N-acetylcysteine (NAC)
The verdict
Mixed results as an add-on to standard PCOS ovulation induction; not reliably effective across trials.
An antioxidant/amino-acid derivative, commonly added to clomiphene citrate for PCOS patients who don't respond to clomiphene alone.
What the evidence shows
Evidence is genuinely mixed: several trials report improved ovulation/pregnancy rates as an adjuvant to clomiphene in clomiphene-resistant PCOS; at least one RCT found no significant difference in follicle count, endometrial thickness, or pregnancy rate. No Cochrane-graded synthesis specific to this use identified.
Evidence tier
Very limited evidence⚪ A handful of small trials, often single-source or industry-funded, not independently replicated.
Sources
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