Supplement·Interactions·Reviewed June 9, 2026
Soy Isoflavones interactions.
Soy Isoflavones has 4 documented interactions in the NutriStack database: 2 that need timing or caution and 2 that work synergistically. The full list, with what each pairing does, is below.
Soy Isoflavones at a glance.
A quick, data-grounded summary. The full table is below.
Soy Isoflavones has 4 documented interactions in the NutriStack database: 2 that need timing or caution and 2 that work synergistically. The full list, with what each pairing does, is below.
Everything that interacts with soy isoflavones.
Every supplement and medication in the NutriStack database with a documented interaction with this substance, highest-severity first. Open any pair for the mechanism and sources.
| Substance | Interaction | What happens |
|---|---|---|
| Iron | Timing Sensitive | Soy foods and phytates can reduce non-heme iron absorption when taken together with iron supplements. |
| Levothyroxine | Timing Sensitive | Soy isoflavones (genistein and daidzein) can reduce levothyroxine absorption by binding to the medication in the gastrointestinal tract, forming... details → |
| Calcium | Synergy | Calcium adequacy supports bone-health goals often paired with soy isoflavones. |
| Vitamin D3 | Synergy | Vitamin D sufficiency supports calcium absorption and bone remodeling. |
The full soy isoflavones profile.
Benefits, dosing by goal, forms, and the cited evidence for this supplement.
Common soy isoflavones questions.
Quick answers drawn from the table above.
What interacts with Soy Isoflavones?
In the NutriStack database, Soy Isoflavones has 4 documented interactions with other supplements and medications. The most notable include Iron, Levothyroxine, Calcium, and Vitamin D3.
What works well with Soy Isoflavones?
Soy Isoflavones pairs synergistically with Calcium and Vitamin D3 in the NutriStack database. Synergy still depends on dose and timing; open any pair for the detail.
Can you take Soy Isoflavones with Iron?
NutriStack classifies the Soy Isoflavones and Iron pairing as timing sensitive: Soy foods and phytates can reduce non-heme iron absorption when taken together with iron supplements. Separate iron supplements from soy-heavy meals or soy isoflavone products by at least 2 hours when treating deficiency.
Check your whole stack
See how soy isoflavones fits your routine.
NutriStack screens your full stack for interactions and timing conflicts, and updates the moment you change it.