Global hair growth is a hot market anticipated to reach $4.8 billion by 2026 with an annual growth rate of 8.3% per year(1). Much of the growth may be due to the aging of the population in the U.S., western Europe and Japan, coupled with a desire to have a more youthful appearance attributed to having a full head of hair.
Types of hair loss
There are two types of hair loss–Alopecia Areata and Androgenetic Alopecia, or common male pattern baldness (MPB). MPB is responsible for over 95% of hair loss in men. By age 35, two-thirds of American men will experience noticeable hair loss. By 50, approximately 85% will have significantly thinning hair. Women can also be affected, accounting for 40% of all hair loss. Androgenic Alopecia is believed to be caused by hair follicles that have a sensitivity to dihydrotestosterone (DHT). This causes the follicles to miniaturize, shorten their lifespan and eventually stop producing cosmetically acceptable hair. Other factors believed to contribute to hair loss include nutritional factors, stress and seborrhea. Iron deficiency is a leading cause non-Androgenic related hair loss(2,9).
Hair facts
The average person has 100,000-150,000 scalp hairs and about 5 million hair follicles. Hair grows on its own individual cycle and has the highest rate of cell division in the human body (50 minutes for mitosis). An average hair grows approximately 1 cm per month and has a diameter of 58 to 100 microns. We normally lose 50-100 hairs per day(2).
Healthy hair growth occurs when approximately 90% of hairs are in the Anagen or growth phase, which can last three to five years. In MPB, this can be reduced to 60-80% of hairs. At the end of the Anagen phase, approximately 1% of hair goes into the Catagen phase, a short transition that lasts several weeks. The final transition is the Telogen or resting phase which can last for approximately three months and involves roughly 10% of hairs but can be as high as 20-40% in MPB. Research suggests that the Telogen phase is highest at the end of summer and beginning of fall(3,10).
The most effective topical products are OTC drugs containing 4-pyrrolidiine-2,6-diaminopyrimidine-1-oxide (the active in minoxidil) or Rx oral products containing finasteride. These are the only products allowed to make hair growth claims.
OTC hair growth topical actives
Minoxidil was originally approved as an Rx antihypertensive medication then approved as a topical Rx drug in 1988 to slow/stop hair loss and promote hair regrowth. It is believed to act as a vasodilator promoting scalp microcirculation. The 2% formulation was switched to an OTC drug in 1996 and the 5% product in 1998. About 40% of men experience hair regrowth after three to six months using minoxidil, and it must be used indefinitely to maintain the benefit. It is the only topical approved drug to prevent hair loss(4).The current trend in minoxidil formulations is to add cosmetic ingredients in order in increase efficacy. However, under the current monograph, no significant changes can be made to the originally approved formulations.
Ketoconazole is a OTC antifungal dandruff agent that also has been shown to have hair growth activity. One study from 1998 compared ketoconazole and minoxidil to see which had the best effects on hair growth. The researchers discovered that 2% ketoconazole shampoo increased the size and proportion of anagen hair follicles at a similar rate to the minoxidil spray. Another paper from 2004 claimed that ketoconazole may inhibit DHT(6,7,8).
Rx hair growth oral actives
Finasteride is a synthetic drug for the treatment of benign prostatic hyperplasia and MPB. It is a type II 5α-reductase inhibitor that prevents the conversion of testosterone to dihydrotestosterone (DHT). It is the only Rx oral pill approved to prevent hair loss(5). In a five-year study of men with mild to moderate hair loss, two out of three of the men who took one milligram of finasteride daily regrew some hair. In contrast, all men in the study who were not taking finasteride lost hair. In the same study, 48% of those treated with finasteride experienced visible regrowth of hair, and an additional 42% had no further loss(5).
Marketed cosmetic oral/topical products and devices can only claim that they help support a healthy scalp and hair growth. Many topical products also claim to increase volume and diameter making hair appear thicker.
Cosmetic laser hair growth devices
The theory of laser treatment for hair loss is that low-dose laser treatments increase circulation and stimulation that encourages hair follicles to grow hair. These devices can cost between $700 and $3,000. Published clinicals have been criticized as not being independently performed with disappointing anecdotal results in individuals using these devices. According to a 2014 study, low-level laser therapy appeared to be safe and effective for hair growth in both men and women. A 2013 study of 41 males ages 18 to 48 found that laser hair treatment provided a 39% increase in hair growth over a period of 16 weeks(6).
Cosmetic oral supplements/topical products
Innéov Densilogy (Vitamin D3, Omega 3 Association (ALA + EPA + DHA), Zinc-Nestle/L’Oreal) was shown in a three month clinical to improve hair volume in 80% of women and diameter in 62% of women. Improved hair quality was also seen in 90% of women. Numerous studies have shown that oral gelatin, cysteine, biotin, and amino acids can also promote hair growth(11, 12, 13, 14).
The best cosmetic topical hair growth actives are normally ones that have been clinically shown to increase the Anagen/Telogen ratio versus placebo. This means they can prolong growth while shortening the resting phase of hair causing an increase in hair number. The best actives are mixtures that work by complementary or synergistic mechanisms and increase the Anagen/Telogen ratio. These can be found on ulprospector.com by searching for hair growth/hair loss. Trichogen VEG LS 9922, AnaGain, Capixyl, Redensyl, Procapril, and Baicapil are representative ingredients.
References
- https://www.grandviewresearch.com/press-release/global-alopecia-market
- https://www.americanhairloss.org/
- http://www.naturalhairgrowth101.com/hair-growth-facts.html
- https://en.wikipedia.org/wiki/Minoxidil
- https://en.wikipedia.org/wiki/Finasteride
- https://www.healthline.com/health/laser-treatment-for-hair-loss#does-it-work
- https://www.ncbi.nlm.nih.gov/pubmed/9669136
- https://www.ncbi.nlm.nih.gov/pubmed/14729013
- https://www.webmd.com/skin-problems-and-treatments/hair-loss/news/20060516/hair-loss-may-be-iron-deficiency#1
- https://www.bustle.com/p/why-do-i-lose-more-hair-in-winter-seasonal-hair-loss-is-totally-a-thing-heres-what-causes-it-3192578
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3509882/
- Randazio S.D., Morgantl P., titled: “The Influence of gelatin cysteine supplementation on the amino acids composition of human hair”, accepted for presentation on XVI Intern. Congress of Dermatology May 23-28,1982, Tokyo.
- Gehring,W., Gloor, M.; “Das Phototrichogramm als Verfahren zur Beurteilung haarwachstumfördernder Präparate am Beispiel einer Kombination von Hirsefruchtextrakt, L-Cystin und Calciumpanthotenat), Zeitschrift für Hautkrankheiten, 2000; 75(7/8):419-423.
- https://www.lorealparisusa.com/beauty-magazine/hair-care/all-hair-types/how-to-grow-hair-faster.aspx
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Really a beautiful and useful Article. Many thanks for giving such an informative article.
Great summary of the hair growth options, and ones that are approved by the FDA.