How to Say "potency" in Spanish
The Spanish word for “potency” is “eficacia” — B1 level. This is a very common word in everyday Spanish.

Examples
La eficacia de la vacuna está probada.
The effectiveness of the vaccine is proven.
Queremos mejorar la eficacia de nuestro equipo de trabajo.
We want to improve the effectiveness of our work team.
El plan fue ejecutado con gran eficacia.
The plan was executed with great effectiveness.
It's a Feminine Word
Since 'eficacia' ends in '-a', it is a feminine noun. You should always use feminine words with it, like 'la eficacia' or 'una eficacia'.
Abstract Nouns and Articles
When talking about 'effectiveness' in a general sense in Spanish, you usually need to use the word 'la' (the) before it, unlike in English.
Confusing it with 'Efficiency'
Mistake: “Using 'eficiencia' when you mean 'getting the result done'.”
Correction: Use 'eficacia' for reaching a goal (getting results) and 'eficiencia' for how well you used your time or resources to get there.
Related Translations
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