TLDR The study concluded that certain areas of the scalp and beard are safe for hair transplant donor sites in Indian men.
In 2019, a study was conducted on 580 Indian men to determine safe donor zones for hair transplantation. The researchers found that the safe donor zone in the scalp was 2.5 cm to 8 cm from the midline in the occipital region, and 1 cm above the highest crease of the ear to 7 cm above. For the beard, it was 2 cm below the lower border of the mandible to 2 cm above the thyroid cartilage. The mean follicular unit (FU) density in the scalp and beard was 78.2/cm2 and 49.7/cm2, respectively. The total available number of FUs for extraction in the scalp areas 1, 2, and 3 and beard, considering 25% extraction, was 2064, 3097, 3612, and 824, respectively. The study also found variations in hair density among different racial groups. The findings were significant for planning hair transplantation surgeries, providing guidelines for safe extraction of hair follicles without causing visible thinning or scarring.
14 citations,
May 2014 in “Archives of plastic surgery” The position of the parietal whorl can predict safe donor areas for hair transplants in Korean men with male pattern baldness.
88 citations,
January 2013 in “Indian Journal of Dermatology, Venereology and Leprology” Minoxidil and finasteride effectively treat hair loss.
83 citations,
April 1999 in “Dermatologic Surgery” The research found that for a typical hair density, about 11 square centimeters of donor scalp is needed to get 800 hair grafts for transplantation.
67 citations,
September 1997 in “Dermatologic Surgery” The document concludes that good cosmetic outcomes in hair transplantation depend on the surgeon's artistic skill and careful planning.
32 citations,
September 1997 in “Dermatologic Surgery” Mini-micrografting in hair transplants can give similar density to older methods with fewer sessions.
29 citations,
September 1997 in “PubMed” Follicular transplantation can greatly improve hair restoration if done with detailed planning and patient evaluation.
May 2020 in “Hair transplant forum international” Most Indian men aged 50-55 have a safe area for hair transplants, but selection should be careful to avoid overharvesting.
5 citations,
March 2018 in “Dermatologic Surgery” The study found that most donor sites are good for hairline restoration in Southeast Asian women, but hair characteristics should match for a natural look, and aging can reduce hair density and diameter.
9 citations,
April 2017 in “International Journal of Dermatology” Different areas of the scalp have varying hair thickness, useful for different types of hair transplant needs.
9 citations,
March 2017 in “Dermatologic Surgery” Asian men with hair loss have different follicular densities: East/Southeast 61.1, South 63.5, West 63.6 FU/cm².
January 2012 in “The Journal of Practical Medicine” 
40 citations,
June 2009 in “Journal of Cutaneous Pathology” AGA patients have fewer hairs and smaller follicles; T:V ratio above 4:1 may indicate AGA.
41 citations,
December 2008 in “International Journal of Dermatology” South Korean women with hair loss have lower hair density and thickness compared to healthy women.
33 citations,
April 2005 in “British Journal of Dermatology” Aging alone barely affects the number of hair follicles, meaning hair loss is minimal without other conditions like androgenetic alopecia.
