investigational

adjective

in·​ves·​ti·​ga·​tion·​al in-ˌve-stə-ˈgā-sh(ə-)nəl 

1

: of or relating to investigation

investigational activities

2

: relating to or being a drug or medical procedure that is not approved for general use but is under investigation in clinical trials regarding its safety and efficacy

an investigational new drug

Examples of investigational in a Sentence

Recent Examples on the Web

Nonapproved stem cell products are investigational and are under review to see if the therapy can treat many other conditions. — Phoebe Quinton, AJC.com, 15 June 2026

Investigators say the scheme, which involved two trials for an investigational drug meant to treat asthma attacks, began around February 2019 and continued through 2022, according to Olivera’s criminal information. — Isabel Rivera, Miami Herald, 12 June 2026

Some people taking the investigational medication retatrutide lost an average of 30 percent of their body weight in about 2 years. — Emily Kay Votruba, EverydayHealth.com, 8 June 2026

Thanks in part to investigational therapies and ongoing research efforts, Roman, now 7, and Stella, now 6, have lived beyond the life expectancy given to them at diagnosis. — Tereza Shkurtaj, PEOPLE, 31 May 2026

Word History

First Known Use

1905, in the meaning defined at sense 1

Rhymes for investigational

• associational
• civilizational
• coeducational
• configurational
• consociational
• denominational
• improvisational
• organizational
• orientational
• preoperational
• representational
• aspirational