Topical Products to Treat and Manage Hair Loss

From the scientifically and clinically studied options, there are three types of products that can be applied topically: 1 to 5% Minoxidil (Rogaine); Peppermint Oil and Lavender Oil; and 0.2% Caffeine solution.

• ​Minoxidil has been extensively studied and is the only other product besides Finasteride (an oral drug), approved by FDA for the treatment of androgenetic alopecia. 
• Peppermint Oil and Lavender Oil have been studied on mice only; both oils have been found to be approximately as effective as 3% Minoxidil.
• 0.2% Caffeine Solution has been studied on human volunteers and has been found to be approximately as effective as 5% Minoxidil, with less side effects.

Minoxidil 

What minoxidil is and how it works

Androgenetic Alopecia (AA), that in men results in the male pattern hair loss, appears to be the reason behind the hair loss in 95% of male hair loss cases and some 40 - 50% of hair loss cases in women. AA is caused by the impact of a testosterone by-product dihydrotestosterone (DHT) on hair follicles. It appears that DHT attaches to androgen receptors on hair follicles on the head leading to the miniaturization of follicles and shortening of the anagen, the hair growth phase. Treatments that block DHT may prevent or reverse hair loss caused by androgenetic alopecia (See also Finasteride).

Minoxidil is a a pyrimidine derivative (2,4-diamino- 6-piperidino-pyrimidine-3-oxide); it is an adenosine triphosphate (ATP)-sensitive potassium channel (KATP channel) opener. Minoxidil's mechanism of action for the hair regrowth has not been precisely established; it is thought though to be a DHT blocker.
​Minoxidil has only been approved by FDA and demonstrated its effectiveness in peer-reviewed studies for the androgenetic alopecia (Badri, 2018). However, it may be somewhat effective for other types of hair loss too; off-label Minoxidil is also used in the treatment of Alopecia Areata, alopecia induced by chemotherapy, before and after hair transplant to minimize hair loss; scarring alopecia; hereditary alopecia. 

Minoxidil is also sold under the brand name Rogaine. 

Minoxidil is applied topically on the scalp twice daily; the first results are visible after eight weeks of treatment; the maximal results are reached after six to 12 months of treatment.

Minoxidil concentration and effectiveness

Minoxidil appears to be moderately effective in hair regrowth in 40 to 50% of the cases of androgenetic alopecia.

• One small scale study showed that 7 out of 16 participants (43%) with androgenetic alopecia experienced a moderate improvement in hair regrowth after 4 months of twice-a-day application of 5% Minoxidil foam (Hournaz H, 2016). An improvement and patient satisfaction was higher in those who continued to use the product for 6 months. 
• The more advanced the hair loss, the stronger minoxidil concentration is required. The typical concentration recommended for women is 2% up to 5%; for men 5%. 
• The studies were only done with 1%, 2%, and 5% minoxidil concentrations.
• In one study of 393 patients with androgenetic alopecia, either 2% or 5% Minoxidil was used for 48 weeks (Olsen EA, 2002). 5% Minoxidil was found to result in 45% more hair regrowth than 2% Minoxidil. 
• There are no studies, only anecdotal evidence for the use of 10% Minoxidil. Given that Minoxidil has been shown to be dose dependent, it is possible that 10% may be more effective than 5% and it may be effective where the 5% solution did not produce the desired or significant results. The 10% minoxidil is not endorsed by FDA since it was not clinically tested.  ​

minoxidil pros and cons

Advantages - relatively inexpensive; non-invasive; severe allergic reactions are rare.
Drawbacks  - many users of Minoxidil experience scalp itching; it requires a prolonged effort and discipline of twice-a-day application and that is the primary reason why many people cease the treatment (Mapar MA, 2007); unlikely to produce a dramatic cosmetically acceptable hair regrowth (Gupta, 2015). ​

Lavender Oil and Peppermint Oil

studies and effectiveness

Only rodent studies were conducted to evaluate effectiveness of Peppermint Oil and Lavender Oil for the hair loss treatment; both studies were done on female mice. 
The studies showed that these two oils were at least as effective as minoxidil in promoting hair regrowth - 

• Peppermint oil (applied once a day, six days a week, for four weeks). At week 4, Peppermint Oil treated mice showed hair growth about 92%, whereas the 3% minoxidil group - about 55% (Young, 2014); 
• Lavender oil (LO), 3% and 5%, (applied once a day, five days a week, for four weeks). At week 4, 3% LO group and 5% LO group showed 90% and 95% hair growth respectively, while 3% minoxidil produced 99.8% hair growth. All three treatments resulted in significantly increased number of hair follicles, deepened hair follicle depth, and thickened the dermal layer (Lee, 2016).

Assuming that the peppermint oil and lavender oil are also effective for humans, it is not clear what type of hair loss they may help addressing. ​Also, if these oils are effective for humans, likely at least a 6-months long application is required to produce results (not four weeks as with mice).

Advantages - easy to use, inexpensive, no side effects, natural.
Drawbacks - the efficacy is unclear, it has not been studied on humans; the inconvenience of having one's head covered with oil; requires a consistent diligence in application.

0.2% Caffeine Solution

study and effectiveness

A recent study (Dhurat R, 2018) compared effectiveness of 0.2% caffeine solution to that of 5% Minoxidil in treating androgenetic alopecia in males.
The caffeine liquid used was Alpecin Liquid by Dr. Kurt Wolff. 
​Over 200 men participated in the study.
The caffeine solution was applied twice a day for 6 months. 

The study established that the caffeine solution is almost as effective, with less itchiness, as Minoxidil 5%.
The use of both products twice a day for 6 months resulted in approximately 10% more of hair in anagen phase, the active phase of the hair follicle growth (a 20% improvement compared to the baseline). ​​​