Hair follicles come in different shapes and sizes, affecting hair texture and width. Some people have wider follicles-and therefore, thicker hair strands-than other people. Genetics influence hair thickness, but other factors like hormones and age are important factors, too.
When estrogen levels are high, hair tends to be thicker than usual; When they're low, it can cause hair loss, says Joshua Zeichner, M.D., director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City.
Nearly everyone has some hair loss with aging. The rate of hair growth also slows. Hair strands become smaller and have less pigment. So the thick, coarse hair of a young adult eventually becomes thin, fine, light-colored hair.
"Your hair bundles peak at around 12 years old." Then, sadly, as you age, bundles of four become bundles of three, bundles of three become bundles of two, and it's all downhill from there. End result: hair appears thinner and less full.
Hair will generally be at its best in the early 20s, says Burg, because “hair shafts are thick and cuticles are tight.” Women may see changes if they are stressed, extreme dieting or using contraception.
Thicker strands of hair are more likely to have a defect, making them more prone to breakage, the researchers believe. Lustrous, thick hair may be desirable but it is not necessarily the strongest. Scientists said thin hair tends to be stronger than thicker locks, after looking at the way they break.
The bottom line. There's no strong evidence to support using biotin for hair growth or to prevent hair loss in people without a deficiency. Because hair thinning and poor hair growth are sometimes associated with a biotin deficiency, correcting a deficiency can help restore hair growth in some people.
Sources of Biotin
Foods that contain the most biotin include organ meats, eggs, fish, meat, seeds, nuts, and certain vegetables (such as sweet potatoes) [2,12].
Takeaway. Your body makes enough biotin on its own through your dietary intake each day. Therefore, you shouldn't take biotin supplements unless directed by your doctor. There are some rare health conditions that can cause some people to need biotin supplements on a regular basis.
Zinc supports hair growth, strengthens hair follicles and increases thickness. Just as zinc deficiency can cause hair loss, so can excess levels of zinc. Taking zinc supplements in moderation with proper medical advice is key.
No — shaving hair doesn't change its thickness, color or rate of growth.
“People are just not very good observers, but there's just no science behind hair growing back thicker,” says Amy McMichael, chair of the Department of Dermatology at Wake Forest Baptist Health.
11 in the journal Matter, shows that thin hair tends to be stronger than thick hair because of the way it breaks. "We were very surprised by the result," says first author Wen Yang, a nanoengineering researcher at the University of California San Diego.
Both of your parents give you two pieces of genetic information, called alleles, that determine what your hair type will be. The two alleles from your biological father combine with two alleles from your biological mother, giving you four in all.
More than 90% of Han Chinese, 70% of Japanese and Thai people, and 60% to 90% of Native Americans carry the “thick hair" version of the gene. Meanwhile it's almost nonexistent in people of African and European descent. Both age and sex can also affect your hair shaft thickness.
Hair growth can often be traced to testosterone, a potent male hormone. Both sexes produce testosterone in their bodies, but to different degrees, of course. Testosterone stimulates hair growth on the face and body. Generally, the more testosterone, the faster and coarser body and facial hair will grow.
Androgens, such as testosterone (T), dihydrotestosterone (DHT), and their prohormones dehydroepiandrosterone sulfate (DHEAS) and androstenedione (A) are the key factors in the growth of terminal hair.
Your hormones are out of balance.
A sudden increase in hair growth or loss in women is often caused by an imbalance of male hormones, which are naturally present in both men and women in differing amounts. If you get an increase in testosterone, for example, excess hair can be the result.
By removing damaged hairs, haircuts promote healthy hair growth and stops the spread of split ends through the strands. This allows long-term hair health with less need for expensive products or conditioners. It is recommended to trim hair once every four months to maintain perfect hair health.
Rossi generally tells his patients they should wash their hair once or twice per week. But if you've had chemical treatments that can make your hair drier — such as bleach, perms or relaxers — you might want to wash it less than once weekly to avoid breaking or brittle hair or split ends, he said.
Only riboflavin, biotin, folate, and vitamin B12 deficiencies have been associated with hair loss.