The science of hair loss is evolving. If you are experiencing hair loss, you have probably either heard of or used one of the “big 4” hair loss treatments—Minoxidil, Finasteride/Dutasteride, Ketoconazole shampoo, and microneedling. Popularized by a medical student looking for solutions to their hair loss, these medications can slow shedding and, in some cases, promote regrowth. But, they don’t tackle one of the biggest hidden culprits behind hair loss: follicular aging and cellular senescence.
Minoxidil
Minoxidil, originally sold under the brand name Rogaine, has remained a staple in hair loss treatments, partially because it is the only over-the-counter topical treatment for male and female pattern hair loss approved by the FDA. It works by locally dilating blood vessels in the scalp, enhancing blood flow to increase the delivery of oxygen and essential nutrients to hair follicles, supporting their function, and extending the hair cycle's anagen (growth) phase. By promoting prolonged anagen and shortening telogen (resting phase), Minoxidil treats the symptoms of pattern balding, age-related thinning, and stress-induced hair loss, helping to increase follicle size and density over time.[1]
Despite its efficacy, Minoxidil has a few key limitations. While it stimulates regrowth, it does not prevent follicular miniaturization or reverse the effects of cellular senescence, two key drivers of progressive hair thinning. Because Minoxidil doesn't address the root causes of hair loss, if you stop using it suddenly and haven’t addressed the root cause of your hair loss, hair reliant on it can quickly re-enter the shedding phase, undoing much of the progress made.[2] At the same time, minoxidil is not safe for pregnant women as it may cause birth defects.[3]
Topical Minoxidil is safe for most users, though some report an oily, greasy feeling, and others may experience scalp irritation.[3] Oral Minoxidil—sometimes prescribed off-label—has additional risks, such as lowering blood pressure, hypertrichosis, edema, tachycardia, and weight gain.[3]
Finasteride & Dutasteride
Finasteride and Dutasteride are 5-alpha reductase inhibitors that block the conversion of testosterone into dihydrotestosterone (DHT), a hormone associated with pattern balding. Finasteride reduces DHT levels by selectively inhibiting Type 2 5-alpha reductase, slowing the progression of follicular miniaturization and helping preserve hair density.[4] Dutasteride is often considered stronger because it inhibits both Type 1 and Type 2 5-alpha reductase enzymes.[4] While both require prescriptions, only Finasteride is an FDA-approved treatment for male pattern baldness, with dutasteride being commonly prescribed off-label.
That said, Finasteride and Dutasteride aren’t one-size-fits-all solutions. While they effectively target hormone-driven hair loss, they don't prevent age-related thinning or other types of hair loss that aren’t androgen-mediated. One of the biggest concerns with oral Finasteride and Dutasteride is their potential side effects. While many tolerate these treatments well, some men report erectile dysfunction, mood swings, and even anxiety or depression.[5,6] Since they can disrupt endocrine function, both Finasteride and Dutasteride are not safe for pregnant women and may impact fertility.[7]
Ketoconazole shampoo
Ketoconazole is an antifungal medication that has shown some potential in treating hair loss by increasing the number of hair follicles in the growth (anagen) phase and reducing hair shedding. While some clinical studies indicate that ketoconazole contributes to increased hair shaft diameter and reduces the effects of DHT, further large-scale randomized controlled trials are necessary to validate its long-term clinical significance.[8]
Yet, some choose to skip this step as part of the “big 4” as ketoconazole shampoo is not considered safe for pregnant women or those with damaged skin.[9]
Microneedling
Microneedling has emerged as a promising method to tackle hair loss while boosting the effects of other hair loss treatments you use. It does this by creating tiny micro-injuries in the scalp that kick the body’s natural healing process into high gear. Though its precise mechanism is still under investigation, research suggests that microneedling enhances hair follicle activity by activating stem cells in the hair bulge region, increasing the expression of hair growth-related genes and triggering the release of platelet-derived and epidermal growth factors.[10]
When combined with other hair loss treatments, like minoxidil, microneedling can help increase your skin's absorption through the microchannels it creates in your skin.[11]
While generally well tolerated by both men and women, microneedling should only be performed on clean skin to avoid introducing bacteria into the skin.
The Missing Piece Of Hair Loss: Cellular Senescence
Emerging research into aging and hair loss indicates that cellular senescence may be one of the biggest hidden causes of progressive hair thinning and follicle dysfunction [12]. Yet, it is completely overlooked in traditional hair loss treatments.
Over time, as your hair follicles go through repeated growth cycles, they accumulate senescent cells—damaged cells that no longer function properly but refuse to be cleared away. These cells release inflammatory molecules called senescence-associated secretory phenotype (SASP) factors, which create a toxic environment for healthy hair follicles. The result? Weaker hair, more shedding, and slower regrowth.[12,13]
That's where ingredients designed to reduce senescent cells, like OneSkin's OS-01 peptide, come in. These ingredients, called senomorphics, reduce the release of inflammatory factors associated with senescence and help reset and restore healthy tissue function. [14,15] In fact, the OS-01 peptide shows promise for addressing senescence in both hair and skin models.[14,15]
Key Takeaways
- While the “big 4” hair loss treatments can reduce shedding, they fail to counteract cellular senescence, which weakens follicles and accelerates hair loss.
- Minoxidil enhances blood flow and extends hair growth, but it doesn’t target root causes of hair loss.
- While Finasteride and Dutasteride help combat androgen-mediated hair loss, they do nothing to counteract aging-induced hair thinning or other non-androgen-mediated hair loss.
- Microneedling can help improve hair growth and scalp health, but may not improve overall follicular longevity.
References
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6691938/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10149432/
- https://www.ncbi.nlm.nih.gov/books/NBK482378/
- https://pubmed.ncbi.nlm.nih.gov/27549867/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC6388756/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC10066399/
- https://pubmed.ncbi.nlm.nih.gov/30863034/
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3262531/
- https://www.jaad.org/article/S0190-9622(02)70063-7/fulltext
- https://pmc.ncbi.nlm.nih.gov/articles/PMC3746236/
- https://pubmed.ncbi.nlm.nih.gov/34714971/
- https://www.sciencedirect.com/science/article/pii/S1534580720302318
- https://pubmed.ncbi.nlm.nih.gov/39614601/
- Based on data from clinical studies and/or lab studies conducted on human skin samples, 3D skin models, and skin or hair cells in the OneSkin lab. Explore more at oneskin.co/claims
- Zonari, A., et al. Senotherapeutic peptide treatment reduces biological age and senescence burden in human skin models. npj Aging, 9(1), 1-15. 2023. https://www.nature.com/articles/s41514-023-00109-1
- https://www.sciencedirect.com/science/article/abs/pii/S037851221400325
