To those unfamiliar with D-aspartic acid, the name may sound totally foreign.
Essentially, it’s a molecule made in your body or obtained through protein-containing foods. Or through supplements.
What it Does
D-aspartic acid is one form of aspartic acid, the other one is L-aspartic acid. The difference is that L-aspartic acid is used to build protein molecules, whereas D-Aspartic Acid is not. Instead, D-Aspartic Acid has a direct impact on your hormones and nervous system.
The hormone part is particularly interesting. D-aspartic acid is often sold in testosterone boosters. Some research suggests it may activate certain parts of the brain that nudge testes to make more of the chief male hormone.
D-AA and Weight Loss?
All of this sounds interesting, but you’re probably wondering by this point, what does this have to do with D-aspartic acid and weight loss? “Can it help me lose weight or not?”
The answer is that D-aspartic acid is unlikely to help you lose weight, at least not directly on its own.
Although research is still not conclusive on whether D-AA boosts testosterone in humans or not, if it does, it means that it could somewhat stimulate fat loss because higher testosterone levels equal faster metabolism.
Studies – Are There Any?
Not on fat loss specifically. Most of the studies on D-AA are focused on men’s testosterone boosting potential. Most of them come from animals or are done in vitro, aka, on a petri dish.
A 2017 study review from International Journal of Reproductive Biomedicine suggests that while animal evidence looks promising, the few human studies that we do have found mixed results. 
A 2009 human clinical trial showed that D-AA improved luteinizing hormone levels, which is a precursor to testosterone. Both LH and testosterone levels were elevated from supplementation.  There are a few other trials showing similar results.
But there are also those which found no results, or in some cases, a slight and temporary drop in baseline T count.
A 2017 study led by Geoffrey W Melville, Jason C Siegler, and Paul W M Marshall showed just that. This was a follow-up to their previous study which showed a small decrease in testosterone levels in healthy, young resistance trained men. This time, they wanted to see the long-term results; the study lasting 90 days. They found that T levels didn’t decrease in these same men, but there was no increase either. 
But this study is not a good indicator of how D-AA supplements will work for most men. Why? Because they used a huge 6g of D-AA per day on these men. Whereas the best D-AA containing supplements use much lower dosages. 1.5g per day is more than enough, and usually the dosage that should lead to positive outcomes if other studies are to go by.
D-AA isn’t a bad supplement. It certainly has the potential to enhance male health; specifically, testosterone.
For weight loss, though, there are many compounds that are better that can be supplemented in its stead. Such as magnesium, zinc, Ashwagandha, green tea extract, cayenne pepper extract, glucomannan, and other proven fat burning and appetite suppressing supplements.
- Roshanzamir F, Safavi SM. The putative effects of D-Aspartic acid on blood testosterone levels: A systematic review. Int J Reprod Biomed. 2017 Jan;15(1):1-10. PMID: 28280794; PMCID: PMC5340133.
- Topo E, Soricelli A, D’Aniello A, Ronsini S, D’Aniello G. The role and molecular mechanism of D-aspartic acid in the release and synthesis of LH and testosterone in humans and rats. Reprod Biol Endocrinol. 2009 Oct 27;7:120. doi: 10.1186/1477-7827-7-120. PMID: 19860889; PMCID: PMC2774316.
- Melville GW, Siegler JC, Marshall PWM. The effects of d-aspartic acid supplementation in resistance-trained men over a three month training period: A randomised controlled trial. PLoS One. 2017 Aug 25;12(8):e0182630. doi: 10.1371/journal.pone.0182630. PMID: 28841667; PMCID: PMC5571970.