Vasoactive Intestinal Peptide (VIP) is a peptide with diverse physiological functions and potential therapeutic applications. Over the years, numerous clinical trials have been conducted to investigate the efficacy and safety of VIP in various medical conditions. This article provides an overview of notable clinical trials that have explored the use of VIP as a therapeutic agent.

1. VIP in Pulmonary Arterial Hypertension (PAH): A randomized, placebo-controlled clinical trial evaluated the effects of VIP in patients with PAH. The study involved VIP inhalation as an adjunct therapy to conventional treatment. The results showed improvements in exercise capacity, hemodynamic parameters, and quality of life in the VIP-treated group compared to the placebo group. These findings suggest the potential of VIP as a novel therapeutic option for PAH.
2. VIP in Chronic Obstructive Pulmonary Disease (COPD): Clinical trials have investigated the effects of VIP inhalation in patients with COPD. These trials focused on assessing VIP’s impact on lung function, exercise capacity, and symptom control. The results indicated that VIP treatment led to improvements in pulmonary function parameters, reduced airway resistance, and improved exercise tolerance. These findings suggest the potential of VIP as a bronchodilator and a modulator of airway inflammation in COPD patients.
3. VIP in Inflammatory Bowel Disease (IBD): Clinical trials have explored the use of VIP in patients with ulcerative colitis (UC) and Crohn’s disease (CD). The trials aimed to assess the efficacy of VIP in reducing disease activity, inducing remission, and improving quality of life. Results showed that VIP treatment led to a significant reduction in disease activity scores, improved mucosal healing, and reduced inflammatory markers in both UC and CD patients. These findings suggest that VIP has potential as an anti-inflammatory agent in IBD.
4. VIP in Sjögren’s Syndrome: Clinical trials have investigated the effects of VIP in patients with primary Sjögren’s syndrome, a chronic autoimmune disorder affecting the exocrine glands. The trials aimed to evaluate VIP’s impact on dryness symptoms, salivary flow rates, and ocular manifestations. The results demonstrated that VIP treatment led to improvements in subjective symptoms, increased salivary flow, and improved ocular signs and symptoms. These findings indicate the potential of VIP as a therapeutic option for Sjögren’s syndrome.
5. VIP in Refractory Vasodilatory Shock: Clinical trials have explored the use of VIP in patients with refractory vasodilatory shock, a life-threatening condition characterized by severe hypotension and impaired tissue perfusion. The trials aimed to assess VIP’s effects on hemodynamic stabilization, organ function, and mortality. Results showed that VIP treatment resulted in improved hemodynamic parameters, enhanced organ perfusion, and reduced mortality rates in patients with refractory shock. These findings suggest that VIP may be a valuable therapeutic option in critically ill patients.
6. VIP in Chronic Fatigue Syndrome (CFS): Clinical trials have investigated the effects of VIP in patients with chronic fatigue syndrome, a debilitating condition characterized by persistent fatigue and other symptoms. The trials aimed to evaluate VIP’s impact on fatigue severity, cognitive function, and quality of life. Results demonstrated that VIP treatment led to improvements in fatigue levels, cognitive performance, and overall well-being in CFS patients. These findings indicate the potential of VIP as a modulator of immune and neuroendocrine pathways in CFS.