Any type of hair thinning is annoying and even alarming. That's especially true if it happens suddenly or occurs only in certain spots on your scalp. Losing hair on the side of one's head, which Paradi Mirmirani, MD, a dermatologist with Kaiser Permanente likes to describe as "marginal alopecia," may also include thinning sideburns and baldness on the sides.
These and other pattern hair loss types are common in both men and women, but also quite treatable, especially if remedies — such as shampoos and topical treatments and hair growth supplements — are begun in a timely and patient manner. Keep in mind: It takes a while for hair to regrow.
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Here's more about the causes of hair thinning on the sides of the head, how it can be fixed and whether certain nutrients can help.
What Causes Thinning and Baldness on the Sides of the Head?
Some amount of daily hair loss is totally normal. But if you're experiencing noticeable thinning or baldness on the sides of the head, there could be a number of reasons behind it. Here's what's likely happening:
Hormones can be a big factor in thinning hair or hair loss.
For instance, one of the factors behind androgenic alopecia — or pattern hair loss — is androgens, a type of hormone, according to the National Library of Medicine (NLM). Having high levels of these hormones in hair follicles means shorter, thinner hair, per the NLM. This type of hair loss appears differently for people assigned female at birth and people assigned men at birth.
"For men, this hair thinning is most likely to occur at the hairline and the top of the scalp, while for women the first sign is a widening of the part, though it can also affect the sides and edges," says Robert Finney, MD, a board-certified cosmetic dermatologist at Entière Dermatology.
Hair thinning may also be prompted by a change in the body's hormonal balance, which can occur during pregnancy, childbirth and menopause, according to the Mayo Clinic. Decreasing estrogen levels after pregnancy, for instance, lead to shedding hair, per the American Academy of Dermatology Association (AAD). Typically, this is a temporary situation. Decreased estrogen, along with lower progesterone, is also a culprit for hair loss during menopause, according to the Cleveland Clinic.
And a thyroid condition can be the cause, as can some medical conditions related to the immune system, such as alopecia areata which results in patchy hair loss, according to the Cleveland Clinic.
Traction alopecia is a type of hair loss that occurs with repeated tight pulling of the hair.
"Hair loss on the front edges and sides can be worsened by chronic tension or traction, which is more common in women due to tight ponytails and certain braided styles," Dr. Finney says. Wigs and the regular wearing of tight hats that rub in these areas can also contribute to traction alopecia, he adds.
Certain drugs — including ones used to treat cancer, arthritis, heart conditions, depression, gout and high blood pressure — may also impact hair thinning and baldness, according to the Mayo Clinic.
High doses of vitamin A, whether through food or supplements, can also be a factor, per a December 2018 review in Dermatology and Therapy that examined the role of vitamins and minerals in hair loss.
Experiencing extremely stressful life events such as the loss of a loved one, a traumatic accident or another emotional or physical shock may cause hair loss.
Hair can grow back after stress-related loss, per the Mayo Clinic.
For most people, what you eat isn't likely a major factor leading to hair loss.
"Vitamin deficiencies that lead to hair loss are extremely uncommon in the developed world, unless the individual has been on a crash diet and hasn't been consuming enough calories to sustain normal functions," Dr. Finney explains. But hair loss and thinning may occur if there's a malabsorption disorder or genetic deficiency, he says.
How Do You Fix Thinning Hair on the Sides?
Treatments and remedies for hair thinning at the sides depend on the causes.
"The main thing to know is to start early, be consistent with treatment and avoid judging results for at least three to six months," Dr. Finney says. He recommends taking "before" photos so that you can monitor your progress and note the difference at various intervals.
Here's how pattern baldness as well as traction alopecia can be addressed:
- Medications: "For androgenetic alopecia there are a whole range of treatments including minoxidil (topical and oral) and spironolactone, which is also topical and oral," Dr. Finney says. In its topical form, minoxidil is sold under the name Rogaine.
- Injections: Experts also cite platelet-rich plasma injections as another treatment.
- Dermarolling: This tool uses tiny needles (that aren't terribly painful) to stimulate collagen and circulation on the head or beard area to promote hair growth. Microneedling may be more effective than topical applications of minoxidil, according to a January 2022 study in the Journal of Cosmetic Dermatology.
- Laser light therapy: A non-surgical hair loss treatment that uses low-light laser therapy devices to prompt cell growth and stimulate the hair follicles.
- Different hair styles: Traction alopecia can be reversed "if the tension or traction is avoided and breaks from tight hair designs are taken," Dr. Finny says. Less hair washing and special attention paid to the types of products used on the hair can also make a difference, per the Mayo Clinic.
Can Hair Grow Back After Thinning?
"Hair can definitely regrow after thinning," Dr. Finney says.
When it comes to genetic hair loss, the hair miniaturizes prior to falling out so it's easier to thicken up these "baby" hairs than it is to regrow, Dr. Finney says. "It's also easier to regrow if the hair has not been gone that long — later stages of hair loss are always harder to treat."
Dr. Mirmirani agrees. "As long as there's no damage to the hair follicles, there can be regrowth," she says.
FAQs About Hair Thinning
Still curious about hair thinning? Here are some of the more frequently asked questions posed to doctors as well as some expert advice.
Which Nutrient Deficiencies Can Cause Hair to Fall Out?
If you're trying to keep the hair you have, focus on iron.
While experts aren't precisely sure how this mineral affects hair loss, it is known that an iron deficiency is a cause of hair loss, according to a January 2017 article in Dermatology Practical & Conceptual. Aim to include iron-rich foods such as dark leafy greens, beans, dried fruit, fortified cereals and red meat in your diet.
What Vitamins Should You Take for Hair Loss?
Eating well can help you achieve healthier skin and hair, especially if you focus on vitamins A, E and D, according to the Mayo Clinic.
"And there has been some evidence related to rosemary oil, caffeine and topical vitamin A in hair loss, although the latter is most helpful when combined with things like minoxidil," Dr. Finney says.
Can Thin Hair Become Thick Again?
If you were born with thin hair, you won't easily achieve thickness later on in life. But the medications mentioned above, particularly minoxidil, can work to prevent further hair loss and offer the appearance of thicker hair, per the Mayo Clinic.
"The goal for all treatment options is to regrow hair — and we also hope to thicken the diameter of individual hairs, which improves the appearance of density," Dr. Finney says. Be prepared to stick with treatment for several months, however, or even up to a year as slow progress is very much the norm.
- National Library of Medicine: "Androgenetic alopecia"
- American Academy of Dermatology Association: "HAIR LOSS IN NEW MOMS"
- Mayo Clinic: "Hair Loss"
- Cleveland Clinic: "Is My Thyroid Condition to Blame for My Hair Loss?"
- Dermatology and Therapy: "The Role of Vitamins and Minerals in Hair Loss: A Review"
- Mayo Clinic: "Can stress cause hair loss?"
- Dermatology Practical & Conceptual: "Diet and hair loss: effects of nutrient deficiency and supplement use"
- Mayo Clinic: "What you eat promotes radiant hair, skin and nails naturally"
- Mayo Clinic: "Preventing hair loss in women"
- Cleveland Clinic: "Hair Loss in Women"
- Mayo Clinic: "Mayo Clinic Minute: Expert advice for women with thinning hair"
- Journal of Cosmetic Dermatology: "Microneedling for Hair Loss"
Is this an emergency? If you are experiencing serious medical symptoms, please see the National Library of Medicine’s list of signs you need emergency medical attention or call 911.