4. Compound the minoxidil with different topical agents or via other drug delivery strategies to allow minoxidil to penetrate the scalp better.
There is a major interest in the hair research community to figure out how best to get minoxidil into the scalp. Different vehicles, use of so called nanoparticles as well as other techniques are the focus of many studies.
It’s also clear that use of adjuvants like retinoids can help make minoxidil more effective. Before we look at this concept further, it’s important to understand a few concepts. In order for minoxidil to do it’s job, it needs to be converted to minoxidil sulphate. Hair follicles have the machinery to help with this but some people’s hair follicles are not really that good at it. Scientifically, we say that some people’s hair follicles lack high levels of an enzyme known as “sulfotransferase” and so they cannot convert minoxidil into the active form that actually does all the work. (The public does not yet have minoxidil sulfotransferase testing kits available to them but this technology may be coming at some point in the near future.) For year now, it has been known that mixing retinoids with minoxidil makes minoxidil work better. It has long been thought that retinoids irritate the scalp and somehow by doing so allow minoxidil to get into the scalp. Now, based on interesting work published by Sharma and colleagues in 2019 it’s realized that retinoids upregulate the minoxidil sulfotransferase enzyme and by doing so help generate greater amounts of active minoxidil sulphate in the scalp.
The use of derma rolling may be yet another strategy to get more minoxidil into the scalp. Scalp Micro-needling" (dermrolling) is a technique whereby a controlled injury is created in the scalp. Skin injury (at least in some situations) can stimulate the production of growth factors and inflammatory cytokines that promote skin healing and possibly hair growth. A "dermaroller" is one such device to cause controlled injury. A dermaroller consists of teeth of different lengths that are attached to a wheel. Dermarollers of 0.5 mm, 1 mm, 1.5 mm are common. These are "rolled" back and forth across the skin to create redness. A 2013 study of 100 patients supports benefit of dermarolling. The study set out to determine in patients who use topical minoxidil (Rogaine, etc) could achieve even further benefit by dermarolling. In the study, half the patients received daily minoxidil and the other half of the patients received weekly dermarolling sessions (using a 1.5 mm dermaroller) in addition to minoxidil treatment. Results showed that patients using a dermaroller achieved greater benefits than those using minoxidil alone. Specifically, 82 % of patients receiving dermarolling felt they achieved greater than a 50 % benefit in their hair compared to just 4.5 % receiving minoxidil alone. Physicians rated the improvements similarly. Hair counts (at an up close level) were increased in the dermarolling group compared to the minoxidil alone group (91.4 vs 22.2 respectively). These studies support the potential benefit of dermarolling - especially to increase the efficacy of minoxidil. More studies need to be done to verify or refute these results as well as to determine the optimal parameters for dermarolling. These include comparisons of daily vs weekly vs monthly treatment and comparisons of 0.5 mm needles, 1 mm or 1.5 mm needles. Studies are also needed to determine if any proportion of patient actually worsen with dermarolling.
5. Eat the minoxidil (or eat more).
If someone has androgenetic alopecia but is not able to achieve high enough concentrations of minoxidil deep under the scalp with use of topical minoxidil, switching from topical minoxidil to oral minoxidil could make sense. As reviewed above, in order for minoxidil to do it’s job, it needs to be converted to minoxidil sulphate. Hair follicles have the machinery to help with this but some people’s hair follicles are not really that good at it. Scientifically, we say that some people’s hair follicles lack high levels of an enzyme known as “sulfotransferase” and so they cannot convert minoxidil into the active form that actually does all the work. When oral minoxidil is ingested, the liver does the job of converting the minoxidil to minoxidil sulphate - bypassing the need for the hair follicle to do this job.
Patients who don’t respond to topical minoxidil may respond to oral minoxdil. Similarly, patients who don’t respond to very low doses (like 0.25 mg to 0.5 mg) may respond to moderate doses (like 1-2-5 mg). Of course, increasing the dose may increase side effects like headaches, swelling, fluid retention, hives and excessive hair growth on the body.
References
Dhurat R, et al. A randomized evaluator blinded study of effect of microneedling in androgenetic alopecia: a pilot study. Int J Trichology. 2013.
Ghonemy S et al. Efficacy and safety of a new 10% topical minoxidil versus 5% topicalminoxidil and placebo in the treatment of male androgenetic alopecia: a trichoscopic evaluation. J Dermatolog Treat. 2019 Oct 21:1-6. doi: 10.1080/09546634.2019.1654070. [Epub ahead of print]
Jeong WY et al. Transdermal delivery of Minoxidil using HA-PLGA nanoparticles for the treatment in alopecia. Biomater Res. 2019 Oct 31;23:16. doi: 10.1186/s40824-019-0164-z. eCollection 2019.
Sharma A et al. Tretinoin enhances minoxidil response in androgenetic alopecia patients by upregulating follicular sulfotransferase enzymes. Dermatol Ther. 2019 May;32(3):e12915. doi: 10.1111/dth.12915. Epub 2019 Apr 23.