Maximum safe dose of thiamine from supplements

There hasn’t been established a maximum safe dosage of thiamine. Even daily doses of 5 mg are considered pretty safe. Side effects may occur when we take extremely high thiamine dosages of more than 500 mg from supplements for long periods of time.

Health benefits of thiamine

Thiamine is a water-soluble B-vitamin. It’s also known as vitamin B1.

Thiamine is crucial for energy metabolism. It’s involved in glucose, amino acid, and lipid metabolism. Thus, people who want to lose weight should get adequate amounts of thiamine daily.

Moreover, thiamine is important for the synthesis of certain hormones and for the proper activity of certain enzymes.[1,2]

Severe thiamine deficiency may cause memory loss, visual disturbances, and weak muscles. Additionally, it may affect the nervous and cardiovascular system.

The recommended daily intake of thiamine is 1.2 mg for men and 1.1 mg for women, respectively. Children and teenagers need lower dosages. Only pregnant and lactating women need higher doses. They should get at least 1.4 mg of thiamine a day. 

What’s the maximum safe dosage of thiamine (vitamin B1)?

Actually, the body can store only small amounts of thiamine. Hence, we should get thiamine from food or supplements every day.

In fact, there aren’t reports of severe adverse effects from high thiamine dosages of 50 mg. Neither from foods nor supplements. Thus, the Food and Nutrition Board hasn’t established a maximum daily limit for thiamine.[3]

Moreover, high doses above 5 mg aren’t absorbed as effectively. Excess thiamine is excreted through urine.

But, there are thiamine (or vitamin B1) supplements which contain doses up to 500 mg. This dose is hundreds of times higher than the recommended daily intake. Even these extremely high dosages are unlikely to cause any adverse effect.[4]

In any case, avoid taking extremely high dosages of thiamine from supplements for a long time. You should always consult your healthcare provider before taking any dietary supplement.

On the other hand, we can’t get too much thiamine from food.

When should we get high doses of thiamine from supplements?

Healthy people who follow a well-balanced diet can get more than enough thiamine. Actually, there are many animal-based and plant-based foods high in thiamine.

But, obesity, poor diet, alcohol abuse, excessive carbohydrate consumption, major trauma, surgery, diabetes and other diseases may increase the risk of thiamine deficiency. In these cases, people may benefit from taking high dosages of thiamine, which only supplements can provide. The recommended daily dose isn’t enough.[5]

Additionally, calcium and magnesium deficiency negatively affects thiamine levels in the body!

Diuretics may also cause thiamine depletion.[6]

You can find a wide variety of thiamine supplements on iHerb.

Side effects of extremely high doses of thiamine

In rare cases of extremely high dosages of thiamine from supplements, people have reported adverse effects such as sensation of warmth, sweating, itching and discoloration of the skin, and even allergic reactions.[7]

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