Men’s sexual health: Supporting testosterone and nitric oxide production with nutraceuticals


Why nutraceuticals that specifically address testosterone and nitric oxide levels may have a positive impact on male sexual function.

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A decline in libido and sexual function is not unusual as men age—and this frequently interferes with intimacy in romantic relationships. Healthy sexual function is a multifactorial process requiring healthy hormone production, healthy circulation, adequate energy levels, and proper mental wellbeing.

Research suggests that nutraceuticals that specifically address testosterone and nitric oxide levels can have a positive impact on male sexual function. Before discussing the specific nutraceuticals, let’s first review the decline of testosterone and nitric oxide in aging men.

Testosterone Decline

Testosterone (T) levels in men fall progressively with age. A significant percentage of men over the age of 60 years have serum T levels that are below the lower limits of levels in young adult men (age 20-30 years).1 Some studies2 show that men experience a gradual and progressive decline in total T levels that takes place at a rate of approximately 1% per year beginning in their thirties; other studies3 show an average annual decline of 1%-2% total T levels, with an even more rapid decline in free T. This reduction is implicated in reduced libido and sexual function.

Nitric Oxide Decline

Nitric oxide (NO), a compound produced by the body, is necessary for vasodilatation of blood vessels and, consequently, erectile function. NO production, however, declines steadily with increasing age in healthy humans.4 In the coronary circulation of aging adults, a loss of 75% of endothelium-derived NO was shown in 70- to 80-year-old patients compared to young, healthy 20 year olds.5


Although there are several nutraceuticals that can help promote healthy testosterone levels, the one I’m going to focus on in this article is root of ashwagandha (Withania somnifera), which has been used in Ayurvedic medicine6 for over 3000 years. The traditional therapeutic actions of ashwagandha have been said to include tonic, aphrodisiac, narcotic, diuretic, anthelmintic, astringent, anti-inflammatory, sedative, alterative, thermogenic, and stimulant effects.7,8

In one 90-day, two-arm, double-blind, randomized, placebo-controlled, parallel-group study,9 the effects of ashwagandha root extract (KSM-66 brand of ashwagandha, 675 mg/day in three doses, n=21) or placebo (n=25) on spermatogenic activity and serum hormone levels in 46 patients with oligospermia were examined. The results with ashwagandha were:

  • 167% increase in sperm count (P<0.0001)
  • 53% increase in semen volume (P<0.0001)
  • 57% increase in sperm motility (P<0.0001)
  • 17% increase in serum testosterone (P<0.01)
  • 34% increase in luteinizing hormone (P<0.02)

Another eight-week randomized, prospective, double-blind, placebo-controlled clinical study10 was conducted to examine the effects of the ashwagandha root extract (KSM-66 brand, one 300-mg capsule twice daily) or placebo on muscle strength and endurance, size and recovery, testosterone, and body fat in 50 healthy and physically active males (18-45 years of age, n=25 for each group) with little experience in resistance training. Creatine kinase (CK) was assessed as a biomarker of recovery from muscle injury. Compared to placebo, these were the results of ashwagandha supplementation:

  • Significantly increased muscle strength (bench press) (P<0.001)
  • Significantly increased muscle size (arm) (P<0.05)
  • Increased serum testosterone 15% (P<0.05)
  • Significantly reduced body fat percentage (P<0.05)

Plant Superfood Blend

While there are a few nutraceutical options for increasing nitric oxide (NO) levels (including arginine, citrulline, and beetroot), perhaps my favorite is a plant superfood blend known as Spectra. Besides being a powerful antioxidant with a high ORAC value,11,12,13 a crossover, double-blind, placebo-controlled, single-dose study14 on the effects of this superfood blend (100 mg/day) showed that it resulted in a meaningful reduction of cellular inflammatory response and also increased bioavailable NO concentration 64%.


Given the prevalence of decreased testosterone and nitric oxide in aging men, the use of these nutraceuticals offers an option for helping to increase levels of these vital biochemicals, with a high margin of safety and efficacy.

Gene Bruno, MS, MHS, RH (AHG) possesses 42 years of dietary supplement industry experience. With a master’s degree in nutrition and a second master’s degree in herbal medicine, he has a proven track record of formulating innovative, evidence-based dietary supplements. Mr. Bruno currently serves as both the vice president of scientific and regulatory affairs at NutraScience Labs and professor of nutraceutical science at Huntington University of Health Sciences.


  1. Wang C et al. “Investigation, treatment and monitoring of late-onset hypogonadism in males: ISA, ISSAM, EAU, EAA and ASA recommendations.” European Journal of Endocrinology, vol. 159, no. 5 (November 2008): 507-514
  2. Matsumoto AM. “Andropause: Clinical implications of the decline in serum testosterone levels with aging in men.” The Journals of Gerontology: Series A, Biological Sciences and Medical Sciences, vol. 57, no. 2 (February 2002): M76-M99
  3. Araujo AB et al. “Endocrinology of the aging male.” Best Practices & Research. Clinical Endocrinology & Metabolism, vol. 25, no. 2 (April 2011): 303-319
  4. Torregrossa AC et al. “Nitric oxide and geriatrics: Implications in diagnostics and treatment of the elderly.” Journal of Geriatric Cardiology, vol. 8, no. 4 (December 2011): 230-242
  5. Vita JA et al. “Coronary vasomotor response to acetylcholine relates to risk factors for coronary artery disease.” Circulation, vol. 81, no. 2 (February 1990): 491-497
  6. Anonymous. Monograph. Withania somnifera. Alternative Medicine Review, vol. 9 (2004): 211-214
  7. Singh N et al. “An overview on ashwagandha: A Rasayana (rejuvenator) of Ayurveda.” African Journal of Traditional, Complementary, and Alternative Medicines, vol. 8, 5 Suppl (2011): 208-213
  8. Uddin Q et al. “Phytochemical and pharmacological profile of Withania somnifera Dunal: A review.” Journal of Applied Pharmaceutical Science, vol. 2, no. 1 (2012): 170-175
  9. Ambiye VR et al. “Clinical evaluation of the spermatogenic activity of the root extract of ashwagandha (Withania somnifera) in oligospermic males: A pilot study.” Evidence-Based Complementary and Alternative Medicine. Published online November 28, 2013.
  10. Sachin W. “Effects of ashwagandha root extract (Withania somnifera) on muscle strength, size and recovery, testosterone, and body fat in healthy adults.” Unpublished; 2014: 25 pgs.
  11. Certificate of Analysis. Customer: Van Drunen Farms. Sample Identification: Batch #: B-10516b. Description: Spectra, Powder, 19600000N850. Date of report: 08/06/2010. Brunswick Laboratories, 200 Turnpike Rd, Southborough, MA 01772 USA
  12. Certificate of Analysis. Customer: Van Drunen Farms. Sample Identification: Batch #: B-11202b. Description: Spectra, Powder, 04910000N850. Date of report: 03/25/2011. Brunswick Laboratories, 200 Turnpike Rd, Southborough, MA 01772 USA
  13. Certificate of Analysis. Customer: Van Drunen Farms. Sample Identification: Batch #: B-11670b. Description: Spectra, Powder, 24210000N850. Date of report: 09/30/2011. Brunswick Laboratories, 200 Turnpike Rd, Southborough, MA 01772 USA.
  14. Nemzer BV et al. “New insights on effects of a dietary supplement on oxidative and nitrosative stress in humans.” Food Science & Nutrition, vol. 2, no. 6 (November 2014): 828-839
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