NSTK · 01.2026Independent supplement reference
NutriStack
Edition 1.0Updated August 1, 2026

Supplement × Prescription·Evidence index

Metformin and Vitamin D3: what the published research says

PubMed indexes 8 records that name Metformin and Vitamin D3 together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.

Read this first

An evidence index, not guidance.

Every statement below is attributed to a named, dated, linked source.

This page lists published research relevant to Metformin and Vitamin D3. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.

The research

8 studies naming Metformin and Vitamin D3.

Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.

Mitigating diabetes-related complications: Empowering metformin with cholecalciferol and taurine supplementation in type 2 diabetic rats.

World journal of diabetes · 2024 · PMID 39192867

“The supplementation of CHO and TAU with MET showed the potential to significantly improve metabolic parameters and protect against diabetic complications through its antioxidative, anti-inflammatory, and anti-apoptotic effects.”

Attia et al. · Authors' conclusion

Names both Metformin and Vitamin D3 in its title.

Efficacy of Adding Sitagliptin to Ongoing Metformin on Metabolic Profile, Triglyceride-Glucose Index, Vitamin D3, and Liver Tests in Patients Type 2 Diabetes Mellitus and Nonalcoholic Fatty Liver Disease: A Double-Blind Randomized Clinical Trial.

Current therapeutic research, clinical and experimental · 2024 · PMID 39582742

“Sitagliptin + metformin therapy led to significantly greater improvements in FBS, TC, TG, SGPT, vitD3, and TG-G compared with the metformin monotherapy group. Other biomarkers also decreased more in the sitagliptin + metformin group than in the metformin group, but these differences did not reach statistical significance.”

Yaribeygi et al. · Authors' conclusion

Names both Metformin and Vitamin D3 in its title.

Vitamin D3 potentiates the nephroprotective effects of vildagliptin-metformin combination in a rat model of metabolic syndrome.

Fundamental & clinical pharmacology · 2022 · PMID 34453360

Retracted PublicationAnimal study

“Due attention has been paid to the crucial role of dipeptidyl peptidase-4 inhibition and sirtuin-1/5' adenosine monophosphate-activated protein kinase activation as novel therapeutic targets to optimize renoprotection. The apparent potentiating effect, evoked upon coadministration of vitamin D3 with vildagliptin-metformin combination, may provide a cornerstone for further clinical investigations.”

Wahba et al. · From the abstract

Names both Metformin and Vitamin D3 in its title.

Cholecalciferol and metformin protect against lipopolysaccharide-induced endothelial dysfunction and senescence by modulating sirtuin-1 and protein arginine methyltransferase-1.

European journal of pharmacology · 2021 · PMID 34710370

Human subjects

“In silico results identified the presence of vitamin D response element (VDRE) sequence on PRMT1 suggesting that VDR could regulate PRMT1 gene expression. Further characterization of the cellular events associated with the dual compound challenge, using gene silencing approach or adenoviral constructs for SIRT1 and/or PRMT1 under inflammatory stress, could identify therapeutic strategies to address the endothelial consequences in vascular inflammation-mediated…”

Raj et al. · From the abstract

Names both Metformin and Vitamin D3 in its title.

Vitamin D3 potentiates the nephroprotective effects of metformin in a rat model of metabolic syndrome: role of AMPK/SIRT1 activation and DPP-4 inhibition.

Canadian journal of physiology and pharmacology · 2021 · PMID 33108744

Animal study

“The study has verified the nephroprotective effects of metformin and vitamin D3 in MetS, accentuating the critical role of AMP-activated protein kinase/sirtuin-1 activation and dipeptidyl peptidase-4 inhibition. Given the synergistic effects of the combination, vitamin D3 is worth being investigated as an additional therapeutic agent for preventing MetS-induced nephropathy.”

Wahba et al. · From the abstract

Names both Metformin and Vitamin D3 in its title.

Vitamin D3 enhances antitumor activity of metformin in human bladder carcinoma SW-780 cells.

Die Pharmazie · 2015 · PMID 25997253

Human subjects

“Vitamin D3 combined with metformin exhibited obvious inhibitory effects on the cell proliferation and apoptosis induction in SW-780 cells. The underlying anti-tumor mechanism might be related to inhibiting the expressions of p-Bcl-2, Cyclin D1, c-Myc, p-IGF-IR, p-mTOR, p-P70S6K, p-S6 and activating the expression of Bax.”

Guo et al. · Authors' conclusion

Names both Metformin and Vitamin D3 in its title.

Limitations

What this evidence cannot tell you.

Search-based evidence indexes have real limits, and it is worth being explicit about them:

NutriStack

Track what you actually take.

NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Metformin, Vitamin D3, and several hundred other substances.

The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.

NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.