Can you take ashwagandha and magnesium together?
Yes, if ashwagandha is safe for you. No health source we checked lists a clash between them. But in the one trial that gave both, people did no better than on the ashwagandha mix alone.
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Can you take ashwagandha and magnesium together?
Yes, if ashwagandha is safe for you. We checked the NHS, the US health agency for herbal remedies (NCCIH) and the trials. None lists a clash between the two.
That isn’t proof they’re safe together. Only one trial has given both, and it lasted just 2 weeks.
The bigger question is the herb. The NHS says 400 mg or less a day of magnesium from supplements is unlikely to cause any harm. Ashwagandha has a longer list of people who should avoid it.
| Question | Magnesium | Ashwagandha |
|---|---|---|
| What trials found for sleep | A small gain in people who slept badly, from low-quality trials. | A small gain, bigger in people with insomnia. |
| Side effects | Diarrhoea, at more than 400 mg for a short time. | Drowsiness, upset stomach, diarrhoea and being sick. |
| How much or how long | 400 mg or less a day from supplements is unlikely to cause harm. | No UK safe dose. May be safe for up to 3 months. |
Sources: NHS; NCCIH; Magnesium review; Ashwagandha review
So the check that matters is the herb. See who should skip it below.
Does taking them together work better?
Not in the one trial that tested it. In it, 103 healthy, active adults took supplements for 2 weeks.
The morning mix had 600 mg of ashwagandha and another herb, rhodiola. The evening mix had 145 mg of magnesium and two other ingredients, L-theanine and apigenin.
| Group | Stress | Sleep quality |
|---|---|---|
| Morning mix (ashwagandha) | Lower than on dummy pills. | Better than the group on both. |
| Evening mix (magnesium) | No clear change. | No clear difference. |
| Both mixes | No clear change. | Less gain than the morning mix alone. |
| Dummy pills | The comparison. | The comparison. |
Source: Mastrofini 2026
The authors think the ingredients may work on the same systems, so the gains may not stack.
Take it lightly. It was short, in healthy people, mixed five ingredients and was paid for by a supplement company. The sleep results were early findings.
Two men on the morning mix stopped because of side effects, such as diarrhoea or dizziness. Both got better within 48 hours of stopping.
Want to try both anyway? A practical idea is to start one at a time. Both can cause diarrhoea, so you’ll know which one did it.
Who should not take ashwagandha?
NCCIH says to avoid it in pregnancy and not to use it while breastfeeding. It isn’t recommended if you:
- are about to have surgery
- have a thyroid condition
- have an autoimmune condition, where your immune system attacks your own body
NCCIH says people with prostate cancer that is sensitive to hormones should avoid it.
The NHS also says not to take herbal medicines if you have kidney or liver problems.
| Medicine | What it’s for |
|---|---|
| Diabetes medicines | Lowering blood sugar. |
| Blood pressure medicines | Lowering high blood pressure. |
| Immunosuppressants | Calming the immune system. |
| Sedatives | Making you calm or sleepy. |
| Anticonvulsants | Preventing seizures. |
| Thyroid hormone | Treating an underactive thyroid. |
Source: NCCIH
On any medicine? The NHS says to check with a pharmacist first. Never stop or change a prescribed medicine without your prescriber.
Liver injury is rare, but NCCIH says a number of cases have been linked to ashwagandha. UK safety experts are reviewing its safety. More in ashwagandha side effects and herbal supplements and your liver.
How much to take, and when?
The NHS says you should be able to get all the magnesium you need from a varied diet. Adults aged 19 to 64 need 300 mg a day (men) or 270 mg (women).
- 400 mg a day or belowNHS: unlikely to cause any harm.
- Above 400 mg a dayNHS: can cause diarrhoea if taken for a short time.
Source: NHS
Check the label for the amount of magnesium itself, often called elemental magnesium, not the weight of the whole tablet ingredient. The trial’s 2 g of magnesium L-threonate gave just 145 mg.
No UK body sets a safe dose of ashwagandha. Sleep trials used 120 to 600 mg a day for 6 to 12 weeks. NCCIH says it may be safe for up to 3 months.
No source we found gives a best time of day. The joint trial gave ashwagandha in the morning and magnesium in the evening. For forms and doses, see which magnesium to take and too much magnesium.
Will ashwagandha and magnesium help me sleep?
Each may help a little on its own. A review of 5 ashwagandha trials found a small gain in sleep, too big to be chance. It was bigger in people with insomnia (trouble getting to sleep or staying asleep), at 600 mg a day or more, and from 8 weeks.
For magnesium, 3 small trials in older adults with insomnia found people fell asleep about 17 minutes faster. But the evidence was low to very low quality. In 155 adults who slept badly, 250 mg a day gave a small benefit.
The NHS says insomnia usually gets better by changing your sleeping habits. It also says to check with your doctor before taking anything for sleep.
Six NHS sleep habits to try first
- Only go to bed when you’re sleepy.
- Wake up and get out of bed at the same time every day.
- Relax for at least 1 hour before bed, for example with a bath or a book.
- Keep your bedroom dark and quiet. Use curtains, blinds, an eye mask or ear plugs if needed.
- Don’t smoke or drink alcohol, tea or coffee for at least 6 hours before bed.
- Don’t nap during the day.
Source: NHS: insomnia
More in sleep habits that work and ashwagandha for anxiety and sleep.
When to speak to a GP
The NHS says to see a GP if:
- changing your sleeping habits has not helped your insomnia
- you’ve had trouble sleeping for months
- your insomnia is affecting your daily life in a way that makes it hard for you to cope
Ask for an urgent GP appointment or get help from NHS 111 if your skin or the whites of your eyes look yellow. You may also have itchy skin, darker pee and paler poo than usual.