Theophylline
Sexual Well-Being
In plain English
Theophylline is an old asthma medicine that relaxes smooth muscle and widens blood vessels. It appears here in a topical arousal cream, on the theory that increasing local blood flow could aid arousal. There are no good studies showing it works applied to the skin for sexual arousal. Its use in this setting is experimental and unproven.
The science
Theophylline is a methylxanthine that acts as a non-selective phosphodiesterase inhibitor (raising cAMP/cGMP and relaxing smooth muscle) and a non-selective adenosine-receptor antagonist; at low concentrations it also activates histone deacetylase-2. These vasodilatory/smooth-muscle-relaxing properties provide the theoretical basis for inclusion in topical arousal creams. However, there is no credible clinical trial evidence that topical theophylline improves sexual arousal or function, and its established, FDA-approved use is systemic treatment of asthma/COPD, where it has a narrow therapeutic index (nausea, arrhythmias, seizures with toxicity) and numerous drug interactions. Topical compounded use for sexual arousal is off-label, unproven, and not an FDA-approved formulation. The pharmacology cited below describes mechanism only, not efficacy for sexual indications.