Vitamin B12 to combat hair loss?

Hair has a lifespan ranging from 2 to 7 years and is continuously replaced throughout the hair cycle. This begins with the birth of the hair at the root of the hair follicle. The growth of the hair shaft is accompanied by intense metabolic activity and significant differentiation of keratinocytes. During this period, the hair is implanted in the dermal papilla where blood exchanges occur. 3 to 6 years after the birth of the hair, a physical break occurs between the dermal papilla and the hair bulb where the shaft is anchored. No longer receiving the elements it needs, the hair ceases to grow and falls out naturally after a few months.

Essential to the human body, vitamin B12 may also play a significant role in hair growth. This is suggested by a recent study. The study involved 651 women, 455 of whom were experiencing telogen effluvium, which is a rapid and widespread hair loss . The blood levels of vitamin B12 and other nutrients were monitored in all participants. The researchers measured an average vitamin B12 level significantly lower in women suffering from telogen effluvium, around 232.13 pg/mL, compared to 306.41 pg/mL in women without hair problems. They then concluded that a vitamin B12 deficiency could cause hair loss. However, this observation is not universally accepted in the scientific community, as other similarly conducted studies have not shown a significant difference in vitamin B12 levels between individuals with and without telogen effluvium.

Currently, the link between vitamin B12 deficiency and hair loss is still a subject of debate.

Regarding a potential protective effect of vitamin B12 on hair through topical application or oral intake, there are reasons to be optimistic. A study in vitro conducted with human hair follicles showed that adding vitamin B12 to the culture medium resulted in an increase in the elongation of the hair shaft. Adding 2.5 µg/mL and 25 µg/mL led to respective increases of 6.2 ± 2.1% and 15.4 ± 3.8% in shaft growth. The mechanism involved appears to be as follows: vitamin B12 could stimulate the translation of the ß-catenin messenger RNA. This is a signalling molecule that allows the transition between the telogen phase, or hair shedding phase, and the anagen phase, or growth phase. By stabilising and/or initiating the latter, vitamin B12 could reduce hair loss.

Even though the role of vitamin B12 in hair growth still needs to be confirmed through clinical trials, it is possible that it may help to combat hair loss.