Advances in Sexual Medicine, 2012, 2, 47-53
http://dx.doi.org/10.4236/asm.2012.24008 Published Online October 2012 (http://www.SciRP.org/journal/asm)

D-Aspartate, a Key Element for the Improvement of
Sperm Quality
Gemma D’Aniello1, Salvatore Ronsini1, Tiziana Notari1, Natascia Grieco1, Vincenzo Infante2,
Nicola D’Angelo2, Fara Mascia3, Maria Maddalena Di Fiore4, George Fisher5, Antimo D’Aniello1,2,4,*
1

Department of Obstetrics, Gynaecology and Physiology of Human Reproductive (IVF Unit),
Hospital “S. Luca”, Vallo della Lucania (SA), Italy2
Department of Human Clinical Chemistry of Poly-Diagnostic Center “Igea Sant’Antimo”,
Via degli Oleandri Sant’Antimo (NA), Italy

3

Department of Clinical Chemistry, Diagnostic Center “Fleming Laboratory”, Brescia, Italy
4

Department of Life Science, University of Naples Federico II, Naples, Italy
Department of Physical Sciences, Barry University, Miami Schores, USA
Email: daniello.antimo@gmail.com

5

Received July 18, 2012; revised August 22, 2012; accepted September 2, 2012

ABSTRACTIntroduction: D-Aspartate is an endogenous amino acid involved in LH and testosterone release in humans. In thisstudy we investigate the impact of nutritional supplementation of sodium D-aspartate on the improvement of sperm
quality in sub-fertile patients and the rate of pregnancies that occurred with their partners. Materials and Methods: A
group of 30 patients affected by oligo-asthenozoospermia and a group of 30 patients affected by asthenozoospermia
were treated with a daily dose of sodium D-aspartate for 90 days. After which, the change in spermatozoa concentrationand their motility and the pregnancies that occurred with their partners were recorded. Results: We found that the
supplementation of D-aspartate significantly increased the concentration and the motility of spermatozoa. In oligoasthenozoospermic patients the increase of sperm concentration was found to be 2.0-fold, P < 0.001 (from a mean of 8.2 ±4.5 million spermatozoa/ml of seminal plasma before treatment to a mean of 16.5 ± 5.5 million after treatment). In asthenozoospermic patients, the increase of spermatozoa was 1.6-fold, P < 0.001 (from a mean of 29.9 ± 5.7 million
spermatozoa/ml before treatment to a mean of 48.7 ± 12.8 after treatment). The same positive effects also occurred forsperm motility. Oligo-asthenozoospermic patients showed an increase of rapid progressive spermatozoa motility from amean of 15.5% ± 4.4% before treatment to a mean of 23.1% ± 4.7% after D-aspartate treatment (1.49-fold increased, P <0.001). The same effects occurred in oligo-asthenozoospermic patients. In these subjects the increase of rapid progressive spermatozoa motility was 1.86-fold (from 11.6% ± 3.9% before treatment to 21.6 ± 7.5 after treatment, P <0.001). In addition, the treatment of D-aspartate in these patients consequently led to a significantly increased numberof pregnancies occurring in the partners of the treated patients. Conclusions: Treatment of sub-fertile patients withsodium D-aspartate improved the number and the motility of the spermatozoa and consequently improved the rate of
pregnancies of their partners.
Keywords: D-Aspartate; Oligo-Asthenozoospermia; Asthenozoospermia; Pregnancies

1. Introduction
Reproductive disturbance has been a growing problem indeveloped countries during the last decades. According
to WHO more than 10% of men worldwide are infertile,
contributing to the growing demand for assisted reproduction techniques such as in vitro fertilization (IVF) andalso intracytoplasmic sperm injection (ICSI) in which thequality of the spermatozoa should be the best possible
option. These observations suggest that male infertility isa serious and increasing phenomenon. Various factors*

Corresponding author.

Copyright © 2012 SciRes.

are responsible for man infertility. Sociological factors,
over-production of reactive oxygen species (ROS) [1],spermatozoa DNA degradation [2]. The reduction of
sperm concentration and motility constitutes the maincause of male infertility. There are several literature reports of studies carried out on the use of nutritional supplements in order to improve semen quality in infertile
subjects. A wide number of antioxidants have been proposed to improve sperm quality and prevent sperm damage: vitamin E, vitamin C, coenzyme Q10, folic acid,glutathione, selenium and zinc are among the molecules
tested for such purposes [3]. Coenzyme Q10 plays a
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G. D’ANIELLO ET AL.

general role in transporting electrons in the mitochondria
and it protects the cell membrane from oxidative stress[4]. Folic acid is involved in providing carbon group for
purine and pyrimidine production and plays an importantrole in the synthesis of DNA [4], as well as being a potent scavenger of oxidizing free radicals by binding themethyl donors methionine and S-adenosylmethionine [6].
Lycopene and vitamins A, C and E are other antioxidant
reagents also used as supplementation to improve sperm
quality, but no evidence exists that the use of these supplements alone can improve semen parameters [7]. Additional evidence shows that vitamin E significantly decreased DNA fragmentation rates and increased sperm
quality [8]. Zinc and selenium are trace elements present
in the seminal plasma that have an important antioxidantrole [9]. L-carnitine and acethyl-L-carnitine [10], as wellas L-Arginine [11], also have been proposed as nutritional supplements to improve sperm quality.
In this study we describe the use of another amino acid,D-aspartic acid (D-Asp), for the improvement of sperm
quality in sub-fertile patients. This amino acid is an endogenous molecule occurring in nervous and endocrine
glands in different species of animals including mammals
and man and is involved in the hormone release at the
hypothalamus hyphophysis-gonadal axis [12,13]. D-Asp
is the stereochemical enantiomer of naturally occurring
L-aspartic acid, differing by the configuration of the
α-carbon atom (Figure 1). For this reason D-Asp is metabolized specifically by the enzyme D-aspartate oxidase(EC 1.4.3.1) which oxidizes D-aspartate to oxaloacetate[14]. D-Asp is present in all endocrine glands including
the testis. It also occurs in the seminal plasma and in
spermatozoa, and a direct correlation between its concentration in seminal plasma and semen quality has beenfound [15]. In addition, D-Asp is able to stimulate testosterone synthesis in rat Leydig cells [16] and capable ofimproving semen quality in rabbits [17]. Lastly, we
found that oral assumption of sodium D-aspartate in humans induces serum elevation of LH and testosterone[18]. Based on these results, in the present study weinvestigated whether supplementation of sodium Daspartate could improve sperm quality in oligoasthenozoospermic and asthenozoospermic subjects and consequently improve the pregnancy rate in their partners.

2. Materials and Methods
This study was carried out at the IVF (In Vitro Fertilization) Unit of the Department of Obstetrics, Gynecology
and Physiopathology of Human Reproduction, Hospital“S. Luca”, Vallo della Lucania, Italy. The study cosisted
in testing the effects of sodium D-aspartate on sperm
quality in oligo-asthenozoospermic and asthenzospermic
patients who were unable in the least two years to impregnate their partners. These subjects came to the hospital
Copyright © 2012 SciRes.

Figure 1. Linear and Stereochemical formula of D-asparticand L-aspartic acid. Chemical structure of D-aspartic acidand L-aspartic acid by using a linear formula (panel A) anda carbonium presentation based on the tetrahedral configuration (panel B).

for medical examination of semen quality and, in thecase of oligoasthenozoospermia or asthenozoospermia,
were prescribed to consume for 90 days an oral foodsupplement consisting of sodium D-aspartate, dissolved
in half a glass of water or fruit juice, at lunch or at dinner.
Before start experimentation, permission from all ptientswas asked and obtained to conduct this study. The doseof sodium D-aspartate consisted of 10 ml of 2.0 M sdium
D-aspartate (composed of 2.66 g of D-aspartic acid neutralized with 0.46 g of NaOH in 10 ml distilled water, atfinal pH (6.5 - 7.0). This food integrator was marketed in
Italy by two pharmaceutical companies: 1) Pharmaguidasrl, which marketed the food integrator containing Daspartate under the commercial name ”DADAVIT” and 2)
Merck-Serono s.a.s. which marketed the food integrator
containing D-aspartate under the name of “GENADIS”.
These companies were authorized to commercialize theintegrator by the Italian Ministry of Health. The recruitedsubjects for this study were subdivided into two subgroups according to their concentration of spermatozoa
in the seminal plasma measured before starting the treatment. The first subgroup consisted of 30 subjects affected by oligo-asthenozoospermia (ages between 27 and43 years) who had a spermatozoa concentration ranging
from 2.5 × 106 to 1.95 × 107 spermatozoa/ml and a rapid
progressive spermatozoa motility between 7% and 16%.
The second group consisted of 30 subjects affected byasthenozoospermia (ages between 28 and 40 years) who
had a spermatozoa concentration raging from 2.0 × 107 to
5.02 × 107 spermatozoa/ml and rapid progressive spermatozoa motility between 7% and 12%.

2.1. Semen Analyses
Sperm ejaculates were collected by masturbation underhygienic conditions, into sterile containers, in a privateroom near the laboratory. Before and after D-aspartate
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treatment, semen of each patient was collected after aperiod of 3 days of sexual abstinence. Semen collectedbefore starting the treatment was considered as control.
After semen liquefaction at 37˚C, the ejaculate volume
was measured by weighing the seminal plasma. Then, aportion of 0.5 ml was stored at −80˚C for future analysisof D-aspartate content, while the remaining portion ofsemen was used for the determination of spermatozoa
concentration and motility. Sperm concentration was measured with a 100 µm deep haemocytometer Neubauer
chamber maintained at 37˚C. For this purpose, 0.5 ml ofseminal fluid was mixed with 0.05 ml of a solution consisting of 20% (v/v) formalin in 10% sodium bicarbonate (NaHCO3) in order to block the movement ofspermatozoa, to have a complete mucolisis of the semen
and a homogeneous distribution of the sperm in thechamber. At least 200 spermatozoa were counted foreach sperm analysis. If the seminal plasma contained ahigh concentration of spermatozoa, the sperm wasdiluted with a solution prepared by dissolution of 50 g of
NaHCO3 and 10 ml of formalin 35% (v/v) in 1000 ml ofdistilled water. Sperm motility was examined by using
the Computer-Assistant Semen Analysis (CASA) which
has the advantages of the quantitative assessment ofsperm kinematics. The motility was evaluated as: 1 rapid
progressive motility (spermatozoa moving actively, either linearly or in a large circles with a speed of >25µm/sec at 37˚C), 2) moderate motility (absence of progression, swimming in a small circles) and 3) slow sperm
motility (slow linear movements, zigzag moving spermatozoa and vibrating in situ moving spermatozoa).
Each semen analysis was carried out at the same time by
two biologists. If the counts of the spermatozoa and/or
the percentage of sperm motility of the two operators
were not consistent, the analysis was repeated. In order togive an exact comparative evaluation of spermatozoa
concentration per ml of ejaculate, a correction factor
based on the difference of volume of the ejaculate before
and after treatment was used. When the semen containedmoderate to large agglutination of spermatozoa, it was
not included in the study. Morphology and vitality were
determined according to the guidelines of WHO manual
[19].

49

of seminal plasma was mixed with 0.4 ml of 0.2 M trichloroacetic acid and centrifuged. The supernatant was
neutralized with 1.0 M NaOH and 50 µl of this sample
was used for the HPLC analysis.

2.3. Serum Clinical Analysis
In order to exclude possible side effects of sodium Daspartate treatment, each participant underwent a medical examination and various blood analyses before andafter therapy to evaluate their general state of health. The
blood parameter analyses were the following: 1) complete blood and platelets count (performed with HBxL80,
HORIBA Medical, 34184Montpellier, France); 2) serum
concentration of the following metabolites: glucose, urea,
ammonia, cholesterol, triglycerides, creatinine, uric acid,sodium, potassium, calcium, magnesium, iron and copper;3) the following enzymes: aspartate aminotransferase,alanine aminotransferase, alkaline phosphatase, acid phosphatase, prostatic phosphatase, cholinesterase and lactate
dehydrogenase (performed with LaB Taurus, Instrument
Laboratory SpA, Milan, Italy); 4) the following serum
hormones: testosterone, luteinizing hormone, follicle stimulating hormone (FSH), thyroid stimulating hormone(TSH), triiodothyronine (T3), thyroxin (T4), free triiodothyronine (FT3) and free thyroxin (FT4) (performed with
UnicellTM Dx1800, Beckman Counter with, Inc., 2505
Kraemer BLVD, Germany); and e) serum protein electrophoresis (performed with INTERLAB G26, Interlab
srl, Roma, Italy).

2.4. Statistical Analyses
Statistic analyses were conducted using Stat-View program (version 4, Abacus Concepts, Berkeley, CA, USA).
The comparison of spermatozoon concentration/ml ofseminal plasma, the total sperm concentration per ejaculate and the sperm motility between the groups of subjects before and after the treatment with D-aspartate, andthe concentration of D-aspartate in the seminal plasma inthe subjects between before and after treatment with
D-aspartate were analyzed by analysis of variance withrepeated measurements (one way ANOVA). Each parameter value was reported as mean ± SD. Statisticalsignificance was set at P < 0.05.

2.2. Determination of D-Aspartic Acid in
Seminal Plasma

3. Results

D-Aspartic acid in the seminal plasma was determinedby an HPLC method combined with the use of D-aspartate oxidase (D-AspO) as previously described [12]. The
HPLC analysis (Figure 2) was carried out at the Zoological Station “A. Dohrn” of Naples, Italy and also in
the laboratory of chemistry of Prof. G. Fisher at Barry
University of Miami (FL) and the mean values were calculated by the comparison the two data. In brief, 0.1 ml

The results obtained in this study indicated that in botholigo-asthenozoospermic and asthenozoospermic subjects that treatment with sodium D-aspartate improved
significantly the concentration of spermatozoa and theirmotility. Concerning the sperm concentration, we foundthat in oligo-asthenozoospermic patients the mean number of spermatozoa went from a basal value of 8.2 ± 4.5
million/ml of seminal plasma to 16.5 ± 5.5 million/ml,

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(a)

(b)

(c)

(d)

Figure 2. Typical HPLC separation and determination of D-aspartic acid from human seminal plasma. Panel (a): HPLC
amino acids profile from a standard mixture consisting of 50 pmoles of D-Asp (D-aspartic acid) and 100 pmoles of L-Asp(L-aspartic acid) and 100 pmoles of other standard L-amino acids; Panel (b): HPLC profile of the same amino acids standard
mixture as used in panel (a), but after treatment with D-aspartate oxidase (D-AspO) to oxidize D-Asp in order to ascertain if
the peak observed at elution time of 5.6 min, was actually D-Asp; Panel (c): HPLC analysis of free amino acids of typicalseminal plasma from a normospermic patient purified on cation exchange resin corresponding to 10 µl of the original sample;
Panel (d): HPLC analysis of the same sample as used in panel (c), but after treatment with D-AspO. The peak of D-Asp completely disappeared from the standard mixture of amino acids (panel (b)) and from the seminal plasma (panel (d)), after incubation of the sample with D-aspartate oxidase, indicating that the peak area of D-Asp was entirely due to D-Asp.

showing a 2.0-fold increase (P < 0.001). The same effectwas observed on the total concentration of spermatozoa
per ejaculate that went from 30.1 ± 14.7 million/ejaculate
to 45.9 ± 24.4 million/ejaculate, a 1.52-fold increase (P <0.001) (Table 1). An analogous improved phenomenon
was observed in the asthenozoospermic patient group,
where a significant increase of the number of spermatozoa occurred, going from a basal value of 29.9 ± 5.7 million/ml of seminal fluid to 48.7 ± 12.6 million/ml, with a
1.63-fold increase (P < 0.001). The total number of spermatozoa/ejaculate was also significantly increased by
1.57-fold, (from a value of 97.1 ± 36.1 million/ejaculate
to 153.0 ± 47.0 million/ejaculate (P < 0.001) (Table 1).
Concerning the spermatozoa motility, we found a significant increase of spermatozoa motility in both oligoasthenozoospermic and asthenozoospermic patients subjects. In the group of oligo-asthenozoospermic subjects,
the mean value of the rapid progressive sper Nmatozoa
Copyright © 2012 SciRes.

motility went from 15.5% ± 4.4% to 23.1% ± 4.7% (1.49
fold increase, P < 0.001), and the total sperm motility
also increased significantly from 30.6% ± 9.3% to 54.4%± 9.7% (1.77-fold increase, P < 0.001) (Table 2). In thegroup of asthenozoospermic subjects, sodium D-aspartate treatment also induced a significant increase of rapid
progressive motility and of total spermatozoa motility. In
this case, in fact the treatment induced a 1.86-fold increase in rapid progressive motility (P < 0.001) goingfrom a basal value of 11.6% ± 3.9 % before treatment to21.6% ± 7.5% after treatment, and the total sperm motility went from 25.2% ± 8.1% to 45.7% ± 10.9 % (1.81fold increased) (Table 2).
An interesting aspect of this study is the very significant increased number of pregnancies that occurred in
the partners of the treated patients. In fact, among the 60
partners of subjects who were treated with sodium Daspartate, 16 of them became pregnant which corresponds
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Table 1. Sperm concentration in oligo-asthenozoospermic
and asthenozoospermic patients treated with sodium Daspartate.
1st group: 30-Oligo-Asthenozoospermic patients
Concentration of spermatozoa/
Total concentration of*
ml of seminal plasma
spermatozoa/ejaculate (n.×106)
6(n. × 10 )BeforeAfter
BeforeAfter
Treatment

Treatment

Treatment

Treatment

8.2 ± 4.5

16.5 ± 5.5

30.1 ± 14.7

45.9 ± 24.4

P < 0.001

P < 0.001

2nd group: 30-Asthenozoospermic patients
Concentration of spermatozoa/
Total concentration of*
ml of seminal plasma (n. × 106)spermatozoa/ejaculate (n.×106)
BeforeAfter
BeforeAfter
Treatment

Treatment

29.9 ± 5.7

48.7 ± 12.6
P < 0.001

Treatment

Treatment

97.1 ± 36.1
153.0 ± 47.0
P < 0.001*

Refers to the total number of spermatozoa obtained by multiplying thespermatozoa concentration/ml of ejaculate by total volume of the ejaculate.
The mean and SD were obtained by one-way ANOVA with repeated measurements (Stat-View program). The P value was obtained by comparison of
the data of each group of subjects between before and after D-aspartate
treatment.

Table 2. Sperm motility in oligo-asthenozoospermic andasthenozoospermic patients treated with sodium D-aspartate.
1st group: 30-Oligo-Asthenozoospermic patients
Rapid progressive* spermatozoa
motility ( % of total)

Total spermatozoa** motility(% of total)

BeforeAfter

BeforeAfter

Treatment

Treatment

Treatment

Treatment

23.1 ± 4.7

30.6 ± 9.3

15.5 ± 4.4

P < 0.001

54.4 ± 9.7
P < 0.001

2nd group: 30-Asthenozoospermic patients
Rapid progressive* spermatozoa
motility ( % of total)

Total spermatozoa** motility(% of total)

BeforeAfter

BeforeTreatment

Treatment

Treatment

Treatment

11.6 ± 3.9

21.6 ± 7.5

25.2 ± 8.1

45.7 ± 10.9

P < 0.001

D-aspartate, and four of them became pregnant at thethird month that their partners were treated with Daspartate. In contrast, of 10 pregnancies among 30 partnersof the asthenozoospermic patients, two of them became
pregnant after one month of treatment, four of them
became pregnant after two months of treatment, and fourof them became pregnant after three months of treatment(Table 3).
The last interesting aspect of this study regards theconcentrations of D-Asp in the seminal fluid before andafter treatment. We measured the concentration of D-Asp
in seminal plasma of all patients before and after oral
consumption of sodium D-aspartate at the dose as aboveindicated (see: Materials and Methods). The results indicated that this amino acid increases significantly in concentration following treatment with D-Asp. In fact, themean concentration of D-Asp in oligoasthenzoo-spermic
patients before treatment was 15.0 ± 4.0 nmol/ml ofseminal plasma, whereas after treatment it increased to29.5 ± 7.2 nmol/ml (1.96-fold increased, P < 0.001). In
asthenozoospermic patients before treatment D-aspartateconcentration was 16.3 ± 4.5 nmol/ml of seminal plasma,
whereas after treatment it increased to 32.6 ± 7.5 nmol/ml(2.0-fold increased, P < 0.001) (Table 4).
In order to verify if D-aspartate treatment could induce
unwanted side effects, each patient that had been treatedwith D-aspartate underwent a full blood clinical analysis(as previously detailed in the methods section). None of
the blood metabolites as well as the complete blood andplatelets count was outside the physiological range. The
only variation was observed in the LH and testosterone
Table 3. Number of pregnancies occurring to the partnersof oligo-asthenozoospermic patients and asthenozoospermic
patients before and after treatment with sodium D-aspartate.
Numbers of pregnancies occurring to the partners of
the 30 oligo-asthenozoospermic patients
BeforeAfter D-Aspartate treatment
D-aspartate*
Treatment
After
After
After
% of total*

After

P < 0.001

The patients in this study were the same patients reported in table 1. *Rapid
progressive spermatozoa motility indicated those spermatozoa with a forward motility >25 µm/s measured at 37˚C, expressed as the percent of rapid
progressive spermatozoa motility on total spermatozoa. **Total spermatozoa motility indicate the sum of rapid progressive moving spermatozoa, theslow progressive moving spermatozoa, the zigzag moving spermatozoa andthe vibrating in situ moving spermatozoa and are expressed as total motile
spermatozoa on the total. The mean and SD were obtained by one-way
ANOVA with repeated measurements (Stat-View program). The P value
was obtained by comparison of the data of each group f patients between
before and after D-aspartate.

to a pregnancy rate of 26.6%. In detail, of six pregnancies that occurred among the 30 partners of the oligoasthenozoospermic patients two of them became pregnant
at the second month that their partners were treated with
Copyright © 2012 SciRes.

0%

1 month

2 months

3 months

0%

2%

4%

20%

Numbers of pregnancies occurring to the partnersof the 30 asthenozoospermic patients
BeforeD-aspartate
Treatment*0%

After D-Aspartate treatment
After

After

After

1 month

2 months

3 months

2%

4%

33%

% of total*

20%*

Before treatment indicate the number of pregnancies occurred during thelast two years before starting the D-aspartate treatment. After treatment
indicate the number of pregnancies occurred to the partners of subjects after
the first, the second and the third month of an daily oral dose of D-aspartate.

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Table 4. D-Aspartic acid concentration in seminal plasma of
patients before and after treatment with sodium D-Aspartate (nmole/ml).
BeforeAftertreatment

treatment

15.0 ± 4.0

29.5 ± 7.2

1st group
30 Oligo-Asthenozoospermic patients
Mean ± SD
Student’s t-test

P < 0.001

2nd group:
30 Asthenozoospermic patient
Mean ± SD
Student’s t-test

16.3 ± 4.5

32.6 ± 7.5

P < 0.001

The determination of D-aspartic acid was carried out by HPLC by using the
OPA-NAC method [19]. The statistical data (mean, SD and P value) wereobtained by using the one-way ANOVA, with repeated measurements (StatView program).

concentrations that were found to be increased between
1.3 - 1.6 fold compared to their basal levels in the Daspartate group. However, the increased levels of LH andtestosterone observed in this study were in agreementwith the previously reported results [18] demonstratingthat D-aspartate has the capacity to increase LH and testosterone blood levels. Therefore, D-aspartate treatment
for a prolonged time (90 days) is in no way harmful tohealth.

4. Discussion
D-Aspartic acid is an endogenous amino acid in animals
and is synthesized in the endocrine glands, principally inthe testis, by the conversion of L-aspartate to D-aspartateby a D-aspartate racemase [18]. Previous studies havedemonstrated that D-aspartic acid is involved in endocrine activity in animals and humans in the synthesis andrelease of sexual hormones [12,16-18,20-24]. Also it has
been ddemonstrated that D-aspartate occurs in humanseminal plasma and spermatozoa and that a direct relationship between semen quality and D-aspartate concentration exists [18]. These data thus led us to hypothesizethat D-aspartate plays an important role in steroidogenesis and that its supplementation in sub-fertile patients(oligo-asthenozoospermic and asthenozoospermic) could
improve spermatozoa concentration and motility andconsequently the rate of pregnancies of their partners.
Therefore, we enrolled 60 patients, who in the previous
two years have not fertilized their partners, and treatedthem for three months with an oral supplementation of
sodium D-aspartate. The results obtained from this study
have demonstrated that D-aspartate induces a significant
increase of the number of spermatozoa and of their motility in both oligo-asthenozoospermic and in asthenozoospermic patients, and this phenomenon in turn has
Copyright © 2012 SciRes.

resulted in a very significant increase of the pregnancies
in the women partners of subjects treated with D-aspartate. In fact, among the 30 partners of the oligoasthenozoospermic patients treated with D-aspartate, six of them
became pregnant (rate = 20%), and among the 30 partners of the asthenozoospermic subjects treated with Daspartate 10 became pregnant which corresponds to 33%
of total. In this regard, two pregnancies already occurred
one month after their partners had ingested D-aspartate,
and four pregnancies occurred after the second monththat their partners were treated with D-aspartate. The lastinteresting result obtained in this study is the fact that theconsumption of D-aspartate for a time of almost threemonths did not have any side effects on the health of thesubjects. In fact, we have monitored the principal serum
metabolites indicated for the usual clinic analyses in all
subjects before and after D-aspartate treatment, and wehave observed that in each patient treated with D-aspartate all serum parameters were within the physiologicalvalues, indicating thus that D-aspartate treatment do notcause any damages to the health.
In conclusion, in this study we demonstrated that
sub-fertile men who consumed daily an oral dose of sodium D-aspartate for 2 - 3 months, improved signifycantly their sperm quality in terms of number and mobility of the spermatozoa, and consequently they increased
the possibility to fertilize the own partner. We do notknow the exact molecular mechanism by which thisphenomenon occurs, but we strongly hypothesize that
this events is due to action of D-aspartate in inducing
elevation of testosterone in the testis, which locally is
involved in improving the spermatogenesis and in maturation of male gametes.

5. Acknowledgements
The authors thank Dr. Antimo Cesaro, Administrator of
the “Polydiagnostic Center “Igea Sant’Antimo”, 80029
Sant’Antimo (Italy), Dr. Giuseppe Cammisa, Director of
the Chemical Clinical Laboratory of the same Center andthe technicians Nicola Migliaccio and Gianfranco Silvestre
for their support in clinical analysis. We also thank the
Zoological Station “A. Dohrn” of Naples, Italy, for thepermission to carried out HPLC analysis. A special
thanks to Dr. Fara Mascia of the “Fleming Laboratory”
of Brescia (Italy) for her observations and discussion
about sperm analyses.

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