Table 1 Characteristics of the included studies of ALA on sperm parameters in this systematic review

Raaia et al. [13]

2012

Egypt

Placebo-controlled

Double-blind

30(24)

30(24)

3 months

oral ALA tablets at a dose of 300 mg twice/day (Thiotacid 300 mg; Eva Company, Cairo, Egypt)

History of infertility for more than 1 year, sperm concentration more than 5 million sperms/ ml, low motility: less than 32% progressive motility and less than 40% progressive and nonprogressive motility, no clinical or duplex evidence of varicocele, no evidence of genitourinary tract infection, no clinical symptoms of endocrinal or genetic disorders (e.g. Klinefelter’s syndrome), normal serum follicle-stimulating hormone and testosterone levels, no history of medical diseases (e.g. diabetes, hypertension, liver, or kidney diseases), no concurrent intake of fertility-enhancing medication, and no history of chemotherapeutic medications.

sperm concentration(10⁶/ml)

total motility(grade a+b+c) (%)

progressive motility(grade a+b) (%)

abnormal sperm forms (%)

pregnancy rate (%)

fifth edition(2010)

Haghighian et al. [21]

2015

Iran

Randomized

Triple-blind

Placebo-controlled

24(23)

24(21)

12 weeks

600 mg ALA once daily

unwilling childlessness at least 24 months in duration with a female partner, no medical condition that could account for infertility, and a normal fertile female partner according to investigations. All patients were needed to have stopped all medical therapy ≥ 12 weeks before study initiation

Exclusion criteria included the history of epididymo-orchitis, prostatitis, genital trauma, testicular torsion, inguinal or genital surgery, urinary tract infection, or previous hormonal therapy; another genital disease (cryptorchidism, current genital inflflammation or varicocele); severe general or central nervous system disease and endocrinopathy; use of cytotoxic drugs, immunosuppressants, anticonvulsants, androgens, or antiandrogens; and a recent history of sexually transmitted infection. Patients were also excluded from analysis if they had psychologic or physiologic abnormalities that would impair sexual performance or the ability to provide semen samples; drug or alcohol abuse; hepatobiliary disease; significant renal insuffificiency; occupational and environmental subjections to possible reproductive toxins; a body mass index of ≥ 30 kg/m2; participation in another investigational study; and unlikely availability for follow-up

semen volume(ml)

total sperm number(10⁶/ejaculate)

sperm concentration(10⁶/ml)

progressive motility(grade a+b) (%)

fast progressively motility(grade a) (%)

slow progressively motility(grade b) (%)

non-progressively motility(grade c) (%)

immotile spermatozoa(grade d) (%)

total motility(grade a+b+c) (%)

normal forms(%)

vitality(%)

forth editon(1999)

Abbasi et al. [20]

2020

Iran

Triple-blind

Randomized

Placebo-controlled

30(19)

30(22)

80 days

daily doses of 600 mg of ALA (Raha, Iran)

A total of 60 men aged 19 to 45 years, with uni/bilateral grade II–III varicocele (confirmed by Doppler duplex ultrasonography if ambiguous on palpation) met the inclusion criteria and were enrolled in the study

Individuals with azoospermia, occupational exposure to heat, radiation, and pesticides, a history of mumps, cryptorchidism, solitary testis, urogenital malignancies/infections, endocrinopathies, Sertoli cellonly syndrome, leukocytospermia, scrotal trauma, high fever prior to sampling, recurrent varicocele, severe alcoholism and heavy smoking were not included in this study

sperm concentration (10⁶/ml)

semen volume (ml)

abnormal sperm forms (%)

total motility(grade a+b+c) (%)

progressive motility(grade a+b) (%)

sperm lipid peroxidation(%)

spermlipid peroxidation(intensity)

DNA fragmentation(%)

DNA damage index(%)

sperm protamine deficiency(%)

fifth edition(2010)