What is minoxidil?
Minoxidil originally used as anti hypertensive but currently most commonly used as topical hair restoration agent.
First approved in 1988 to treat androgenetic alopecia (male pattern hair loss), the drug was originally prescribed in oral form to treat high blood pressure. After noticing unexpected hair growth as side effect in patients, the drug was used in trials to treat hair loss. When these trials proved successful, Rogaine was approved by the FDA for this use.
Since then, the patent for Rogaine has expired and manufacturers are now free to produce generic formulations of minoxidil. Typically, these will be 5% concentration, although 2% solutions are also available.
Available in liquid, foam, and spray forms, minoxidil is applied to the scalp twice daily in men and once daily in women – once in the morning and once at night. For maximum effect, it should be left on the scalp for at least four hours before being washed out.
Like most hair loss treatments, minoxidil will only work for as long as you use it. As soon as you stop taking it, hair loss will return to how it was before.
How does minoxidil work?
Despite being FDA approved to treat hair loss, nobody is entirely sure how minoxidil actually works.
Currently, science says that the hormone dihydrotestosterone (DHT) binds to hair follicles and causes them to shrink. This is why DHT-reducing drugs such as finasteride are effective at slowing and reversing hair loss.
But minoxidil has no effect on DHT levels.
As minoxidil is a vasodilator, some claim that its hair-regrowing effects are due to increased blood flow. However, the link between hair loss and blood flow is disputed.
Recent discoveries may shed light on to the mystery of minoxidil however. A recent Top Hair Loss Treatments article described the importance of prostaglandins in hair growth and androgenetic alopecia. And this paper proposes that prostaglandin activation (specifically PGE2) may explain the hair growth-stimulating properties of minoxidil.
For now, though, the exact mechanism by which minoxidil regrows hair is disputed.
How effective is minoxidil?
Even after the initial trials of minoxidil, the FDA concluded that the product will not work for everyone.
And this more recent trial gives an idea of its effectiveness:
“Clinical response to 5% topical minoxidil for the treatment of androgenetic alopecia (AGA) is typically observed after 3-6 months. Approximately 40% of patients will regrow hair.“
This is still a somewhat impressive statistic. It is far more difficult to regrow hair than it is to maintain.
Of course, there are different strengths, dosages, and methods of adminstration with minoxidil. Broadly, though, it is dose dependent, with higher concentrations producing better results than lower concentrations. This study found:
“In men with AGA, 5% topical minoxidil was clearly superior to 2% topical minoxidil and placebo in increasing hair regrowth, and the magnitude of its effect was marked (45% more hair regrowth than 2% topical minoxidil at week 48). Men who used 5% topical minoxidil also had an earlier response to treatment than those who used 2% topical minoxidil.”
Despite the ability of minoxidil to regrow hair, it is not likely to be effective at maintaining it as it does not tackle the root cause: DHT.
As a standalone treatment minoxidil will not prevent DHT from binding to hair follicles and shrinking them. However it works, it doesn’t appear to slow the cumulative damage caused by hormones.
But when used in conjunction with other medications – such as finasteride or dutasteride – it can produce some seriously impressive results. In some cases, patients may see significant and lasting regrowth.
Side effects of minoxidil
Because minoxidil is applied topically, rather than ingested, it is generally quite safe.
However, commonly reported side effects include:
- Itching, redness, or irritation of the treated and surrounding areas
- Dry scalp
- Unwanted hair growth elsewhere
More severe but rare side effects include tachycardia (increased heart rate), chest pain, dizziness, fainting, and swollen hands and feet.
In a nutshell
Unsurprisingly, minoxidil is no miracle hair loss cure.
For some users it can lead to dramatically improved hair – at least initially. For others, it has no effect or actually makes hair worse than before.A genera rule is either it will start growing hair in three months or it will not.
Like all drugs, it has its advantages and disadvantages:
- Regrows hair for many (~40%) of users with male pattern baldness
- Different mechanism of action means it can be used in conjunction with other treatments for better results
- Minimal side effects
- Low cost
- Doesn’t tackle the underlying cause of hair loss (DHT)
- Some formulas can be messy to apply
- Doesn’t work for all types of hair loss
If you do decide to try it out, my advice would be don’t rely on minoxidil alone.
Though you may see an initial improvement with minoxidil only, the hair loss process will still continue if the underlying hormonal causes are not addressed. For this reason, minoxidil is best used in conjunction with other proven hair loss treatments such as hair loss shampoo with anti-dht ingredients.