Piperine is the pungent alkaloid in black pepper (Piper nigrum), commercially standardized as BioPerine (Sabinsa, 95% piperine). Solo-use evidence as a nootropic, thermogenic, or weight-loss agent is thin. The real value is as a bioavailability enhancer: by inhibiting CYP3A4, CYP2C9, CYP1A2, UGT (glucuronidation), and P-glycoprotein efflux, piperine slows first-pass metabolism of co-administered compounds. The canonical result — Shoba 1998 (PMID 9619120) — is a 2000% increase in curcumin AUC in humans with 20 mg piperine. Similar magnitude AUC boosts exist for resveratrol (+229%), EGCG (~30%), beta-carotene, CoQ10, and others. The same mechanism that boosts curcumin also boosts prescription drugs metabolized via CYP3A4 — and ~50% of all therapeutic drugs are CYP3A4 substrates. PBPK modeling at 20 mg/day piperine predicts AUC increases of +31% to +59% for simvastatin, alfentanil, triazolam, cyclosporine, nifedipine, and ritonavir. Verdict: OPTIONAL-ADD, HIGH confidence — only as part of a co-formulated curcumin/resveratrol/quercetin product, never stand-alone; HARD BLOCK for users on Rx CYP3A4/P-gp substrates without prescriber sign-off. For Dylan (20yo MMA athlete, no Rx, on a polyphenol-heavy stack): a BioPerine-paired curcumin product is a reasonable cheap multiplier; isolated BioPerine capsules are unnecessary.