Fladrafinil (CRL-40,941)

Fladrafinil, coded CRL-40,941, is the N-hydroxy analog of flmodafinil and the difluorinated counterpart of adrafinil. Flmodafinil was conceived at Laboratoire L. Lafon, the French company behind adrafinil and modafinil, and was never developed as a medicine (PMID: 30158846); the CRL-40,941 code of fladrafinil places it in the same series. Fladrafinil is sold today only as a research chemical or as an ingredient in unapproved supplements marketed for wakefulness and focus, and interest in it grew alongside the off-label use of modafinil as a cognitive enhancer (PMID: 27928893).

Its pharmacology is best understood as prodrug chemistry. In a human administration study published in 2026, six volunteers each took a single 20 mg dose and gave urine and dried blood spot samples; fladrafinil was converted to flmodafinil, which was then oxidized to flmodafinil acid and flmodafinil sulfone, the same pattern adrafinil follows toward modafinil (PMID: 42210629). The activity therefore belongs mostly to flmodafinil rather than to the parent compound.

For flmodafinil there is one useful animal study, published under the compound names lauflumide and NLS-4. In male C57BL/6J mice with EEG and EMG recording, an intraperitoneal dose of 64 mg/kg produced longer wakefulness than modafinil at 150 mg/kg, without hyperlocomotion and without rebound hypersomnia, and recovery sleep afterwards involved less non-REM sleep and less delta activity than after modafinil (PMID: 30158846). No comparable study exists for fladrafinil itself.

Nothing about efficacy in people has been tested. The single human study measured concentrations and detection windows, not attention, wakefulness or performance (PMID: 42210629). For the class parent, positron emission tomography in ten healthy men showed that modafinil occupied dopamine transporters in caudate, putamen and nucleus accumbens and raised extracellular dopamine, a finding the authors linked to abuse potential (PMID: 19293415). Whether the fluorinated analogs behave the same way at the same exposures has not been measured in humans.

Two practical points come out of the doping-control work. Product labels are unreliable: one supplement bought for that study was labeled at 50 mg/mL of flmodafinil and assayed at 95.7 mg/mL, close to double the stated content (PMID: 42210629). And anyone tested in sport should know that fladrafinil and flmodafinil were added to the 2026 World Anti-Doping Agency Prohibited List under class S6 stimulants and are prohibited in competition, with detection windows of up to a week for the parent compounds and about two weeks for the metabolites (PMID: 42210629). A retrospective screen of about 2000 in-competition samples collected in 2023 and 2024 found none of these compounds, so current use among tested athletes appears low.

There is no FDA or EMA authorization for fladrafinil, no published safety trial, and no pregnancy, cardiac or hepatic data. It is a research-use-only compound in the US market, and the gap between what is claimed for it online and what has actually been measured is wide.

Fladrafinil (CRL-40,941) is available in liquid form.

Compare prices, payment methods, shipping, and COA scores across 1 vendor.

1 of the vendors BodyHackGuide tracks list Fladrafinil (CRL-40,941) (1 listing). Among BodyHackGuide's Fladrafinil (CRL-40,941) listings recorded as in stock with a milligram count, the lowest price per milligram is $0.025/mg at Disguised Alpha and the median is $0.025/mg. The Fladrafinil (CRL-40,941) prices on BodyHackGuide are vendors' listed prices as BodyHackGuide last recorded them, not transactions; the most recent recorded change to a Fladrafinil (CRL-40,941) listing is dated 7 September 2026.

BodyHackGuide holds 1 third-party certificate record for Fladrafinil (CRL-40,941), from Disguised Alpha. No editor has read any of BodyHackGuide's 1 certificate record for Fladrafinil (CRL-40,941). The laboratory named on BodyHackGuide's Fladrafinil (CRL-40,941) certificate record is Freedom Diagnostics Testing, and the test date on it is 16 September 2026. Each vendor page on BodyHackGuide shows how many certificate records BodyHackGuide holds for that vendor and links to each record that has its own page.