Why Thiamine Is Essential for Energy and Focus

Thiamine supports energy production and the nervous system. Find out why that’s so important—and where to find vitamin B1.

3 MIN READ — 03/20/2025

Do you often feel tired, have no appetite, and struggle to concentrate? This might be related to thiamine. Vitamin B1 supports many essential functions in your body, such as energy metabolism and the nervous system. Learn more about this essential B-vitamin here.

What Exactly is Thiamine?

Thiamine is the official name for vitamin B1. It was the first of the eight B-vitamins to be discovered, and because of its important role in supporting nerve cells, the nervous system, and energy metabolism, thiamine is considered a vital nutrient. It’s often referred to as the "nerve vitamin" or "energy vitamin" for this reason.

Our bodies can’t produce vitamin B1 on their own, so we need to get it through food. And since we can’t store this water-soluble vitamin either, it’s important to include thiamine-rich foods in your daily diet.

Fun fact: The discovery was made in the early 20th century by Polish biochemist Casimir Funk, who found that removing the outer layers of rice grains led to nutrient deficiencies and Beriberi (a disease that occurs in people lacking thiamine).

Why is Vitamin B1 So Important?

Vitamin B1 is essential for our bodies as it helps break down proteins and carbohydrates so they can be used for energy. Along with proteins and the trace element manganese, thiamine helps form enzymes in the liver that convert carbohydrates into glucose (sugar), which fuels our energy metabolism.

But that’s not all it does. While most cells in the body can use fats and proteins for energy, nerve and brain cells rely solely on glucose—and therefore on vitamin B1—to perform their functions. Thiamine helps convert glucose into energy, ensuring the flow of information between nerves and throughout the nervous system.

And what else is vitamin B1 good for? The brain also uses glucose to produce serotonin, the so-called "happy hormone." So, maintaining enough vitamin B1 can help support your focus, energy levels, and mental well-being.

What’s the Recommended Daily Intake of Thiamine?

The German Nutrition Society (DGE), along with the nutrition societies of Switzerland, Austria, and the European Food Safety Authority (EFSA), regularly updates reference values for nutrient intake. The recommended daily intake of vitamin B1 depends on age and lifestyle. Here’s a breakdown in milligrams per day:

  • Infants: 0.2 to 0.3
  • Children (up to 13 years old): 0.6 to 0.9
  • Adolescents and teens (up to 19 years old): 1.0 to 1.4
  • Women: 1.0
  • Men (up to 65 years): 1.2 to 1.3
  • Men (65+ years): 1.1

Pregnant and breastfeeding women are recommended to consume slightly more, around 1.2 to 1.3 mg daily.

Which Foods Contain Vitamin B1?

Thiamine is found primarily in plant-based foods, but it’s also present in beef, pork, fish, milk, and eggs. To ensure you’re getting enough vitamin B1, try incorporating the following foods into your diet:

  • Whole wheat and rye
  • Oats
  • Unpolished rice
  • Flours made from oats, wheat, maize, barley, and rye
  • Legumes like peas and beans
  • Potatoes
  • Asparagus
  • Cauliflower and kale
  • Fennel
  • Lamb’s lettuce
  • Carrots
  • Tomatoes
  • Peanuts, walnuts, Brazil nuts, and almonds
  • Sunflower and cashew seeds
  • Lean beef and pork
  • Offal
  • Fish and shellfish
  • Eggs
  • Dairy products

Thiamine is a delicate vitamin and can be lost through heating, washing, or cooking food in water. Storing foods in open air also reduces thiamine content. To retain as much of the vitamin as possible, try to eat these foods raw or prepare them gently.

In addition to a varied, balanced diet, supplements can help ensure you meet your daily thiamine requirements.

These foods contain thiamine.
These foods contain thiamine.

How Can I Recognise a Thiamine Deficiency?

Signs of a thiamine deficiency include:

  • Fatigue and sluggishness
  • Difficulty concentrating
  • Forgetfulness and confusion
  • Loss of appetite
  • Muscle cramps
  • Increased susceptibility to infections due to a weakened immune system

If these symptoms occur frequently, it’s a good idea to discuss them with your doctor.

Overdosing on vitamin B1 is rare with a balanced diet. In the event of an excess, your body will simply excrete it in your urine.

At a Glance

  • 01.

    Thiamine, also known as vitamin B1, is a vital nutrient that supports energy metabolism and the nervous system.

  • 02.

    Since our bodies can’t produce vitamin B1, we need to get it through our diet. A varied, balanced diet helps meet the recommended daily intake, and supplements are also available.

  • 03.

    Vitamin B1 is sensitive to heat, oxygen, UV light, and being stored in water. So, be sure to eat thiamine-rich foods raw or gently cooked.

Article Sources

Food supplements are not a substitute for a balanced and varied diet and a healthy lifestyle. Do not exceed the indicated daily intake. Keep out of reach of children. Please inform and consult your doctor before consuming this product. Not suitable for children and adolescents under 18 years, pregnant or breastfeeding women. Refrain from taking other food supplements containing zinc. Persons taking anticoagulant medication should seek medical advice before consuming vitamin K-containing supplements.

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º Food Supplement. In combination with a healthy diet and exercise.

ª Survey on the awareness of multi-nutrient powders with 211 consumers aged 18 to 49 in Germany, 09/24.

↡ Survey of 527 AG1 customers after 12+ days of use, 2024. The survey was conducted on a previous version of AG1’s continually evolving formulation. The survey results can be transferred to the current version of the formula due to no or scientifically negligible changes in supporting nutrients. Vitamins C, B6, B12, riboflavin, niacin, pantothenic acid, and folate help reduce tiredness and fatigue. Pantothenic acid supports mental performance. Calcium supports normal digestive enzyme function, while biotin maintains normal mucous membranes, such as the gut lining.

Immune System

1: With vitamins A, C, B6 and B12 as well as folate, zinc, copper and selenium, AG1 contributes to the normal function of the immune system. Vitamin C contributes to maintain the normal function of the immune system during and after intense physical exercise.

Energy; Metabolism

2: Vitamins C, B6, B12, riboflavin, niacin, pantothenic acid and magnesium contribute to normal energy-yielding metabolism and to the reduction of tiredness and fatigue. With vitamins C, B6, B12, as well as thiamine, riboflavin, niacin, biotin, pantothenic acid, calcium, phosphorus, copper and manganese, AG1 contributes to normal energy-yielding metabolism. Magnesium contributes to electrolyte balance. Biotin, zinc and chromium contribute to normal macronutrient metabolism.

Cell Protection

3: With vitamins E and C as well as riboflavin, zinc, copper and selenium, AG1 contributes to the protection of cells from oxidative stress. Phosphorus contributes to normal function of cell membranes. Folate, Vitamin B6 and B12 contribute to normal homocysteine metabolism.

Mental Performance; Psychological Function; Nervous System

4: With pantothenic acid, AG1 contributes to normal mental performance. Zinc contributes to normal cognitive function. With vitamins C, B6, B12, B1, B3 and B7 AG1 contributes to normal psychological function and to normal functioning of the nervous system. Calcium contributes to normal neurotransmission.

Skin, Hair & Nails

5: With vitamins A, as well as riboflavin, niacin, biotin and zinc, AG1 contributes to the maintenance of normal skin. Vitamin C contributes to normal collagen formation for the normal function of skin. Vitamin B7, zinc and selenium contribute to the maintenance of normal hair. Zinc and selenium contribute to the maintenance of normal nails.

Hormonal System

6: With vitamin B6, AG1 contributes to the regulation of hormonal activity. Zinc contributes to the maintenance of normal testosterone levels in the blood. Selenium contributes to the normal thyroid function. With chromium, AG1 contributes to the maintenance of normal blood glucose levels.

Digestion

7: Calcium contributes to the normal function of digestive enzymes. Biotin AG1 contributes to the maintenance of normal mucous membranes (e.g. intestinal mucosa).

Muscles

8: With calcium and magnesium, AG1 contributes to normal muscle function.