency depends on the ester or half-life.
Insulin sensitivity / metabolism
Off-labelDose
500–2000 mg / day
Frequency
1–3× / day with meals
Cycle length
Ongoing or in phases
TitratingTitratingAdjusting a dose stepwise against a measured result rather than setting it in advance. up slowly clearly reduces gastrointestinal side effects.
Longevity (discussion)
ExperimentalDose
500–1500 mg / day
Frequency
1–2× / day
Cycle length
Ongoing
Benefit in metabolically healthy people is disputed; possible blunting of training adaptations.
Side effect & countermeasure
Typical problems and what you can do to reduce harm — at a glance. Does not replace medical monitoring.
Problem
Gastrointestinal complaints (especially at the start)
Countermeasure
TitrateTitrateAdjusting a dose stepwise against a measured result rather than setting it in advance. up slowly and take with meals; consider an extended-release form.
Problem
Vitamin B12 deficiency with long-term use
Countermeasure
Check B12 annually and supplement if needed.
Problem
Lactic acidosis risk with impaired kidney function
Countermeasure
Check kidney values (eGFReGFRAn estimate of kidney filtration performance, calculated from creatinine.) before starting and regularly; pause before contrast-agent examinations.
Overview
Metformin has been the most-prescribed oral antidiabetic worldwide for decades and is considered well-studied and comparatively safe when used as intended. In the biohacking and longevity space, it is increasingly discussed off-label — that is, outside its actually approved indication.
Mechanism of Action
Metformin primarily reduces hepatic glucose production (gluconeogenesis in the liver) and improves peripheral insulin sensitivity. In addition, activation of the enzyme AMPK is discussed, which plays a central role in cellular energy metabolism and is part of the hypothesis for why metformin is studied in longevity research (including the TAME trial).
Typical Context
Off-label, metformin is occasionally discussed to support insulin sensitivity during diet/bulking phases and in the longevity context. Important: in people without diagnosed insulin resistance, the benefit is scientifically far less clearly established than in diabetics, and a possible negative influence on training adaptations (especially strength training/hypertrophy) is controversially discussed in research.
Side Effects & Risks
- Common: gastrointestinal complaints (nausea, diarrhea), especially at the start
- Vitamin B12 deficiency possible with long-term use
- Very rare but serious: lactic acidosis, especially with impaired kidney function
- Possible blunting of training adaptations when combined with intense strength training (evidence is inconsistent)
- Contraindicated with severely impaired kidney function and before certain contrast-agent examinations
Blood Work & Monitoring
- Kidney function (eGFR, creatinine) – before starting and regularly during use
- Vitamin B12 – recommended annually with long-term use
- HbA1c / fasting glucose – to assess metabolic status
- Liver values – useful as a complement
Harm-Reduction Notes
- Taking it with meals noticeably reduces gastrointestinal side effects
- Have kidney function checked before starting, especially when combined with other medications
- Off-label use without a diagnosed metabolic disorder should be critically weighed with a physician, including possible negative effects on training adaptation
Legal status by region
Regulation differs considerably between jurisdictions and changes over time. This is a rough orientation, not legal advice — check the rules that apply where you are.
| Region | Regulatory status |
|---|---|
| United States | Prescription-only medicineApproved for defined indications; use outside them is off-label. |
| EU / UK | Prescription-only medicineApproved for defined indications. |
| Canada / Australia | Prescription-only medicine |
| Parts of Asia, Latin America & Middle East | Pharmacy availability variesSeveral countries dispense it without prescription in practice. Rules and enforcement differ and change. |
| Competitive sport | Check the current WADA listSome substances in this class are prohibited, others are not. |