D-Aspartic Acid or Save Your Money?

D-aspartic acid (DAA) was a supplement I remember gaining popularity somewhere around 2008. I remember giving it a shot, as I heard good things, anecdotally of course from the annals of bro science: forums. I was skeptical of trying it but I thought, what the hell, why not. I was incredibly disappointed.

DAA is one of two forms of the amino acid aspartic acid. It’s been hypothesized that DAA can be used as a natural testosterone booster (t-booster). According to examine.com: “D-AA works in the central brain region to cause a release of hormones, such as luteinizing hormone, follicle-stimulating hormone, and growth hormone. It may also build up in the testicles, where it alleviates a rate-limiting step of Testosterone synthesis, which leads to a minor testosterone increase.”

This is another supplement made famous for it’s effects on rats. According to D’Aniello et al. DAA has some very impressive effects on rats. When injected with DAA, rats exhibited a 1.6-fold increase in luteinizing hormone, a 3.0-fold increase in testosterone, and a 2.9-fold increase in progesterone.

Very impressive results, no?

Just like Leptin, however, the results on humans have been zero, zilch, nada. Let’s go over what the current research has shown us.

One of the more interesting pieces of research to those who are supporters of DAA resulted in a 42% increase in serum testosterone after only 12 days of DAA treatment. This study, like the majority of studies on hormones on humans didn’t measure whether these changes in testosterone resulted in anything the average bro wants to know: do I get gainz? Y/N?

In terms of increasing serum testosterone it appeared that DAA might be a great supplement to use if you wanted to increase testosterone and like, not have that increase return any tangible results…

Science is always evolving and new questions were asked. The study above only lasted 12 days, a very short time period. Willoubhy et al. sought out to discover some more juicy details that definitely have more applicability to the strength community. This study would last 28 days, and be combined with heavy resistance training. The researchers would measure DAA’s effect on body composition, muscle strength, and serum hormones associated with the hypothalamo-pituatary-gonadal axis. Their subjects would be resistance-trained men.

The researchers’ hypothesis was that DAA would not increase endogenous testosterone levels or improve strength over a placebo. To keep things short, their hypothesis was pretty much on point: DAA was ineffective at up-regulating the activity of the hypothalamo-pituitary-gonadal axis and had no anabolic effects compared to the placebo.

Well that sucks. Maybe increasing the dosage from 3g/day in the Willoubhy study to 6g per day would do the trick?

Melville et al. sought out to check if the results of DAA on human were dose-dependent. So they compared a placebo group with a 3g/day group and ad 6g/day group on young, trained dudes. These guys were on average 25 y/o, with 3.5 years of lifting experience, with a bodyweight of ~187lbs and bench 1RM of ~225. Not crazy big or strong, but no slouches either.

The results of this study were a curveball to say the least. The 6g/day group had significantly reduced total testosterone compared to the control and 3g/day group.

The results of this are laughable as the conventional wisdom for many supplement takers is to take more and see better results. In the case of DAA, the motto should read ‘take some to remain unchanged, and take more to decrease your testosterone.’

I wanted to close out this article by covering another area that simply doesn’t get enough coverage when it comes to natural t-booster. Increasing your endogenous anabolic hormones doesn’t always equal a better and/or stronger physique. This is supported by research as well.

One of my favorite researchers (believe me, I don’t remember 99% of researchers names unless I know they’re invested in very interesting subject that I feel is applicable) is Dr. Stuart Phillips. This quote from Dr. Phillips has everything you need to know in a concise manner: “the acute post-exercise increases in systemic hormones are in no way a proxy marker for anabolism since they do not underpin the capacity of the muscle to hypertrophy in any measurable way.”

Much of Dr. Phillips research has shown that muscle protein synthesis (MPS)is a much more reflective marker of mass gainz from resistance training. Simply increasing your anabolic hormones in a normal range, won’t necessarily result in increased muscle size.

So how do anabolics work? Because you are elevating your levels to supraphysiological levels. Check this out for more info on that:

To summarize

  • DAA doesn’t seem to elevate hormones in trained young men, but it does in rats…
  • Even if it did elevate specific hormones, the elevation of these hormones most likely would not result in any actual muscle growth


Save your money, eat food, and train hard.