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 Arimistane and Clascoterone (CB-03-01) — mechanism, side effects, legal status, and pricing.
Arimistane is a non-peptide C19 steroidal compound (androstane-based) marketed as a mechanism-based aromatase inhibitor and sold as a gray-market bodybuilding supplement ingredient. It is a 7-keto-DHEA metabolite/degradation product with no approved therapeutic use. The FDA determined in 2021 that arimistane does not meet the definition of a dietary ingredient and fails GRAS criteria for food use. It is prohibited under the WADA Prohibited List (Section S4, Aromatase Inhibitors) and was added to the list in 2017.
Clascoterone is a non-peptide steroidal topical androgen receptor antagonist—a 17α-propionate ester of cortexolone (11-deoxycortisol). Winlevi (clascoterone 1% cream) is FDA-approved (2020) for topical treatment of acne vulgaris in patients 12 years and older. A higher-strength 5% topical solution (Breezula) has completed Phase 3 trials for male androgenetic alopecia but remains investigational for that indication. Despite established androgen-receptor binding, the FDA label states the mechanism of action for acne treatment is unknown.
Arimistane
Clascoterone (CB-03-01)
Category
Legal Status
Mechanism
Side Effects
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Arimistane
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Arimistane
No COA data yet.
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2
COAs
98.8%
Avg purity
2
Labs
No registered efficacy or safety clinical trials exist for arimistane. The only human data are two small anti-doping analytical studies: (1) a single 25 mg oral dose in 3 healthy volunteers produced up to 15 novel urinary metabolites, with parent compound detected in the sulfate fraction and no relevant acute effects on the steroid profile; (2) a separate single-dose study (3 volunteers, up to 10 hours) identified 12 additional reduced/hydroxylated urinary metabolites and detected unchanged parent in urine. In vitro (human placental microsomes): the close analog androst-5-ene-7,17-dione is a time-dependent, NADPH-dependent suicide substrate of aromatase; a series of related androsta-3,5-dien-7-ones/androst-5-en-7-ones competitively inhibited aromatase (Ki 0.058–45 µM), with 17-oxo derivatives more potent than 17-beta-hydroxy derivatives. Arimistane itself was not unambiguously confirmed among the specific tested compounds in the latter study.
Key references
Clascoterone is an FDA-approved prescription drug. Winlevi (clascoterone 1% cream) was approved in 2020 for topical treatment of acne vulgaris in patients 12 years of age and older, based on two identical Phase 3 RCTs (NCT02608450, NCT02608476; n=1421, ages 12+) showing IGA success rates of 18.8% and 20.9% for clascoterone vs. 8.7% and 6.6% for vehicle at Week 12. A separate, higher-strength 5% topical solution (Breezula) has completed a Phase 3 trial (SCALP2, NCT05914805, actual enrollment 762) for male androgenetic alopecia; this indication is investigational/unapproved. In hamster flank-organ models (topical antiandrogen bioassay), CB-03-01 showed strong local antiandrogenic activity—roughly 4× more potent than progesterone, ~3× more potent than flutamide, ~2× more potent than finasteride, and approximately equipotent with cyproterone acetate (Celasco et al., 2004, PMID 15646372). In rat subcutaneous injection and parabiotic rat models, no systemic antiandrogenic activity was observed, supporting a peripherally-selective (non-systemic) antiandrogen profile (Celasco et al., 2004). In human primary sebocyte cultures (in vitro), clascoterone dose-dependently suppressed lipid synthesis and inflammatory cytokine production, significantly outperforming spironolactone at inhibiting inflammatory cytokine synthesis (Rosette et al., 2019, PMID 31141847).
Arimistane (Hormone) and Clascoterone (CB-03-01) (Cosmetic) are in different categories and target different biological pathways. This is a common pattern in multi-compound research protocols. Researchers should monitor the biomarkers from both profiles and watch for interactions listed in each compound’s contraindications. Consult a licensed healthcare provider before combining any 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
Key references
Disclosed Labs