Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of Adrafinil and Fladrafinil — mechanism, side effects, legal status, and pricing.
Adrafinil is a non-peptide synthetic eugeroic (wakefulness-promoting agent) and diphenylmethylsulfinyl-acetohydroxamic acid derivative that functions as a prodrug of modafinil. It was approved in France (marketed as Olmifon) from 1984 to 2011 for narcolepsy but was voluntarily withdrawn due to hepatotoxicity concerns and an unfavorable risk-benefit ratio. Adrafinil is not currently approved in any jurisdiction; the FDA classifies it as an unapproved new drug when sold as a dietary supplement. It is prohibited in competitive sport under WADA’s S6.a Non-Specified Stimulants category.
Fladrafinil (CRL-40,941) is a non-peptide synthetic eugeroic and the bis(4-fluorophenyl)-substituted analog of adrafinil, retaining adrafinil's N-hydroxyacetamide group. Never approved or marketed as a pharmaceutical in any jurisdiction, it is sold exclusively as an unregulated research chemical. Added to WADA's S6 (Stimulants, non-specified) category on the 2026 Prohibited List, effective 1 January 2026.
Adrafinil
Fladrafinil
Category
Legal Status
Mechanism
Side Effects
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Adrafinil
No pricing data yet.
Check Adrafinil prices →Fladrafinil
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Check Fladrafinil prices →COA corpus from Disclosed Labs — independently tested batches only.
Adrafinil
3
COAs
99.8%
Avg purity
2
Labs
Fladrafinil
2
COAs
99.6%
Avg purity
1
Labs
Adrafinil was approved in France for narcolepsy (1985) after initial human testing in 1977–1978, but was voluntarily withdrawn in September 2011 due to hepatotoxicity concerns and an unfavorable risk-benefit ratio. No current registered interventional clinical trials exist; the only registered study is an observational survey listing adrafinil as a queried substance. One published forensic study (n=1) detected adrafinil (0.8 ng/mg) and modafinil (0.5 ng/mg) in beard hair 10 days after a single 200 mg oral dose in one adult volunteer. Preclinical studies in aged beagle dogs found oral 20 mg/kg adrafinil improved discrimination learning but impaired working memory in a delayed nonmatching-to-position task over 8 days. Rat studies of the metabolite modafinil showed dose-dependent increases in locomotor activity and extracellular dopamine.
Key references
No clinical trials for any therapeutic indication exist; no FDA approval has been granted. The only identified human data are: (1) a 2026 peer-reviewed pharmacokinetics/metabolism study for anti-doping purposes (Krug et al., Drug Testing and Analysis), which administered fladrafinil orally to healthy volunteers and confirmed metabolism to flmodafinil, flmodafinil acid, and flmodafinil sulfone; and (2) unverified patent-holder claims from 1984 describing oral 50 mg capsules for hypersomnia/psychasthenia with reported 'excellent results' over 2–8 weeks—this is not an independently published or peer-reviewed trial. Animal studies (mice/rats, intraperitoneal, 16–256 mg/kg) from the 1984 Lafon patent reported reduced barbiturate-induced sleep duration, increased spontaneous motor activity, reduced inter-group aggression, improved motor recovery following hypoxic stress, and prolonged amphetamine-induced stereotypy.
Adrafinil and Fladrafinil are both in the Cognitive category and may have overlapping mechanisms. Researchers should review both profiles carefully, understand the mechanisms of action, and monitor the relevant biomarkers when combining compounds in the same class. As always, consult a licensed healthcare provider before making any decisions about combining research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Disclosed Labs