Evidence: High Potential Benefits: High Safety: Very High
TABLE OF CONTENTS
What is riboflavin 5′-phosphate?
Riboflavin 5′-phosphate is a supplemental form of vitamin B2. This vitamin is essential for many functions in the body, such as burning fat and supporting NAD+ production. Riboflavin supplements are most helpful if you are deficient in the nutrient. If you already get enough vitamin B2 from food, you should not need to take the supplement. However, it can still improve some aspects of your health beyond the baseline. Riboflavin 5′-phosphate is more expensive than regular riboflavin found in most supplements. The effects of those two forms are virtually identical but riboflavin may be slightly better than riboflavin 5′-phosphate for reasons explained below. This article is about the main benefits of riboflavin 5′-phosphate, 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 riboflavin deficiency – Vitamin B2 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 B2 levels are too low, correcting a deficiency is the main benefit of riboflavin 5′-phosphate supplements.
Minor benefits
Reduced homocysteine – High homocysteine levels are associated with a variety of vascular diseases including coronary artery disease, stroke, and dementia. Riboflavin 5′-phosphate can significantly reduce homocysteine levels in some individuals. This benefit mainly applies to people with a somewhat common genetic mutation MTHFR 677TT, which leads to low MTHFR activity. In those people, as little as 1.6 mg of supplemental vitamin B2 can lower homocysteine by around 40%, which is a significant improvement.
Fat loss – To clarify, riboflavin 5′-phosphate supplements won’t necessarily make you burn more fat, but burning fat increases your need for riboflavin. One of the main functions of riboflavin 5′-phosphate is utilizing fat for energy. We also know that the more fat you burn, the more vitamin B2 you need. For example, 20-50 minutes of cardiovascular exercise 6 days a week increases your need for riboflavin by about 40-60%. Anaerobic exercise, such as sprinting and resistance training, may increase your vitamin B2 needs even more. Dieting to lose weight also increases your vitamin B2 needs. In other words, extra riboflavin from supplements won’t aid fat loss but if you are losing fat, be it by exercise, fasting, or other reasons, more vitamin B2 is needed for fat loss and thus cannot be utilized for other functions, such as supporting antioxidant defenses.
Reduced blood pressure – This effect also applies to those with MTHFR 677TT genetic mutation or people deficient in vitamin B2.
Reduced migraines – High doses of riboflavin 5′-phosphate (100-400 mg daily) are effective for reducing the frequency and intensity of migraines. One study has shown similar benefits with 25 mg. If you suffer from migraines, high-dose vitamin B2 is definitely worth the try.
Reduced symptoms of anemia – Vitamin B2 is needed to absorb iron and allow it to make hemoglobin that transports oxygen in red blood cells. Some people experience symptoms of anemia despite consuming high amounts of iron from food and supplements. In that case, anemia is almost always a result of riboflavin deficiency.
Unproven benefits
There is not enough evidence that riboflavin 5′-phosphate notably affects these health metrics, or the science shows little to no efficacy in these areas.
Skin quality – Unfortunately, riboflavin 5′-phosphate 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.
Antioxidant properties – While, vitamin B2 may act as an antioxidant in some cases, supplements have not been shown in human studies to protect cells 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 riboflavin 5′-phosphate doesn’t appear to increase subjective well-being. However, the supplement could improve your well-being if you have a vitamin B2 deficiency.
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
Riboflavin 5′-phosphate is one of the safest supplements on the market since your body can get rid of any excess through urination.
The side effects below are dose-dependent. The risk for them increases (often linearly but sometimes exponentially) as you increase the dose. Some of the side effects only apply to very high doses.
Yellow pee – If you’ve ever taken a B-complex supplement and you noticed your pee to be yellow after, it was because of riboflavin. This effect is not something to worry about, it is just a sign your body doesn’t need as much vitamin B2 and it’s flushing out the excess.
Increased iron absorption – Since riboflavin 5′-phosphate increases iron absorption, it may worsen iron toxicity if you already have excess iron in your system.
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 riboflavin 5′-phosphate?
You should probably avoid taking the supplement if you:
already consume enough riboflavin from food
experience a severe adverse reaction after taking the supplement
do not mind taking regular riboflavin instead (since it is cheaper and possibly a little safer)
are on a tight supplement budget (since there are more cost-effective supplements on the market for most people)
Who will benefit the most?
You should consider taking the supplement if you:
are an active individual (Exercise-induced fat loss significantly increases your need for riboflavin. 20-50 minutes of cardiovascular exercise 6 days a week increases your need for riboflavin by about 40-60%. Anaerobic exercise, such as sprinting and resistance training, may increase your riboflavin needs even more.)
are on a plant-based diet (deficiencies in riboflavin are 3-4 times more common in vegans and vegetarians)
are fasting or restricting your calorie intake (Both of these can lead to fat loss, which increases your need for vitamin B2.)
are on a high-fat diet (The more fat you consume, the more riboflavin you need.)
experience symptoms of deficiency, or you know you are deficient based on blood tests
have a genetic mutation known as MTHFR 677TT, which leads to low MTHFR activity
experience symptoms of iron deficiency despite getting enough iron (Vitamin B2 is needed to absorb iron and for iron to function properly.)
drink alcohol (Alcohol worsens the absorption of vitamin B2, making alcoholics more likely to become deficient.)
don’t get enough vitamin B2 from food
have a high budget for supplements (Assuming that it doesn’t contain impurities, the supplement is extremely safe in most cases and rarely does more harm than good if you stick to regular doses.)
Forms of riboflavin supplements
There are two main forms of vitamin B2 supplements:
Riboflavin – This form is cheaper and either just as good or better (as explained in the following paragraph).
Riboflavin 5′-phosphate – This form is also known as riboflavin 5′-monophosphate or FMN (flavin mononucleotide). Riboflavin 5′-monophosphate is closer to what you would get from food. Another reason why people think FMN could be better than regular riboflavin is that this form is already active. Some people, such as those with hypothyroidism and hypoadrenalism, absorb regular riboflavin rather poorly, which makes them choose FMN instead. However, for the vast majority of people, including those with hypothyroidism and hypoadrenalism, there is no difference between regular riboflavin and FMN. This is because when you take riboflavin 5′-monophosphate, your body cuts the phosphate from it and turns it into regular riboflavin anyway. At best, FMN is just as effective and safe as regular riboflavin. At worst, people with digestive issues who have a problem cutting the phosphate from riboflavin 5′-phosphate may absorb this form poorly. This is why regular riboflavin is superior.
In short, those two forms are almost identical as far as their effects but regular riboflavin is a safer choice for people with digestive issues. FMN does not appear to be superior in any way and is not worth the extra money.
Symptoms of riboflavin deficiency
The most common signs of deficiency include:
anemia that persists even if you get enough iron
elevated homocysteine
exercise intolerance
migraines
high blood pressure
fatigue
swollen throat
skin crack
itching
dermatitis around the mouth
blurred vision
depression
hyperemia and edema around the throat
liver degeneration
hair loss
reproductive issues
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 B2. 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 B2. The more of these symptoms you have and the more severe they are, the more likely you are to have a deficiency.
How much riboflavin 5′-phosphate should you take?
The RDA (recommended daily allowance) for this nutrient is 1.3 mg for men and 1.1 mg a day for women. While this amount should be enough to prevent a clinical deficiency, you may need more vitamin B2 for optimal health.
Since one of the main functions of vitamin B2 is burning fat, you need more of the vitamin if you burn more fat. Therefore, those who exercise, fast, or are on high-fat diets, need significantly more riboflavin. For example, 20-50 minutes of cardiovascular exercise 6 days a week increases your need for riboflavin by about 40-60%. Anaerobic exercise, such as sprinting and resistance training, may increase your riboflavin needs even more.
Tanning beds also increase your need for vitamin B2.
Also, those with low MTHFR activity need significantly more riboflavin. If you don’t know your genetic results, your best bet is to go through a list of symptoms of riboflavin and folate deficiency. Those with low MTHFR activity tend to experience these symptoms more often than others.
2-5 mg is a better target to shoot for if you are after optimal health and not just preventing a clinical deficiency.
Whether you should try to get a lower range (2 mg) or a higher range (5 mg) depends on the factors mentioned above, such as exercise, diet, and MTHFR. Taking more than 5 mg should not be necessary even if you have low MTHFR activity and burn a lot of fat.
Perhaps the only reason why you’d want to take a dose higher than 10 mg is if you suffer from migraine headaches. Megadosing with 25-400 mg daily can be very effective for preventing migraines and reducing their severity. The higher end of the range (100 mg taken 3-4 times a day) is slightly more effective than the lower end (25 mg once a day) but the difference is not too big.
The upper safety limit has never been established and probably doesn’t exist. While there is little to no reason to take over 400 mg, even much higher doses don’t seem to cause any harm.
Food sources of riboflavin
Liver provides the most riboflavin out of all foods. Other organ meats, legumes, almonds, mushrooms, and many vegetables also provide a high amount.
Nutritional yeast by itself doesn’t contain much vitamin B2 but it is often fortified with the nutrient. The same applies to white flour.
One thing worth noting is that vitamin B2, just like other water-soluble nutrients, dissolves into water when boiled. Therefore, food sources lose 5-30% of riboflavin when you boil them.
The easiest way to find out how much vitamin B2 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 riboflavin 5′-phosphate
Since vitamin B2 is water-soluble, you do not need to take it with food to absorb it properly. If you take higher doses (50 mg or more), taking the supplement on an empty stomach might cause stomach upset so it’s better to take high doses with food.
Whether you take the supplement in the morning or the evening doesn’t matter. It does not interrupt your sleep in any way.
One thing to consider is that vitamin B2 increases the absorption of iron. This is a great thing if you are anemic and possibly problematic if you suffer from iron overload.
Interactions with other supplements
Vitamin B6 Riboflavin is needed to convert plant-based vitamin B6 (pyridoxine) to its bioactive form, pyridoxal 5′-phosphate (PLP). Not getting enough riboflavin increases the risk for vitamin B6 deficiency. Supplementing with pyridoxine increases your need for riboflavin.
Alcohol Alcohol worsens the absorption of vitamin B2, making alcoholics more likely to become deficient.
Where to buy riboflavin 5′-phosphate
Amazon seems to be the best option for ordering riboflavin 5′-phosphate 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 supplement 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.
Keep the supplements in a cold, dark, and dry place, and they will remain just as potent for many months or even years.
The supplement doesn’t directly reduce acne, unfortunately.
Not really. Riboflavin 5′-phosphate is one of the safest supplements on the market and has never been shown to be toxic. The worst thing that can happen if you take too much riboflavin 5′-phosphate is that you will not absorb it and it will make your urine bright yellow.
Despite what many people believe, regular, cheap riboflavin is just as good if not better than Riboflavin 5′-monophosphate, also known as FMN.
Riboflavin 5′-monophosphate is closer to what you would get from food. Another reason why people think FMN could be better than regular riboflavin is that this form is already active. Some people, such as those with hypothyroidism and hypoadrenalism, absorb regular riboflavin rather poorly, which makes them choose FMN instead. However, for the vast majority of people, including those with hypothyroidism and hypoadrenalism, there is no difference between regular riboflavin and FMN. This is because when you take riboflavin 5′-monophosphate, your body cuts the phosphate from it and turns it into regular riboflavin anyway. At best, FMN is just as effective and safe as regular riboflavin. At worst, people with digestive issues who have a problem cutting the phosphate from riboflavin 5′-phosphate may absorb this form poorly. This is why regular riboflavin is superior.
The most common reason people become deficient is that they don’t get enough vitamin B2 from their diet. However, many things can hurt your vitamin B2 status and increase your need for this nutrient. These include exercising, high-fat diets, fasting, fat loss in general, sun exposure, alcohol, and a few others.
You may need more of the nutrient if you: – experience signs of deficiency, or know that you are deficient from blood tests – have a genetic mutation known as MTHFR 677TT, which leads to low MTHFR activity – are an active individual (Exercise-induced fat loss significantly increases your need for vitamin B2. 20-50 minutes of cardiovascular exercise 6 days a week increases your need for riboflavin by about 40-60%. Anaerobic exercise, such as sprinting and resistance training, may increase your vitamin B2 needs even more.) – are on a plant-based diet (deficiencies in vitamin B2 are 3-4 times more common in vegans and vegetarians) – are fasting or restricting your calorie intake (Both of these can lead to fat loss, which increases your need for vitamin B2.) – are on a high-fat diet (The more fat you consume, the more riboflavin you need.) – experience symptoms of iron deficiency despite getting enough iron (Vitamin B2 is needed to absorb iron and for iron to function properly.) – drink alcohol (Alcohol worsens the absorption of vitamin B2, making alcoholics more likely to become deficient.) – don’t get enough vitamin B2 from food – have a high budget for supplements (Assuming that it doesn’t contain impurities, the supplement is extremely safe in most cases and rarely does more harm than good if you stick to regular doses.)
Riboflavin 5′-phosphate gets absorbed within 2 hours after you consume it. The nutrient stays in your system for about 24 hours. After 24 hours, only around 9% of vitamin B2 will be present in your system.
In the long-term, it typically doesn’t take long until you start taking the supplement to start noticing the benefits. Some of them will come immediately and some of them will take up to one month.
Unfortunately, riboflavin 5’phosphate (FMN) is sometimes sourced from meat and animal products. Since regular, cheap riboflavin is just as effective and may be safer for people with digestive issues, there is no reason to take riboflavin 5′-phosphate instead anyway.
Riboflavin 5′-phosphate is water-soluble, which means you don’t have to take it with food to absorb it well.
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.
