Menopause supplements: what the evidence shows, honestly

The regulatory point that explains a lot

In most countries supplements are regulated as food rather than medicine. They do not have to demonstrate efficacy before sale, manufacturing standards vary, and what the label says is present is not independently guaranteed unless a third party has tested it.

This is why a supplement can be sold with confident claims that would be unlawful for a medicine, and why the gap between marketing and evidence is structural rather than incidental.

Where there is a genuine role

Vitamin D and calcium support bone health, and bone loss accelerates around the final period. The important qualification is that they support bone within requirements; taking more than needed does not provide more benefit, and high-dose calcium supplementation specifically has been questioned on cardiovascular grounds while dietary calcium has not.

Iron is worth mentioning because it is the deficiency most often relevant in perimenopause, from heavy bleeding, and it is the one that should be taken based on a blood test rather than taken speculatively. Iron supplementation without deficiency is not benign.

Modest, mixed, or contested

• Soy isoflavones: some trials show a small reduction in hot flashes, others none. Effects may depend on whether your gut bacteria produce equol, which only a minority of people do. Dietary soy is safe
• Black cohosh: mixed trial evidence, and rare but documented reports of liver injury, which is why some regulators require a warning
• Red clover: weak and inconsistent evidence for vasomotor symptoms
• Magnesium: widely marketed for sleep and cramps, with limited trial evidence specifically in menopause. Generally well tolerated; excess causes diarrhoea
• Omega-3: the evidence for hot flashes is weak, and a large trial found no benefit for dry eye
• Evening primrose oil: repeatedly tested for hot flashes without convincing benefit

Risks people do not expect

Supplements interact with medicines. St John's wort is the clearest example: it induces liver enzymes and reduces the effectiveness of a long list of drugs including some hormonal contraceptives and anticoagulants.

Phytoestrogen-containing supplements raise a question in women with hormone-sensitive breast cancer that dietary soy generally does not, because concentrated extracts differ from food. This is a conversation with an oncology team.

Multi-ingredient menopause blends make this worse by combining several active botanicals at undisclosed doses, so an interaction or adverse effect cannot be attributed to anything.

How to evaluate a claim

Useful questions: is there a randomised trial, or only a mechanism and testimonials? Was it tested against placebo, which matters enormously here because placebo response for hot flashes in trials is consistently large? Is there third-party testing of the product itself?

The large placebo effect is the key to understanding this field. It is why almost any menopause supplement produces convincing personal accounts of improvement, and why uncontrolled evidence carries so little weight.

When to see someone

Tell a clinician or pharmacist what you take, including supplements, particularly before surgery and alongside anticoagulants, thyroid medication, anticonvulsants or cancer treatment.

Ask for vitamin D and ferritin to be measured rather than supplementing speculatively. Both are common deficiencies, both cause fatigue attributed to hormones, and both are guided better by a result than by a guess.