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

Again, in thousands of patients with heart disease, the investigational medication fared no better than a placebo. — Adam Cohen, Oklahoman, 22 Sep. 2026

In April, the FDA accepted an investigational new drug application for a drug that uses an ibogaine derivative, which researchers hope will provide the benefits of ibogaine, but without the hallucinogenic trip or potential heart toxicity. — Brenda Goodman, CNN Money, 21 Sep. 2026

One of the buzziest investigational drug examples is retatrutide, which is currently in phase 3 trials. — Kara McGrath, Allure, 15 Sep. 2026

Shares of Merck have jumped 45% year to date as clinical trials for its investigational and experimental drugs continue to produce positive results. — Liz Napolitano, CNBC, 20 Aug. 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