Metformin

For an informed discussion with your doctor or pharmacist. This information collection is not a clinically validated interaction checker. Missing data do not establish safety. Do not change or stop prescribed medicines on the basis of this information. The findings apply to the specific conditions studied; laboratory and animal studies cannot be directly extrapolated to humans.

Active substance: Metformin

Examples of brand names: Glucophage [DE]

ATC code: A10BA02

Main use (for orientation): Type 2 diabetes

Documented research summary

Direct combinations of metformin with CBD or THC were investigated in human skin fibroblasts (PMID 35955938): model- and endpoint-dependent changes in cell viability and wound closure, not clinical glucose or hypoglycaemia evidence. Many animal papers compare metformin only as a separate control arm. The clinical diabetes source Jadoon 2016 cited in review PMID 41633759 was cross-checked in the freely accessible author manuscript: CBD had no effect on glycaemic parameters; the trial and its mixed diet/metformin subgroup do not isolate a metformin interaction. This citation cannot establish clinically proven CBD–metformin hypoglycaemia.

Uncertainties and limitations

The diabetes RCT allowed various stable antidiabetic medicines or diet. THCV effects in a post-hoc diet/metformin subgroup are not an isolated metformin pair effect. Cell concentrations cannot be extrapolated as patient doses.

Missing data do not establish safety. Research is limited by the documented sources, search terms, languages and accessibility.

Separately recorded findings

2 separately recorded findings. Each statement applies to its documented study context.

CBD – laboratory and animal studies

Finding ID: B0431

Type of result: Preclinical endpoint

Observation: After 5 days, metformin/CBD reduced MTT viability of healthy cells. No significant wound-closure advantage over vehicle in senescent cells.

Mechanism: Model-dependent pharmacodynamic endpoints in healthy or stress-induced senescent human skin fibroblasts; no pharmacokinetic mechanism assessed.

Study type: Original in vitro study

Context studied: CCD-1064Sk cells; metformin 500 µM, CBD 2 µM. MTT/neutral-red/scratch assays with different exposure durations.

Clinical interpretation: Clinical significance unresolved

Limitations and uncertainties: Not a glucose/hypoglycaemia interaction or clinical anti-ageing effect; comparison with vehicle does not automatically establish an interaction relative to both individual substances.

Original sources for this finding: The Effects of Nutrient Signaling Regulators in Combination with Phytocannabinoids on the Senescence-Associated Phenotype in Human Dermal Fibroblasts. [VD_MED_35955938]

THC – laboratory and animal studies

Finding ID: B0432

Type of result: Preclinical endpoint

Observation: Metformin/THC reduced MTT viability of healthy cells after 5 days; the neutral-red endpoint also changed. No significant wound-closure advantage over vehicle in senescent cells.

Mechanism: Model-dependent pharmacodynamic endpoints in human skin fibroblasts; no clinical pharmacokinetics assessed.

Study type: Original in vitro study

Context studied: CCD-1064Sk; metformin 500 µM, THC 2 µM. The triple arm with CBD is a separate exposure context, not equivalent to the THC individual pair.

Clinical interpretation: Clinical significance unresolved

Limitations and uncertainties: In-vitro endpoints, not a clinical hypoglycaemia or skin-treatment claim. Different assays and comparator groups limit interpretation.

Original sources for this finding: The Effects of Nutrient Signaling Regulators in Combination with Phytocannabinoids on the Senescence-Associated Phenotype in Human Dermal Fibroblasts. [VD_MED_35955938]

References and access status

[VD_LABEL_D0241] METFORMIN HYDROCHLORIDE (METFORMIN) TABLET, FILM COATED, EXTENDED RELEASE [MYLAN PHARMACEUTICALS INC.] – DailyMed SPL

Original source / bibliographic reference

Authors: Marketing authorisation holder / label provider according to the linked DailyMed product information

Year: 2026

Source type: Regulatory product information (US SPL)

Source access – 23 October 2026: Source destination was accessible when checked.

Bibliographic attribution or source identity cross-checked.

[VD_MED_35955938] The Effects of Nutrient Signaling Regulators in Combination with Phytocannabinoids on the Senescence-Associated Phenotype in Human Dermal Fibroblasts.

Original source / bibliographic reference

Authors: Gerasymchuk M, Robinson GI, Kovalchuk O, Kovalchuk I.

Year: 2022

Source type: research-article; Journal Article

DOI: 10.3390/ijms23158804

PMID: 35955938

Source access – 23 October 2026: Automated direct retrieval was restricted; this does not establish that the link is broken.

Bibliographic attribution or source identity cross-checked.

PubMed – bibliographic reference / abstract

PubMed Central – full-text access according to the literature database – Archive attribution confirmed by Europe PMC metadata. Direct retrieval was not fully verified here; access may require a browser check.

Europe PMC – full-text access according to the literature database – Listed as freely available HTML full text in the official Europe PMC metadata. Direct retrieval was not fully verified here.

[VD_MED_41633759] Cannabinoids and drug-drug pharmacokinetic interactions: Deciphering the risks.

Original source / bibliographic reference

Authors: Papakyriakopoulou P, Valsami G, Ismailos G.

Year: 2026

Source type: review-article; Review; Journal Article

DOI: 10.1002/bcp.70430

PMID: 41633759

Source access – 23 October 2026: Automated direct retrieval was restricted; this does not establish that the link is broken.

Bibliographic attribution or source identity cross-checked.

PubMed – bibliographic reference / abstract

PubMed Central – full-text access according to the literature database – Archive attribution confirmed by Europe PMC metadata. Direct retrieval was not fully verified here; access may require a browser check.

Europe PMC – full-text access according to the literature database – Listed as freely available HTML full text in the official Europe PMC metadata. Direct retrieval was not fully verified here.

[VD_PRIMARY_JADOON2016] Efficacy and Safety of Cannabidiol and Tetrahydrocannabivarin on Glycemic and Lipid Parameters in Patients With Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled, Parallel Group Pilot Study

Original source / bibliographic reference

Authors: Jadoon KA; Ratcliffe SH; Barrett DA; Thomas EL; Stott C; Bell JD; O'Sullivan SE; Tan GD

Year: 2016

Source type: Randomised placebo-controlled pilot study; accepted author manuscript

DOI: 10.2337/dc16-0650

Source access – 23 October 2026: Automated direct retrieval was restricted; this does not establish that the link is broken.

Bibliographic attribution or source identity cross-checked.

PubMed – bibliographic reference / abstract

Research as of 23 October 2026. Not all original full texts could be reviewed in full. Source accessibility and the strength of scientific evidence must be assessed separately. An accessible link does not establish medical approval; a bibliographic record with an abstract does not replace the original full text.

Drug search and explanation of the evidence · Guide: cannabinoids and medicines · Author and responsibility