The evidence, honestly

One of the most studied non-hormonal options for hot flashes, and the results genuinely conflict. A 2001 randomized trial in breast cancer survivors found it performed no better than placebo. The most rigorous trial on perimenopausal women broadly (the HALT study, 351 participants) also found no significant benefit over placebo. Other, smaller trials — and a 2023 review of 22 studies — found it potentially helpful for some symptoms, with clearer support for hot flashes than for mood. Some women respond well at higher doses over 8+ weeks; many don't.

The most encouraging recent data in this category. Separate randomized, double-blind, placebo-controlled trials — one in 100 perimenopausal women over 8 weeks, another in 60 women over 56 days — found meaningful improvements in symptom scores, sleep, and stress versus placebo. Sample sizes remain small and come from a limited number of research groups, so we'd call this promising rather than settled.

One of the best-supported ingredients for a specific use: vaginal dryness and discomfort. Randomized trials comparing hyaluronic acid vaginal gel against low-dose estrogen cream found comparable improvement, including a multicenter trial of 133 women. A broader review of 17 studies found consistent improvement in vulvovaginal symptoms. It doesn't reverse underlying tissue changes the way vaginal estrogen can, but for symptom relief the evidence is genuinely solid.

Calcium and D3 have one of the longest, most consistent evidence bases in this category — decades of research support bone density and fracture-risk reduction after menopause. Vitamin K2's role is newer, with a thinner evidence base than calcium and D3 alone.

One of the most extensively studied supplement categories in medicine, and the honest summary is genuinely mixed. Omega-3s reliably lower triglycerides, but large recent trials on major cardiovascular events show modest-to-null benefit in the general population. CoQ10's evidence is thinner still — reasonable support for people on statins, weaker for general prevention.

Worth flagging directly: the evidence on D-mannose shifted meaningfully in 2024. An earlier trial (308 women) found it worked about as well as a prophylactic antibiotic. A much larger, more rigorous trial published in JAMA Internal Medicine in 2024 (598 women) found no significant benefit over placebo. Cranberry's active compounds (proanthocyanidins) have somewhat better support at a properly standardized dose — around 36mg PACs/day is the threshold research points to.

Research on specific probiotic strains for vaginal pH balance and gut-hormone interactions is an active and genuinely promising area, though strain-specific — results with one studied strain don't necessarily generalize to a different blend. Look for products naming their specific studied strains rather than "proprietary blend."

This category is studied extensively, and the honest summary is modest effects at best. Research generally shows small, statistically significant but practically minor changes in metabolic markers — nothing close to the dramatic claims common in this space.

A growing base of small-to-moderate randomized trials shows improved skin elasticity and hydration after 8–12 weeks of daily use. Evidence for hair strength specifically is thinner than for skin. Many trials in this space are industry-funded and would benefit from independent replication.

Widely marketed for libido, but the human research base is thin — small trials, short durations, inconsistent results. Some women report a subjective benefit, but this is one of the more speculative ingredient categories in the space.

Each has a reasonable evidence base for one specific claim: modestly reducing the duration and severity of a cold once it starts, not preventing illness altogether. That's a real, if narrower, benefit than most immune marketing implies.

Rhodiola has a reasonably encouraging small-trial base for reducing fatigue and stress-related symptoms, similar in spirit to the ashwagandha research above. Holy basil's evidence is a step behind, with fewer rigorous trials.