What is magnesium with B6 good for?
Mostly PMS and stress, and the proof is thin. Check the B6 first. The trials gave 30 to 50mg a day, three to five times the NHS limit for B6 from supplements.
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What is magnesium B6 good for?
It has been tested mainly for PMS (premenstrual syndrome, the symptoms some women get in the days before a period) and stress. The results were small. The NHS says supplements such as B6 and magnesium may help PMS, but there’s not much evidence that they work.
| Who was tested | What they took a day | What happened |
|---|---|---|
| 44 UK women with mild PMS | 200mg magnesium and 50mg B6, for one cycle. | No overall difference between tablets. The mix eased anxiety-type symptoms a little. |
| 150 Iranian women with PMS | 250mg magnesium and 40mg B6, for two cycles. | Every group improved, even the dummy tablet. The mix improved most. |
| 264 stressed adults with low blood magnesium | 300mg magnesium and 30mg B6, for 8 weeks. | Stress fell by about the same amount with or without the B6. |
Sources: De Souza 2000; Fathizadeh 2010; Pouteau 2018
The UK trial’s authors called the effect modest. They said more studies are needed before anyone recommends it.
Night cramps? A Cochrane review (a careful summary of the trials) found magnesium alone, without B6, is unlikely to help older adults with muscle cramps. See magnesium for cramps.
Taking it for PMS? The NHS suggests a symptom diary for at least 2 cycles first. You can take it to a GP.
How much B6 is safe in magnesium B6?
Turn the pack over and find the vitamin B6 line. That line is the B6 mg, and it matters more than the magnesium.
The NHS says don’t take more than 10mg of B6 a day from supplements, unless a doctor advises it. All three trials gave more: 30mg to 50mg.
- 10 mg or belowWithin the NHS limit for supplements.
- Above 10 to just under 200 mgOver the NHS limit. The effect is unclear.
- 200 mg or aboveCan cause loss of feeling in the arms and legs.
Source: NHS: vitamin B
At 200mg or more a day, B6 can cause loss of feeling in the arms and legs. This usually gets better once you stop.
But in a few cases, after large amounts and particularly for more than a few months, it can be permanent. Between 10mg and 200mg, the NHS says the effect is unclear.
Add the B6 in any multivitamin or B complex you take. The total is what counts.
Does B6 help magnesium work better?
Not in the biggest trial. Over 8 weeks, stress scores fell 44.9% with the mix and 42.4% with magnesium alone.
The authors said adding B6 was not better than magnesium alone. Several of them worked for Sanofi, the company that makes the tablet.
In a smaller group with severe stress, the mix did 24% better. That is one subgroup in one trial, not proof.
In the UK PMS trial, the B6 didn’t change how much magnesium people passed in their urine. The authors also found the form they used, magnesium oxide, was poorly absorbed.
Want magnesium on its own? See which magnesium to take. For worry and nerves, see magnesium for anxiety.
Who might magnesium with B6 suit?
Most people don’t need it. The NHS says a varied, balanced diet should give you all the magnesium and B6 you need.
| Nutrient | Adults need a day (19 to 64) | From supplements |
|---|---|---|
| Magnesium | 300mg for men, 270mg for women. | 400mg or less a day is unlikely to cause harm. |
| Vitamin B6 | About 1.4mg for men, 1.2mg for women. | No more than 10mg a day, unless a doctor advises it. |
Sources: NHS: vitamin B; NHS: other minerals
B6 comes from pork, chicken, some fish, peanuts, oats, bananas and milk. Magnesium comes from spinach, nuts and wholemeal bread.
The trials point to one group: women with PMS. Even there, the effect was small and the trials were short.
The NHS also suggests regular exercise, a balanced diet and plenty of sleep for PMS. See what helps PMS.
Before you buy magnesium with B6
- Find the mg of B6 per daily dose, not per tablet.
- Keep B6 from supplements to 10mg a day or less, unless a doctor advises more.
- Keep magnesium from supplements to 400mg a day or less.
- Add any multivitamin or B complex you also take.
- On a medicine? Check with a GP or pharmacist before you start.
Sources: NHS: vitamin B; NHS: other minerals; NHS: PMS
What are the side effects of magnesium B6?
Magnesium first. Taking more than 400mg for a short time can cause diarrhoea. See can you take too much magnesium.
Then B6. At 200mg or more a day it can damage the nerves in your arms and legs. Doctors call this peripheral neuropathy.
Signs include numbness and tingling in the feet or hands, and burning, stabbing or shooting pain. You may also lose balance and co-ordination, or get muscle weakness, especially in the feet.
Taking a medicine? The NHS says check with a GP or pharmacist before you start a regular supplement. Never stop or change a prescribed medicine without your prescriber.
When to speak to a GP
See a GP if:
- You get pain, numbness, tingling or loss of feeling in your hands or feet, or loss of balance or weakness.
- You have PMS, and lifestyle changes haven’t helped or it affects your daily life.
- You take a medicine and want to start a regular supplement.
- You think you need more than 10mg of B6 a day.
Call 999 or go to A&E if you have symptoms of PMDD, a severe form of PMS, and feel suicidal.
Wondering about tingling? See blood tests for tingling and numbness and vitamin B6 blood test results.