What is the benefit of folic acid and PABA?

December 9, 2025 •

4 min read

Over 70 countries worldwide mandate the fortification of grain products with folic acid, a synthetic form of vitamin B9, to help prevent birth defects. Yet, some confusion remains between this vital nutrient and para-aminobenzoic acid, or PABA, an older supplement often associated with similar health claims. Understanding what is the benefit of folic acid and PABA reveals they serve distinct purposes in the body, with stark differences in their essentiality and scientific backing.

Quick Summary

Folic acid is a vital B vitamin essential for DNA, red blood cell formation, and preventing birth defects. PABA is not an essential nutrient for humans, but a compound used by bacteria to create folate. Its marketed benefits for skin and hair health have limited scientific support. The key takeaway is the difference in their proven roles and importance for human health.

Key Points

Folic Acid is Essential: The synthetic form of vitamin B9, folic acid, is crucial for human health, supporting DNA synthesis, cell division, and red blood cell production.
PABA is Not Essential: PABA is a nonessential compound for humans, meaning the body does not depend on external sources for it.
Pregnancy Health: Adequate folic acid intake is critical for preventing neural tube defects in developing babies and is a cornerstone of prenatal care.
PABA's Role in Bacteria: PABA acts as a precursor for folate synthesis in bacteria, but humans are unable to perform this conversion efficiently.
Unsubstantiated PABA Claims: Many promoted benefits of PABA for hair color restoration and anti-aging have limited scientific evidence in humans.
Safety Concerns with High-Dose PABA: Taking high doses of PABA supplements can pose significant health risks, including liver and kidney damage.
Distinct Functions: Folic acid has medically proven benefits, especially related to fetal and cellular development, whereas PABA's human health applications are either historical, unproven, or associated with safety issues at high levels.

Understanding the Distinct Roles of Folic Acid and PABA

While often mentioned in similar contexts due to their historical link and association with the B-vitamin complex, folic acid and PABA are fundamentally different in their function and relevance to human health. One is a proven, essential nutrient with critical roles, while the other is a nonessential compound with limited and sometimes conflicting scientific evidence for its proposed uses. Delving into their specific functions provides clarity for anyone considering these supplements.

The Proven Benefits of Folic Acid

Folic acid is the synthetic, more easily absorbed version of folate, a water-soluble B-vitamin (B9). It is crucial for a multitude of biological processes, making it a cornerstone of prenatal and general health. Its benefits are extensive and well-documented:

Prevents Neural Tube Defects (NTDs): This is perhaps folic acid's most well-known and critical role. For those who are or could become pregnant, adequate folic acid intake before and during early pregnancy dramatically reduces the risk of NTDs, such as spina bifida and anencephaly.
Supports DNA and Cell Growth: Folic acid is a key player in the creation and repair of DNA and RNA. This function is essential for proper cell growth, division, and function throughout life.
Aids Red Blood Cell Formation: It works with vitamin B12 to produce healthy red blood cells, which prevents megaloblastic anemia. This condition can cause fatigue, weakness, and shortness of breath.
Maintains Brain and Mental Health: Research indicates a link between low folate levels and decreased cognitive function, dementia, and depression. Supplementation may help improve brain function and mood.
Promotes Heart Health: Folic acid helps break down the amino acid homocysteine. High levels of homocysteine are associated with an increased risk of heart disease, so folic acid can help lower this risk.

The Ambiguous World of PABA

Para-aminobenzoic acid, or PABA, was once considered a B-vitamin (often called Bx or B10) but is no longer recognized as an essential nutrient for humans. While it is a precursor for folate synthesis in bacteria, humans lack the necessary enzymes to complete this conversion.

Its uses are less definitive and include:

Historical Sunscreen Ingredient: PABA was a common ingredient in early sunscreens due to its ability to absorb UVB rays. However, it was associated with allergic reactions and skin irritation, leading most modern formulations to be PABA-free.
Skin and Hair Claims: It has been promoted for benefits like slowing skin aging and restoring hair pigmentation. Scientific evidence for these effects is limited and largely inconclusive in humans.
Fibrotic Skin Disorders: Prescription PABA salts have been used to treat conditions like Peyronie's disease and scleroderma. However, the evidence for its effectiveness is mixed and limited.

A Note on Safety: While PABA is found in foods like whole grains and mushrooms, high-dose supplementation is potentially unsafe and can lead to serious side effects, including liver and kidney problems. Consultation with a healthcare provider is essential before considering high doses.

Comparing Folic Acid and PABA


Feature	Folic Acid	PABA (para-aminobenzoic acid)
Essential for Humans?	Yes, vital for several bodily functions.	No, considered a nonessential nutrient.
Primary Function	DNA synthesis, cell growth, red blood cell production.	Precursor for folate synthesis in bacteria, protein metabolism.
Primary Benefits	Prevents neural tube defects, supports heart and brain health.	Marketed for skin/hair health; limited evidence.
Dietary Sources	Fortified cereals, legumes, leafy greens, citrus fruits.	Whole grains, eggs, milk, meat, mushrooms, yeast.
Safety in High Doses	Generally safe in supplemental amounts up to 1 mg daily; very high doses can mask B12 deficiency.	Potentially unsafe; doses over 12g daily linked to serious liver/kidney issues.
Topical Use	Not typically used topically.	Historically used in sunscreens; now largely avoided due to allergy risk.

Dietary Sources and Absorption

Folate vs. Folic Acid: It's important to distinguish between folate, the naturally occurring form of vitamin B9, and folic acid, the synthetic version. The body absorbs folic acid more efficiently than folate found in food.

Sources of Folate (Vitamin B9):

Leafy Green Vegetables: Spinach, kale, and romaine lettuce.
Legumes: Lentils, chickpeas, and black beans.
Fruits: Oranges, bananas, and papaya.
Fortified Grains: Breakfast cereals, breads, and pasta.

Sources of PABA:

Whole Grains: Such as oats and barley.
Animal Products: Liver, eggs, and milk.
Other: Mushrooms, molasses, and brewer's yeast.

Conclusion

In summary, the benefits of folic acid are extensive and medically proven, particularly for reproductive health and general cellular function. PABA, while historically significant and still included in some supplements, lacks the scientific evidence to support most of its marketed health claims for humans. The most important takeaway is that folic acid is a critical nutrient for human health, while PABA is not considered essential. Making informed nutritional decisions based on scientific evidence is key to ensuring you get the nutrients you truly need. Always consult a healthcare professional before starting any new supplement regimen.

For more detailed information on folic acid and folate, see the National Institutes of Health (NIH) Office of Dietary Supplements website.

Frequently Asked Questions

No, PABA is not a true vitamin for humans. While it was once classified as part of the B-complex group (vitamin Bx or B10), it is now considered a nonessential nutrient because the human body and its gut bacteria can produce it.

The primary and most critical benefit is the prevention of neural tube defects (NTDs), which are serious birth defects affecting the baby's brain and spine. It is recommended for all women of childbearing age to take folic acid.

PABA is a chemical precursor that bacteria use to synthesize folate (vitamin B9). While humans do get PABA from food and gut bacteria, we do not rely on this pathway for our folate needs and must get folate or folic acid from our diet.

PABA was used for its ability to absorb UV rays. However, it was found to cause allergic reactions and skin irritation in some people and was later replaced by more modern, stable, and less allergenic alternatives.

At high doses, PABA is considered potentially unsafe and can lead to serious side effects, including nausea, vomiting, skin rashes, and severe liver and kidney problems.

While generally safe within recommended dosages, excessive intake of folic acid (typically over 1,000 mcg daily) can mask the symptoms of a vitamin B12 deficiency, which can cause nerve damage if left untreated.

Excellent food sources of folate include dark green leafy vegetables like spinach, legumes such as lentils and chickpeas, and citrus fruits like oranges. Many grain products in the U.S. are also fortified with folic acid.