For LOW TESTOSTERONE, the amino acid L-arginine boosts nitric oxide production which directly parallels increasing testosterone levels. Nitric oxide and testosterone are inextricably linked. Because lower nitric oxide levels suppress testosterone production, which in turn causes nitric oxide levels to continue decreasing, supplementing with L-arginine can break the vicious cycle. As L-arginine helps nitric oxide levels to rise again, testosterone output comes back up.
Testosterone is one of the key hormones for optimal men’s health. Not only is the maintenance of a normal testosterone level vital for a man’s sexual health, it is now known to be critical for his emotional health and longevity as well. Unfortunately, testosterone levels in men today are at historic lows, independent of chronological aging.1 Although we suspect environmental influences, we do not yet have a clear understanding behind this substantial decrease. A flood of testosterone boosters has appeared on the market, a few with dangerous side effects and many others that are ineffective or useless.
L-arginine is a semi-essential amino acid, meaning that it can be made by the body but its production may be low, depending on factors such as age, mental or physical stress, or health situations in which the tissues require higher amounts. Though adult bodies make some arginine and it is found in small amounts in nuts, seeds, and legumes, it frequently needs to be consumed through supplementation to achieve ample tissue levels.
Testosterone and nitric oxide play very important roles in the male human body, and both are needed in order to have healthy emotional, physical, and sexual function. If either gets too low, the other will soon follow suit.
L-arginine is converted into nitric oxide (NO), facilitated by the enzyme NO synthase. Then in turn, nitric oxide stimulates testosterone production. Nitric oxide is a signaling molecule, which acts as an intra‐ and intercellular messenger for the control of several cellular functions, including hormone secretion. Specifically, in vitro studies demonstrated that nitric oxide increases gonadotrophin, a hormonal precursor necessary to produce testosterone.2 In addition, nitric acid causes blood vessels to open wider, improving blood flow. In the penis, NO synthase must be present in sufficient amounts for proper blood influx into the erectile tissues.
Nitric oxide, made from L-arginine, has several important influences on testosterone levels:
- Sleep: The body produces a significant amount of testosterone during sleep. Nitric oxide controls the release of acetylcholine in the brain, which regulates sleep/wake cycles. Decreased nitric oxide levels lead to diminished sleep, which in turn suppresses testosterone production.3 L-arginine encourages better sleep, via improved nitric oxide, which can boost healthy testosterone production.
- Mood: Testosterone levels fluctuate with mood, and tend to rise with happiness and success, and drop with stress, depression, and other emotional disorders. Low nitric oxide levels increase the risk of clinical depression, which can in turn lead to low testosterone levels.4 Because L-arginine is a precursor for nitric oxide, it helps to lift mood and increase a sense of well-being, resulting in higher testosterone output.
- Exercise: Studies have shown that physical activity increases serum testosterone levels. Taking L-arginine can provide the body with this building block to make more nitric oxide, leading to higher testosterone levels.
- As a precursor to nitric oxide which encourages blood vessels to open wider, improving blood flow, L-arginine helps erectile function. Because nitric oxide enhances testosterone levels, L-arginine may also help male sexual health by leading to better testosterone production by the testes. (An interesting side note is that the drug Viagra raises endothelial nitric oxide: this enhances healthy testosterone output, as well as penile circulation).
Research studies confirm that men who take L-arginine consistently for two to six months benefit from markedly increased testosterone levels. These men also experience better mood and feelings of motivation, as well as improved sexual functions including stronger libido and erectile capacity. Men with low testosterone levels commonly have low nitric oxide and NO synthase levels, and L-arginine brings excellent results for these patients.
In our clinic, we recommend a well-researched, sustained-release preparation which is necessary to maintain ample tissue levels of L-arginine over 24 hours with just two capsules daily. Plain L-arginine is rapidly metabolized and used up by the body, so blood levels drop fast if it is not taken frequently throughout the day. Each nitric acid molecule is also very short-lived and rapidly cleared from tissues, and so a slow-release L-arginine formula is crucial to maintaining stable testosterone levels.
Recommendation: L-arginine, complexed with a time-release matrix including methylcellulose, such as Time-Sorb®, 1,000 mg one to two times daily with any meals, or as directed by your healthcare provider.
- Travison, Thomas G., et al. “A population-level decline in serum testosterone levels in American men.” The Journal of Clinical Endocrinology & Metabolism 92.1 (2007): 196-202.
- Valenti, Sandra, et al. “Biphasic effect of nitric oxide on testosterone and cyclic GMP production by purified rat Leydig cells cultured in vitro.” International journal of andrology 22.5 (1999): 336-341.
- Wittert, Gary. “The relationship between sleep disorders and testosterone in men.” Asian journal of andrology 16.2 (2014): 262.
- McIntyre, Roger S., et al. “Calculated bioavailable testosterone levels and depression in middle-aged men.” Psychoneuroendocrinology 31.9 (2006): 1029-1035.
- Andrew PJ, Mayer B (Aug 1999). “Enzymatic function of nitric oxide synthases.” Cardiovascular Research. 43 (3): 521–31.