In the context of fast-paced and high-pressure modern lifestyles, sleep quality among adults is facing serious challenges. Growing consumer dissatisfaction with conventional sleep aids—particularly melatonin due to next-day side effects—has accelerated interest in safer, plant-based alternatives. Recent research highlights SIVI, a standardized pink passionflower (Passiflora incarnata L.) extract rich in GABA and flavonoids such as vitexin, as a promising natural ingredient for improving sleep quality and reducing stress. A randomized, double-blind, placebo-controlled clinical study demonstrated significant improvements in stress levels, sleep duration, sleep onset, and overall sleep quality without safety concerns. This article reviews the clinical findings, traditional uses, phytochemical composition, mechanisms of action, and additional potential benefits of Passiflora incarnata, while maintaining a cautious and evidence-based perspective relevant to human health.
In the fast-paced and high-pressure background of modern life, adult sleep quality is facing serious challenges. Gallup data reveal the prevalence of this issue: in 2023, 73% of American adults slept less than 8 hours per night, and 20% slept 4 hours or less per night, representing increases of 10.6% and 42.9% respectively compared with 2013. In addition, 63% of American adults reported that they need more sleep.
Gallup
This growing sleep crisis has directly driven the rapid development of the sleep aid market. According to data from Allied Market Research, the global sleep aid market was valued at USD 6.8 billion in 2023 and is projected to reach USD 11.8 billion by 2034.
However, current mainstream solutions on the market are not entirely satisfactory. Melatonin accounts for 35.8% of the sleep supplement market, yet it has notable side effects. A 2022 report by Nutritional Outlook pointed out that 40% of users experience adverse effects such as dizziness the next day. As a result, the market is quietly shifting toward safer options, with as many as 82% of consumers expressing strong interest in natural supplements that improve sleep.
Recently, a Chilean health ingredient supplier, Select Ingredients, introduced SIVI, an ingredient designed to improve sleep quality and relieve stress. SIVI is a plant-based, melatonin-free pink passionflower extract containing high concentrations of GABA and standardized to more than 5% vitexin. In addition, Select Ingredients collaborated with a research team from the Ayurveda College of Pune to publish a randomized, double-blind, placebo-controlled study in the journal Cureus, verifying the efficacy of SIVI in improving sleep quality and reducing stress.
DOI: 10.7759/cureus.56530
Clinical Evidence: SIVI for Stress Reduction and Sleep Quality
This study recruited 65 healthy men and women aged 18–60 with stress and insomnia. Participants were randomly assigned to either the SIVI group (32 individuals) or the placebo group (33 individuals). The SIVI group took capsules containing 600 mg of SIVI daily before bedtime, while the placebo group took identical-looking placebo capsules. The study lasted 30 days, with assessments conducted on Day 0, Day 15, and Day 30.
The study found that as SIVI intake duration increased, participants experienced significant reductions in stress and notable improvements in sleep duration. After one month of SIVI supplementation, participants’ stress levels decreased by 27.67%, and sleep duration increased by 13.33%, with results significantly superior to the placebo group. Furthermore, after one month of continuous use, participants showed significant reductions in sleep onset time and insomnia severity. The PSQI score decreased from 14.72 to 9.00, representing a 40% improvement in sleep quality.
Figure. Effect of SIVI (Passiflora incarnata extract) on stress assessed using PSS
In addition, the study reported no safety concerns associated with SIVI. At the end of the trial, participants in the SIVI group showed normal ranges in pulse, respiratory rate, body temperature, complete blood count, liver function tests, and kidney function tests.
Traditional Use and Bioactive Components of Passiflora incarnata
Pink passionflower (Passiflora incarnata L.), also known as passionflower, is a climbing vine of the Passifloraceae family, native to the southeastern United States. It was first documented by Spanish explorers in 1529 and later became one of the most commonly used species in Western herbal medicine. Today, pink passionflower is cultivated in Europe, Asia, Africa, and Oceania, valued for both ornamental and medicinal purposes. It has also been introduced in Chinese provinces such as Jiangsu, Guangdong, and Guangxi.
Pink passionflower has a long history of use. Early European travelers in North America observed that the Algonquin people of Virginia and the Creek people of Florida consumed its fruit. Later, its aerial parts (including leaves, flowers, and fruits) were widely used in traditional medicine in Europe, Asia, and Africa to address various symptoms.
As pink passionflower has been included in multiple national pharmacopeias and supported by increasing clinical research, its range of applications has gradually expanded. In the United States and Russia, Passiflora incarnata extract (PIE) is used in combination with other herbs to help manage anxiety, insomnia, sedation, and to support withdrawal from nicotine or alcohol dependence. In Korea, PIE is mainly used to prevent and alleviate menopausal syndrome. In Japan, PIE is combined with other herbs for sedation and sleep induction. In China, pink passionflower is currently used only as a skin-conditioning agent in cosmetics.
GABA, flavonoids, alkaloids, and volatile oils are the main bioactive substances in pink passionflower. Their synergistic effects form the basis of its wide medicinal value.
1) GABA
GABA (γ-aminobutyric acid) is a key inhibitory neurotransmitter in the central nervous system. It reduces neuronal excitability, helping the brain enter a relaxed state, thereby suppressing excessive cortical activity and creating conditions for emotional stability and natural sleep onset. One study found that among extracts of 21 plants (in dried form), including passionflower, ginseng, valerian, and ginkgo, PIE contained the highest GABA level at 629 mg/100 g.
2) Flavonoids
Flavonoids are the main compounds in pink passionflower, accounting for about 2.5%, primarily present in the leaves. These include vitexin, isovitexin, orientin, isoorientin, apigenin, kaempferol, and quercetin. The concentration of vitexin is significantly higher than in other Passiflora species. In addition, benzoflavones, which have regulatory effects on the central nervous system, are extracted from the aerial parts at approximately 132.8 mg/100 g.
3) Alkaloids
The alkaloids in pink passionflower are mainly monoterpenoid indole alkaloids with a β-carboline core structure, mostly found in the fruit. These include harman, harmol, harmaline, and harmine, which may act as monoamine oxidase inhibitors and have been studied for potential roles in improving depression, Parkinson’s disease, and Alzheimer’s disease.
4) Volatile oils
The essential oils of pink passionflower include phenethyl alcohol (1.2%), acetaldehyde (1.4%), phytol (1.9%), and aroma-related components such as α-pinene, limonene, and isopropylbenzene.
Mechanisms of Sleep and Stress Support
Pink passionflower is listed in the Martindale Herbal Pharmacopoeia as a sedative and antispasmodic and is used in combination with various medicines in 24 countries. The British Herbal Compendium and the German Commission E have recognized its anxiolytic effects and indicated its use for sleep disorders, restlessness, and anxiety.
Modern studies suggest that effective modulation of the GABAergic system in the central nervous system is the core mechanism by which pink passionflower improves sleep and mood.
Research shows that PIE enhances GABA’s inhibitory effects through two pathways: first, its active compounds bind to GABA-A and GABA-B receptors, increasing their sensitivity to GABA signaling; second, PIE inhibits the reuptake of GABA at cortical synapses, thereby prolonging GABA’s activity.
Vitexin, an active flavonoid compound in PIE, plays an important role in modulating the GABAergic system. Studies indicate that vitexin can act directly on the benzodiazepine binding site of the GABA-A receptor, mimicking the pharmacological effects of benzodiazepine drugs (such as diazepam), thereby enhancing GABA’s inhibitory effects and achieving sedation, anxiolytic effects, and sleep support.
In addition, vitexin may also regulate monoamine and cholinergic neurotransmitter systems, synergistically helping to counter stress, improve mood, and provide neuroprotective functions.
Additional Potential Benefits of Passiflora incarnata
1) Support in substance dependence
The anti-addictive effects of pink passionflower have been documented in several national pharmacopeias. Research has found that benzoflavones in PIE can reduce tetrahydrocannabinol (THC) levels in the brains of mice, thereby helping to mitigate cannabis dependence. Benzoflavones (BZF) in PIE may also reduce dependence on diazepam and nicotine in mice and alleviate withdrawal reactions.
2) Improvement of menopausal syndrome
Declining ovarian hormone levels during menopause lead to increased physiological and psychological changes. Most menopausal women experience symptoms such as insomnia, depression, fatigue, palpitations, and vasomotor symptoms. One study found that after taking PIE for six weeks, patients showed significant improvement in menopausal symptoms.
3) Analgesic effects
Neuropathic pain is caused by a series of neurobiological events that induce excessive electrical excitability in somatosensory pathways, leading to hyperesthesia, hypoesthesia, hyperalgesia, paresthesia, or allodynia. Research indicates that PIE produces dual, broad-spectrum analgesic effects for both acute and chronic pain by simultaneously activating GABA receptors and opioid receptors in the brain.