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PMS (premenstrual syndrome)

What the NHS, NICE and the National Association for Premenstrual Syndromes say about the evidence on vitamin B6, calcium, magnesium and herbal remedies.

PMS is the name for the symptoms women can experience in the weeks before a period, the NHS says. Supplements such as vitamin B6, calcium, vitamin D and magnesium are often suggested, but the NHS says there is not much evidence behind them, and NICE's summary for GPs says the same of complementary treatments and supplements in general. The National Association for Premenstrual Syndromes, a clinician-led charity, updated its guideline in 2026: it no longer advises high-dose vitamin B6, and it advises against several herbal remedies.

NHS: If PMS affects your daily life, a GP can talk through the treatments available.

Each line below is a short summary of what the named source says, with a link to read it in full. None of it is medical advice.

Limited evidence

Vitamin B6
A B vitamin found in pork, poultry, some fish, peanuts, soya beans, oats, bananas and milk.
- NHS: Named among supplements for PMS, with not much evidence behind them.
- NAPS: High doses are no longer advised, because of the risk of nerve damage.
Also covered by NICE.
Calcium and vitamin D
A mineral held mostly in bones and teeth, and the vitamin the body makes in sunlight.
- NICE: Limited evidence for calcium and vitamin D, as for most supplements for PMS.
- RCOG: Little evidence overall for complementary therapies, though many women try them.
Also covered by NHS and NAPS.
Magnesium
A mineral found in spinach, nuts and wholemeal bread, among other foods.
- NAPS: Limited evidence, as for calcium and zinc.
- NHS: Named among supplements for PMS, with not much evidence behind them.
Also covered by NICE.
Agnus castus (chasteberry)
The berry of the chaste tree, sold as a herbal remedy.
- NICE: The most promising of these, but there is not yet enough evidence.
- NAPS: Some evidence; not to be taken in pregnancy or while breastfeeding.
Also covered by RCOG.

No good evidence

Evening primrose oil
Oil pressed from the seeds of the evening primrose plant.
- NAPS: Some evidence for breast pain, none for PMS itself.
Also covered by RCOG and NICE.

Advised against

St John's wort
A flowering plant sold as a herbal remedy.
- NAPS: Not recommended: a risk of interactions with medicines, and no evidence for PMS.
Black cohosh
The root of a North American plant, sold as a herbal remedy.
- NAPS: Not recommended: no evidence, and a risk of liver damage.

Things to check

NHS: Do not take more than 10mg of vitamin B6 a day in supplements unless a doctor advises it.
NHS: Check with a GP or pharmacist before taking regular supplements if you also take medicines.
NAPS: If you try a herbal remedy, try one at a time for at least three months, with the THR mark.
NAPS: Self-help should not delay seeing a doctor when PMS is severe.
NHS: More than 400mg of magnesium a day from supplements can cause diarrhoea.

If you take medication, are pregnant, or have a health condition, check with a pharmacist or GP first.

Sources

PMS (premenstrual syndrome)NHS. Page last reviewed: 18 June 2024PMS symptoms, things to try yourself, GP options, complementary therapies and PMDD.
Premenstrual syndrome: Scenario: Management of premenstrual syndromeNICE Clinical Knowledge Summaries. Last revised in September 2024NICE's summary for GPs on lifestyle, supplements and prescribed options for PMS.
Managing premenstrual syndrome (PMS)Royal College of Obstetricians and Gynaecologists, RCOG Patient Information Committee. Published March 2018, currently under reviewHow PMS is diagnosed and the lifestyle, complementary, medical and surgical options.
NAPS Treatment Guidelines Updated 2026National Association for Premenstrual Syndromes. Updated 2026The charity's clinical guideline on diagnosing and managing PMS, step by step.
B vitamins and folic acidNHS. Page last reviewed: 03 August 2020Each B vitamin: where it comes from, how much people need, and how much is safe.
Vitamins and minerals - OthersNHS. Page last reviewed: 03 August 2020Other vitamins and minerals, including how much magnesium is safe to take.

Sources checked 28 September 2026. Prices checked 20 October 2026, ranked purely by price per dose. Which sources these pages use.

Limited evidence

Vitamin B6

Calcium and vitamin D

Magnesium

Agnus castus (chasteberry)

No good evidence

Evening primrose oil

Advised against

St John's wort

Black cohosh

Things to check

Sources