This page describes pharmacological agents that may have legal restrictions, side effects, and drug interactions in your jurisdiction. Information is for educational research only — consult a clinician before considering any compound.
Nortadalafil
Our depth — beyond the mirror
Deeper analysis, verdict reasoning, and per-archetype recommendations from our research team.
▸ Editor's verdict WATCH-LIST HIGH
Nortadalafil has no upside over the FDA-approved parent (tadalafil) for any user with legitimate access. Tadalafil generic is $0.30-0.80 per 20mg pill via the same Indian pharmacies that sell modafinil — same gray-market sourcing reality, but with 20+ years of safety data, validated PK, and FDA-grade purity. Nortadalafil's only purchase is "research-chem-only sourcing" framing — i.e., scenarios where you genuinely cannot get tadalafil. For a 20yo with telehealth access AND existing Indian-pharmacy supplier relationships, that scenario is hypothetical. Stays on watch-list because the class itself is interesting (the cognitive-flow / vascular hedge is real for tadalafil) and because nortadalafil shows up as an adulterant in counterfeit "natural male enhancement" products — worth knowing how to recognize and avoid. Verdict would change to SKIP-ALWAYS only if FDA escalated to schedule it; would never change to OPTIONAL-ADD because the cleaner alternative dominates.
▸ Decision matrix by user profile Per-archetype
| Archetype | Verdict | Rationale |
|---|---|---|
★20-30, brain-priority, high cognitive workload (this archetype) | WATCH-LIST | Tadalafil dominates on every axis. The only "value" of nortadalafil literacy is recognizing it on FDA recall lists. |
30-50, executive maintenance | WATCH-LIST | Same reasoning. Tadalafil daily 2.5-5 mg is the actual play here. |
50+, mild cognitive decline | WATCH-LIST | The dementia-incidence observational signal is for tadalafil/sildenafil, not nortadalafil. Use the validated parent compound. |
Anxiety-prone | WATCH-LIST | Class is neutral on anxiety; no reason to introduce purity uncertainty. |
High athletic load, tested status | WATCH-LIST | PDE5i are not currently WADA-banned, but counterfeit supplements often co-contain banned anabolics — purity uncertainty is the issue. |
Sleep-disordered | WATCH-LIST | Class doesn't affect sleep architecture. |
Recovery-focused (post-injury, post-illness) | WATCH-LIST | — |
Strength/anabolic-focused | WATCH-LIST | — |
Curious about the cognitive-flow / vascular hedge | U | tadalafil daily 2.5 mg, not nortadalafil. The case for the class is the case for tadalafil specifically. |
- ★20-30, brain-priority, high cognitive workload (this archetype)WATCH-LIST
Tadalafil dominates on every axis. The only "value" of nortadalafil literacy is recognizing it on FDA recall lists.
- 30-50, executive maintenanceWATCH-LIST
Same reasoning. Tadalafil daily 2.5-5 mg is the actual play here.
- 50+, mild cognitive declineWATCH-LIST
The dementia-incidence observational signal is for tadalafil/sildenafil, not nortadalafil. Use the validated parent compound.
- Anxiety-proneWATCH-LIST
Class is neutral on anxiety; no reason to introduce purity uncertainty.
- High athletic load, tested statusWATCH-LIST
PDE5i are not currently WADA-banned, but counterfeit supplements often co-contain banned anabolics — purity uncertainty is the issue.
- Sleep-disorderedWATCH-LIST
Class doesn't affect sleep architecture.
- Recovery-focused (post-injury, post-illness)WATCH-LIST
- Strength/anabolic-focusedWATCH-LIST
- Curious about the cognitive-flow / vascular hedgeU
tadalafil daily 2.5 mg, not nortadalafil. The case for the class is the case for tadalafil specifically.
▸ Subjective experience (deep)
(All from gray-market RC-vendor reports — extremely low-confidence, no controlled trial data.)
- Onset: ~30-60 min oral (faster than tadalafil per gray-market reports — consistent with the more polar / more rapidly absorbed structural argument)
- Peak: ~1-3 hr
- Plateau: ~4-6 hr (much shorter than tadalafil's 24-36 hr "weekend pill" plateau)
- Taper: trails out by ~10-12 hr
- Characteristic effects (claimed): vasodilation feel, easier erection, mild headache and flushing similar to tadalafil at equivalent doses. Some users report it "feels weaker" — which is consistent with the ~half-potency in vitro IC50.
- Side effect spread (claimed): similar profile to tadalafil but compressed into shorter time window. The fundamental class side-effects (headache, back pain, dyspepsia, NAION risk, priapism risk) all plausibly carry over.
The lack of validated clinical reports means none of this should be weighted heavily.
▸ Tolerance + cycling deep dive
- Tolerance buildup: Unknown for nortadalafil specifically; tadalafil shows minimal receptor downregulation in years of daily dosing, and the class is generally tolerance-stable.
- Recommended cycle: N/A — not recommended.
- Reset protocol: N/A.
▸ Stacking deep dive
Synergistic with
N/A — do not use, but if used, the synergy/conflict map mirrors tadalafil:
- L-citrulline / L-arginine (NO precursors): theoretical additive
- Methylene blue, citicoline, agmatine: mild theoretical additives via NO/cGMP nodes
- Beta-alanine, taurine, creatine: pharmacologically neutral
Avoid stacking with (class-wide hard contraindications)
- Nitrates of any form (nitroglycerin, isosorbide, "poppers"/amyl nitrite) — ABSOLUTE CONTRAINDICATION. Severe, potentially fatal hypotension. This is the headline FDA warning for every nortadalafil supplement recall.
- Alpha-blockers (tamsulosin, doxazosin, terazosin) — additive hypotension
- Riociguat / sGC stimulators — contraindicated; redundant pathway hit
- Strong CYP3A4 inhibitors (ketoconazole, ritonavir, clarithromycin, grapefruit) — assumed AUC raise, but unmeasured for nortadalafil specifically
- Strong CYP3A4 inducers (rifampin, carbamazepine, St. John's Wort) — assumed exposure drop
Neutral / safe co-administration
Unknown — no human interaction data.
▸ Drug interactions deep dive
Assumed CYP3A4 substrate by structural analogy to tadalafil. No formal interaction studies exist. The FDA safety messaging treats nortadalafil as functionally equivalent to tadalafil for nitrate-interaction risk — which is the only interaction warning that survives the "no human data" caveat because the mechanism is so direct.
▸ Pharmacogenomics
Unknown for nortadalafil specifically. CYP3A4/5 polymorphisms presumably matter (slow metabolizers higher AUC; ultrarapid lower) but no PGx data has been generated. NOS3 (eNOS) baseline NO production presumably modulates response magnitude as it does for tadalafil.
▸ Sourcing deep dive
| Path | Vendor | Cost | Reliability | Notes |
|---|---|---|---|---|
| Research chemical | Kimera Chems, ApexBio, MedChemExpress | $30-80 / 1 g | Low | "Not for human consumption" disclaimer; COA inconsistent across vendors and lots |
| Adulterated supplement (unintentional purchase) | Various sketchy Amazon / direct-to-consumer | $20-60 / bottle | Zero | The most common real-world exposure pathway; the user does not know he is consuming nortadalafil. FDA recalls examples: Sustain, Schwinnng, Arize, Endurea, MR.7 SUPER 700000, Vitality |
| Tadalafil generic (the dominant strategy instead) | Indian pharmacy (AllDayChemist, ReliableRX, BuyModa, AfinilExpress) — same vendors he uses for modafinil | $0.30-0.80/pill 20mg | Medium-high | Same gray-market sourcing reality as nortadalafil, but with FDA-validated active ingredient and 20+ years of safety data |
| Tadalafil generic (US legitimate) | Hims, Roman, Mark Cuban Cost Plus, GoodRx + local pharmacy | $10-20/mo | High | Telehealth Rx pathway is trivial for ED indication |
The user-archetype lesson: there is no realistic sourcing scenario in which nortadalafil is preferable. Tadalafil is the cleaner product at the same price across both gray-market and legitimate paths.
▸ Biomarkers to track (deep)
- N/A — not recommended for use. If used despite recommendation, the class-wide tadalafil monitoring panel applies:
- Baseline: resting BP (3-day average), HR, lipid panel, hsCRP, liver panel, baseline visual acuity
- During use: resting + orthostatic BP, headache frequency, back/myalgia tracking, vision symptoms
- Stop signs: any sudden vision change → ophthalmology immediately; priapism → ER
▸ Controversies / open debates Live debate
- Is there any legitimate use case for nortadalafil? Not for anyone with telehealth or established gray-market tadalafil access. The hypothetical case ("a researcher in a jurisdiction where tadalafil is unavailable but nortadalafil somehow is") is so narrow it doesn't apply to a US-based user.
- Will FDA escalate nortadalafil to scheduled-drug status? Plausible — the agency has done this with sibutramine analogs and cathinone analogs after enough enforcement actions. As of 2026, nortadalafil is still treated as an "undeclared drug ingredient" rather than a separately scheduled compound.
- Why does it keep showing up in supplements? Patent-evasion and analytical-detection-evasion. The original nortadalafil scaffold gets caught by FDA labs, so clandestine chemists iterate to N-cyclohexyl-, N-cyclopentyl-, 2-hydroxypropyl- variants. Liu 2023 and Xu 2016 are essentially the analytical-arms-race front line.
- Half-life: 6 hours or longer? The widely cited ~6 hr figure comes from limited animal-PK and chemistry-vendor literature; one credible-but-not-registrational dataset suggests it could trend longer at lower doses. Net: not nailed down, and probably never will be without a registrational program no one will fund.
▸ Verdict change log
- 2026-05-10 — Initial verdict: WATCH-LIST, HIGH confidence. Rationale: the FDA-approved parent compound (tadalafil) is dominant on price, purity, PK validation, and safety data; nortadalafil's only role on this user's stack is "things to recognize and avoid" in adulterated-supplement screening.
▸ Open questions / gaps Open
- Will any analytical chemistry group publish a definitive human-PK study on nortadalafil? Unlikely without a regulatory mandate.
- Selectivity panel against PDE6, PDE11 — would clarify whether nortadalafil's side effect profile differs from tadalafil's. Probably never measured rigorously.
- FDA enforcement trajectory — escalation to scheduled status would fully close the WATCH-LIST verdict to SKIP-ALWAYS.
- New variants in the wild — N-cyclohexyl, N-cyclopentyl, 2-hydroxypropyl already documented; the next wave (N-allyl, N-fluoroethyl, etc.) is predictable from medicinal-chemistry priors.
References
Liu et al. 2023 — Isolation and characterization of a novel tadalafil analogue adulterant, N-cyclohexyl nortadalafil, in a dietary supplement (J Pharm Biomed Anal, PMID 36841095)
analytical-chemistry detection of designer-adulterant nortadalafil variants
View StudyXu et al. 2016 — Isolation and characterization of a tadalafil analogue, N-cyclopentyl nortadalafil in health supplement (J Pharm Biomed Anal, PMID 26580820)
earlier designer-adulterant characterization
View StudyJin et al. 2024 — UPLC-MS/MS-Based Target Screening of 90 PDE5 Inhibitors in 5 Dietary Supplements (Molecules, PMID 39125006)
detected 2-hydroxypropyl nortadalafil in nutritional wine; broad screening framework
View StudyLi, Xu, Moezzi 2021 — Identification of Erectile Dysfunction Drugs in Dietary Supplements by LC Ion Trap MS (J Diet Suppl, PMID 32351143)
LC-MS detection methodology including nortadalafil class
View StudyTucker et al. 2018 — Unapproved Pharmaceutical Ingredients Included in Dietary Supplements Associated With FDA Warnings (JAMA Network Open, PMID 30646238)
776 contaminated supplements 2007-2016, sexual-enhancement category dominant
View StudyRing et al. 2005 — Effect of Tadalafil on CYP3A4-mediated Clearance (Clin Pharmacol Ther)
establishes tadalafil's primary metabolic route is methylenedioxy ring opening to catechol, NOT N-demethylation; supports framing that nortadalafil is a synthetic analog rather than an in-vivo tada…
View StudyFDA — Today The World Recalls Sustain and Schwinnng (Feb 2024) — undeclared tadalafil + nortadalafil
FDA — Today The World Recalls Arize Herbal (Feb 2024) — undeclared nortadalafil
Tadalafil prescribing information (FDA label, Cialis)
class PK / safety reference for the parent compound
View SourceHow was your experience with this compound?
Anonymous · one vote per session · results below at 5+ votes.
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