PABA: A Cure in Search of a Disease
PABA (para-aminobenzoic acid) is a naturally-occurring compound that is perhaps best known as an ingredient in topical sunscreens. Although other UV-absorbing agents have largely replaced it, PABA lingers on in the marketplace as a medical/industrial chemical.
PABA is sometimes considered to be part of the vitamin B complex, but it’s not a true vitamin at all. Although it’s found in foods and is a precursor for folic acid synthesis, humans lack the enzymes needed to convert PABA to this essential nutrient – only plants and microorganisms can pull off this particular trick. Theoretically, intestinal bacteria could convert PABA into folate, but this pathway has not been shown to be a useful source of folate in the human diet – which is why dieticians and mainstream nutritional researchers recommend consuming folate-rich foods or supplements directly.
Ironically, PABA is also sold as a nutritional supplement, even though it’s not a human nutrient at all. There is no required amount nor any known symptoms of deficiency. According to a safety assessment by the EU’s Scientific Committee on Consumer Products…
“The toxicokinetics of PABA is characterized by fast oral absorption, biotransformation by the major routes acetylation and glycine conjugation, the minor route by glucuronidation in the liver and kidney, and a fast and almost complete elimination via the urine within 24-hours.”
In other words, it’s absorbed, detoxified and excreted… badda-bing, badda-boom.
Despite this unpromising metabolic profile, however, many, many health/disease claims have been made for PABA. If you visit any number of alternative health/nutrition sites, you will likely “learn” that PABA supplementation is useful for…
- Restoring the natural color of graying hair
- Boosting fertility
- Protecting against oxidative stress caused by ozone and toxic air pollutants
- Treating fibrotic skin diseases
- Treating vitiligo
- Reducing the inflammation of arthritis
- Reducing fatigue
- Preventing wrinkles and other visible signs of skin aging.
Unfortunately, the relatively few clinical studies supporting these claims are a) outdated; b) small; c) flawed; or d) some combination of all three. For example, fertility claims for PABA are based on a small, “one-off” study conducted in 1942. Claims for PABA as an ozone/air pollution fighter appear to rest solely on in-vitro experiments that describe PABA as a “sink” for singlet oxygen. The hair-color restoration work dates to 1950, and was effective for only 5 out of 20 patients being treated with large doses of PABA for other conditions.
Probably the best-supported clinical use of PABA is in the treatment of Peyronie’s Disease – an awkward and sometimes painful syndrome in which fibrotic scar tissue forms under the skin of the penis, causing it to curve upwards when erect. A placebo-controlled trial using 12g/day of Potaba (a potassium salt of PABA) demonstrated that it can stabilize the condition and halt further progression – but it’s not a cure.
The evidence that PABA can help with other inflammatory skin diseases is conflicting, and research on the subject has long since moved on.
Under the circumstances, there seems to be little rationale for taking PABA as a supplement: if fills no known nutritional need; and there’s precisely zero evidence that taking it on a daily basis will improve one’s health, prevent the development of degenerative disease or reduce wrinkles (except, perhaps, when used as a sunscreen).
For those who still wish to experiment with oral PABA supplements, however, the following caveats apply:
1. Case reports exist of liver damage, vitiligo and nephritis correlated to the consumption of large amounts of PABA. While PABA appears safe at typical supplemental doses (300mg – 400mg), chronic consumption of doses > 8g should be avoided in the absence of medical supervision.
2. Do not take PABA while taking prescription sulfa antibiotics. Sulfa antibiotics are, in fact, PABA analogs, which are designed to block bacterial folate synthesis. Taking PABA supplements will interfere with the effectiveness of these medications.
