Ashwagandha extract increases testosterone and strength; reduces cortisol

Withania somnifera (also known as Ashwagandha or Indian ginseng) is used as a herb in Ayurvedic medicine and is claimed to have potent aphrodisiac, sedative, rejuvenative and life prolonging properties. It is also categorised as adaptogen (helps body cope with stressful conditions). Ashwagandha is used for many conditions and purposes but so far there is not enough data available to confirm its use for any of them. Interestingly the name aswagandha is a combination of the word ashva, meaning horse, and gandha, meaning smell as the root has a strong horse-like aroma [8].

Typical dosage

Typical and effective ashwagandha dose is somewhere between 300 to 500 mg daily. Some manufacturers dose their supplements with far lower dose than researchers use in their experiments. However, optimal Ashwagandha dose is 6000 mg per day divided into three similar doses throughout the day [7,9].

Rejuvenating Effect of Ashwagandha

A study by Venkataraghavan and others [1] demonstrated that Ashwagandha may be useful as a growth promoter and increase hemoglobin (molecule in red blood cells that carries oxygen) in the blood in growing children. Another clinical study in normal healthy male volunteers aged 50 to 59 also showed that 3/grams of purified Withania somnifera powder per day significantly increases hemoglobin and red blood cell count [2]. 71,4 % of subjects from that same study also reported improved sexual performance. According to these studies Withania somnifera may prove useful in younger and older populations as a general health tonic. Improved quality of life was reported by 50 healthy male/female athletic adults ingesting 500 mg of WS for 8 weeks [17].

Ashwagandha Benefits for Exercise

Withania somnifera has historically been used for treating stress-related health conditions. Biswajit and other researchers [3] investigated the effects of Withania somnifera root in chronically stressed humans. Their findings confirm Ashwagandha’s traditionaly claimed antistress-adaptogenic effect. After 60 days a significant decrease in serum cortisol was noted in all 98 patients that completed the study. Because of this effect many companies add Withania somnifera root and leaf extract in their supplements as a cortisol suppressant. However, this study was not independent, it was funded by Natreon Inc. – the patent holder for Withania somnifera extract.

Ashwagandha as Testosterone Booster

According to Mohammad Kaleem et al. [4] prospective study treatment with Withania somnifera effectively reduced oxidative stress. The results also demonstrated that treatment of infertile men (with suboptimal levels of testosterone) with 5 grams per day of ashwagandha root extract also significantly increased serum testosterone and luteinizing hormone levels and reduced the levels of follicle-stimulating hormone and prolactin compared to control group [4]. There were also noted significantly increased in sperm count, concentration, and motility among infertile men [4]. Guta A. et al. [10] reported normalized hormone balance (normalizing the reduction in testosterone concentrations) in infertile men after administering 5,000 mg ashwagandha root daily for 3 months. In a pilot study [12] where 46 infertile men ingested root extract of Ashwagandha (675 mg/day in three doses for 90 days) reported a significant increase in testosterone levels (by 17%). The same impact on hormone levels was also noted in recent animal study [5]. An experimental study from 2016 [11] also reported increased testosterone with M-A-T combo (Mucuna Pruriens, Ashwagandha and Tribulus Terrestris). M-A-T 1 group received 10 mg Mucuna, 10 mg Ashwagandha and 10 mg Tribulus, while M-A-T 2 received 20g of each. Both groups had a significantly increased testosterone, follicle-stimulating hormone and luteinizing hormone while there was no significant differences between M-A-T 1 and M-A-T 2.

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Effects of Ashwagandha on Muscle Mass and Strength

57 young male subjects (18-50 years old) with some experience in resistance training were put on a periodized strength training program and given either placebo or 300 mg of ashwagandha root extract twice daily for 8 weeks. Compared to the placebo, ashwagandha group had significantly greater increases in muscle strength on the bench-press exercise (almost 20 kg over placebo) and the leg-extension exercise (by 5 kg). There were also significant improvements in muscle size, serum testosterone, and muscle recovery as measured by plasma creatine kinase. [13] Another interesting study from 2014 [14] designed to investigate the effect of supplementation of Withania somnifera on the core muscle strength and stability in thirty two male hockey players reported significantly increased strength after 4 and 8 weeks of supplementation (500 mg capsules of aqueous roots of Ashwagandha twice daily). Exploratory study [15] evaluating activity of Ashwagandha for 30 days (750 mg/day x10 days, 1.000 mg/day x 10 days, 1.250 mg/day x 10 days) in healthy subjects reported significant increase of strength in muscle activity as measured by hand grip strength, quadriceps strength, and back extensor force. There were also reported improvements in the physical performance and strength parameters in healthy volunteers receiving ashwagandha aqueous extract 500 mg/day for 8 weeks [17].

Other Possible Uses

Nootropic

Ashawagandha has been used traditionally and commonly as a tonic and nootropic agent. One study in animals [6], which was later retracted, reported improved memory (nootropic-like effect) in memory deficient mice. Significant learning and memory enhancement was observed also with the protein extract of Withania somnifera in mice [16].

Improved Energy

Ashwagandha is also used as a general tonic to increase energy and prevent disease which may be partially related to its effect on the immune system [2]. Glycowithanolides and sitoindosides (isolated from Withania somnifera) showed improvements in immunomodulatory and central nervous system (antistress, memory, and learning) [2].

Improved Sleep Quality

In six out of eighteen healthy volunteers, improvement in quality of sleep was reported [15].

Erectile Dysfunction

Ashwagandha seems ineffective in the management of psychogenic erectile dysfunction (originating from the mind or psyche) [7]. Both ashwagandha and placebo groups exhibited significantly improved erection quality and sexual performance; thus effect was credited to placebo effect [7].

Side Effects and Toxicology

Toxicity studies show that ashwagandha appears to be a safe compound with little to no side effects [2]. However, large doses of ashwagandha may cause diarrhea and stomach upset [8]. There is some evidence that ashwagandha might cause miscarriages, therefore, it should be avoided during pregnancy [8]. No significant changes in liver and kidney functions (ALT, AST, creatine, ALP and urea) was observed in animal models feed 10 and 20 mg of ashwagandha extract daily [11]. A 30 day administration of relatively high dose of WS (up to 1250 mg daily) was well tolerated by all subjects but one. One volunteer showed increased appetite, libido, and hallucinogenic effects with vertigo at the lowest dose (750 mg/daily) and was withdrawn from study [15].