MedicationWell-studiedMedication

Tadalafil (Cialis)

Also known as Tadalafil

Half-life

~17

What is Tadalafil (Cialis)?

PDE5 inhibitor with 36-hour half-life. Daily dosing used for ED and cardiovascular benefits.

How Tadalafil (Cialis) works

PDE5 inhibition increases cGMP signaling in corpus cavernosum and vascular smooth muscle, improving NO-mediated vasodilation.

Benefits & uses

Common uses: Erectile dysfunction, blood pressure, pulmonary hypertension, vasodilation, muscle pumps.

Tadalafil (Cialis) dosage

Protokol doesn't recommend doses for prescription or controlled compounds. Any figures below are reference or observational reports — dosing should be set with a qualified clinician.

Reference range: Prescription-dependent (as-needed or low daily dose); doctor-directedClinical or reference range, not a personal recommendation.

Tadalafil (Cialis) half-life

~17.5 hours

Tadalafil (Cialis) side effects

Headache, flushing, back pain, nasal congestion. Contraindicated with nitrates.

Headache/flushing
Dyspepsia or back pain
Hypotension with nitrates
Headache
Back/muscle aches (characteristic)
Facial flushing
Indigestion
Nasal congestion

Warnings & monitoring

Prescription medication — requires a doctor. 🔴 NEVER combine with nitrates. Long half-life means side effects/interactions persist longer.

Tadalafil (Cialis) interactions

with PT-141
Caution · mild
Both compounds lower blood pressure via different mechanisms (MC4R vs PDE5). Combined use can cause significant hypotension — start with minimal doses and assess tolerance individually before combining.
Timing: Use lowest effective doses; monitor blood pressure; do not combine with alcohol
with Testosterone
Compatible
Low-dose daily tadalafil complements TRT for erectile function, cardiovascular health, and pulmonary blood pressure. Well-studied in combination — no clinically significant pharmacokinetic interaction.
Timing: Tadalafil daily (5 mg) alongside TRT is a common combination

Track Tadalafil (Cialis) in Protokol.

Log doses, model half-lives, check interactions, and line it all up against your bloodwork. Free on iPhone and Android.