What Is PABA (Para-aminobenzoic Acid) Used For and What Are the Side Effects?

PABA (para-aminobenzoic acid) is a natural substance found in some foods and it is part of the B complex group. PABA is a precursor to folate and it helps certain skin conditions.

PABA (para-aminobenzoic acid) is a natural substance found in some foods. PABA supplements are likely safe to take, though topical products often cause reactions. 

PABA stands for para-aminobenzoic acid. It’s sometimes called vitamin Bx or B10 and belongs to the B complex group, though it’s not a vitamin. PABA is an essential nutrient for plants, bacteria, and some animals, but not for humans. 

PABA is found in foods like mushrooms, molasses, whole grains, liver, spinach, and Brewer’s yeast. It’s an ingredient in sunscreen and medications, and it’s also used as a UV-protection coating in the pulp and paper industry.

You can find PABA supplements in pharmacies and health food stores. PABA is generally considered non-toxic, though there are known side effects. 

PABA was once used for skin and hair care and as a treatment for some diseases. It may have some benefits, but studies show mixed results. 

Precursor for folate

Vitamins are nutrients that are essential for proper body function and health. The problem is your body can’t make them or can't make enough of them, so you must get them from your food. Folate, or vitamin B9, is one of these vitamins. 

You need folate to make DNA, RNA, and proteins. It’s also essential for healthy red blood cells, breaking down a harmful substance called homocysteine, and healthy nervous system development in unborn babies.

PABA is a precursor for folate. Bacteria in your gut make PABA, which is then converted into folate. However, these bacteria don’t make enough to serve your body. You need to get folate or folic acid from food. 

Sun protection

PABA was a popular ingredient in sunscreens until recently. It helps absorb and break down UVB radiation through chemical reactions and stops the harmful effects of radiation on the skin. 

PABA is photosensitive and allergenic, though, and can cause rashes and sensitivity to sunlight. The government plans to reclassify PABA as not generally safe for sunscreens.

Might help skin conditions

PABA is also used in some autoimmune skin disorders, including scleroderma, dermatomyositis, and Peyronie’s disease. Some results suggest it isn’t effective, though.

Scleroderma is a condition where your immune system mistakenly causes your skin to scar and become thick, hard, and tight. There are different types of scleroderma. Some affect only your skin, muscles, joints, and bones, and others cause widespread scarring and tightening in all your organs. 

PABA helps tissues take up more oxygen, which leads to anti-scarring activity. Some studies show forms of PABA improve systemic scarring, the severity of skin issues, and overall survival. Others show that taking PABA gradually softens skin, lowers scarring, and increases range of motion. 

The studies on PABA therapy are old, though, and the results are conflicting. In a small randomized study, some patients with scleroderma took 12 grams of PABA daily while others took a sugar pill. After 48 weeks, there were no skin changes in either of the two groups.

Peyronie’s disease is another skin disorder that causes scars under the skin of the penis. The scars pull on the tissues and cause the penis to curve or bend during an erection. The disease can cause painful erections and make it hard to have sex. 

PABA might help Peyronie’s disease, but results are also mixed. Some studies show it has no effect, while others show it doesn’t reverse the condition but can stop it from worsening. 

Increases antibiotic activity

Even though PABA is an essential nutrient for some bacteria, it has antibacterial activity. On its own, PABA directly stops the growth of Listeria, Salmonella, and E. coli strains. 

It can also increase the strength of antibiotic medications against medication-resistant strains of Staph and Pseudomonas bacteria. While promising, it might not be helpful in treatment because it’s poorly absorbed. Your body quickly gets rid of most of PABA, so it likely won't stay in the body long enough to help an infection. 

Temporarily re-pigments gray hair

One of the oldest uses for PABA is to re-pigment gray hair, as far back as 1941. The first study showed that 200 milligrams of PABA daily can darken gray hair. 

Later studies showed the same results. Patients taking PABA for scleroderma and dermatomyositis also had re-pigmented hair after 2 to 10 months. The gray hair returns after you stop taking PABA.

While PABA is non-toxic at normal doses, it often causes allergic reactions and digestive issues. There are reports of other rare side effects, too.

Digestive upset

PABA supplements or pills can cause stomach upset, including nausea, vomiting, and diarrhea. Patients in clinical studies also report headaches after taking PABA.

Rashes

A common side effect of PABA in creams or sunscreens is an itchy, red rash. Large doses of PABA, around 1000 milligrams, might also make you sensitive to the sun, leading to a rash when your skin is exposed to sunlight. 

Liver injury

There are a few reports of PABA causing liver injury in patients treated for Peyronie’s disease. They fully recovered within four months of stopping the medication. 

Blocks CoQ10

Almost every cell uses a substance called CoQ10 or ubiquinone for energy production and DNA protection. Yeasts and bacteria use PABA to make CoQ10, but humans can’t. PABA seems to block CoQ10. 

Some lab dish studies show that PABA interferes with CoQ10 status. PABA treatment on nerve cells led to a 54 percent decrease in CoQ10 levels, which caused a 67 percent decrease in energy production. 

PABA treatment also caused a four-fold increase in free radical damage in mitochondria, called the energy centers of the cell. In theory, PABA could cause problems for some people with mitochondrial diseases that cause problems making CoQ10. 

While it sounds concerning, it might not translate to real life. In animal studies, PABA supplements didn’t affect CoQ10 levels. Plus, your body gets rid of PABA very quickly, so it’s unlikely to cause low CoQ10 levels.

PABA is non-toxic and likely safe to take as a supplement. PABA is no longer used in sunscreen because it often causes rashes and allergic reactions. Talk to your doctor first if you want to use PABA for your health.