Tadalafil
Also known as Cialis, Adcirca, Tad, Generic Cialis
A long-acting PDE5 inhibitor best known as Cialis. Technically a drug, not a peptide — but a staple in men's-health and longevity protocols thanks to its blood-flow, blood-pressure and prostate benefits at low daily doses.
Medical status: FDA-approved for erectile dysfunction and benign prostatic hyperplasia / enlarged prostate (Cialis), and for pulmonary arterial hypertension (Adcirca).
Also commonly used for (off-label)
- Daily 2.5–5 mg micro-dosing for blood pressure and blood-vessel (endothelial) health
- Better blood flow, pump and vascularity in the gym
- Prostate comfort and urinary symptoms
- Confidence and performance without timing a pill
- Longevity protocols aimed at cardiovascular ageing
Off-label and research uses are what people report, not approved indications. Talk to a clinician before using any of them.
How it's taken (route)
swallowed as a capsule or pill, usually on an empty stomach
New to peptides? Start with the beginner's guide.
- Typical frequency
- 2.5–5 mg once daily, or 10–20 mg as needed
- Half-life
- Around 17.5 hours — effects can last up to 36 hours
- Regulatory status
- FDA-approved prescription medication for erectile dysfunction and benign prostatic hyperplasia (Cialis) and pulmonary arterial hypertension (Adcirca)
No syringe needed
Tadalafil is taken oral capsule or tablet, so there is no U-100 syringe draw for it.
What it does
Tadalafil relaxes the smooth muscle lining blood vessels, which improves blood flow throughout the body. It is best known for treating erectile dysfunction, but the same mechanism supports a growing list of uses: relief from urinary symptoms caused by an enlarged prostate (BPH), lower pressure in the lungs' arteries, better exercise blood flow and "pump" in the gym, and healthier blood-vessel (endothelial) function overall. Typical dosing is 2.5–5 mg once daily for steady daily benefits, or 10–20 mg taken 30–60 minutes before sexual activity. The low daily dose is what most longevity and men's-health protocols use, because it keeps blood levels stable around the clock.
Mechanism
Tadalafil blocks an enzyme called phosphodiesterase type 5 (PDE5). PDE5 normally breaks down cGMP, a signalling molecule that relaxes blood-vessel walls. By slowing that breakdown, tadalafil lets cGMP accumulate, so blood vessels stay more relaxed and dilated — improving blood flow to the penis, prostate, lungs and working muscle. Because one dose lasts up to 36 hours (compared with 4–6 hours for sildenafil), it earned the nickname "the weekend pill" and works well as a once-daily microdose.
Stacks well with
- PT-141Blood flow covered, plus direct arousal and desire signalling from the brain.
- Testosterone CypionateCommon pairing when libido or performance also has a hormonal side.
- OxytocinPhysical performance alongside the bonding and connection side.
Popular combinations reported in the community and research literature — not a recommendation. Adding peptides multiplies side-effect risk; check with a clinician.
Commonly reported side effects
- Headache
- Facial flushing and warmth
- Nasal congestion
- Indigestion or acid reflux
- Back pain and muscle aches (a tadalafil signature — usually fades within 48 hours)
- Dizziness or light-headedness from lower blood pressure
- Rare: sudden vision or hearing changes — stop and seek medical care
Contraindications noted
- Anyone taking nitrates (nitroglycerin, isosorbide) — the combination can crash blood pressure
- Riociguat or other guanylate cyclase stimulators
- Recent heart attack or stroke, or severe unstable heart disease
- Very low blood pressure, or uncontrolled high blood pressure
- Severe liver or kidney disease without prescriber supervision
- Caution with alpha-blockers and heavy alcohol — the blood-pressure drops add up
Research notes
Tadalafil is one of the most-studied vascular drugs ever made. Beyond its approvals for erectile dysfunction, BPH and pulmonary arterial hypertension, researchers have explored daily low-dose use for endothelial function (the health of the blood-vessel lining), blood-pressure support, insulin sensitivity, exercise capacity, and even altitude sickness. Because endothelial dysfunction is a core feature of cardiovascular ageing, daily micro-dosing (2.5–5 mg) has become a popular longevity and men's-health protocol. Generic tadalafil is inexpensive and widely prescribed, so most people get it through a doctor or telehealth clinic rather than a research supplier.