How do you feel when you need folic acid? Symptoms and signs explained

November 13, 2025 •

4 min read

Folate deficiency can occur in just a few weeks if your dietary intake is insufficient. Knowing how do you feel when you need folic acid is crucial, as the symptoms can often be vague and overlap with other conditions, making them easy to dismiss. This deficiency impairs red blood cell production, leading to a wide range of physical, neurological, and psychological issues that can worsen over time.

Quick Summary

A folic acid deficiency can cause symptoms such as fatigue, weakness, pale skin, shortness of breath, and mouth ulcers. It can also lead to mood changes, irritability, and cognitive issues due to its impact on the nervous system. The signs often develop gradually and can be easily missed.

Key Points

Subtle Onset: Folate deficiency symptoms often begin gradually, with fatigue and low energy being among the first, easily overlooked signs.
Oral Health Clues: A red, swollen, or tender tongue (glossitis) along with frequent mouth ulcers can signal a lack of folic acid.
Mental Fog: Cognitive issues like poor concentration, memory problems, and general confusion are common neurological effects of deficiency.
Mood Disruptions: Psychological symptoms, including increased irritability and depression, can arise because folate is crucial for synthesizing mood-regulating neurotransmitters.
Anemia is Key: Many of the most severe symptoms, such as pale skin, heart palpitations, and shortness of breath, are caused by megaloblastic anemia, a direct result of the deficiency.
Requires Blood Test: Self-diagnosis is unreliable; a blood test is necessary to distinguish between a folate deficiency and a similar vitamin B12 deficiency.

Understanding the Insidious Nature of Folate Deficiency

Folate is a B vitamin vital for producing red blood cells and DNA, affecting nearly every bodily function. Unlike some other nutrients, the body does not store large amounts of it, which means a consistent, healthy intake is essential to avoid a deficit. The symptoms of a deficiency often start subtly and can gradually worsen, making early detection difficult without specific knowledge. Many people first notice a persistent feeling of being unwell, which is often misattributed to stress or a busy lifestyle. Identifying the underlying cause of this chronic fatigue is key to proper treatment.

The Physical Manifestations of Low Folic Acid

As the deficiency progresses, more specific physical symptoms tend to appear. The lack of sufficient, healthy red blood cells reduces oxygen transport throughout the body, triggering a cascade of issues. One of the most common signs is anemia, which can cause:

Extreme tiredness and lethargy: A persistent feeling of exhaustion that doesn't improve with rest.
Paleness: The reduced number of red blood cells can cause skin to appear pale, particularly on the inner eyelids and nail beds.
Shortness of breath: The heart may have to work harder to pump oxygenated blood, leading to breathlessness, even during light activity.
Heart palpitations: An irregular or racing heartbeat can be a sign of the body's struggle to compensate for low oxygen levels.
Dizziness and headaches: Reduced oxygen flow to the brain can cause lightheadedness and headaches.

Oral and Digestive Symptoms

A folic acid deficiency can also cause noticeable symptoms in and around the mouth and affect the digestive system. The tongue may become red, tender, and swollen, a condition known as glossitis. Mouth ulcers and sores are also common, which can be painful and interfere with eating. Many people report a reduced or altered sense of taste, making food less enjoyable and potentially contributing to a decreased appetite and weight loss. Diarrhea is another gastrointestinal symptom that can arise from folate deficiency.

Neurological and Psychological Effects

Folate's role in the nervous system means a deficiency can significantly impact mental health and cognitive function. Folate is required for synthesizing key neurotransmitters, and its absence can disrupt brain chemistry. The psychological symptoms are often similar to those caused by a vitamin B12 deficiency and can include:

Mood changes: Many individuals experience depression, increased irritability, and mood swings.
Cognitive issues: Difficulty concentrating, memory problems, and general confusion are common, sometimes leading to a condition resembling dementia in severe cases.
Nerve issues: Numbness, tingling sensations (paresthesia), and muscle weakness can occur as nerve function is impaired.

Understanding Folic Acid Deficiency vs. Iron Deficiency

While both folate and iron deficiencies can cause anemia, they affect the body in different ways. The type of anemia and the specific symptoms can differ, as shown in the table below. It is important to note that diagnosis should always be confirmed by a healthcare provider through blood tests.


Aspect	Folic Acid Deficiency	Iron Deficiency
Type of Anemia	Megaloblastic anemia (abnormally large, immature red blood cells)	Microcytic anemia (smaller, paler red blood cells)
Mechanism	Impairs DNA synthesis and cell division in red blood cell production	Insufficient iron for hemoglobin synthesis
Key Symptoms	Fatigue, weakness, glossitis, mouth sores, cognitive issues, depression	Fatigue, weakness, shortness of breath, cold hands/feet, brittle nails
Associated Symptoms	Diarrhea, reduced taste, irritability	Cravings for non-food items (pica), dizziness
Treatment	Oral folic acid supplements and dietary changes	Iron supplements and increased intake of iron-rich foods

Diagnosing and Treating a Deficiency

If you suspect a folic acid deficiency, a healthcare provider will typically order a blood test to measure the folate level in your serum. Because symptoms can overlap with a vitamin B12 deficiency, a test for B12 will often be conducted simultaneously. Treatment is straightforward and typically involves oral folic acid supplements, often for several months, to restore proper levels and resolve symptoms. A doctor will also recommend dietary changes to incorporate more folate-rich foods like leafy greens, citrus fruits, and fortified cereals.

Conclusion: Recognizing the Signs and Taking Action

Feeling unwell can have many causes, but a persistent combination of fatigue, mouth sores, and cognitive fogginess should prompt you to consider a nutritional deficiency. Understanding how do you feel when you need folic acid empowers you to seek timely and appropriate medical attention. Fortunately, this condition is easily treatable once diagnosed, and prompt action can prevent more serious complications, including megaloblastic anemia and potential neurological issues. Early recognition and intervention, guided by a healthcare professional, are crucial for a swift recovery and overall improved health. For more information, consider reading resources from reputable health organizations such as the NHS guide on vitamin B12 and folate deficiency anaemia.

Frequently Asked Questions

One of the earliest and most common signs is persistent fatigue and a lack of energy that doesn't improve with rest. Other initial symptoms can include irritability, pale skin, and a general feeling of being unwell.

Yes, low folic acid can have a significant impact on your mood. It can lead to depression, increased irritability, and mood swings because folate is involved in the synthesis of neurotransmitters that regulate mood.

Extreme tiredness, or fatigue, is a very common and early symptom of a folic acid deficiency. This happens because a lack of folate impairs the production of healthy red blood cells, which are responsible for carrying oxygen throughout your body.

While both can cause fatigue and paleness, a folic acid deficiency typically causes megaloblastic anemia (large, immature red blood cells), and can cause a sore tongue and neurological symptoms. An iron deficiency causes microcytic anemia (small, pale red blood cells) and is not usually associated with nerve damage.

Yes, a severe folic acid deficiency can cause neurological problems. This can include cognitive issues such as memory loss and difficulty concentrating, as well as numbness and tingling in the hands and feet.

Yes, a healthcare provider can order a blood test to measure the level of folate in your blood. This is the most reliable way to confirm a folic acid deficiency and rule out other conditions that cause similar symptoms.

Good dietary sources of folate include leafy green vegetables like spinach, asparagus, and broccoli, as well as citrus fruits, beans, peas, and fortified grains and cereals.

If a pregnant woman has a folic acid deficiency, there is an increased risk of serious birth defects called neural tube defects, which affect the brain and spinal cord. That's why supplementation is highly recommended for women who are or may become pregnant.