Synonyms of efficacy

efficacy

noun

ˈe-fi-kə-sē 

as in effectiveness

the power to produce a desired result

questioned the efficacy of the alarms in actually preventing auto theft

Synonyms & Similar Words

• effectiveness
• efficaciousness
• efficiency
• productiveness
• ability
• efficacity
• effectualness
• capability
• edge
• strength
• potency
• capacity
• puissance

Antonyms & Near Antonyms

• ineffectiveness
• inefficiency
• inability
• inadequacy
• ineffectuality
• ineffectualness
• incompetence
• incompetency
• inadequateness

Example Sentences

Recent Examples of efficacy

They can be synthesized such as medications like insulin and GLP-1 drugs, which have both been FDA approved for safety and efficacy following clinical trials. — ABC News, 28 Oct. 2026

And if any of the peptides actually showed promise of efficacy, reputable pharmaceutical companies will have less incentive to follow up with thorough clinical trials if the peptide is already widely available. — Beth Mole, ArsTechnica, 28 Oct. 2026

And despite their popularity, probiotics are not recommended for preventing travelers’ diarrhea, as their efficacy is still unknown. — Andrés Henao, The Conversation, 27 Oct. 2026

Huynh described the phase 3 results as clinically meaningful and likely to support regulatory approval, but said the primary efficacy result landed at the low end of investor expectations. — Annika Kim Constantino, CNBC, 23 Oct. 2026