Can I take Selenium and Vitamin C together?

Yes, if you separate them in time. Selenium and Vitamin C have a documented timing-sensitive interaction. High-dose vitamin C may reduce selenite to elemental selenium, which is not absorbable. Does not affect selenomethionine forms.

What kind of interaction is it?

Timing-sensitive: the two substances can be taken on the same day but should be separated by a minimum time window.

Is this interaction backed by published research?

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

Interaction databaseSupplement × SupplementReviewed May 2026

Selenium and Vitamin C, timing-sensitive.

Q: How does this affect a NutriStack Stack Score?

-5 to your Stack Score per scored timing-sensitive row.

High-dose vitamin C may reduce selenite to elemental selenium, which is not absorbable. Does not affect selenomethionine forms.

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: Selenium and Vitamin C
Pair type: Timing Sensitive
Evidence (highest tier): Moderate
Source citations: 2 sources
Stack Score effect: −5 to your Stack Score (per scored timing-sensitive row).
Scope: Supplement × Supplement
Last verified: May 30, 2026

Timing Sensitive · Moderate evidence

Timing Sensitive

What is happening. High-dose vitamin C may reduce selenite to elemental selenium, which is not absorbable. Does not affect selenomethionine forms.

Mechanism. Ascorbic acid reduces selenite (SeO3²⁻) to elemental Se(0) in the GI tract, rendering it insoluble and unabsorbable. Selenomethionine is absorbed via methionine transporters, unaffected by redox.

Recommendation. If using sodium selenite form, separate from high-dose vitamin C by 2 hours. Selenomethionine is unaffected.

Minimum separation. 120

Sources (2)

Stack Score

How this pair moves the number.

Effect on the composite score

If both Selenium and Vitamin C are in the same stack, this pair applies −5 to your Stack Score (per scored timing-sensitive 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