Does metformin contain pork or any pork-derived ingredients?

Short Answer

Most metformin tablets do not contain pork or pork‑derived ingredients; they are generally made with synthetic or plant‑based excipients like cellulose, hypromellose, povidone, silica, magnesium stearate, and film‑coating agents. ^{[1] [2]} Some specialized combination kits or capsule products may include gelatin, which is typically animal‑derived, but standard metformin tablets themselves are usually gelatin‑free. ^[3]

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What’s in Metformin? (Active vs. Inactive)

• Active ingredient: Metformin hydrochloride (the glucose‑lowering component). ^[1]
• Inactive (excipients): These help form the tablet, control release, and protect stability; common ones in metformin tablets include:
  • Cellulose derivatives (microcrystalline cellulose, hypromellose/HPMC, ethylcellulose). ^{[1] [4]}
  • Polymers for extended release (ammonio methacrylate copolymers). ^[1]
  • Povidone (binder), corn starch (filler), silicon dioxide (flow agent). ^{[2] [1]}
  • Magnesium stearate (lubricant) and coating components like talc and titanium dioxide. ^[1]
    These are not pork‑derived. ^{[1] [2]}

Several official labels for metformin extended‑release tablets list excipients such as ammonio methacrylate copolymers, hypromellose, magnesium stearate, and silicon dioxide; none of these are pork products. ^[1] Other labels list cellulose, povidone, and corn starch again, not pork‑derived. ^[2]

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Gelatin and Metformin: Important Nuance

• Standard metformin tablets (immediate or extended‑release): Typically do not use gelatin in the tablet core or coating. ^{[1] [4] [5] [6]}
• Combination kits or capsule formats: Some products packaged as kits or using capsule shells may list gelatin among inactive ingredients, and pharmaceutical gelatin is generally animal‑derived (often bovine or porcine unless specified). ^[3]

A representative metformin‑tyrosine kit lists gelatin as an inactive component, highlighting that non‑tablet forms and certain kits can include animal‑derived gelatin. ^[3] Many tablets avoid gelatin entirely by relying on cellulose‑based matrices and polymer coatings. ^{[1] [4]}

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Examples from Official Labels

Common metformin tablet excipients (no pork)

• Ammonio methacrylate copolymers, hypromellose, silicon dioxide, magnesium stearate, dibutyl sebacate (ER film polymer/plasticizer system). ^[1]
• Lactose monohydrate, microcrystalline cellulose, ethylcellulose, stearic acid, oleic acid in some film‑coated ER tablets. ^[4]
• Povidone, corn starch, hypromellose, polyethylene glycol in immediate‑release tablets. ^[2]

These labels do not list gelatin or any pork‑derived ingredients. ^{[1] [4] [2]}

Product that does include gelatin (not a standard tablet)

• A metformin hydrochloride/tyrosine kit lists gelatin among inactive ingredients. ^[3]

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Practical Guidance for Pork‑Free Needs

• Ask for “tablet” formulations: Immediate‑release or extended‑release tablets from common manufacturers are generally pork‑free, as they rely on cellulose and synthetic polymers rather than gelatin. ^{[1] [4]}
• Avoid capsule products or kits if uncertain: Capsule shells often use gelatin unless labeled vegetarian (e.g., HPMC capsules). The metformin‑tyrosine kit is an example that contains gelatin. ^[3]
• Verify the specific product label: Metformin is produced by multiple manufacturers, and excipients can vary; checking the exact label ensures alignment with dietary or religious requirements. ^{[1] [4] [2]}
• If gelatin is a concern, request vegetarian alternatives: Many metformin tablets already meet this need; if a capsule is the only option, ask for HPMC (vegetarian) capsules explicitly. ^{[1] [4]}

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Summary Table: Typical Excipients by Metformin Product Type

Product type	Example inactive ingredients (typical)	Gelatin listed?	Notes
Immediate‑release tablet	Povidone, corn starch, hypromellose, polyethylene glycol, magnesium stearate	No	Standard tablets; excipients are synthetic/plant‑based. [2]
Extended‑release tablet (polymer matrix)	Ammonio methacrylate copolymers, hypromellose, silicon dioxide, magnesium stearate, dibutyl sebacate	No	Common ER systems; no pork‑derived components listed. [1]
Film‑coated ER tablet	Lactose monohydrate, microcrystalline cellulose, ethylcellulose, stearic acid, oleic acid, silicon dioxide	No	Film coat uses cellulose/plant/synthetic agents. [4]
Kit/capsule product	Gelatin, silicon dioxide, magnesium stearate (plus actives)	Yes	Gelatin is animal‑derived unless specified vegetarian. [3]

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Bottom Line

Based on multiple official labels, standard metformin tablets (both immediate‑release and extended‑release) do not list pork or pork‑derived ingredients and typically do not contain gelatin. ^{[1] [4] [2]} However, certain kits or capsule products associated with metformin can include gelatin, which is animal‑derived, so it’s best to verify the specific product’s label. ^[3]