Tadalafil is a phosphodiesterase type 5 (PDE-5) inhibitor originally developed for the treatment of erectile dysfunction (ED) and pulmonary arterial hypertension (PAH).
It works by relaxing vascular smooth muscle and improving blood flow through enhanced nitric oxide (NO)–cGMP signaling. Compared to similar compounds such as sildenafil, tadalafil has a longer half-life, providing sustained vasodilatory activity for up to 36 hours.
In sports physiology, tadalafil has been studied for its potential to enhance oxygen delivery and vascular function under hypoxic conditions, although its performance-enhancing use is not approved and may fall under anti-doping restrictions.
Main effects of tadalafil
💓 Improves vascular dilation and peripheral circulation
🫁 Supports pulmonary blood flow and oxygenation
⚡ May reduce muscular fatigue through better tissue perfusion
🧠 Enhances endothelial nitric oxide signaling
💧 Decreases pulmonary vascular resistance
🩸 Promotes smooth muscle relaxation and cardiovascular efficiency
How to take tadalafil
Administration
Route: Oral, taken with water
Timing: 30–60 minutes before intended activity or once daily (for therapeutic use)
Half-life: Approximately 17–18 hours
Food interaction: Minimal; may be taken with or without meals
Dosage
Typical range: 5–20 mg depending on indication
Duration of effect: Up to 36 hours
Non-medical or performance-enhancing use is not recommended
Possible side effects
Mild headache, facial flushing, or nasal congestion
Indigestion or stomach discomfort
Back pain or mild muscle aches
Dizziness due to lowered blood pressure
Rarely: visual changes (blurred or tinted vision)
Contraindications
Concurrent use with nitrate medications or NO donors
Severe cardiovascular disorders or recent heart attack/stroke
Uncontrolled hypertension or hypotension
Severe renal or hepatic impairment
Known hypersensitivity to tadalafil or related agents
How to store
Keep at room temperature (20–25 °C / 68–77 °F)
Store in a dry, dark place, away from sunlight and moisture
Keep out of reach of children
How does tadalafil work
Tadalafil selectively inhibits the enzyme phosphodiesterase type 5 (PDE-5), which normally breaks down cyclic guanosine monophosphate (cGMP) in smooth muscle cells.
When nitric oxide (NO) is released during sexual stimulation or physical exertion, it activates guanylate cyclase, increasing cGMP levels. Elevated cGMP promotes relaxation of vascular smooth muscle, leading to vasodilation and enhanced blood flow.
By blocking PDE-5, tadalafil prolongs the action of cGMP, maintaining vessel relaxation and improving circulation to target tissues. In pulmonary vessels, this results in reduced arterial pressure and improved oxygen exchange, which explains its clinical role in pulmonary hypertension and the physiological interest in sports contexts.
