When I see an ingredient show up on nearly every formula for a given supplement, I feel compelled to investigate. Not the least because it’s my job, but also out of scientific curiosity.
Needless to say, D-Aspartic Acid, or D-Asp, has shown up in all the best T-Boosters, so I’m giving my readers a peek behind the scientific curtain to find out if there’s any truth behind the hype.
What You Need to Know
Perhaps one of the most cited studies on D-Asp was conducted ten years ago in Italy. It has since become the benchmark for D-Asp human studies. They found that after only 12 days, 87% of the men had testosterone increases. The increases were so large that even taking the other 13% of men into account, total increases for the group were 33%!
The mechanism of D-Asp was also studied, which is important to note. This means that the scientists didn’t merely measure the effect, but also took measurements to see how it was working. This eliminates potential interference from other variables. What the researchers found was that D-Asp is so influential on LH that 3 after stopping use, men still had a 14% higher LH in their blood. This LH is directly responsible for higher testosterone production in men.
All of this is interesting, and very promising, but we have seen in other areas of science that simply increasing the amount of something (like testosterone) doesn’t always lead to different health outcomes. That’s why it’s important to not just measure if D-Asp increases testosterone–but to see if D-Asp improves the physical markers of testosterone, as well.
In a landmark study a few years after the first, another team of Italian scientists set about to measure sperm outcomes for men taking D-Asp. They found a 2-fold increase in sperm concentration, and a 1.86-fold increase in the sperm motility among men treated with D-Asp. This also resulted in a higher rate of pregnancies.
These data are spectacular because they show that testosterone increases due to D-Asp are actually having biological impacts on the men involved. Of course, sperm health isn’t everything. What about overall fitness measures?
Fitness and Strength
In a peer-reviewed journal, researchers recently published their data on healthy athletes taking D-Asp before and after workouts. They found that the D-Asp athletes had increases in their one-rep max bench, and significant increases in their squat max – after only 14 days.
It’s also noteworthy that these men were only 22 years old, on average. This means that they were not yet suffering from low-T, and still saw skeletal muscle increases in only two weeks.
How D-Asp Works
D-Asp has been seen in its highest concentrations in the embryos of humans and animals. This led some researchers to investigate what mechanism it might be fulfilling. Some of the earliest research into it found that it is an amino acid chain that helps the brain select from different hormones for expression in later biological functions.
This was borne out in the Italian studies, that found D-Asp playing a role in how the brain sends signals to other endocrine (hormone) systems, telling the various organs like the testes which hormones to produce, and in which amounts.
This has culminated in literally hundreds of studies in animals and humans showing that D-Asp undisputedly plays a role in testosterone expression.
The verdict, I would say, is pretty well in. There’s no such thing as too much scientific study, and as many of the researchers I’ve quoted would say, more human data is definitely needed. But in the meantime, D-Asp has been shown as not only effective, but safe.