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Hyd2.5
Hydrafinil (Fluorenol) Research
Mostly mechanism / observationalLimited safety
5 peer-reviewed studies
What the evidence says
Mostly mechanism / observational
Most Hydrafinil (Fluorenol) studies are mechanism or observational rather than RCTs that measure a clinical effect — keep findings provisional.
Most evidence is from mixed-quality randomised trials published 1997–2026.
Based on 5 studies · 2 RCTs
Confidence
Low
By outcome
Safety profile
Mostly mechanism / observational5 studies
Focus & attention (modafinil-class, unproven for hydrafinil)
Mostly mechanism / observational4 studies
Wakefulness & fatigue
Mostly mechanism / observational3 studies
Cognition (modafinil-class evidence)
Too few graded studies2 studies
Sleep disruption / insomnia
Too few graded studies1 study
Wakefulness timing & vigilance
Too few graded studies1 study
Active research area
2 studies in the last 5 years
199720112026
1Systematic Review2015
When more complex assessments are used, modafinil appears to consistently engender enhancement of attention, executive functions, and learning. Importantly, we did not observe any preponderances for side effects or mood changes.
Battleday RM, Brem AK. · European Neuropsychopharmacology (2015)
MODAFINIL (parent), NOT FLADRAFINIL: a systematic review of modafinil for cognitive neuroenhancement in healthy non-sleep-deprived adults — included here to show what the RELATED drug does, not what fladrafinil does
Found modest, task-dependent benefits to attention, executive function and learning with modafinil, especially on more complex tasks
Cited by fladrafinil vendors as if it were fladrafinil evidence — it is NOT; fladrafinil is a different fluorinated analogue/prodrug with no human cognition trials
Compared with placebo, modafinil 200 and 400 mg significantly increased the mean sleep latency on the Maintenance of Wakefulness Test by 40% and 54% ... Modafinil produced no changes in blood pressure or heart rate ... As little as a 200-mg daily dose of modafinil is therefore an effective and well-tolerated treatment.
Broughton RJ, Fleming JA, George CF, Hill JD, Kryger MH, Moldofsky H, Montplaisir JY, Morehouse RL, Moscovitch A, Murphy WF. · Neurology (1997)
MODAFINIL (parent), NOT FLADRAFINIL: a randomized, double-blind, placebo-controlled crossover trial of modafinil for excessive daytime sleepiness in narcolepsy — real human evidence for the PARENT drug
Modafinil reduced objective and subjective daytime sleepiness vs placebo and was generally well tolerated in this supervised clinical population
Establishes the modafinil-class wakefulness effect in humans — but for modafinil, NOT for the unstudied analogue/prodrug fladrafinil
Treatment with modafinil resulted in significant improvement in two objective measures of EDS ... The most frequent adverse experience was headache ... The data indicate that modafinil has an excellent safety profile and is very well tolerated.
US Modafinil in Narcolepsy Multicenter Study Group. · Neurology (2000)
MODAFINIL (parent), NOT FLADRAFINIL: a large multicenter randomized placebo-controlled trial of modafinil for excessive daytime somnolence in narcolepsy — parent-drug human evidence
Modafinil improved objective wakefulness vs placebo; the most frequent adverse event was headache — the kind of symptom extrapolated to fladrafinil
Reinforces the modafinil-class effect AND its typical adverse-event profile in supervised humans, for the PARENT compound only
Little information on the human metabolism and urinary elimination of hydrafinil (9-fluorenol) exists. In order to support preventive anti-doping activities concerning compounds such as hydrafinil, a pilot elimination study was conducted with three healthy male volunteers receiving a single oral dose of 50 mg of hydrafinil.
Knoop A, Fußhöller G, Haenelt N, Goergens C, Guddat S, Geyer H, Thevis M. · Drug Testing and Analysis (2021)
HYDRAFINIL-SPECIFIC (the only direct human study): a doping-control pilot in which three healthy male volunteers each took a single 50 mg oral dose of hydrafinil (9-fluorenol), characterizing how it and its phase I/II metabolites are excreted in urine and detected
Explicitly states that 'little information on the human metabolism and urinary elimination of hydrafinil exists' — documenting the near-total absence of human pharmacology, not any clinical benefit
Identified intact hydrafinil plus primarily hydroxylated and glucuronidated/sulfo-conjugated metabolites — human pharmacokinetic/metabolite data, relevant to detection windows
We have disclosed the 9-fluorenol-catalyzed reductive dehalogenation of aryl halides. 9-Fluorenol, a readily available and structurally simple organic compound, serves as a catalytic single-electron reductant under light- and electricity-free conditions.
Koike S, Kashihara M, Nakao Y. · Chemistry, an Asian Journal (2026)
NOT a nootropic study: this is synthetic organic chemistry in which 9-fluorenol (the chemical sold as hydrafinil) is used as a catalytic single-electron reductant to dehalogenate aryl halides
Included to illustrate what the genuine peer-reviewed literature on 9-fluorenol actually consists of — analytical and synthetic chemistry of the molecule, NOT human or animal nootropic pharmacology
Confirms 9-fluorenol is a simple, readily-available organic compound; it says nothing about cognition, wakefulness, efficacy or safety in any organism