Trial reportPloS one2017
The effects of d-aspartic acid supplementation in resistance-trained men over a three month training period: A randomised controlled trial.
Trial report in PloS one, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 14 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
14 citing papers in PubMed, 1 synthesis or guideline pooled it, 28 citations in OpenAlex.
- Rational and Translational Implications of D-Amino Acids for Treatment-Resistant Schizophrenia: From Neurobiology to the Clinics.Biomolecules · 2022Pooled it
- Trial
- Fatigability of the knee extensors following high- and low-load resistance exercise sessions in trained men.European journal of applied physiology · 2022Trial
- The Association of Low Muscle Mass With Serum Sex Hormones and Sex Hormone-Binding Globulin.Journal of cachexia, sarcopenia and muscle · 2025Article
- Prevalence of extra-articular deformity (EAD) and tibia vara (TV) in patients undergoing total knee arthroplasty (TKA) in Indian population.Journal of clinical orthopaedics and trauma · 2025Article
- Genome-wide association study of maternal plasma metabolites during pregnancy.Cell genomics · 2024Article
- Comparison of the Regenerative Metabolic Efficiency of Lipid Extracts from MicroalgaeAntioxidants (Basel, Switzerland) · 2024Article
- Aspartic Acid in Health and Disease.Nutrients · 2023Review
- Fatigue, pain, and the recovery of neuromuscular function after consecutive days of full-body resistance exercise in trained men.European journal of applied physiology · 2021Article
- New Evidence on the Role of D-Aspartate Metabolism in Regulating Brain and Endocrine System Physiology: From Preclinical Observations to Clinical Applications.International journal of molecular sciences · 2020Review
- D-Aspartic Acid in Vertebrate Reproduction: Animal Models and Experimental DesignsBiomolecules · 2019Review
- Effects of Probiotic Supplementation on Selected Parameters of Blood Prooxidant-Antioxidant Balance in Elite Athletes: A Double-Blind Randomized Placebo-Controlled Study.Journal of human kinetics · 2018Article
- ISSN exercise & sports nutrition review update: research & recommendations.Journal of the International Society of Sports Nutrition · 2018Review
- The Emerging Role of Altered d-Aspartate Metabolism in Schizophrenia: New Insights From Preclinical Models and Human Studies.Frontiers in psychiatry · 2018Review
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
3 authors at 1 institution in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
contextResearch on d-aspartic acid (DAA) has demonstrated increases in total testosterone levels in untrained men, however research in resistance-trained men demonstrated no changes, and reductions in testosterone levels. The long-term consequences of DAA in a resistance trained population are currently unknown.
objectiveTo evaluate the effectiveness of DAA to alter basal testosterone levels over 3 months of resistance training in resistance-trained men.
designRandomised, double-blind, placebo controlled trial in healthy resistance-trained men, aged 18-36, had been performing regular resistance training exercise for at least 3 d.w-1 for the previous 2 years. Randomised participants were 22 men (d-aspartic acid n = 11; placebo n = 11) (age, 23.8±4.9 y, training age, 3.2±1.5 y).
interventionD-aspartic acid (6 g.d-1, DAA) versus equal-weight, visually-matched placebo (PLA). All participants performed 12 weeks of supervised, periodised resistance training (4 d.w-1), with a program focusing on all muscle groups. MEASURES: Basal hormones, total testosterone (TT), free testosterone (FT), estradiol (E2), sex-hormone-binding globulin (SHBG) and albumin (ALB); isometric strength; calf muscle cross-sectional area (CSA); calf muscle thickness; quadriceps muscle CSA; quadriceps muscle thickness; evoked V-wave and H-reflexes, were assessed at weeks zero (T1), after six weeks (T2) and after 12 weeks (T3).
resultsNo change in basal TT or FT were observed after the intervention. DAA supplementation (n = 10) led to a 16%, 95% CI [-27%, -5%] reduction in E2 from T1-T3 (p<0.01). The placebo group (n = 9) demonstrated improvements in spinal responsiveness (gastrocnemius) at the level of the alpha motoneuron. Both groups exhibited increases in isometric strength of the plantar flexors by 17%, 95% CI [7%, 28%] (p<0.05) as well as similar increases in hypertrophy in the quadriceps and calf muscles.
conclusionsThe results of this paper indicate that DAA supplementation is ineffective at changing testosterone levels, or positively affecting training outcomes. Reductions in estradiol and the blunting of peripheral excitability appear unrelated to improvements from resistance training.
trial registrationAustralian New Zealand Clinical Trials Registry ACTRN12617000041358.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.