Evidence: Low Potential Benefits: Reasonable Safety: Very High
TABLE OF CONTENTS
What is thiamine?
Thiamine (vitamin B1) is an essential nutrient of the B vitamin class. The main role of this nutrient is to burn carbohydrates and fat for energy. Thiamine supplements are most helpful if you are deficient in the nutrient. If you already get enough vitamin B1 from food, you should not need to take the supplement, but it can still improve some aspects of your health beyond the baseline. This article is about the main benefits of thiamine as a supplement, its potential side effects, the best time to take it, and more.
Potential benefits
It is important to note that all of the potential benefits mentioned below are dose-dependent. Generally, the higher the dose, the more pronounced the effects are. However, they do reach a plateau at a certain point. We will discuss the best dosing protocol later in this article.
Major benefits
Correcting a thiamine deficiency – Vitamin B1 deficiency can be terrible for your health and overall quality of life. Fortunately, a severe deficit is relatively rare. A mild deficiency is much more common and can lead to many problems mentioned later in the article. If you are experiencing symptoms of deficiency or know that your vitamin B1 levels are too low, correcting a deficiency is the main benefit of thiamine supplements.
Reducing symptoms of PMS – High doses (100 mg daily) of thiamine dramatically decrease the symptoms of premenstrual syndrome (PMS), such as hot flushes, anxiety, cramps, bloating, acne, headaches, and mood swings. This is by far the most notable benefit of vitamin B1 supplements for women experiencing PMS.
Minor benefits
Reduced blood pressure – One study has shown a minor reduction in blood pressure (2.3-4.3%) in people with hyperglycemia (high blood glucose) who took 300 mg daily for 6 weeks. This benefit may and may not apply to those with normal blood glucose and blood pressure levels.
Protection from AGEs – Thiamine may help counter the production of advanced glycation end-products (AGEs), which are substances that contribute to neurodegeneration.
Unproven benefits
There is not enough evidence that thiamine notably affects these health metrics, or the science shows little to no efficacy in these areas.
Skin quality – Unfortunately, thiamine doesn’t seem to help with acne, wrinkles, or other skin problems. It also doesn’t help hydrate the skin or keep it elastic.
Blood flow – Scientific studies have never shown a significant effect on blood flow.
DNA protection – The supplement has not been shown in human studies to protect DNA from oxidative damage.
Inflammation – The supplement doesn’t significantly affect CRP (C-reactive protein) or other markers of inflammation.
Triglycerides – There is no significant influence, or at least it has never been observed.
Brain health and cognition – The supplement does not directly improve brain health and cognitive abilities.
Testosterone – The supplement does not significantly affect DHT, free testosterone, or total testosterone levels.
Cholesterol – The supplement has no direct effect on HDL or LDL cholesterol levels.
Cancer – The supplement has never been shown in reliable human studies to affect cancer rates or tumor growth.
Thyroid hormones – There is no significant interaction between the supplement and serum T3 and T4.
Well-being – Supplementation with thiamine doesn’t appear to increase subjective well-being. However, the supplement could improve your well-being if you have a vitamin B1 deficiency.
Weight loss and fat loss – Taking the supplement doesn’t notably affect weight loss or burning of fat.
Strength and muscle growth – The supplement does not help you increase strength or muscle mass faster. Reliable human studies have never shown this effect.
Asthma – The supplement has not been shown to help with asthma to a significant degree.
Power output during exercise – The supplement does not directly influence power output during aerobic or resistance training. It does not impact VO2 max or aerobic endurance either.
Kidney function – The supplement does not significantly change kidney function biomarkers.
Sleep quality – The supplement does not directly improve sleep quality. It also does not seem to affect sleep duration.
Stress and anxiety – The supplement does not affect cortisol levels, at least not directly.
Metabolic rate – The supplement does not speed up your metabolism or slow it down.
Possible side effects
Thiamine supplements are one of the safest supplements on the market. The vitamin has no known toxicity and all the potential side effects below are rare and by no means dangerous. The only exception is the TTFD form (Fursultiamine) which has the potential to cause liver toxicity and should be avoided.
Stomach upset – This side effect can only occur if you take very high doses at once. There is nothing to worry about if you experience stomach upset after taking vitamin B1. However, it is an indication that you don’t need to take such as high amount.
Nausea – Just like stomach upset, this side effect is not dangerous but can be unpleasant.
Contamination – Contaminated supplements are uncommon in the USA and other well-regulated countries. However, if you wish to buy products from China, India, or other countries without strict regulations, beware that the supplements may be contaminated. Either way, you need to choose the brand you order from wisely. It is highly recommended to check the certificates or read through some reviews for the specific product before you buy it. The FDA (Food and Drug Administration) has the power to regulate dietary supplements but can only do so after they have been on the market for a while. That’s because supplement companies are not obligated to announce to the FDA when releasing a new product on the market. The FDA has to discover the product and test it for potential impurities, which can take a lot of time. During that time, the supplement can be sold on the market even if it’s impure. Also, the supplement companies can change their manufacturers at any time without announcing it to the FDA.
Who should not take thiamine?
You should probably avoid taking the supplement if you:
already get enough from food
do not experience PMS (since that is the main notable benefit of the supplement outside fixing a deficiency)
experience a severe adverse reaction after taking the supplement
are on a tight supplement budget (since there are more cost-effective supplements on the market)
Who will benefit the most?
You should consider taking the supplement if you:
drink lots of alcohol (alcohol hurts the absorption of thiamine, worsens your liver’s ability to store the vitamin, and hurts its activation for use with our enzymes)
experience symptoms of deficiency, or you know you are deficient based on blood tests
vomit a lot (since we tend to lose vitamin B1 through vomit)
suffer from liver diseases (many of them make it harder to store vitamin B1)
are on a high-carb diet (since the main role of thiamine is burning carbohydrates and you need 2 times more thiamine to burn carbohydrates for energy than to burn fat – however, high-carb diets also tend to provide more vitamin B1)
are on a very low-carb, ketogenic, or carnivore diet (while you do not need as much thiamine when you lower your carbohydrate intake, foods low in carbohydrates also tend to be low in vitamin B1)
experience PMS (Premenstrual syndrome)
don’t get enough thiamine from food
are an HIV/AIDS patient
have a high budget for supplements (assuming that it doesn’t contain impurities, the supplement is safe in most cases and rarely does more harm than good if you stick to regular doses)
Forms of vitamin B1 supplements
The forms of vitamin B1 supplements include:
Thiamine HCl – The hydrochloride form is the cheapest and most common.
Thiamine mononitrate – This form is more stable than thiamine HCl, meaning the supplements will likely stay potent for longer. As far as the effects on the body, mononitrate and HCl are virtually identical.
Benfotiamine – While some believe that benfotiamine is better at getting into the nervous system than other forms, this claim has never been proven. Unlike other forms, benfotiamine is fat-soluble and needs to be taken with food to get absorbed well.
Thiamine pyrophosphate (TPP) – Also called thiamine diphosphate or cocarboxylase, this form is the activated form of vitamin B1. There is a case to be made that TPP could be more effective for people who have energy problems (thyroid, low adrenals, diabetes, etc.). However, there is no scientific data to support these claims.
Fursultiamine (TTFD) – This form is generally more expensive than the other forms and slightly less bioavailable. The main concern with TTFD is its potential to cause liver toxicity. This form is by far the worst and should be avoided.
All forms above get absorbed well and are almost identical as far as their effects on the body. All of them are also vegan-friendly. Therefore, which form you choose doesn’t really matter. One exception is TTFD, which should definitely be avoided.
Cheaper equals better in the case of vitamin B1, assuming the supplements you are buying are pure.
Symptoms of thiamine deficiency
The most common signs of deficiency include:
High blood glucose
Increased heart rate
Weakness
Confusion
Apathy
Tingling, weakness, numbness, or pain in the feet and hands (beriberi)
Weak muscles around the eyes
Worsened body movement control
Amnesia
Wernicke’s encephalopathy
Korsakoff’s psychosis
Seizures, paralysis, and death (although those are extremely rare)
Keep in mind that these signs are just indications of a deficiency. If you experience some of them, it does not necessarily mean you need more vitamin B1. On the other hand, some people may be deficient even though they are completely asymptomatic.
With that said, if you experience many or most of these symptoms, there is a high chance that you are not getting enough vitamin B1. The more of these symptoms you have and the more severe they are, the more likely you are to have a deficiency.
How much thiamine should you take?
The RDA (recommended daily allowance) for this nutrient is 1.2 mg for men and 1.1 mg for women. This should be enough to avoid deficiency although how much vitamin B1 you should optimally get depends on many factors.
Since you need two times more thiamine to burn carbohydrates than to burn fat, people on a high-carb diet tend to need more vitamin B1. Even then, 1.1 or 1.2 mg should be enough but a slightly higher amount may be better. Also, high-carb diets tend to provide more thiamine than low-carb diets.
For women experiencing symptoms of premenstrual syndrome (PMS), 100 mg is probably the best dose to take to minimize these symptoms.
The upper safety limit for vitamin B1 doesn’t exist. Even extremely high doses do not seem to be harmful in any way since you can get rid of any excess thiamine through urine.
Unless you suffer from PMS or are trying to correct a severe deficiency, taking more than 100 mg daily should not be necessary. Also, the higher the dose you take, the higher the risk for side effects, even though there are not many of them.
Food sources of thiamine
The richest food sources include nutritional yeast, legumes, and whole grains. As little as 2 teaspoons of nutritional yeast or 3-4 oz of legumes or whole grains should provide more than enough vitamin B1.
Enriched flour often has thiamine added to it as a public health measure to prevent deficiency.
Other foods tend to contain very little thiamine or are inconsistent in the amounts they provide. For example, some types of meat do contain a decent amount of thiamine but the amounts in meat are fairly inconsistent.
Some foods can hurt your vitamin B1 status even if they contain vitamin B1. Raw fish and shellfish are an example. Sulfite as a food additive can also increase your need for thiamine.
The easiest way to find out how much thiamine you are getting in your diet is with Cronometer.com – this free app allows you to track all vitamins, minerals, and more.
Best time to take thiamine
Since vitamin B1 is water-soluble, you do not need to take it with a source of dietary fat to increase its absorption. Whether you take it with food or on an empty stomach doesn’t make much difference if any. The exception to this rule is benfotiamine, which is fat-soluble.
Whether you take the supplement in the morning or the evening doesn’t matter. It does not interrupt your sleep in any way.
Interactions with other supplements
Calcium While thiamine is extremely effective for reducing the symptoms of PMS (premenstrual syndrome), it is even more beneficial in this regard when paired with calcium supplements. This is especially the case for women who are deficient in calcium.
Where to buy thiamine
Amazon seems to be the best option for ordering thiamine supplements in most countries. They offer some very affordable products backed by many positive reviews. Also, you can choose from a wide range of brands without having to search through other markets on the internet.
Beware some brands display the dosage per serving instead of per pill or capsule. Therefore, you may accidentally buy something less potent than you intended. Do not fall for this marketing trick.
FAQ
You can take the vitamin daily and do not need to cycle it. However, it is certainly not a problem if you don’t take it daily. Not taking the supplement every once in a while could lead to better absorption, but no studies have proven this.
All of these options are fine. The two most important things to consider are the price and dosing. Powders are almost always the cheapest form. However, to dose them correctly, you may need a highly accurate scale (preferably 0.001g). You can get one for as little as $20 from Amazon. Dosing the powders also takes some time that can add up over months or years. The disadvantage of capsules is that they are sometimes made of unethical ingredients, such as bovine gelatine.
Yes. The nutrient doesn’t impact your sleep in any negative way in the short term.
The supplements rarely go bad, but they can lose potency over time. Thiamine mononitrate is likely a little more stable than the other forms of thiamine on the market, such as hydrochloride.
Keep the supplements in a cold, dark, and dry place, and they will remain just as potent for many months or even years.
It doesn’t directly reduce acne, unfortunately.
Probably not. Even extremely high doses appear to have zero adverse effects and toxicity has never been noted. With that said, taking over 100 mg a day is by no means necessary.
Cheaper equals better in the case of vitamin B1, assuming the supplements you are buying are pure.
All supplemental forms of thiamine get absorbed well and are almost identical as far as their effects on the body. All of them are also vegan-friendly. Therefore, which form you choose doesn’t really matter.
The most common reason people become deficient is that they don’t get enough thiamine from their diet. However, many things increase your need for vitamin B1 and make you more likely to become deficient. These include alcohol, raw fish, and sulfite. Also, the more carbohydrates you consume, the more vitamin B1 you need but this should not be a concern because carbohydrate-rich foods, such as whole grains and legumes, often contain high amounts of vitamin B1.
You may need more of the nutrient if you: – experience signs of deficiency, or know that you are deficient from blood tests – drink lots of alcohol (alcohol hurts the absorption of thiamine, worsens your liver’s ability to store the vitamin, and hurts its activation for use with our enzymes) – vomit a lot (since we tend to lose vitamin B1 through vomit) – suffer from liver diseases (many of them make it harder to store vitamin B1) – are on a high-carb diet (since the main role of thiamine is burning carbohydrates and you need 2 times more thiamine to burn carbohydrates for energy than to burn fat – however, high-carb diets also tend to provide more vitamin B1) – are an HIV/AIDS patient – are on a very low-carb, ketogenic, or carnivore diet (while you do not need as much thiamine when you lower your carbohydrate intake, foods low in carbohydrates also tend to be low in vitamin B1) – experience PMS (Premenstrual syndrome) – don’t get enough thiamine from food
You can store around 20 mg of thiamine in your liver. The vitamin can stay in the liver for up to 18 days.
In the long-term, it typically takes around a month after you start taking the supplement to start noticing benefits.
Yes, the vast majority of thiamine supplements on the market are vegan-friendly.
The nutrient is water-soluble and does not need to be taken with food to increase its absorption. The exception to this rule is benfotiamine, which is fat-soluble.
No, it doesn’t. The supplement does not interfere with fasting in any significant way.
References
Most of the information provided in this guide is supported by scientific research that can be found and verified in the PubMed medical library. We excluded from consideration studies that are either confounded or have a high conflict of interest.
