Ashwagandha (Withania somnifera) is one of the most important herbs in Ayurveda, where it has been used for centuries as a “rasayana”, a tonic for strength and resilience. It’s now one of the best-selling supplements in the US. Here’s what the evidence shows, and how to use it safely.

What people use it for

• Everyday stress and feeling “wired but tired”
• Sleep quality
• Energy, stamina and recovery from exercise

What studies show

• Stress and anxiety: several small clinical trials found that people taking ashwagandha root extract for 6 to 8 weeks reported lower stress scores and lower levels of the stress hormone cortisol than people taking a placebo.
• Sleep: some studies suggest modest improvements in how quickly people fall asleep and how well they sleep.
• Exercise: a few studies in active adults found small gains in strength and endurance.

Most studies were small and short, often lasting 8 to 12 weeks, so the results are promising but not conclusive. Ashwagandha isn’t a treatment for anxiety disorders, depression or insomnia. If those affect your daily life, talk to a doctor.

How to take it

• Studies typically used 250 to 600 mg of root extract a day. Follow the directions on your product.
• Take it with food to reduce stomach upset. Many people take it in the evening.
• Give it 4 to 8 weeks before judging the effect.
• Buy from a reputable brand, such as Himalaya Ashvagandha.

Side effects

• Common: upset stomach, diarrhoea, nausea and drowsiness
• Rare but serious: liver injury. Stop taking it and see a doctor straight away if you notice yellow skin or eyes, dark urine, pale stools, itching or pain in the upper right tummy.

Who should avoid it

• Pregnant women: high doses may cause miscarriage. Avoid it if pregnant or trying to conceive, and while breastfeeding.
• People with thyroid conditions: it may raise thyroid hormone levels
• People with autoimmune diseases such as rheumatoid arthritis, lupus or MS, as it may stimulate the immune system
• People with liver disease
• Anyone due to have surgery in the next 2 weeks, because it may add to the effects of anaesthesia

Drug interactions

Check with a doctor or pharmacist before taking ashwagandha if you take:

• Sedatives or sleeping tablets
• Thyroid medicine
• Diabetes or blood pressure medicines, as it may lower blood sugar and blood pressure
• Immune-suppressing medicines

Frequently asked questions

How long does ashwagandha take to work?

Most studies looked at results after 6 to 8 weeks of daily use.

Can I take ashwagandha every day?

Studies have used daily doses for up to about 3 months. Long-term safety isn’t well known, so talk to your doctor if you plan to take it for longer.

Should I take ashwagandha in the morning or at night?

Either works. If it makes you drowsy, take it in the evening.

Does ashwagandha help with weight loss?

Not directly. By helping with stress and sleep, it may support healthy habits. See our guide to Ayurvedic herbs for weight loss and sleep and weight loss.

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist. Supplements are not evaluated by the FDA to diagnose, treat, cure or prevent any disease.

Permethrin 1% creme rinse, sold in the US as Nix and other brands, is one of the most widely used over-the-counter treatments for head lice. Used correctly, alongside careful combing, it clears many cases. Here’s how to get the best result, and what to do if lice keep coming back.

How it works

Permethrin is an insecticide that attacks the nervous system of lice. It kills live lice and some eggs (nits), and leaves a small amount on the hair that can keep working for several days.

Who can use it

• Adults and children aged 2 months and over, following the label
• Babies under 2 months, and anyone pregnant or breastfeeding: ask a doctor first
• Don’t use it if you’re allergic to chrysanthemums or ragweed, or if the scalp is broken or infected

How to use permethrin 1%, step by step

1. Wash the hair with a shampoo that has no conditioner, then towel dry. Conditioner can coat the hair and stop the treatment working.
2. Shake the bottle and apply enough to soak the hair and scalp, especially behind the ears and at the back of the neck.
3. Leave it on for 10 minutes, then rinse with warm water over a sink, not in the shower, to limit skin contact.
4. Comb through with a fine-toothed nit comb, section by section, to remove dead lice and eggs.
5. Don’t wash the hair again for 1 to 2 days.
6. Check again and repeat on day 9 if you find live lice, to kill any lice that have hatched since.

Why it sometimes fails

In many parts of the US, head lice have become resistant to permethrin. If you still find live, moving lice 8 to 12 hours after treatment, or after the second treatment, the lice may be resistant. Repeating permethrin again and again won’t help.

Alternatives if permethrin doesn’t work

• Ivermectin 0.5% lotion (Sklice), available over the counter in the US since 2020. A single 10-minute treatment usually works without combing. See our guide to head lice treatment.
• Spinosad or malathion lotion, which need a prescription
• Wet combing alone with conditioner and a nit comb every 3 to 4 days for 2 weeks, which needs no chemicals

Around the home

• Wash pillowcases, hats and towels used in the last 2 days in hot water, or seal them in a bag for 2 weeks
• Soak combs and brushes in hot water for 10 minutes
• Check everyone in the home, and only treat people who have live lice
• There’s no need for insecticide sprays on furniture or carpets

Side effects

Mild itching, redness or tingling of the scalp is common and usually fades. Itching can also continue for a while after lice are gone, as a reaction to the bites. Wash off and get help if you notice swelling, a rash or trouble breathing.

Frequently asked questions

Is permethrin 1% the same as permethrin 5%?

No. The 1% creme rinse is for head lice and is sold over the counter. The 5% cream is a prescription treatment for scabies, which is applied to the whole body. See scabies symptoms and treatment.

Can my child go to school after treatment?

Yes. US health organisations advise that children don’t need to miss school because of head lice.

Do I need to treat the whole family?

Check everyone, but only treat people who have live lice.

More in our Lice and Parasites guide: all our articles on this topic in one place.

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist. Always read and follow the label.

Pinworms are the most common worm infection in the US, especially in children aged 5 to 10. The good news is that they’re easy to treat. In the US, the main over-the-counter treatment is pyrantel pamoate, sold under names such as Pin-X and Reese’s Pinworm Medicine. Here’s how to use it properly.

How pyrantel works

Pyrantel paralyses adult pinworms in the gut so they lose their grip and pass out in the stool. It acts mainly inside the bowel, and very little is absorbed into the body.

Who can use it

• Adults and children aged 2 and over, following the label
• Children under 2 or weighing under 25 lb (about 11 kg): ask a doctor first
• Pregnant or breastfeeding: ask a doctor before use

How to take it

• Dose is based on body weight. Use the weight chart on the pack, and the measuring cup or spoon supplied. Don’t guess.
• It’s a single dose, taken at any time of day, with or without food. The liquid can be mixed with milk or juice.
• A second dose after 2 weeks is commonly recommended by doctors, because pyrantel doesn’t kill eggs, and newly hatched worms can restart the infection. Check with your doctor or pharmacist.

Treat the whole household

Pinworm eggs spread easily on hands, bedding, towels and toys, so doctors often recommend treating everyone in the home at the same time, even if they have no symptoms. Ask your doctor about anyone under 2 or pregnant.

Stop pinworms coming back

• Wash hands with soap after using the toilet and before eating, and keep nails short
• Shower each morning to wash away eggs laid overnight
• Change underwear daily and wash pyjamas, bedding and towels in hot water
• Discourage nail-biting and scratching around the bottom
• Vacuum and wipe surfaces such as toilet seats and door handles

Possible side effects

Most people have none. Some get nausea, vomiting, tummy cramps, diarrhoea, headache or dizziness. Stop and see a doctor if you have a rash or anything that worries you.

When to see a doctor

• Symptoms don’t clear after the second dose
• The child is under 2, or the person is pregnant
• You’re not sure it’s pinworms. A doctor can confirm it with a simple “tape test”.
• Severe tummy pain, or worms seen in other places

Doctors may prescribe a different medicine, such as mebendazole or albendazole, if pyrantel isn’t suitable. Read more in our guide to pinworm symptoms and treatment.

Frequently asked questions

How fast does pyrantel work?

It starts working within a day, and the itching usually eases within a few days. Eggs can survive on surfaces for 2 to 3 weeks, so hygiene and the second dose matter.

Can I buy pyrantel without a prescription?

Yes, in the US it’s available over the counter for adults and children aged 2 and over.

Do pets spread pinworms?

No. Human pinworms only live in people, so you don’t need to treat your pets.

More in our Lice and Parasites guide: all our articles on this topic in one place.

This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist. Always read and follow the label.