Peivandi 2010.

Methods	Randomised double‐blind cross‐over trial Duration of study: unclear, from 2005 to 2006
Participants	Country: Iran Population: infertile men, N = 30 Mean age: 29.5 (SD 5.48) years Inclusion criteria: at least two abnormal spermograms based on WHO criteria with a two‐week interval during four weeks, normal range of gonadotropins, testosterone an prolactin concentrations Exclusion criteria: variocoele, testicular atrophy, ejaculatory disorders, use of medications, azoospermia, endocrinological disorders, ICSI candidacy or other causes of infertility
Interventions	L‐carnitine 2 g (n = 15) versus Placebo (n = 15) Duration of treatment: 8 weeks, washout period of 8 weeks, changed intervention and use for 8 more weeks
Outcomes	Sperm parameters
Notes	Abstract in English, full text in Arabic. Contacted the author and he is filling out the data extraction sheets. Author responded but data queries remain contacted again re SDs and pregnancies in first phase of cross‐over. Author responded saying that the data were given in SDs and there were 3 pregnancies in the first phase 2018: added data on progessive motility for first phase (2 months).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not mentioned
Allocation concealment (selection bias)	Low risk	Quote: "sealed opaque envelopes"
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Quote: "Double blind". Placebo used.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "outcome assessor was blinded"
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Quote: "loss to follow up was not accounted for"
Selective reporting (reporting bias)	Unclear risk	Outcomes reported. No protocol available.