Across 3 randomized controlled trials, 1 study reported a beneficial moderate-sized effect of vitamin E on sperm morphology, while 2 studies found neutral small-sized effects. The evidence base is small (3 studies) and preliminary, with a median study duration of 90 days. Most studies used oral doses of 100 mg (twice or thrice daily) in clinical populations of infertile men.
Caveats: Evidence base is small (only 3 studies) — conclusions should be considered preliminary. Many of the included studies did not reach statistical significance — effect may be smaller than the predominant direction suggests. Only 1 of 3 studies reported a statistically significant benefit; the other two found no significant improvement from vitamin E alone, with any improvements attributed to co-administered treatments (e.g., M. sativa or carob). All studies were in clinical infertile populations; results may not generalize to healthy men.
only progressive sperm motility and morphology improved in the control group
percentage of normal morphology changed from ... 2.0 ± 0.9% to 2.6 ± 1.2% in placebo ... The improvements in M. sativa group are significantly better than placebo group (P = 0.00, 0.01 and 0.04, respectively).
morphology (p = 0.001 Cohen's d = .93) ... were significantly higher in the carob group