Table of Contents
Introduction
Withania somnifera (L.) Dunal, commonly known as ashwagandha, is an evergreen shrub that is cultivated in tropical and subtropical regions of Asia, Africa, and Europe. It has been used in traditional Ayurvedic and Unani medicine systems as an adaptogen, which is a compound that helps the body resist and adapt to stressors [2,3]. Ashwagandha is known for its rich phytochemical content, including steroidal lactones (withanolides) and alkaloids [5-7].
In recent years, there has been growing interest in the potential efficacy of ashwagandha as a natural remedy for stress and anxiety. Clinical trials have investigated its effects on stress reduction, anxiety management, and sleep improvement. This article will review the available evidence on the efficacy and safety of ashwagandha as a natural remedy for stress and anxiety.
Stress and Anxiety
Efficacy
Several clinical trials have examined the effects of ashwagandha on stress and anxiety reduction. A systematic review conducted in 2021 identified seven studies that investigated the use of ashwagandha extracts for treating stress and anxiety [7]. These studies involved a total of 491 adults from India who had self-reported high stress and anxiety or a diagnosed anxiety disorder. The participants were randomized to receive ashwagandha or a placebo for 6 to 8 weeks.
The studies used various ashwagandha extracts, including root alone (KSM-66), root and leaf (Sensoril or Shoden), or unspecified parts. The dosage ranged from 240 to 1,250 mg/day of extract or 12,000 mg/day of whole root granules. The results showed that ashwagandha significantly reduced stress and anxiety levels, improved sleep quality, reduced fatigue, and decreased serum cortisol levels compared to the placebo. Higher doses of 500 to 600 mg/day appeared to have greater benefits.
Three additional studies published after the 2021 review also demonstrated the beneficial effects of ashwagandha on perceived stress. These studies involved participants taking ashwagandha root and leaf extracts (NooGandha and Prolanza) or an ashwagandha root extract (Gaia Herbs) [8-10]. The participants reported improvements in stress levels, anxiety, depression, food cravings, sleep quality, psychological well-being, memory, focus, and overall well-being.
Sleep
Limited research suggests that ashwagandha extracts may also have a positive impact on sleep. In a study conducted in India, participants with self-reported sleep problems were randomized to receive an ashwagandha root and leaf extract (Shoden) or a placebo for 6 weeks [12]. The ashwagandha group reported greater improvements in sleep quality, sleep efficiency, total sleep time, sleep latency, and awakening after sleep onset compared to the placebo group. They also reported an overall improvement in quality of life.
Another study in India investigated the effects of an ashwagandha root extract (KSM-66) on sleep quality in participants with and without insomnia [4]. The results showed that the ashwagandha extract improved sleep quality, sleep onset latency, mental alertness upon waking, and perceived anxiety symptoms in participants with insomnia. Participants without insomnia also reported improved sleep quality.
A systematic review and meta-analysis that included five studies found that ashwagandha extract had a small but significant effect on improving sleep compared to a placebo [13]. The studies involved participants with or without insomnia, and the dosage of ashwagandha ranged from 250 to 600 mg/day. The benefits were more prominent with a dosage of 600 mg/day and a treatment duration of at least 8 weeks.
Safety
Ashwagandha has been well tolerated in clinical trials for up to 3 months of use. Common side effects include stomach upset, loose stools, nausea, and drowsiness [7,14]. However, long-term safety data is limited, and the potential adverse effects of extended use are unknown.
There have been reports of more serious side effects associated with ashwagandha use, including liver injury. Some individuals developed liver dysfunction and hyperbilirubinemia after using ashwagandha in combination with other medications [15-19]. These cases improved after discontinuing the ashwagandha supplement, but the contents of the products were not independently verified in all cases.
Ashwagandha may also affect thyroid function. Some studies have shown an increase in blood thyroxine levels in individuals taking ashwagandha [20-23]. This suggests that ashwagandha may interact with thyroid hormone medications. Additionally, ashwagandha may interact with other medications, including antidiabetes medications, antihypertensives, immunosuppressants, and sedatives [7,24].
Experts advise against the use of ashwagandha during pregnancy and breastfeeding due to the potential risk of spontaneous abortion and unknown effects on infants [7,24-28]. Ashwagandha may also increase testosterone levels, making it potentially unsafe for individuals with hormone-sensitive prostate cancer [27,28].
Implications for Use
The available evidence suggests that ashwagandha may be an effective natural remedy for reducing stress and anxiety and improving sleep quality. However, more research is needed to determine the optimal dosage, duration of treatment, and long-term safety of ashwagandha use.
It is important to note that the studies conducted so far have used various ashwagandha preparations and doses, making it difficult to establish specific recommendations. Furthermore, most studies have been conducted within traditional medical systems, and the effects of ashwagandha as a dietary supplement outside of these systems are still unclear.
Ashwagandha has been well tolerated in short-term use, but the safety of long-term use is unknown. It is recommended to consult with a healthcare professional before starting any new supplement regimen, especially for individuals with pre-existing medical conditions or those taking medications.
In conclusion, ashwagandha shows promise as a natural remedy for stress, anxiety, and sleep improvement. However, more research is needed to fully understand its efficacy, safety, and optimal use.
