N-Acetylcysteine for Menstrual Pain in Teens

This antioxidant has mixed results in psychiatry, and now shows promise in dysmenorrhea

STUDY: Al Khafaji WR et al, Georgian Medical News 2026

STUDY TYPE: Randomized controlled trial

FUNDING: Independent

Background

Primary dysmenorrhea, or painful periods without underlying pelvic disease, affects up to 90% of adolescents and is typically treated with NSAIDs or hormonal contraceptives. Both options have drawbacks, including GI side effects and hormonal disruption. Oxidative stress drives much of the pain, and this trial tested the antioxidant n-acetylcysteine (NAC).

The Study

• 50 adolescents aged 13–19 with moderate-to-severe dysmenorrhea, randomized to NAC 600 mg twice daily or placebo for 5 days at the start of each period, over 3 cycles; double-blind.

Results

NAC reduced average pain scores from a baseline of roughly 7 to 4.6, compared to 5.9 in the placebo group; a 1.3-point difference on the 0–10 VAS that crossed the threshold for clinical meaningfulness.

Ibuprofen use dropped by nearly half in the NAC group compared to placebo (667 mg per cycle versus 1,300 mg).

Urinary 8-iso-prostaglandin F₂α fell about 25% in the NAC group (0.6 vs. 0.8 ng/mg creatinine), suggesting the pain relief is related to reduced oxidative stress, not just a placebo effect.

Side Effects

None.

Limitations

Small, short-term, single center.

Practice Implications

1. Good to know of this potential benefit when recommending NAC for psychiatric use.
2. Unfortunately, its psychiatric benefits are unclear, with mixed results in cannabis use, trichotillomania, depression, OCD, and addictions. It may also protect the kidneys on lithium.
3. While the data is not strong enough for those single disorders, I’d consider it for patients with multiple (eg, bipolar depression, on lithium, with dysmenorrhea). Here are lab-tested products.