Fladrafinil

Fladrafinil belongs to the eugeroic class of wakefulness-promoting compounds, a small family that also includes modafinil, its prodrug adrafinil, and the closely related flmodafinil ^[1]. Structurally it is a fluorinated analogue of adrafinil, sometimes described as bisfluoroadrafinil, in which the two phenyl rings of the parent molecule each carry a fluorine atom; its molecular formula is C15H13F2NO3S ^[1]. Like adrafinil, it is an N-hydroxy compound, carrying a hydroxamic acid group that the body can remove during metabolism ^[1].

The molecule was developed by the French pharmaceutical company Lafon, the same firm behind adrafinil and modafinil, and was assigned the internal code CRL-40,941 ^[1]. It was covered by patents filed in the 1980s but was never developed into an approved medicine ^[1]. In the years since, it has appeared instead on the grey market for cognitive enhancers, sold by online vendors as a research chemical or nootropic rather than dispensed through pharmacies ^[1][2].

Interest in fladrafinil rests largely on the reputation of its chemical relatives as fatigue-fighting and alertness-boosting agents ^[2]. In early animal work it was reported to have antiaggressive properties that adrafinil lacked, and to be several times more potent than adrafinil in that respect ^[1]. Direct human study of the compound is scarce; the most detailed modern investigation was carried out for anti-doping purposes, and it showed that once ingested, fladrafinil behaves as a prodrug that the body converts into flmodafinil, with both parent drugs and their acid and sulfone metabolites detectable in urine and blood over an extended window ^[3].

Fladrafinil has not been approved as a drug in the United States or elsewhere and is not a scheduled controlled substance, occupying an unregulated space similar to other designer nootropics ^[1][2]. In sport, however, it is explicitly banned; both fladrafinil and flmodafinil fall under the World Anti-Doping Agency category of S6 stimulants and are prohibited in competition ^[3]. It is typically encountered as a bulk powder or in capsules supplied by online retailers rather than in any standardized pharmaceutical form ^[2].

Adverse effects are genuinely UNKNOWN for this compound. There is no published safety study, no adverse event profile, no overdose or poisoning case report, no drug interaction study and no long term data specific to fladrafinil; searches for case reports returned nothing. The 2026 study dosed six volunteers at 20 mg without reporting a safety problem, but it was a six person excretion study that did not set out to measure adverse events, and absence of reporting is not evidence of safety.

Risks are frequently assumed from modafinil, which is a different, approved drug carrying specific warnings for serious rash including Stevens-Johnson syndrome and toxic epidermal necrolysis, psychiatric reactions, and CYP3A4 induction that reduces the effectiveness of hormonal contraceptives; NONE of these has been studied for fladrafinil, so extending them is inference rather than established fact.

REGULATORY: WADA added fladrafinil, by exact chemical name 2-[bis(4-fluorophenyl)methylsulfinyl]-N-hydroxyacetamide, to the S6.A non-specified stimulants section of the 2026 Prohibited List, alongside flmodafinil; S6 substances are prohibited in competition, so an athlete taking this faces a positive test, and the 2026 study warns that detection windows for both the parent drugs and their metabolites are long. It is not approved by the FDA or any other regulator for any indication and was never marketed.

It is not a lawful dietary ingredient in the United States and FDA laboratory work treats it as an unapproved drug found in products sold as supplements. It is not specifically listed in any US Controlled Substances Act schedule; the Federal Analogue Act does not reach it, because that statute covers analogues of Schedule I and II substances and modafinil is Schedule IV. Jurisdictions with blanket psychoactive substance laws, such as the UK Psychoactive Substances Act 2016, would likely capture its supply, though no specific determination was located.

Fladrafinil was developed by the French pharmaceutical company Lafon Laboratories, the same firm behind adrafinil and modafinil, and was assigned the developmental code CRL-40,941. It was patented in the 1980s as part of Lafon's benzhydryl sulfinyl series but was never advanced into clinical use or brought to market as a medicine. Its close structural relatives modafinil and adrafinil went on to commercial and clinical success, whereas fladrafinil remained an obscure laboratory compound. In more recent years it has resurfaced outside the medical setting, circulating informally as an online research chemical and nootropic. Controlled human data specific to fladrafinil remain sparse, so most of what is known is extrapolated from its better-studied relatives.

Fladrafinil is followed with interest by the nootropics community as a fluorinated cousin of modafinil, valued for the clean, non-jittery wakefulness associated with the eugeroic class. A 2026 doping-analysis study confirmed that it behaves as a prodrug, converting in the body to flmodafinil, which grounds community discussion in measured pharmacology rather than speculation. Enthusiasts appreciate that eugeroics tend to promote alertness without the strong euphoria or crash of classical stimulants. It is honest to note that controlled human efficacy and safety trials of fladrafinil itself have not been published, so expectations are largely inferred from modafinil. It is also classified as a prohibited stimulant under anti-doping rules.