We use essential cookies (authentication, your saved goals/stack) by default. With your permission we’ll also enable privacy-respecting analytics (Vercel Web Analytics, anonymous load-time metrics) and error-replay diagnostics (Sentry — DOM snapshots only when an error fires) so we can fix bugs faster. Learn more about cookies
Hydrafinil (9-fluorenol; fluorenol) — an essentially UNSTUDIED grey-market 'research chemical' wakefulness-promoter marketed as a more-potent modafinil alternative, with NO human efficacy trials and effectively no nootropic pharmacology of its own
A grey-market 'research chemical' sold online as a more-potent modafinil alternative — hydrafinil (9-fluorenol) is marketed by vendors as a eugeroic, wakefulness-promoting nootropic. The CRITICAL fact is the near-total ABSENCE of evidence: there are NO human clinical trials of hydrafinil for any cognitive or wakefulness use, no approval, and effectively no peer-reviewed pharmacology of 9-fluorenol AS A NOOTROPIC. The vendor 'more potent than modafinil' claims trace to unpublished/secondary sources, not to any published human or even solid animal efficacy trial. The only legitimate literature that touches 9-fluorenol is analytical chemistry (a single human pilot study mapped how a 50 mg oral dose is metabolized and eliminated for doping-control detection — three volunteers, pharmacokinetics only) and unrelated synthetic-chemistry / environmental work on fluorene derivatives — NONE of it nootropic efficacy. This is the thinnest 'absence of evidence' entry in the library. Harms are extrapolated from the wakefulness/modafinil class and are UNPROVEN for hydrafinil specifically: insomnia, anxiety, headache, raised blood pressure and heart rate; layered on top of grey-market unknowns — unverified identity, purity and dose, no safety data at all, and no medical supervision. It is NOT an approved medicine, NOT a dietary supplement, and there is no human use this library can recommend. Informational, harm-reduction entry only — the honest takeaway is that hydrafinil's benefit and safety are essentially unstudied in humans.
Research compound — not a dietary supplement
Hydrafinil (Fluorenol) is a research compound, not a regulated dietary supplement. It is sold for research or off-label use. The evidence below is largely preclinical (animal and in-vitro) or early-stage, so no evidence score is assigned. This page is provided for transparency and education — it is not a recommendation to use. Consult a qualified healthcare provider, and be aware that purity, dosing, and legal status vary by jurisdiction.
What the evidence says
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 confidenceBy outcome
Hydrafinil (9-fluorenol) is a grey-market 'research chemical' sold as a more-potent modafinil alternative with NO published human efficacy trials and effectively no peer-reviewed nootropic pharmacology of its own. The only hydrafinil-specific human literature is a 2021 pilot doping-control study in which three volunteers took a single 50 mg oral dose, mapping metabolism/detection (Knoop 2021) — human pharmacokinetics, but neither efficacy nor safety. The only other directly-named literature is unrelated synthetic chemistry of 9-fluorenol (Koike 2026). The supporting modafinil studies cited here (Battleday & Brem 2015 systematic review; Broughton 1997 and US Modafinil Study Group 2000 RCTs) are the PARENT-CLASS drug modafinil, NOT hydrafinil — a distinct compound — and cannot be transferred to it. The vendor 'more potent than modafinil' claim has no published human or solid animal trial behind it. The dominant signal is therefore an almost complete ABSENCE of evidence, against an extrapolated modafinil-like harm profile (insomnia, anxiety, raised BP/HR, misuse/dependence) and grey-market quality risk — so the score sits low, slightly below even other research-chemical entries because hydrafinil is the most thinly studied of the set.
Hydrafinil — chemically 9-fluorenol (9H-fluoren-9-ol) — is a grey-market 'research chemical' sold online and marketed by vendors as a eugeroic (wakefulness-promoting) nootropic and a more-potent alternative to modafinil.
The honest description of its evidence base is that it BARELY HAS ONE, and what little exists is not about whether it works.
There are NO published randomized controlled trials of hydrafinil in humans, no approved indication anywhere in the world, no published animal efficacy trials establishing a nootropic effect, and no pharmacovigilance data on the material people actually buy.
The widely-repeated vendor claim that hydrafinil is 'roughly 40% more potent than modafinil' and 'less likely to cause overstimulation' traces to unpublished or secondary internet sources — not to any peer-reviewed human or even rigorous animal study.
The only legitimate, hydrafinil-specific literature is analytical: a 2021 pilot elimination study in which three healthy male volunteers each took a single 50 mg oral dose so that investigators could characterize how 9-fluorenol and its phase I/II metabolites are excreted in urine and detected for sports doping control.
That is genuine human pharmacokinetic data — it confirms people ingest and metabolize the compound — but it tests detection and metabolism, NOT efficacy or safety.
Beyond that, the peer-reviewed record for '9-fluorenol' / 'fluorenol' is unrelated: synthetic and catalytic organic chemistry (9-fluorenol used as a reagent or single-electron reductant) and environmental toxicology of fluorene and its derivatives.
None of it speaks to cognition, wakefulness, or human safety as a nootropic. Because hydrafinil is structurally and (claimed) functionally framed as a modafinil-class wakefulness agent, the only way to anticipate its effects is by extrapolation from modafinil — a related but genuinely different molecule.
That modafinil evidence is real: a systematic review of modafinil for cognitive neuroenhancement in healthy non-sleep-deprived adults found modest, task-dependent benefits to attention and executive function (Battleday & Brem 2015), and randomized trials established modafinil for the excessive daytime sleepiness of narcolepsy (Broughton 1997; US Modafinil in Narcolepsy Multicenter Study Group 2000).
But it would be dishonest to present any of that as hydrafinil evidence — hydrafinil is not even an established structural analogue of modafinil in the way flmodafinil is; it is a distinct fluorene alcohol whose receptor pharmacology, potency, metabolites and toxicity in humans are essentially uncharacterised, sold outside any quality system at doses no trial has validated.
The expected harm profile is therefore extrapolated from modafinil rather than measured for hydrafinil: insomnia, headache, anxiety and nervousness, and raised blood pressure and heart rate, plus the dependence/misuse potential of any wakefulness-promoting psychostimulant.
Layered on top is the grey-market reality: a 'research chemical' of unverified identity, purity and dose, taken with no medical supervision, no blood-pressure or cardiac monitoring, and unknown drug interactions.
The evidence score sits low and the level is 'Emerging' precisely because the dominant signal here is an ABSENCE — no human efficacy data and no human safety data for hydrafinil at all, only a single three-person pharmacokinetic/detection study and unrelated chemistry.
This is an informational, harm-reduction entry: the responsible conclusion is that hydrafinil is an essentially unstudied compound sold as a nootropic on vendor claims that the published literature does not support, not a supported intervention, and there is no human use this library endorses.
Hydrafinil (9-fluorenol) is marketed as a eugeroic — a wakefulness-promoting agent in the loose 'modafinil-like' category. Vendors claim it promotes alertness and is more potent than modafinil. There is NO published human or rigorous animal efficacy study behind this; the wakefulness mechanism is asserted by marketing and extrapolated from the modafinil class, not demonstrated for hydrafinil.
Wakefulness-promoting agents of the modafinil class act substantially via raising synaptic dopamine and modulating wake-regulating monoamine circuits, which also underlies the misuse/dependence potential of the class. Any such action for hydrafinil is inferred from the class only — 9-fluorenol's own receptor and transporter pharmacology in humans is essentially uncharacterised in the published literature.
Because hydrafinil is sold as an unregulated 'research chemical', the substance, its purity, its actual dose and its metabolites are not assured. The only hydrafinil-specific human study characterized how a 50 mg oral dose of 9-fluorenol is metabolized (hydroxylated, glucuronidated/sulfo-conjugated) and excreted in three volunteers — useful for doping-control detection, but underscoring that what a buyer ingests, and how the body handles it, is not guaranteed to match any label or any modafinil reference.
How Hydrafinil (Fluorenol) works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Avoid — hydrafinil is essentially unstudied in humans, of unverified identity and dose, and carries an extrapolated modafinil-class harm profile (insomnia, anxiety, raised BP/HR, misuse potential). There is no human evidence of benefit and the 'more potent than modafinil' claim has no published basis.
Avoid — modafinil-class agents raise blood pressure and heart rate, and hydrafinil is taken with no monitoring.
Avoid — stimulant wakefulness agents can worsen these conditions; hydrafinil has no human safety data.
Avoid — hydrafinil and its metabolites are detectable in urine and may be considered for anti-doping prohibition.
Avoid entirely — no human safety data of any kind for hydrafinil.
Combining hydrafinil with caffeine, ADHD stimulants or other sympathomimetics compounds the expected rise in blood pressure, heart rate, anxiety and insomnia; the additive effect is uncharacterised in a product of unknown potency and identity.
Stacking a CNS stimulant of unknown pharmacology with antidepressants, antipsychotics or MAOIs risks additive cardiovascular and psychiatric effects; hydrafinil has no interaction data, so the combination is uncharacterised and unsafe to assume benign.
Hydrafinil's effects on drug-metabolizing enzymes are entirely uncharacterised, so any concurrent prescription is an unmonitored, unpredictable interaction. The modafinil class is known to modulate CYP enzymes, but this cannot be assumed identical for a distinct compound.
Tip: Expected of any wakefulness-promoting eugeroic; an agent sold to suppress sleepiness is likely to disrupt sleep. There is no validated human dosing to limit this — the only harm-reduction note is that evening exposure is worse than morning.
Tip: These are the most common modafinil-class adverse effects and are extrapolated to hydrafinil. With an unstudied compound of uncertain potency there is no dose-finding to bound them; stop use if they occur.
Tip: Modafinil-class agents raise BP and HR; hydrafinil is taken without any cardiovascular monitoring. Anyone with heart disease, arrhythmia or hypertension should avoid it entirely.
Tip: A grey-market 'research chemical' of unverified identity and purity can contain the wrong compound, the wrong dose or contaminants, producing unpredictable and potentially serious effects with no safety data to anticipate them. There is no way to mitigate this short of not using unregulated product.
Tip: As a claimed wakefulness psychostimulant, hydrafinil carries misuse and psychological-dependence potential by extrapolation from the class; unsupervised escalating use in a grey-market setting compounds the risk.
The current evidence for Hydrafinil (Fluorenol) is insufficient to assign an evidence score, based on 5 indexed studies. A grey-market 'research chemical' sold online as a more-potent modafinil alternative — hydrafinil (9-fluorenol) is marketed by vendors as a eugeroic, wakefulness-promoting nootropic. The CRITICAL fact is the near-total ABSENCE of evidence: there are NO human clinical trials of hydrafinil for any cognitive or wakefulness use, no approval, and effectively no peer-reviewed pharmacology of 9-fluorenol AS A NOOTROPIC. The vendor 'more potent than modafinil' claims trace to unpublished/secondary sources, not to any published human or even solid animal efficacy trial. The only legitimate literature that touches 9-fluorenol is analytical chemistry (a single human pilot study mapped how a 50 mg oral dose is metabolized and eliminated for doping-control detection — three volunteers, pharmacokinetics only) and unrelated synthetic-chemistry / environmental work on fluorene derivatives — NONE of it nootropic efficacy. This is the thinnest 'absence of evidence' entry in the library. Harms are extrapolated from the wakefulness/modafinil class and are UNPROVEN for hydrafinil specifically: insomnia, anxiety, headache, raised blood pressure and heart rate; layered on top of grey-market unknowns — unverified identity, purity and dose, no safety data at all, and no medical supervision. It is NOT an approved medicine, NOT a dietary supplement, and there is no human use this library can recommend. Informational, harm-reduction entry only — the honest takeaway is that hydrafinil's benefit and safety are essentially unstudied in humans. Representative study: PMID 26381811.
The commonly studied dose of Hydrafinil (Fluorenol) is There is no established or legitimate human dose. Hydrafinil (9-fluorenol) is an essentially UNSTUDIED grey-market 'research chemical' with no human clinical trials, no approval, and no pharmacovigilance — this library does NOT provide a dosing protocol. Vendors and forums quote figures in the tens of milligrams orally, extrapolated from vague modafinil comparisons, but these are unverified for a product of unknown purity and identity, taken without medical supervision or monitoring. The only human datapoint is a 2021 doping-control pilot study in which three volunteers each took a single 50 mg oral dose of hydrafinil so investigators could map its metabolism and urinary elimination — a detection study, NOT a dosing or efficacy recommendation. There is no published animal efficacy dose for hydrafinil at all.. Individual needs vary — start at the lower end of the range and adjust based on how you respond.
The best time to take Hydrafinil (Fluorenol) is in the morning. It can be taken on an empty stomach. Wakefulness-promoting agents of the modafinil class are taken in the morning to avoid insomnia; an agent sold expressly to suppress sleepiness is especially likely to disrupt sleep if taken later in the day.
Hydrafinil (Fluorenol) should be used with caution — talk to a healthcare provider before taking it. The most commonly reported side effects are insomnia / disrupted sleep, headache, nausea, anxiety & nervousness, raised blood pressure & heart rate. Use caution if any of these apply to you: Any human use — hydrafinil is an essentially UNSTUDIED grey-market 'research chemical' (9-fluorenol) with no human efficacy or safety trials, no approval, and product of unverified identity, purity and dose; it is NOT a dietary supplement and NOT an approved medicine; Anyone seeking it for focus, wakefulness or 'nootropic' enhancement — there is no human evidence of benefit for hydrafinil and an extrapolated modafinil-class harm profile; Anyone with cardiovascular disease, arrhythmia, uncontrolled hypertension, or left-ventricular hypertrophy — modafinil-class agents raise blood pressure and heart rate.
Caffeine
Likely helpsBlocks adenosine receptors to boost alertness, reaction time, and endurance — one of the most proven ergogenic aids.
Citicoline
Probably helpsDual precursor to acetylcholine and phosphatidylcholine — enhances memory, focus, and brain cell membrane repair.
Nicotinamide Riboside
Mostly mechanism / observationalA vitamin B3 precursor that reliably raises cellular NAD+ levels and is well tolerated — but human trials have so far shown mostly null or mixed results on the functional outcomes (muscle, metabolism, blood pressure, cognition) that elevation is meant to drive.
Theacrine
Mostly mechanism / observationalCaffeine-like purine alkaloid from kucha tea. Small RCTs suggest subjective energy and mood benefits and good safety, but objective performance gains are inconsistent.
Explore: Best supplements for Athletic PerformanceBest supplements for Focus, Memory & Mood
Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 5 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
Tap node to isolate • Pinch to zoom • Tap edge for research