There are numerous ingredients that can support thinning hair and facilitate hair growth. A bit about each of them, below.
Minoxidil
This is the only over-the-counter topical with meaningful clinical data proving its efficacy in treating hair loss, according Dr. Rieder. It’s a vasodilator, meaning it widens blood vessels. “This improves blood flow to the hair follicles, stimulating growth as well as improving delivery of key nutrients to the scalp,” Dr. Kahn adds. It also helps enlarge the follicle and extend the growth phase of hair, resulting in thicker, longer strands. (Caffeine is another common vasodilator found in hair products, though it’s not as proven as minoxidil.) Best for genetic hair loss, minoxidil is also available as an oral prescription. Both men and women can benefit from using it, but it’s best to avoid minoxidil during pregnancy as it could cause potential risks to a growing fetus.
Finasteride and Dutasteride
These oral prescriptions work by suppressing dihydrotestosterone, or DHT, the hormone that shrinks hair follicles, explains Dr. Reszko. (Note that naturally-derived topicals, like saw palmetto extract, can also reduce DHT.) These medications are best for men with genetic hair loss; dutasteride is often recommended for more severe thinning. They are only prescribed to women under medical supervision who are either postmenopausal or have undergone a hysterectomy as they are classified as Category X drugs by the FDA, meaning they are incompatible with pregnancy as there is a proven risk of serious birth defects.
Anti-Dandruff Actives
Anti-dandruff actives include ketoconazole, zinc pyrithione, and selenium sulfide. “There is some data that anti-dandruff shampoos have anti-inflammatory effects that can help to promote new hair growth,” Dr. Rieder says. These three anti-fungal ingredients also have other important merits that can help address thinning: Ketoconazole shows anti-DHT properties that can help reduce androgen sensitivity, per Dr. Reszko, while the other two help exfoliate the scalp. Removing excess buildup on the scalp provides a healthier foundation for hair growth.
Peptides
Both Dr. Kahn and Reszko recommend peptides, especially copper peptides (also known as GHK-Cu). In addition to having anti-inflammatory properties, they activate hair-follicle stem cells, extending the growth phase and upregulating genes involved with growth and the delivery of copper to the follicles. You can treat yourself with this active using topical formulas or get even more targeted treatment with copper-peptide scalp injections from a provider. Other peptides for hair growth include acetyl tetrapeptide, biotinoyl tripeptide-1, and oligopeptide-41. Often found in trademarked ingredient complexes like Procapil or Capixyl, these can help strengthen the follicle, making hair more resistant to shedding.
Rosemary Oil
This all-natural option works by improving circulation and reducing inflammation, says Dr. Reszko. “In some studies, it performs similarly to minoxidil over time,” she adds. She recommends rosemary oil as a plant-based alternative treatment for those who have mild thinning, including postpartum hair loss, or are sensitive to stronger treatments.
Marine Collagen
Dr. Rieder likes the data on marine collagen when taken as an oral supplement, noting that it’s consumed in high quantities in societies with fish-heavy diets and in certain populations with thick hair. One study of marine collagen’s effect on hair showed that marine collagen achieved hair growth comparable to that of finasteride, enhancing hair regrowth and increasing the expression of hair growth factors, making it a nice addition to the wellness routine of someone with male- or female-pattern baldness.
