Tadalafil (Cialis)

Tadalafil selectively inhibits phosphodiesterase type 5 (PDE5), the enzyme responsible for degrading cyclic guanosine monophosphate (cGMP) in smooth muscle cells. cGMP is the second messenger that mediates nitric oxide (NO)-dependent vasodilation. By inhibiting PDE5, tadalafil allows cGMP to accumulate, causing prolonged smooth muscle relaxation and vasodilation in multiple vascular beds — including penile corpus cavernosum (erectile function), pulmonary vasculature, skeletal muscle vasculature (improved pumps), and prostatic/bladder neck smooth muscle (BPH relief). Unlike sildenafil and vardenafil, tadalafil also mildly inhibits PDE11, which is expressed in skeletal muscle, prostate, and testes.

Oral bioavailability is approximately 36% (independent of food intake — major advantage over sildenafil). Peak plasma concentration in 2 hours (range 0.5-6 hours). Protein binding approximately 94%. Metabolized primarily by CYP3A4 to a catechol metabolite (methylcatechol glucuronide) that is at least 13,000-fold less potent for PDE5. Terminal half-life of 17.5 hours, but pharmacological effects persist 24-36 hours. Reaches steady state in approximately 5 days at daily dosing. Excreted primarily in feces (61%) and urine (36%).

• ✓Significantly improves erectile function during AAS cycles when libido or function is impaired
• ✓Enhanced vasodilation provides noticeably better muscle pumps during training
• ✓Mild blood pressure reduction (3-5 mmHg systolic) — beneficial for AAS users with elevated BP
• ✓Ultra-long duration of action (24-36 hours) — daily dosing provides continuous coverage
• ✓No food interaction — can be taken at any time without affecting absorption
• ✓Improved exercise capacity and oxygen delivery through enhanced blood flow
• ✓Daily low-dose use improves prostate health and urinary symptoms
• ✓Improved penile blood flow may help maintain penile tissue health during suppressive cycles
• ✓Psychological confidence boost knowing sexual function is supported

• ⚠Headache (most common — 15-20% of users, usually diminishes with regular use)
• ⚠Nasal congestion and sinus pressure
• ⚠Back pain and myalgia (2-6% — more unique to tadalafil due to PDE11 inhibition)
• ⚠Facial flushing
• ⚠Dyspepsia/heartburn
• ⚠Dizziness from blood pressure reduction
• ⚠Visual disturbances (rare — mild blue tinge or light sensitivity)
• ⚠Priapism (extremely rare — seek immediate medical attention if erection persists 4+ hours)
• ⚠Lower limb edema at higher doses

Contraindications

• 🚫Concurrent nitrate medications (nitroglycerin, isosorbide) — LIFE-THREATENING hypotension risk
• 🚫Concurrent alpha-blocker use at high doses (can cause severe hypotension)
• 🚫Severe cardiovascular disease, recent MI, or unstable angina
• 🚫Severe hepatic impairment (Child-Pugh C)
• 🚫Severe renal impairment (dose adjustment needed)
• 🚫Hypotension (systolic <90 mmHg)
• 🚫Known hypersensitivity to tadalafil
• 🚫Retinitis pigmentosa or NAION history
• 🚫Recreational use of poppers (amyl/butyl nitrite) — causes dangerous BP drops

• 1.Daily 5mg dosing is the sweet spot for most AAS users — continuous erectile support, better pumps, mild BP reduction, no need to time around sexual activity
• 2.Unlike Viagra, food does not affect tadalafil absorption — take it whenever
• 3.The back pain/myalgia side effect is unique to tadalafil (PDE11 inhibition in skeletal muscle) — if this bothers you, switch to sildenafil
• 4.Start with 5mg to assess tolerance before going to 10-20mg as-needed doses
• 5.Do NOT combine with poppers/nitrates under any circumstances — this combination can be fatal
• 6.Many users report that daily tadalafil makes their steroid cycle significantly more enjoyable from a quality-of-life perspective
• 7.The BP-lowering effect is mild but real — beneficial for users whose BP rises on cycle, but be cautious if already on antihypertensives
• 8.Pre-workout 10mg provides dramatically enhanced pumps, especially for arm, chest, and shoulder training
• 9.Headaches typically diminish after 3-5 days of daily use as the body adjusts

1. [1]Forgue ST et al. Tadalafil pharmacokinetics in healthy subjects. Br J Clin Pharmacol. 2006;61(3):280-288.
2. [2]Kloner RA et al. Cardiovascular safety of tadalafil. Am J Cardiol. 2003;92(9A):37M-46M.
3. [3]Porst H et al. Efficacy and tolerability of tadalafil for treatment of erectile dysfunction. Int J Impot Res. 2003;15(Suppl 2):S18-S22.