Medication·Interactions·Reviewed June 9, 2026
Tadalafil interactions.
Tadalafil has 3 documented interactions in the NutriStack database, including 1 flagged to avoid or as a serious conflict. The full interaction list is below. None of this is a substitute for your prescriber's advice.
Tadalafil at a glance.
A quick, data-grounded summary. The full tables are below.
Tadalafil has 3 documented interactions in the NutriStack database, including 1 flagged to avoid or as a serious conflict. The full interaction list is below. None of this is a substitute for your prescriber's advice.
Substances that interact with tadalafil.
Every supplement and medication in the NutriStack database with a documented interaction with this drug, highest-severity first. Open any pair for the mechanism and sources.
| Substance | Interaction | What happens |
|---|---|---|
| St. John's Wort | Conflict | St. John's Wort can induce CYP3A4, the main metabolic pathway for tadalafil. This may lower tadalafil exposure and reduce its effectiveness for... details → |
| L-Arginine | Caution | Same mechanism as sildenafil + L-arginine. Tadalafil has a 36-hour half-life, making the interaction window much longer than sildenafil. details → |
| L-Citrulline | Synergy | L-Citrulline can raise plasma L-arginine and nitric-oxide signaling, while tadalafil preserves cGMP by inhibiting PDE5. A small randomized crossover... |
The full tadalafil profile.
Uses, typical dosing, side effects, and the cited evidence for this medication.
Common tadalafil questions.
Quick answers drawn from the tables above.
What interacts with Tadalafil?
In the NutriStack database, Tadalafil has 3 documented interactions. The most notable include St. John's Wort, L-Arginine, and L-Citrulline. Check any specific combination before taking it and confirm with your prescriber.
Which substances should I avoid with Tadalafil?
Tadalafil is flagged against 1 substance in the database, including St. John's Wort. These pairings carry a higher risk and should be reviewed with a clinician before combining.
Is it safe to take St. John's Wort with Tadalafil?
NutriStack classifies the St. John's Wort and Tadalafil pairing as conflict: St. John's Wort can induce CYP3A4, the main metabolic pathway for tadalafil. This may lower tadalafil exposure and reduce its effectiveness for erectile dysfunction,... Avoid St. John's Wort while using tadalafil unless your prescriber specifically approves it. If you stop St. John's Wort, do not change tadalafil... Always confirm with your prescriber.
Check your whole stack
See how tadalafil fits your supplements.
NutriStack screens your full routine for interactions and depletions, and updates the moment you change it.