Indian ginseng, better known as ashwagandha (Withania somnifera), has been used in Indian Ayurvedic medicine for roughly three thousand years. The name comes from Sanskrit: “ashwa” means horse, and “gandha” means smell. So ashwagandha literally means “smells like a horse.” Not the most appealing name, but apparently the root does have a distinctly horsey odour.

It belongs to a category of herbs called adaptogens. The idea behind adaptogens is that they help your body cope with stress and restore balance. Other plants in this category include maca, Panax ginseng, Siberian ginseng (eleuthero), and rhodiola.

The plant itself is an evergreen shrub native to India, the Middle East, and parts of Africa. It produces small orange-red berries, though it’s the roots that get used medicinally. The Latin species name “somnifera” means sleep-inducing, which gives you a hint about one of its traditional uses.

Ashwagandha contains several active compounds, including withanolides (the main bioactive chemicals), saponins, alkaloids, and various amino acids. Laboratory studies suggest these compounds have anti-inflammatory, antioxidant, and possibly immune-modulating effects. Whether these translate to meaningful benefits in humans is another matter entirely.

What does the research actually show?

I should be upfront here: ashwagandha research is still in its early stages. Most studies are small, many lack proper controls, and the supplement industry has an obvious financial interest in positive results. That said, there are some areas where the evidence looks reasonably promising.

1. Anxiety and stress reduction

This is probably where ashwagandha has the strongest evidence. A systematic review and meta-analysis published in 2014 examined five randomised controlled trials and found that ashwagandha supplements significantly reduced scores on anxiety and stress scales compared to placebo [1].

The effect sizes weren’t enormous, but they were consistent across studies. Participants taking ashwagandha reported feeling less anxious and stressed than those taking placebo pills.

How might it work? The leading theory involves cortisol, the stress hormone. Several studies have measured lower cortisol levels in people taking ashwagandha, though the relationship between cortisol and subjective stress is complicated and not always straightforward [2].

One 2012 study gave 64 adults with chronic stress either ashwagandha root extract (300 mg twice daily) or placebo for 60 days. The ashwagandha group showed a 27.9% reduction in serum cortisol levels compared to a 7.9% reduction in the placebo group [2]. They also reported feeling significantly less stressed on standardised questionnaires.

I’ll admit the anti-anxiety evidence is reasonably convincing, at least for mild to moderate everyday stress. For clinical anxiety disorders, you’d want to talk to a doctor rather than self-treating with supplements.

2. May support male reproductive health

Several studies have examined whether ashwagandha can improve sperm quality in men with fertility problems. The results have been cautiously positive.

A 2013 study gave ashwagandha root powder to 46 men with low sperm counts for 90 days. By the end of the study, participants showed increases in sperm count (167%), semen volume (53%), and sperm motility (57%) [3]. Testosterone levels also increased. However, this study lacked a placebo control group, which limits how much we can conclude.

Another study from 2010 found similar improvements in sperm parameters among men with stress-related fertility problems [4]. The researchers suggested that ashwagandha’s stress-reducing effects might partly explain the improvements, since psychological stress can affect hormone levels and sperm production.

For psychogenic erectile dysfunction specifically, the evidence is less encouraging. A 2011 randomised controlled trial found no significant difference between ashwagandha and placebo for men with erectile dysfunction caused by psychological factors [5].

Bottom line: ashwagandha might help improve sperm quality, possibly through stress reduction and mild testosterone effects. It probably won’t fix erectile dysfunction that stems from psychological causes.

3. Female sexual function

A small study published in 2015 examined whether ashwagandha could help women experiencing sexual difficulties [6]. Fifty healthy women reporting low sexual satisfaction were randomised to receive either ashwagandha root extract or placebo for eight weeks.

The ashwagandha group reported improvements in arousal, lubrication, orgasm, and satisfaction on a validated sexual function questionnaire. They also had more successful sexual encounters over the study period.

The proposed mechanism involves testosterone. Women produce small amounts of testosterone, and low levels can contribute to reduced libido. Ashwagandha may modestly increase testosterone in women, which could explain the effects.

However, this was a single small study. I wouldn’t read too much into it until larger trials confirm the findings.

4. Exercise performance and muscle strength

This one surprised me. Several studies suggest ashwagandha might actually improve physical performance during exercise.

A 2015 randomised controlled trial gave ashwagandha root extract to 57 young men participating in resistance training over eight weeks [7]. Compared to placebo, the ashwagandha group gained more muscle strength, had greater increases in muscle size, recovered faster (measured by creatine kinase levels), and had higher testosterone levels.

Another study from 2012 examined VO2 max, a measure of cardiovascular fitness, in 50 athletic adults [8]. Those taking ashwagandha for 12 weeks showed greater improvements in maximum oxygen consumption compared to placebo. They also reported better quality of life.

The performance-enhancing effects might involve ashwagandha’s impact on testosterone, cortisol (high cortisol can break down muscle), or direct effects on muscle cells. Whatever the mechanism, this is one of the more interesting applications that doesn’t get much attention.

5. Obsessive-compulsive disorder (adjunct therapy)

Obsessive-compulsive disorder affects roughly 1-3% of the population. Standard treatment involves selective serotonin reuptake inhibitors (SSRIs) and cognitive behavioural therapy, but many people don’t respond fully to these treatments.

A 2016 study examined whether adding ashwagandha to standard SSRI treatment might provide additional benefit [9]. Thirty patients with OCD were randomised to receive either ashwagandha extract or placebo alongside their usual SSRI medication for six weeks.

The ashwagandha group showed greater improvements on the Yale-Brown Obsessive-Compulsive Scale compared to the placebo group. The effect was statistically significant but modest.

The researchers suggested that ashwagandha might enhance serotonin synthesis or affect serotonin receptor sensitivity, potentially complementing the mechanism of SSRI medications.

This is preliminary evidence from a single small study. Nobody should stop their prescribed OCD medications to take ashwagandha instead. But as an add-on therapy, it might warrant further research.

Side effects and safety concerns

Ashwagandha appears reasonably safe for most healthy adults when taken at typical supplement doses for up to three months. Common side effects are usually mild and include stomach upset, diarrhoea, and nausea, particularly at higher doses [10].

However, there are several important safety considerations:

Pregnancy and breastfeeding: Animal studies suggest ashwagandha may cause miscarriage at high doses. Pregnant women should avoid it entirely. Safety during breastfeeding is unknown, so it’s best avoided then too.

Thyroid conditions: Ashwagandha may increase thyroid hormone levels. If you have an overactive thyroid (hyperthyroidism) or take thyroid medications, this could cause problems. People with underactive thyroid (hypothyroidism) taking levothyroxine should be cautious, as ashwagandha might change their dosage requirements [11].

Autoimmune diseases: Because ashwagandha may stimulate immune function, it could theoretically worsen autoimmune conditions like rheumatoid arthritis, lupus, Hashimoto’s thyroiditis, or multiple sclerosis. This is a theoretical concern rather than a proven problem, but caution seems reasonable.

Blood sugar and blood pressure: Ashwagandha may lower both blood glucose and blood pressure. If you take diabetes medications or blood pressure drugs, this could cause levels to drop too low.

Surgery: Stop taking ashwagandha at least two weeks before any scheduled surgery. It may slow down the central nervous system and could interfere with anaesthesia and other medications used during operations.

Drug interactions: Ashwagandha may interact with sedatives, sleeping pills, and medications that suppress the immune system. If you take any prescription medications, check with your pharmacist or doctor before starting ashwagandha.

Stomach ulcers: Ashwagandha may irritate the gastrointestinal lining. People with peptic ulcers should probably avoid it.

Liver concerns: There have been rare case reports of liver injury associated with ashwagandha supplements [12]. While this appears uncommon, people with liver disease should be cautious.

Dosage

Most studies have used ashwagandha root extract at doses between 300-600 mg daily, often divided into two doses. Some studies used higher doses up to 1,250 mg daily without major problems, but sticking to studied doses seems sensible.

Look for products standardised to contain a specific percentage of withanolides (usually 2.5-5%), as this ensures consistent potency. The extract forms (like KSM-66 or Sensoril) have more research behind them than raw root powder.

The bottom line

Ashwagandha has reasonable evidence for reducing everyday stress and anxiety, and possibly for improving sperm quality in men with fertility concerns. The exercise performance benefits are interesting but need more research. Effects on female sexual function and OCD are preliminary.

It’s not a miracle herb, and the research has limitations. But compared to many supplements, ashwagandha has a decent evidence base. If you’re interested in trying it for stress reduction, it’s relatively safe for most healthy adults to experiment with for a few months.

That said, supplements aren’t a substitute for addressing underlying health problems. Persistent anxiety, fertility difficulties, or other ongoing symptoms warrant a conversation with a healthcare provider rather than self-treatment with herbs.

References

Pratte MA, Nanavati KB, Young V, Morley CP. An alternative treatment for anxiety: a systematic review of human trial results reported for the Ayurvedic herb ashwagandha (Withania somnifera). J Altern Complement Med. 2014;20(12):901-908. doi:10.1089/acm.2014.0177
Chandrasekhar K, Kapoor J, Anishetty S. A prospective, randomized double-blind, placebo-controlled study of safety and efficacy of a high-concentration full-spectrum extract of ashwagandha root in reducing stress and anxiety in adults. Indian J Psychol Med. 2012;34(3):255-262. doi:10.4103/0253-7176.106022
Ambiye VR, Langade D, Dongre S, Aptikar P, Kulkarni M, Dongre A. Clinical evaluation of the spermatogenic activity of the root extract of Ashwagandha (Withania somnifera) in oligospermic males: a pilot study. Evid Based Complement Alternat Med. 2013;2013:571420. doi:10.1155/2013/571420
Mahdi AA, Shukla KK, Ahmad MK, et al. Withania somnifera improves semen quality in stress-related male fertility. Evid Based Complement Alternat Med. 2011;2011:576962. doi:10.1093/ecam/nep138
Mamidi P, Thakar AB. Efficacy of Ashwagandha (Withania somnifera Dunal. Linn.) in the management of psychogenic erectile dysfunction. Ayu. 2011;32(3):322-328. doi:10.4103/0974-8520.93907
Dongre S, Langade D, Bhattacharyya S. Efficacy and safety of ashwagandha (Withania somnifera) root extract in improving sexual function in women: a pilot study. Biomed Res Int. 2015;2015:284154. doi:10.1155/2015/284154
Wankhede S, Langade D, Joshi K, Sinha SR, Bhattacharyya S. Examining the effect of Withania somnifera supplementation on muscle strength and recovery: a randomized controlled trial. J Int Soc Sports Nutr. 2015;12:43. doi:10.1186/s12970-015-0104-9
Shenoy S, Chaskar U, Sandhu JS, Paadhi MM. Effects of eight-week supplementation of Ashwagandha on cardiorespiratory endurance in elite Indian cyclists. J Ayurveda Integr Med. 2012;3(4):209-214. doi:10.4103/0975-9476.104444
Jahanbakhsh SP, Manteghi AA, Emami SA, et al. Evaluation of the efficacy of Withania somnifera (Ashwagandha) root extract in patients with obsessive-compulsive disorder: A randomized double-blind placebo-controlled trial. Complement Ther Med. 2016;27:25-29. doi:10.1016/j.ctim.2016.03.018
National Center for Complementary and Integrative Health. Ashwagandha. NCCIH. https://www.nccih.nih.gov/health/ashwagandha. Updated January 2024.
Sharma AK, Basu I, Singh S. Efficacy and safety of ashwagandha root extract in subclinical hypothyroid patients: a double-blind, randomized placebo-controlled trial. J Altern Complement Med. 2018;24(3):243-248. doi:10.1089/acm.2017.0183
Björnsson HK, Björnsson ES, Avula B, et al. Ashwagandha-induced liver injury: A case series from Iceland and the US Drug-Induced Liver Injury Network. Liver Int. 2020;40(4):825-829. doi:10.1111/liv.14393