What is vitamin B10 also known as?

January 12, 2026 •

3 min read

According to historical research, the organic compound para-aminobenzoic acid, commonly referred to as PABA, was first identified in the mid-19th century and later called vitamin B10. This article clarifies what is vitamin B10 also known as, exploring its history, functions, and distinction from true B vitamins.

Quick Summary

Para-aminobenzoic acid, or PABA, is the organic compound historically referred to as vitamin B10. While it was once considered a B complex vitamin, it is not an essential nutrient for humans.

Key Points

PABA is Vitamin B10: Para-aminobenzoic acid (PABA) is the compound historically referred to as vitamin B10.
Not a True Vitamin: PABA is not considered an essential nutrient for humans, as it is synthesized by our gut bacteria.
Precursor for Folate: PABA acts as a building block for folate synthesis in bacteria, though humans must obtain most of their folate from food.
Sunscreen History: PABA was famously used in early sunscreens due to its ability to absorb UVB rays, but it is no longer recognized as safe and effective for this purpose by the FDA.
Potential Side Effects: High oral doses of PABA can cause side effects like nausea, diarrhea, and potential liver damage.
Drug Interactions: PABA can interfere with the effectiveness of sulfa-based antibiotics and should be used with caution.
Dietary Sources: PABA is naturally found in foods such as liver, eggs, mushrooms, and whole grains.

The Identity of Vitamin B10: Para-aminobenzoic Acid (PABA)

Vitamin B10 is not recognized as a true vitamin today, but is the historical name for the compound para-aminobenzoic acid, abbreviated as PABA. PABA is an organic compound that was once considered part of the B vitamin complex, though humans do not require it as an essential nutrient because our gut bacteria can synthesize it. Though not officially a vitamin, PABA is known for its role in the bacterial synthesis of folate (vitamin B9) and its historical uses in topical and oral applications.

The Historical and Modern Use of PABA

PABA's history includes its use as an active ingredient in early sunscreens due to its ability to absorb ultraviolet (UVB) rays. While effective, its use fell out of favor after being linked to allergic skin reactions in some people and the development of more stable and effective alternatives. The U.S. Food and Drug Administration (FDA) no longer recognizes PABA as safe and effective for use in sunscreen, but it can still be found in some cosmetic products. As a supplement, PABA has been historically promoted for various conditions, though much of the evidence is limited or dated.

Functions of PABA in the Body

Despite not being a classic vitamin, PABA serves several roles:

Assists in Folate Production: It is an intermediate molecule that many bacteria use to synthesize folate, or vitamin B9. While our gut bacteria produce some PABA, the amount is not sufficient to meet human folate needs, so dietary intake of folate is still essential.
Antioxidant Properties: PABA exhibits antioxidant properties that can help neutralize free radicals, protecting cells from damage.
Skin Health: It has been linked to protecting skin from UV radiation and has historically been suggested for treating conditions like vitiligo and scleroderma, though scientific backing is sparse.
Hair Color Retention: In earlier studies, PABA supplements were shown to help with hair repigmentation in people with prematurely gray hair, but this effect has not been widely researched recently, and results may not be permanent.

Dietary Sources of PABA

While not essential to obtain from food, PABA can be found in a variety of dietary sources:

Liver
Eggs
Brewer's yeast
Mushrooms
Spinach
Whole grains
Molasses

PABA vs. Essential B Vitamins: A Comparison

The following table highlights the key differences between PABA (historically vitamin B10) and other essential B vitamins that are required for human health.


Feature	PABA (Vitamin B10)	Essential B Vitamins (e.g., B1, B2, B3, B9, B12)
Classification	Not a true vitamin; part of the B complex historically	Essential vitamins required for survival
Human Requirement	Not an essential nutrient; synthesized by gut bacteria	Must be obtained from diet or supplementation
Primary Function	Precursor for bacterial folate synthesis	Varied metabolic roles; energy production, cellular function, etc.
Deficiency Syndrome	No officially recognized human deficiency syndrome	Associated with specific deficiency diseases (e.g., B1-beriberi, B3-pellagra)
Safety and Regulation	High doses can cause side effects; FDA restrictions on some uses	Generally safe within recommended daily allowances

The Safety of PABA Supplements

While PABA is generally considered safe in moderate doses, high supplemental intake is associated with risks and side effects. High doses have been linked to nausea, vomiting, diarrhea, and potential liver damage. PABA may also interfere with the effectiveness of sulfa-based antibiotic drugs, and people with kidney or liver issues are advised against supplementation. As the long-term effects are not fully understood, it is crucial to consult a healthcare provider before taking PABA supplements.

Conclusion

In summary, what was once called vitamin B10 is now known as para-aminobenzoic acid, or PABA. It is not an essential nutrient for humans because our gut bacteria can produce it, setting it apart from the true B vitamins. Historically used in sunscreens and promoted for hair and skin benefits, its effectiveness and safety in oral supplementation are often questioned today. Anyone considering PABA supplements should exercise caution and consult with a medical professional, particularly if taking other medications or having pre-existing health conditions.

Learn more about vitamin B10 and PABA on Healthline, a trusted health information website.

Frequently Asked Questions

Vitamin B10, or PABA, is not considered a true vitamin because humans can produce it naturally with the help of their gut bacteria. By definition, vitamins are essential compounds that the body cannot produce on its own and must be obtained from diet.

PABA is a key intermediate in the synthesis of folate (vitamin B9) for bacteria, which includes the beneficial microbes in the human gut. While this contributes to our folate needs, it is not enough to meet all requirements, so dietary intake of folate remains crucial.

PABA can be found in several food sources, including liver, brewer's yeast, mushrooms, whole grains, spinach, and molasses.

Early studies in the 1940s suggested PABA could help darken gray hair, but modern research on this effect is limited and not conclusive. The repigmentation may also reverse if supplementation is discontinued.

PABA was once a common ingredient in sunscreen because it absorbs UVB rays. However, due to reported allergic reactions and the development of more stable alternatives, the FDA no longer considers it safe and effective for sunscreen use.

Yes, high supplemental doses of PABA have been linked to side effects such as nausea, diarrhea, vomiting, and in some cases, liver problems. PABA also interferes with the effectiveness of sulfa-based antibiotics.

Given that PABA is not an essential nutrient for humans and high doses carry risks, consulting a healthcare provider before taking supplements is recommended. It is especially important to seek medical advice if you have liver or kidney issues or are taking certain medications.