Folic acid 1 mg: what is this dose used for?

last updated: Apr 30, 2021

5 min read

Before food fortification programs became the norm, folate deficiencies were much more common. This is why pregnant women with folate deficiencies had babies with birth defects much more frequently compared to today.Since folic acid can be added to grains, cereals, and other bread products, most of us get enough of this essential micronutrient through the food we eat. But if you get diagnosed with a folate deficiency, you may need to take a folic acid supplement to get your levels back up.

Read on to find out if you’re at risk for a folate deficiency, what symptoms you might experience if you have one, and how to boost your levels. 

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Who should take folic acid 1 mg?

Like any other nutrient, if you don’t get enough folate you can develop a deficiency. If the deficiency is severe enough, you can develop a condition called megaloblastic anemia. With this type of anemia, the body creates extra large red blood cells that are and unable to carry oxygen properly. Symptoms of megaloblastic anemia include fatigue, loss of appetite, shortness of breath, and a red, beefy tongue (Khan, 2020; Socha, 2020): 

Taking a folic acid supplement and eating folate-rich foods can help replenish your levels and reverse these symptoms. A common dosage for treating megaloblastic anemia is 1 mg of folic acid, although you may be recommended to take from 1-5 mg daily until you’re better (Socha, 2020). 

Because vitamin B12 deficiencies also cause this type of anemia, it’s not uncommon to look at both folate and vitamin B12 levels to determine the cause (Socha, 2020). B12 deficiencies can also cause what's called pernicious anemia. If you have this type, increasing vitamin B12 levels is essential as pernicious anemia can cause nerve damage (Rodriguez, 2020). 

While anybody can get megaloblastic anemia, pregnant women are at a higher risk because they need more folate than the average person to help their baby’s nervous system develop. When folate levels are low, your baby is at risk for neural tube defects like spina bifida. Neural tube defects are congenital disorders that affect the brain and spinal cord. 

To prevent neural tube defects, women should take 400-800 mcg of folic acid daily. Even though roughly half of pregnancies are unplanned, it’s better to plan ahead and start taking folic acid at least a month before you become pregnant (US Preventive Services Task Force, 2017). 

What is folic acid and why do you need it? 

Folate is a key player in the health of cells, DNA, and red blood cells, which is why keeping levels in check is so important.  Other essential roles folate plays in our bodies include (Liew, 2016):

  • Cell replication 

  • DNA creation and repair 

  • Red blood cell formation 

  • Heart and blood vessel function 

  • Nervous system development in babies

Folic acid is the synthetic form of folate (also known as vitamin B9). We can’t make this water-soluble vitamin on our own and must get it from food or supplements. The difference is when it comes from food it’s called folate, and when it comes from supplements it’s folic acid.Rest assured, most people have normal folate levels, but there are certain health conditions that can put you at risk for deficiencies. 

Who is at risk for folate deficiency?

Since the government made it mandatory to fortify food a few decades ago, less than 1% of people have an actual folate deficiency (Stanhewicz, 2017). While folate deficiencies are rare, certain health conditions can put you at risk for one. Since folate and folic acid are absorbed in the intestines, people with conditions that affect absorption can have a harder time getting enough. Some conditions that affect absorption include (Pan, 2017; Socha, 2020): 

  • Celiac disease

  • Ulcerative colitis

  • Crohn’s disease

  • Tropical sprue  

Some people have a genetic defect that makes it harder for their bodies to absorb folate and folic acid called the MTHFR deficiency. People with this condition need to be extra aware of how much folate they get from their diet as it’s easier for them to develop a deficiency (Hiraoka, 2017).  

Symptoms of a folate deficiency 

Folate deficiencies develop over time, and it can take anywhere from 8-16 weeks to notice symptoms (Khan, 2020). If you experience any of the following, it could indicate you’re a folate deficiency (NIH, 2017):  

  • Mood changes

  • Forgetfulness

  • Mouth sores

  • Changes in nail, hair, or skin color 

  • Digestive system discomfort

  • Heart palpitations

A folic acid deficiency can develop without you realizing it. Low folate can also cause problems beyond megaloblastic anemia or neural tube defects in pregnant women. Low folate levels can lead to high homocysteine levels, which are associated with diseases of the heart and blood vessels (Hiraoka, 2017). For this reason, it’s a good idea to make sure you’re regularly eating enough folate-rich foods. 

Food sources of folate

For most adults, 0.4 mg of folate, folic acid, or a combination of both is enough to meet their body’s needs. For pregnant women, the daily recommendation ranges from 0.4-0.8 mg daily. If you’re not deficient, you don’t need to take more than 1 mg per day (Krawinkel, 2014; US Preventive Services Task Force, 2017). 

To increase the amount of folate you get from your diet, try the following foods (FDA, n.d.): 

  • Beef liver

  • Boiled spinach

  • Black-eyed peas

  • Fortified cereal

  • Rice

  • Asparagus

  • Brussels sprouts

  • Enriched pasta

  • Romaine lettuce

  • Avocado

  • Broccoli

  • Mustard greens  

Green vegetables are always a good bet for increasing folate. There are other ways to get the most from your food as well. Heat can destroy folate, so being mindful of temperature during the cooking process can increase the number of nutrients you're getting (Khan, 2020). If you’ve been diagnosed with a deficiency, you may need to increase your intake of folate-rich foods as well as take a folic acid supplement. If you're using supplements, you can boost folate levels by taking it on an empty stomach and eating folate-rich meals (Bailey, 2015; NIH, n.d.).

Side effects of folic acid

Folic acid is a supplement that you can find over-the-counter as part of a B complex vitamin. It can also be prescribed on its own by a healthcare professional in higher doses. Folic acid is generally well-tolerated but has potential side effects, as does any medication or supplement. Potential side effects include (State of Florida DOH Central Pharmacy, 2015):

  • Changes in sleep patterns

  • Bitter taste in the mouth

  • Excitement

  • Difficulty concentrating 

  • Irritability

  • Confusion

Many of these side effects were documented when people took doses of 15 mg daily for at least one month––much higher than the 1 mg or lower doses most people take (State of Florida DOH Central Pharmacy, 2015). It's possible to have an allergic reaction to folic acid, causing symptoms like trouble breathing, rash, itching, and generally feeling under the weather.

Drugs interactions with folic acid 1 mg 

There are several prescription drugs that don’t mix well with folic acid including (Socha, 2020; State of Florida DOH Central Pharmacy, 2015):

  • Methotrexate, a medication used to treat cancer and autoimmune disorders 

  • Sulfa medications like trimethoprim

  • Allopurinol, a common gout medication

  • Seizure medications like phenytoin, phenobarbital, or primidone 

Methotrexate blocks folic acid’s actions in the body. Some research shows it can be safely used with folic acid when there is a 24-hour delay between taking each medication (Cline, 2017). If your healthcare provider prescribes folic acid, they can walk you through any possible drug interactions and how to manage your medication schedule safely.  

Should you take folic acid?

Since food fortified with folic acid hit the scene a couple of decades ago, most people get enough folic acid to meet their bodies’ needs. Women who plan to get pregnant should consider taking supplements to boost their folate levels to reduce the risk for neural tube defects (US Preventive Services Task Force, 2017). And more isn’t necessarily better as doses of 1 mg and up may negatively impact a baby’s brain development (Valera-Gran, 2017; Wiens, 2017).

For people diagnosed with megaloblastic anemia, 1 mg of folic acid is typically the starting dose.    

Folic acid is generally safe to take, but it’s best only to use only what you need to help your body thrive. For most people, there are plenty of delicious folate-rich foods to add to your plate.   


If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

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Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

April 30, 2021

Written by

Caitlin Knudsen, RN, BSN

Fact checked by

Yael Cooperman, MD

About the medical reviewer

Yael Cooperman is a physician and works as a Senior Manager, Medical Content & Education at Ro.