White hair can be a source of discomfort for some people, prompting them to seek innovative hair treatments. But is it really possible to repigment white hair? Let's explore the various options together.
Treatment: Is it possible to repigment white hair?
- Where do white hairs come from?
- What repigmentation treatments are currently available?
- An overview of repigmentation effect drugs
Where do white hairs come from?
The emergence of white hair, commonly referred to as canities, is a phenomenon often associated with a decrease in melanin production by melanocytes and a gradual reduction in their number. This natural process usually occurs around the age of 35 years, or later. It's also worth noting that the appearance of white hair can be influenced by other internal or external factors. Studies have, for instance, shown that prolonged stress can impact the functioning of melanocytes, thus disrupting melanin production and leading to a decrease in hair pigmentation.
In addition to stress, deficiencies in vitamins B9, B12, D, selenium, iron or copper can also play a major role in hair colour loss. The underlying mechanisms vary depending on the nutrient in question. For instance, copper promotes the activity of tyrosinase, an enzyme essential for the conversion of tyrosine into melanin. Lastly, the early onset of white hair can be influenced by genetic factors or associated with an autoimmune disease such as vitiligo.
What repigmentation treatments are currently available?
Promising a gradual, natural, and most importantly, non-aggressive recolouring for white hair, repigmenting treatments are formulated to boost the synthesis of melanin by the melanocytes in the hair bulb. To this end, they contain peptides, which are small proteins, that penetrate the scalp to the melanocytes to restart their activity. However, opinions regarding the results obtained are mixed. Some say they have indeed observed a repigmentation of their white hair, while others have seen no change.
One might assume that the following reason is at the root of these disparities in results: the onset of white hair is not solely linked to a loss of melanocyte activity, but also to a gradual decrease in their number. Indeed, these cells are naturally destroyed as they undergo oxidative stress (UV rays, pollution...). Therefore, if we assume that the peptides used by repigmenting treatments are indeed capable of reaching the melanocytes and restarting melanogenesis, they will only have an effect if there are remaining melanocytes at the hair bulb level. This is why such repigmenting treatments remain uncertain to this day.
An overview of repigmentation effect drugs.
Clinical studies have reported that the oral intake of certain medications can repigment white hair, even when the purpose of these treatments was sometimes entirely different. Among the most commonly found molecules are anti-inflammatories, melanogenesis stimulators, and vitamins. Here is an overview of these different compounds and their effects.
The potential of anti-inflammatories to combat white hair has been investigated in several studies. One of the earliest to mention this dates back to 1986. Conducted on 37 healthy individuals aged between 10 and 20 years old, who had premature white hair, this study showed that the intake of psoralen and exposure to UVA light allowed for complete repigmentation of the hair in 46% of the patients and partial repigmentation in 19%. This method, called PUVA therapy, is today used to reduce the symptoms of psoriasis and vitiligo. It is unlikely that it will ever be used to repigment white hair, as one of its side effects is an increased risk of developing skin cancer.
Other cases of repigmentation of grey hair triggered by anti-inflammatory drugs have been reported sporadically. Drugs that activate retinoic acid receptors, specifically acitretin and etretinate, have been associated with repigmentation of grey hair in two patients with pityriasis rubra pilaris and one patient with psoriasis after 6 to 12 months of treatment. However, the associated mechanisms have not been detailed.
Several medications have also demonstrated an effect on melanogenesis. In a study involving patients receiving imatinib for chronic myeloid leukaemia, 7% of the 133 patients exhibited repigmentation of grey hair 2 to 14 months after the commencement of treatment.
Another tyrosine kinase inhibitor, theerlotinib, also induced a progressive repigmentation of the hair of a patient suffering from metastatic lung adenocarcinoma three months after treatment. A case of hair repigmentation associated with erlotinib began after an episode of folliculitis on the scalp.
Finally, studies conducted on vitamins have shown that some of them have an effect on hair colour. This is particularly evident in the repigmentation of prematurely grey hair in two healthy patients one month after starting a treatment with 200 mg per day of calcium pantothenate.
Another study conducted on 27 individuals with grey hair over a period of 8 months demonstrated that the use of 100 mg of calcium pantothenate in combination with 200 mg of PABA (4-aminobenzoic acid) per day allowed two individuals to observe a slight repigmentation of their hair. This study also noted that the repigmented hair returned to grey once the treatment was discontinued.
Important : the various treatments mentioned should under no circumstances be undertaken without medical advice.
RAWNSLEY J. & al. Hair biology: Growth and pigmentation. Facial Plastic Surgery Clinics of North America (2018).
MESINKOVSKA N. & al. Medication-induced repigmentation of gray hair: A systematic review. Skin Appendage Disorders (2020).