How a tiny strip
does big work.

Sildenafil is the active ingredient in Viagra. It belongs to a class of medications called PDE5 inhibitors.

An erection happens when blood flow into the penis increases. Sildenafil blocks an enzyme (PDE5) that breaks down the signal responsible for that blood flow, so when you're aroused, it's easier to get and maintain an erection. It does not create arousal on its own — sexual stimulation is still required.

Used in clinical practice since 1998. Most common side effects are mild headache, flushing, or nasal congestion.

Tadalafil is the active ingredient in Cialis. It's in the same PDE5 inhibitor family as sildenafil but with a much longer half-life.

Same mechanism as sildenafil — it blocks PDE5 to support healthy blood flow during arousal. The difference is duration: a single dose stays active for up to 36 hours, which is why tadalafil is often called the "weekend" medication. Combining it at a lower dose with sildenafil gives you both fast onset and a long window of responsiveness.

Approved by the FDA in 2003. Like sildenafil, it requires sexual stimulation to work and is well-tolerated in most healthy adults.

Oxytocin is a naturally occurring hormone your body produces during physical closeness, hugging, and intimacy. It's often referred to as the "bonding" hormone.

At a low, micro-dose level, oxytocin is included to support a sense of calm, connection, and presence — the emotional side of intimacy that an erection medication alone doesn't address. Early research suggests oral oxytocin may help reduce performance anxiety in some men.

Used off-label in compounded sexual health formulations. The dose in Solved is well below thresholds used in obstetric medicine.