EWG Risk Score:
What is it:
Panthenol, aka Provitamin B5 is is the alcohol analog of pantothenic acid (vitamin B5). This means that it's the metabolic precursor for Vitamin B5; it's inactive until the body metabolizes it. Panthenol is synthesized from a number of sources including honey, molasses, and rice. (Source) (Source)
- This study found that topical application of panthenol and other forms of vitamin B5 increased healing and supressed free radical formation on skin.
- This study found that topical application of panthenol and other vitamins, helped increase skin barrier function, helping to repair and prevent damage from UV rays.
From the UK Expert Group on Vitamins and Minerals Safety Study:
Case reports and some much earlier non-controlled studies describe a lack of acute or chronic toxic effects of pantothenic acid compounds (calcium or sodium pantothenate, panthenol) at very high doses (approximately 10,000 mg/day in some cases for a number of years), although such levels have been associated with diarrhoea and gastrointestinal disturbances. In more recent, controlled studies (generally carried out to assess the potential benefits of pantothenic acid supplementation in specific subgroups, for example, arthritic patients) no side effects have been reported for pantothenic acid supplementation at levels up to approximately 2000 mg/day, for periods of several days to several weeks. However, the small numbers of participants and short duration of these studies limit the value of the data regarding any potential rare or long-term toxic effects.
One non-blind, non-randomised, non-placebo-controlled trial, designed to investigate the effectiveness of megavitamin therapy in improving the behaviour of 41 children with attention deficit disorder, showed significant increases in serum aspartate transaminase levels (indicative of liver damage) in 17 children after 12 weeks of multivitamin therapy (including doses of calcium pantothenate increasing during the study period to a maximum of 1200 mg/day). This effect may have been associated with the nicotinamide component of the multivitamin supplement, although this could not be confirmed as the vitamins were not given separately.
Data regarding the toxicity of pantothenic acid and its commonly-used pharmaceutical forms in experimental animals are limited because of the small numbers of animals used in the studies. In the early 1940’s Unna & Greslin reported acute and chronic toxicity tests with D-calcium pantothenate in mice, rats, dogs and monkeys (Unna and Greslin, 1940, 1941). Acute oral LD50 values were very high 10,000 mg/kg bw, mice and rats), with lethal doses producing death by respiratory failure. An oral dose of 1000 mg/kg bw produced no toxic signs in dogs or in one monkey. Oral dosing (500 or 2000 mg/kg bw/day to rats, 50 mg/kg bw/day to dogs, 200-250 mg/kg bw/day to monkeys) for 6 months produced no toxic signs or weight loss, or evidence of histopathological changes at autopsy. The offspring of rats supplemented with 500 mg/kg bw/day calcium pantothenate were fed diets supplemented with 500 1 mg/kg bw/day calcium pantothenate from weaning; no evidence of toxicity or reduced weight gain, or histopathological changes were observed. The available data do not indicate reproductive or developmental toxicity of pantothenic acid or its commonly used pharmaceutical forms.
Carcinogenicity and genotoxicity
Calcium pantothenate, sodium pantothenate and panthenol were not mutagenic in bacterial tests. No in vivo genotoxicity or carcinogenicity data have been found.
When applied to hair, as in a shampoo or conditioner, panthenol supposedly creates a clear coating on the hair shaft. This makes the hair appear to be shiny. Many companies will claim to "repair" or "strengthen" hair with vitamins. But the silly thing is--they're just coating the hair. Hair is dead. It can't metabolize vitamins. Don't be fooled in to thinking that the "provitamins" are nourishing your hair. At the most it's coating it, but really, it's typically used in combination with dimethicone, which does most of the coating.
All-in-al, panthenol is not a bad ingredient. While it may be useless in a shampoo, it can aid in skin healing, and the only known side effects are intestinal upset when digested in large amounts.