Whatever the answer, it probably is based on misinformation. PABA is an abbreviation that stands for para-aminobenzoic acid. Famous for its ability to protect skin from the reddening rays of the sun, this versatile vitamin in the B-complex family gained a reputation as an anti-graying agent many years before the beach crowd ever heeded its call. Unfortunately, PABA has no effect on graying strands when applied to the hair or scalp. However, it is known to be a component of folic acid involved in protein metabolism. When ingested, PABA is beneficial for seborrheic skin lesions and the regulation of oil glands. It also is helpful in controlling acne and mild blemishes. Look for PABA in wheat germ, yogurt, molasses and green leafy vegetables if you’d like to increase the vitamin in your diet.

PABA started to gain popularity for its sun-protection ability in the Roaring ‘20s when fashion icon Coco Chanel started the tanning trend that lasted the remainder of the century. Savvy sunbathers bought PABA in pill form, mixed it with iodine and mineral oil, shook it up like salad dressing, and then rubbed the concoction from head to toe. Several hours of direct sun exposure produced a deep, golden tan. When the tentative final monograph for sunscreens first was proposed in the 1970s, PABA still was going strong as one of the American sunscreens of choice.

So what went wrong? Several things. PABA has an unpleasant odor; it stains natural fabrics; and it can sting. In other words, it’s not as consumer-friendly as other sunscreens that are available today. From a sunscreen chemist’s viewpoint, PABA presents some challenges. It is hard to keep in a solution; it is pH-reactive; and it is too water-soluble to be a good sunscreen, especially in water-resistant products. It also isn’t as efficient as other more popular sunscreens because it filters rays in the wrong area of the ultraviolet (UV) spectrum to protect from the harshest sunburns. Oddly, its ability to absorb rays in the lower end of the UV range may bring PABA back into use as chemists start to rely on it in new ultrabroad-spectrum sunscreens that protect from UVC light—the rays that shine through ozone-depleted areas of the Earth.

Several sunscreens related to PABA also have helped to ruin its reputation with the American public. Glyceryl PABA, which was used more than PABA in the 1980s, has the oil-soluble nature required for water-resistant sunscreens, but turned out to be a common allergen. This led many consumers to believe that any ingredient with PABA in its name was an allergen. Two other members of the family—amyl dimethyl PABA and octyl dimethyl PABA—are not acids at all. They are esters that are formed when an acid (PABA) reacts with an alcohol, with the excess water removed. This causes the resulting ingredients to be oil-soluble and, therefore, to function as good choices in water-resistant sunscreens. But amyl dimethyl PABA proved to have more serious problems than PABA. Users complained that it stung the eye area, and researchers noted a possible link to cancer. Amyl dimethyl PABA no longer is approved for use in U.S. sunscreens.

The other ester, octyl dimethyl PABA, provides a much better sunscreen. In fact, most sunscreen chemists agree that it is one of the best sunscreen ingredients in the United States, although its relationship to PABA has lessened its use. In fact, until PABA became a consumer no-no, octyl dimethyl PABA was the most popular sunscreen in the world. Now listed as Padimate O on sunscreen labels, its stable molecular structure prevents this ester from breaking down into its PABA parent, so the side effects aren’t a problem. In fact, Padimate O has one of the best sunscreen profiles for absorbing dangerous UV rays.