What kind of interaction is it?

Synergy: a documented combination effect that is stronger or more useful than either substance taken alone.

Is this interaction backed by published research?

Yes. NutriStack lists 2 citation rows for the Insulin Glargine + Vitamin D3 pair, each linking to PubMed by PMID where available. Full sourcing methodology at https://nutristackapp.com/methodology/interactions.

Interaction databaseSupplement × PrescriptionReviewed May 2026

Insulin Glargine and Vitamin D3, a synergy.

Q: Can I take Insulin Glargine and Vitamin D3 together?

Yes. The combination of Insulin Glargine and Vitamin D3 produces a measurable benefit. Vitamin D deficiency is associated with insulin resistance. Repleting low 25-OH vitamin D can modestly improve insulin sensitivity and lower HbA1c in type 2 diabetes. In patients on insulin glargine, this is mostly beneficial and is unlikely to cause hypoglycemia, though basal insulin requirements may fall modestly over weeks to months.

Q: How does this affect a NutriStack Stack Score?

+2 to your Stack Score per scored synergy row.

Vitamin D deficiency is associated with insulin resistance. Repleting low 25-OH vitamin D can modestly improve insulin sensitivity and lower HbA1c in type 2 diabetes. In patients on insulin glargine, this is mostly beneficial and is unlikely to cause hypoglycemia, though basal insulin requirements may fall modestly over weeks to months.

2 primary source citations. Moderate evidence. Last verified May 30, 2026.

Open the interaction checker →Read the methodology

One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.

Sourcing standards·Evidence tiers

From the interaction database

What the row says.

Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.

At a glance

Substances: Insulin Glargine and Vitamin D3
Pair type: Synergy
Evidence (highest tier): Moderate
Source citations: 2 sources
Stack Score effect: +2 to your Stack Score (per scored synergy row).
Scope: Supplement × Prescription
Last verified: May 30, 2026

Synergy · Moderate evidence

Synergy

What is happening. Vitamin D deficiency is associated with insulin resistance. Repleting low 25-OH vitamin D can modestly improve insulin sensitivity and lower HbA1c in type 2 diabetes. In patients on insulin glargine, this is mostly beneficial and is unlikely to cause hypoglycemia, though basal insulin requirements may fall modestly over weeks to months.

Mechanism. Vitamin D modulates insulin signaling via vitamin D receptors on insulin target tissues and pancreatic beta cells and reduces low-grade inflammation that contributes to insulin resistance. Insulin glargine provides 24-hour basal insulin receptor activation. Improved insulin sensitivity gradually reduces basal insulin requirements.

Recommendation. If your 25-OH vitamin D is low (<30 ng/mL), supplementation alongside insulin glargine is reasonable. Continue routine fingerstick monitoring; if you notice fasting lows over weeks to months, ask your prescriber whether your glargine dose should be reduced.

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both Insulin Glargine and Vitamin D3 are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).

The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.

Check your full routine

One pair was the worked example. NutriStack runs every pair in your stack at once.

Drop in your supplements and prescriptions and the public database surfaces every interaction, synergy, timing rule, and contraindication, every one linked to its primary source.

Open the interaction checker →Browse the full research index