Does CoQ10 help with irregular periods during perimenopause?

CoQ10 does not regulate menstrual cycles and there is no evidence that it helps with irregular periods during perimenopause. Perimenopause cycle irregularity is driven by the decline and erratic fluctuation of estrogen and progesterone as your ovaries wind down their reproductive function. These hormonal changes alter the feedback signals between your ovaries, pituitary gland, and hypothalamus that normally orchestrate a predictable monthly cycle. CoQ10 does not participate in this hormonal feedback system and cannot restore or regulate it. Any claim that it does is not supported by research.

The only context where CoQ10 has been studied in relation to reproductive cycles is fertility in women with diminished ovarian reserve, typically during IVF protocols. Some research suggests CoQ10 may improve egg quality by supporting mitochondrial function in oocytes, which are highly energy-dependent cells. A 2018 review in the Journal of Assisted Reproduction and Genetics found modest evidence that CoQ10 improved outcomes in poor-responder IVF patients. However, this is fundamentally different from managing perimenopause cycle irregularity. Fertility-focused research uses CoQ10 to support ovarian function in women trying to conceive, not to regularize cycles that are irregular because ovarian function is naturally declining as part of aging. These are opposite ends of the same spectrum.

The irregular bleeding of perimenopause is not a symptom that benefits from antioxidant support. What is actually happening is anovulatory cycles (cycles where no egg is released), which produce no progesterone and cause the uterine lining to build up erratically and shed unpredictably. Some months there are two periods, some months none. Some cycles are shorter, some dramatically longer. This process is a normal but often uncomfortable part of the perimenopausal transition. Because the uterine lining is behaving unpredictably, new or changed bleeding patterns should be evaluated medically, not managed with supplements, to rule out endometrial hyperplasia or other causes.

If you are taking CoQ10 for other aspects of perimenopause support, the best-absorbed form for women over 40 is ubiquinol, the active form that does not require conversion by the body. Ubiquinone, the more common and less expensive form, requires a conversion step that becomes less efficient with age, making ubiquinol the better choice in midlife. For general mitochondrial and cardiovascular support, studies have used doses in the range of 100 to 300 mg per day. Talk to your healthcare provider about the right dose and whether CoQ10 makes sense for your overall health picture.

If you take warfarin, the interaction with CoQ10 is clinically significant and must be discussed with your prescriber before starting: CoQ10 reduces warfarin's anticoagulant effect and can lower your INR to a subtherapeutic range. CoQ10 also mildly lowers blood pressure, which matters if you are on antihypertensives. For cycle irregularity specifically, there is no supplement with strong evidence for regulation. The most effective interventions, where appropriate, include low-dose oral contraceptives (which also help with irregular bleeding and hot flashes) or progesterone therapy, both of which require a discussion with your provider.

If you are tracking your cycle hoping to identify patterns during perimenopause, it is worth knowing that irregular cycles can persist for years before periods stop entirely. Most women experience increasing irregularity for an average of 4 to 8 years during the transition. Keeping a cycle log gives you useful information to share with your provider and helps you recognize if something unusual is happening that warrants evaluation.

See your doctor about irregular bleeding if you are bleeding more heavily than usual or soaking through a pad or tampon in an hour, bleeding between periods more than occasionally, bleeding that lasts longer than 7 days, any spotting after sex, or if you have not had a period for 12 months and then have any bleeding. This last point is important: any bleeding after 12 consecutive period-free months is considered postmenopausal bleeding and always requires evaluation to rule out endometrial cancer.

The PeriPlan app (https://apps.apple.com/app/periplan/id6740066498) includes cycle and symptom tracking so you can log period timing, flow, and associated symptoms in one place. Having a clear record over several months is far more useful than trying to reconstruct your cycle pattern from memory at a doctor's appointment.

This content is for informational purposes only and does not replace medical advice. Always consult your healthcare provider about your specific situation.