# Tadalafil

*Also known as: Cialis*

Long-acting PDE5 inhibitor; also used off-cycle for BPH/endothelial support.

## Overview

Tadalafil (Cialis) is a long-acting phosphodiesterase type 5 inhibitor used for erectile dysfunction, benign prostatic hyperplasia, and increasingly for daily endothelial support. It inhibits the PDE5 enzyme that breaks down cyclic GMP in smooth muscle, sustaining the nitric-oxide-mediated vasodilatory pathway and improving blood flow in erectile and pulmonary vascular tissue. The compound has a roughly 17-hour half-life, reaches peak plasma in roughly 2.5 hours, and shows about 80% bioavailability, supporting both on-demand and once-daily low-dose dosing with stable steady-state exposure over several days. Effects include sustained erectile function and lower urinary tract symptom relief, while common risks are headache, flushing, dyspepsia, and back pain, with rare priapism and the well-known absolute contraindication with nitrates. Harm reduction centers on never combining it with nitrates, on exercising caution with alpha-blockers, and on watching for cardiovascular strain when used alongside stimulants or anabolic compounds that raise blood pressure.

## Pharmacokinetics

- **Model tier:** advanced
- **Half-life:** 0.7 days (16.9999999992 hours)
- **Cmax:** 1725 ng/mL
- **Tmax:** 0.1 days
- **Bioavailability:** 80%

## Dosing

- **Default dose:** 5 mg
- **Typical range:** 2.5–20 mg
- **Units:** ng/mL

## Harm reduction

- **Interaction notes:** Tadalafil + clenbuterol or trenbolone compounds cardiovascular risk (tachycardia, BP). Monitor closely.

## Source

- **Label:** PMC tadalafil PK
- **URL:** https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1885023/

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**Canonical URL:** https://anabolicdex.com/compounds/tadalafil
**Plot:** https://anabolicdex.com/plot?compound=tadalafil