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Carnitine is a supplement. It has been prescribed for you because your body has a shortage of carnitine. It will help to give you more energy.

Any side-effects tend to be mild. They include feeling sick, diarrhoea, and abdominal discomfort.

Type of medicineA carnitine supplement
Used forCarnitine deficiency
Also calledL-carnitine or levocarnitine
Brands include: Bio-Carnitine®; Carnitor®
Available asTablets, capsules, chewable tablets, oral liquid

Carnitine is a substance which occurs naturally in your body. It is a type of protein. It helps your body turn fat into energy. Supplements of carnitine are given if you have low levels of carnitine for some reason. This may be because your body is not producing sufficient, or because your natural levels are reduced due to some treatment you are having.

Some medicines are not suitable for people with certain conditions, and sometimes a medicine may only be used if extra care is taken. For these reasons, before you (or if appropriate, your child) start taking carnitine it is important that your doctor knows:

  • If you are pregnant or breast-feeding, although carnitine is not known to be harmful to babies.
  • If you have any problems with the way your kidneys work.
  • If you have sugar diabetes.
  • If you are taking any other medicines. This includes any medicines you are taking which are available to buy without a prescription, such as herbal and complementary medicines.
  • If you have ever had an allergic reaction to a medicine.
  • Before you start this treatment, read the manufacturer's printed information leaflet from inside your pack. It will give you more information about carnitine and will provide you with a full list of side-effects which you may experience from taking it.
  • Take carnitine exactly as your doctor tells you to. It is usual to take 2-4 doses each day. Your doctor or pharmacist will tell you what dose is right for you, and this will also be printed on the label of the pack to remind you. The amount may vary from time to time depending on how you respond to the treatment.
  • The are a number of different forms of carnitine available - you may be supplied with tablets, capsules or oral liquid medicine. Check the directions on the label to see how you should take your supply. Some tablets should be swallowed whole with a drink of water, other tablets should be chewed before they are swallowed.
  • Try to get into the habit of taking your doses at the same times of day each day. This will help you to remember to take your doses regularly.
  • If you do forget a dose, take it as soon as you remember. Try to take the correct number of doses each day, but do not take two doses together to make up for a forgotten dose.
  • Try to keep your regular appointments with your doctor. This is so your doctor can check on your progress. You may need to have regular blood and urine tests to check the amount of medicine in your body.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. The table below contains some of the most common ones associated with carnitine. You will find a full list in the manufacturer's information leaflet supplied with your medicine. The unwanted effects often improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following continue or become troublesome.

Carnitine side-effectsWhat can I do if I experience this?
Feeling or being sick, abdominal painStick to simple meals - avoid rich or spicy food
DiarrhoeaDrink plenty of water to replace lost fluids
Body odourIf this becomes troublesome, speak with your doctor

If you experience any other symptoms which you think may be due to the medicine, speak with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

If you buy any medicines, check with a pharmacist that they are safe to take with your other medicines.

If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.

Never take more than the prescribed dose. If you suspect that you or someone else might have taken an overdose of this medicine, go to the accident and emergency department of your local hospital. Take the container with you, even if it is empty.

This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.

Do not keep out-of-date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.

If you have any questions about this medicine ask your pharmacist.

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Helen Allen
Current Version:
Peer Reviewer:
Prof Cathy Jackson
Document ID:
3792 (v23)
Last Checked:
Next Review:
The Information Standard - certified member

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