How does thiamine work?
Vitamin B1 helps the cells in the body convert food into energy.
If you do not have enough vitamin B1 this process cannot work properly. You may have symptoms such as tiredness, loss of appetite and muscle weakness.
Taking a thiamine supplement helps restore normal levels of vitamin B1 in your body. This allows your cells to work properly again and your symptoms should improve.
When will I feel better?
Taking thiamine will start increasing your body's levels of vitamin B1 within a few hours.
However, if you're taking it to treat vitamin B1 deficiency, it may take a few weeks before you start to feel better.
It's important to keep taking your thiamine for as long as the doctor tells you to.
Are there any long-term side-effects?
There are usually no problems taking thiamine for a long time.
Your body absorbs the amount of thiamine (or vitamin B1) that it needs. The rest is passed out of your body through your pee.
Are there other sources of thiamine?
Thiamine is found naturally in many foods.
Good sources of this vitamin include:
- peas, lentils and beans
- yeast or beef extracts (including Marmite and Bovril)
- eggs
- oranges and orange juice
- wheat bran and other wholegrain foods
- pork, beef and liver
- fish
- fortified foods that have thiamine added (including some brands of breakfast cereals, rice, egg noodles and bread)
How will it make me feel?
You will not notice much difference in the short term but over a few weeks you should gradually notice your symptoms improving and begin to have more energy again.
Thiamine is a very safe medicine and you're unlikely to get any side effects.
Will it affect my contraception?
Thiamine will not stop any type of contraception from working. This includes the combined pill and emergency contraception.
However, if thiamine gives you severe diarrhoea for more than 24 hours, your contraceptive pills may not protect you from pregnancy. Check the pill packet to find out what to do.
Find out more:
Can I drive or ride a bike?
Yes. Thiamine will not affect your ability to drive or ride a bike.
Can I drink alcohol while taking thiamine?
Long-term drinking or heavy drinking can stop your body from absorbing thiamine (vitamin B1).
If you're taking thiamine for vitamin B1 deficiency, it's best to avoid drinking alcohol as this will make your symptoms worse.
If you're taking thiamine as a vitamin supplement, avoid drinking too much. Try to keep to the recommended guidelines of no more than 14 units of alcohol a week.
A standard glass of wine (175ml) is 2 units. A pint of lager or beer is usually 2 to 3 units of alcohol.
Is there any food or drink I need to avoid?
Apart from avoiding too much alcohol, you can eat and drink normally when taking thiamine.