What to know about D-aspartic acid supplements for erectile dysfunction

Many supplement manufacturers claim that the amino acid D-aspartic acid can improve erectile dysfunction, usually by increasing testosterone levels. Some research supports this claim, but the science on the benefits of D-aspartic acid is not conclusive.

Many people live with erectile dysfunction (ED). By the age of 50, about 50% of men have some form of ED, and more than 5% are completely unable to get or keep an erection.

While D-aspartic acid (DAA) may have some use in treating ED, other treatments are more likely to work. Furthermore, doctors do not know the potential side effects or long-term consequences of taking DAA.

Keep reading to learn more.
What is D-aspartic acid?
Alternative treatments to D-aspartic acid may be more effective in treating ED.

DAA is an amino acid that is present in the central nervous system and reproductive system.

Research in both animals and humans suggests that it plays a role in the development of the nervous system and may help regulate hormones. This second function could mean that DAA regulates levels of testosterone and other hormones that affect sexual function.

While there are studies showing that DAA may raise testosterone levels, some recent research calls this claim into question.
Does it work for erectile dysfunction?

Proponents of DAA as an ED treatment argue that it can increase testosterone levels, thereby treating ED. However, the relationship between ED and testosterone is not clear, and many people with normal testosterone levels still have ED.

Most people with ED experience decreased blood flow to the penis, often due to cardiovascular health issues, high blood pressure, diabetes, or high cholesterol. Testosterone will not treat these conditions.

In some cases, ED is due to psychological factors, such as depression, relationship problems, or anxiety. There is no evidence to suggest that testosterone can treat these issues.

Increasing testosterone may be helpful for people with low testosterone levels. However, even in this population, there is only limited evidence that DAA works.
D-aspartic acid and testosterone

The findings of studies looking at DAA and testosterone have not been consistent.

A 2017 trial compared a group of 11 male athletes who received DAA supplements with 11 who did not. Both groups participated in 3 months of resistance training. At the end of the study, the DAA group did not have statistically significant increases in testosterone levels or strength.

An earlier study analyzed the role of DAA in both humans and rats. A group of 23 men took daily DAA supplements for 12 days, while 20 others took a placebo. Additionally, 10 rats received either DAA supplements or a placebo for the same length of time. In both humans and rats, the DAA supplement group showed increased synthesis and release of testosterone.

Even earlier data from a study in rats suggest that injecting DAA into the hypothalamus might induce an erection. However, no studies have tested a similar claim in people, and DAA supplements that a person takes orally might not have the same effects as those that a doctor injects.

A 2017 review, in which the authors examined 23 human studies and four animal studies, provides the strongest evidence that DAA may increase testosterone. Most of the included research suggests that DAA may either act on Leydig cells in the testes, which release testosterone, or change behavior in the hypothalamus or pituitary gland, instructing the testes to secrete testosterone.

The authors caution that more research on the role of DAA is necessary before scientists can draw clear or specific conclusions.