Vasomotor Symptoms

Hot flashes and night sweats — vasomotor symptoms, or VMS — are the most recognized menopause symptoms. But recognized is not the same as most experienced or most impactful.

What VMS Are — and What They Are Not

Hot flashes cluster independently from mood, sleep, and cognitive symptoms in analyses of over 147,000 symptom logs from nearly 5,000 women (50). They are the stage-specific hallmark of perimenopause, but they are not the causal hub for the broader menopause experience.

In a US discrete choice experiment (467 women with peri- or postmenopausal VMS), sleep improvement was the most valued treatment attribute (preference weight 0.843), ranked above VMS frequency reduction (0.658) and VMS severity reduction (0.628). Breast cancer risk (0.401) and cardiovascular risk (0.150) had less influence on treatment choice (23). When considering treatment for VMS, the sleep impact deserves attention alongside frequency and severity.

VMS Experience and Care-Seeking Vary by Population

How women experience and manage VMS varies across populations. In Japan, severe VMS affected 6.4% of a 2,188-woman sample, and even among those with severe symptoms, only about 25% visited a medical facility. The primary reason for not seeking care was self-coping — 50.3% reported "I tolerate without visiting" and 28.4% "I deal with by myself." Among those who did seek care, traditional Chinese medicine (Kampo) was prescribed for 55.7% and hormone therapy for 33.2%. The estimated annual cost of VMS-related presenteeism in Japan was approximately 370 billion yen. Only about 40% of women with severe VMS received a Konenki disorder diagnosis (76).

Health Implications — What the Evidence Shows

VMS and Alzheimer's Biomarkers

Physical Activity and Vascular Significance

In a small study of 52 healthy, already-active perimenopausal women (mean physical activity 87 minutes per day — well above guidelines), moderate-to-vigorous physical activity moderated the association between waking hot flash rate and a vascular measure (flow-mediated dilation). The interaction was statistically significant (p=0.04), but physical activity did not independently predict vascular function, and the study does not show that exercise reduces hot flashes. E2 and FSH did not explain the vascular variance. This was cross-sectional and cannot establish causation (54).

Treatment Evidence

Neurokinin Receptor Antagonists — A New Non-Hormonal Class

Fezolinetantⓘ (FDA approved 2023):

In the DAYLIGHT trial (n=453, 16 countries) designed specifically for women unsuitable for hormone therapy, fezolinetant significantly reduced VMS frequency (LSMD -1.93, p<0.001), severity (-0.39, p<0.001), and sleep disturbance (-2.5, p<0.001), with improvements from week 1. Short-term side effects were comparable to placebo (65% vs 61%). However, a hepatotoxicity signal emerged after the trial: the FDA issued a black box warning in December 2024 requiring liver function testing before starting treatment and frequently during the first 9 months (47, 64).

Elinzanetantⓘ:

In the 52-week OASIS-3 phase 3 trial (n=628), elinzanetant reduced VMS frequency by 1.6 events per day more than placebo at week 12 (p<0.001), with 73.8% vs 47.0% reduction in frequency. By week 50, women on elinzanetant averaged 1.4 moderate-severe VMS per day compared to 3.5 on placebo. No hepatotoxic signal was found over 52 weeks. However, treatment-emergent adverse events and discontinuations were higher — any TEAE 70.0% vs 61.1%, discontinuation 12.5% vs 4.1%, somnolence about 4 times higher, and fatigue about twice as high. No endometrial hyperplasia or meaningful BMD changes were observed. Sleep and quality-of-life improvements were descriptive secondary outcomes — the study was not powered to confirm them (83).

A systematic review and meta-analysis of 5 elinzanetant RCTs (n=1,699) confirmed the efficacy signal but also confirmed higher discontinuation due to adverse events (RR 2.18, p=0.0002), headache (RR 2.19), somnolence (RR 2.96), and fatigue (RR 3.39). Serious adverse events were not significantly different. The SR/MA authors explicitly state that elinzanetant should not replace clinical assessment for hormone therapy eligibility (117).

Q-122 — A Distinct Mechanism (Not an NK Receptor Antagonist)

Q-122ⓘ (100 mg twice daily):

Behavioral and Digital Options

Self-administered clinical hypnosis showed a greater responder rate than sham (60.4% vs 42.2%, p=0.006) and a particularly strong signal in a breast cancer subgroup (n=62, p=0.002, η²p=0.16). However, the primary mixed-effects test in the full sample was borderline non-significant (p=0.06), and the effect was specifically on moderate hot flashes — mild, severe, and very severe categories were not significant (96).

A digital menopause app (Caria) reduced hot flash distress, depression, and sleep scores over 6 weeks — but hot flash frequency did not significantly change. The intervention affects how women experience VMS, not how often they occur. Anxiety improved similarly in both arms, sleep improvement was front-loaded (significant from baseline to 3 weeks but not from 3 to 6 weeks), and the sample was iOS-only, mostly White, and recruited through MTurk with education skew — so the finding is promising but not broadly generalizable (67).

Treatment Gaps

In a real-world study of 618 breast cancer survivors on endocrine therapy (US + 5 European countries), 15.2% of all VMS prescriptions were systemic hormone therapy — notable because systemic HT is generally considered higher-risk in many breast cancer survivor contexts, though the dataset did not distinguish ER status or prescribing rationale. About one-third (33.1%) of those with moderate-to-severe VMS had no current prescribed treatment. SSRI/SNRI monotherapy was the most common drug class, with a paroxetine-tamoxifen interaction concern identified. This was pre-NK-antagonist-era data (40).

Questions to Bring to Your Doctor

• "My hot flashes are [frequent/severe/both]. Given my medical history, what treatment options are appropriate — and what does the evidence say about each one?"
• "Sleep disruption is more bothersome to me than the hot flashes themselves. Does that change which treatments we should consider?"
• "I cannot use hormone therapy. What are the evidence-based non-hormonal options, and how do they compare?"
• "I've heard about fezolinetant/elinzanetant. What are the benefits and risks for someone in my situation, including the liver monitoring requirements?"
• "I had breast cancer. Are there treatments being studied specifically for VMS in breast cancer survivors?"