There are many hair loss treatments and medications out there. So, which one is right for you?
The best way to figure that out is to learn about how these treatments work and what their side effects may be.
This article will cover how one particular hair loss medicine, minoxidil, encourages hair growth. It will also compare two brands containing minoxidil – Rogaine and Kirkland – to help you decide which one might be the best solution to your hair loss.
What is Minoxidil?
Before we start comparing the two brands, we should go over exactly what minoxidil is.
Minoxidil is a type of vasodilator, meaning it dilates your blood vessels so that more blood and oxygen can be carried through the body to the heart (1). It’s used to treat high blood pressure and can be applied to the scalp to stimulate hair growth.
Minoxidil can be found in the brand name drugs Rogaine, Kirkland Minoxidil, Apo-Gain, Gen-Minoxidil, Hairgro, Hair Regrowth Treatment, Med Minoxidil, and Minox.
History of Minoxidil
You may be wondering how a vasodilator became known as a hair loss treatment. Minoxidil was originally developed in the 1970s by the company UpJohn to treat severe hypertension, or very high blood pressure (2, 3). During the late 1960s, when the drug was going through clinical trials, executives at the company dismissed the hypertrichosis, or abnormal hair growth in subjects.
However, once the drug was on the market for hypertension, the side effects of the drug became so well-known that the company had to begin marketing it as a topical hair loss treatment.
Because of the side effects of oral minoxidil, the drug is now only used to treat the most severe high blood pressure which has not responsed well to better tolerated anti-hypertensive medications on the market.
Topical minoxidil, though, is now used commonly to treat hair loss. How exactly does that work?
How Does Minoxidil Work For Hair Loss?
Let’s look into the science of topical minoxidil.
Because minoxidil was originally developed to treat hypertension, not hair loss, its mechanism of action when used topically on the scalp hasn’t been established clearly by scientists. However, there is some evidence to account for how minoxidil works on the hair follicles.
Once minoxidil is applied to the scalp, it undergoes a process which transforms it into its more effective form for hair growth, minoxidil sulfate (4). Sulfotransferase, an enzyme present on the scalp, is responsible for this change. Once the minoxidil sulfate has been formed, it affects the phases of hair growth in the hair follicles.
Phases of Hair Growth
There are two parts that make up your hair: the follicle, which is part of the skin on your scalp, and the shaft (5). In the layers of skin that make up the follicle, there is one with a living bulb, where cells divide to create the hair shaft.
In order to understand how minoxidil helps your hair, let’s review the phases of hair growth in the follicle.
The first phase of the cycle is anagen, which is the active phase of hair growth. During anagen, a new hair forms from the follicle and emerges out of the epidermis. It grows rapidly during this phase — about one centimeter a day for 28 days!
The second phase of the cycle is catagen, which is a transitional phase that lasts for two to three weeks (6). The hair stops growing in this phase, and a club forms at the bottom of the sheath.
The last phase of the cycle is telogen, which is the resting phase. This phase lasts for about 100 days in hairs on the scalp. This is the stage in which the scalp sheds hairs. If you’ve inspected a hair that’s shed naturally from the scalp, you’ll see a club at the bottom. This indicates that the hair has completed the cycle of growth and is in telogen.
Telogen’s role in hair loss is important as it’s the stage in which hair loss usually occurs. This is apparent when you look at the disorder telogen effluvium, which is different from Androgenetic Alopecia (AGA, also known as male-pattern baldness).
Telogen effluvium is a condition where your hair thins or sheds to an abnormal extent because it enters the telogen phase prematurely (7). This condition is usually a result of shock or stress to the body.
Minoxidil’s Effect on the Hair Growth Cycle
Now that we understand the phases of hair growth, it’s time for the important question: How can minoxidil affect the life cycle of your hair to reverse hair loss?
- Shorten telogen phase.
- Lengthen anagen phase.
- Open potassium channels within the hair follicle.
Because minoxidil shortens the telogen phase, hair can skip part of the resting phase in the cycle and start to grow earlier than it normally would. And because the anagen phase is lengthened, it means the hair can stay in its active growth phase for a longer period of time before the club forms and the hair is shed from the scalp.
- Stimulation of cell proliferation.
- Inhibition of collagen synthesis.
- Stimulation of proteins that help form blood vessels.
- Prostaglandin (lipids with healing effects) synthesis.
- Prevention of cell death.
However, it’s important to note that these observed effects, and their relationship with hair growth, have yet to be proven definitively by scientists.
Let’s talk more about some of these effects of minoxidil.
Stimulation of Cell Proliferation
It makes sense that if minoxidil stimulates cell proliferation, it could help stimulate cell proliferation on the scalp. In fact, research has shown that minoxidil stimulates dermal papilla cells and epithelial cells, which are cells in the hair follicle and the skin, respectively (7).
We know this because scientists have measured the expressions of ERK after treatment with minoxidil and found that the levels are significantly increased one hour post-treatment. This suggests that minoxidil activates these proteins, which in turn send signals to the cells and encourage them to divide.
Prevention of Cell Death
Minoxidil may also cause hair growth because it prevents cell death, which is known scientifically as apoptosis. The process behind this is similar to how minoxidil encourages cell proliferation.
There is evidence that minoxidil can increase the ratio of bcl-2 to BAX, which are proteins that respectively inhibit and promote apoptosis (15). When minoxidil increases the level of a protein that protects against cell death, it may follow that the anagen phase of the hair follicle these cells make up is extended and the life cycle of the sheath extended.
In other words, minoxidil increases bcl-2 protein and prevents cell death, which makes the active phase of the hair follicle longer, allowing your hair to stay longer on your scalp.
Stimulation of Proteins that Form Blood Vessels
So far, we’ve established that minoxidil stimulates ERKs and bcl-2 proteins. There is evidence that it stimulates another cell, Adipose-derived Stem Cells (ASC), which regulate blood vessel formation (16).
So if the drug really does lend a helping hand to blood vessel formation, what does that have to do with hair growth?
Well, fewer blood vessels, or decreased blood flow to the scalp, may be linked to hair loss.
Some research has found that a protein that encourages blood vessel growth in the skin led to hair growth in mice (17). Although a direct link between minoxidil’s stimulation of ASCs, blood vessel growth, and hair follicle regeneration hasn’t been established, the research indicates that the factors may well be connected.
Minoxidil’s Side Effects
So we’ve talked about the how of minoxidil and honed in on what minoxidil actually does to our scalp cells and hair follicles, but let’s discuss the side effects of the drug itself.
The potential side effects of topical minoxidil include (18):
- Scalp irritation
- Acne at site of application
- Unwanted growth of facial hair
- Chest pain
- Fast Heartbeat
- Swelling in the hands and feet
- Weight gain
- Dizziness and Confusion
- Warmth or tingling in the face and neck
Don’t let this list scare you, though. Besides the first side effect, which is scalp irritation, these occur only rarely.
Does Minoxidil Actually Work?
So does this drug work? And if so, how well?
According to studies, minoxidil works pretty well on two counts:
- Minoxidil helps restore thinning hair
- Minoxidil helps to maintain hair density through long-term application
Let’s take a closer look.
Evidence: Restored Hair Growth
We’ll first look at research that supports the first point.
One study conducted over a year found that a 5% topical minoxidil solution applied to areas of hair loss in males with androgenetic alopecia was at least moderately effective in 84.1 percent of subjects (19).
Another study found that 70 percent of subjects who continued treatment with 3% topical minoxidil for 30 months had at least 50 percent more hair than they had at the beginning of the study (20). This indicates significant hair regrowth!
But how does the treatment measure up against a placebo?
There’s extensive research in this area as well. One study showed that after 24 weeks, subjects treated with 2% topical minoxidil experienced an average increase of 37.6 hairs per reference area, as compared to the placebo hair count increase of 8.8 (21). There are many additional studies that similarly demonstrate the efficacy of topical minoxidil against a placebo.
Evidence: Maintenance of Hair Density
Not all studies indicate hair regrowth at all stages of treatment, but they do indicate efficacy. This is most likely because sometimes the drug prevents the progression of AGA and as a result only pauses or slows the rate of hair loss. So while it may seem like your minoxidil treatment isn’t working to regrow your hair, it may be working quite well to prevent further hair loss.
One study showed that at one or two year intervals after treatment, the majority of patients showed progressive regression (reversal) or stabilization of the bald area (22).
Another demonstrated that subjects that applied 2% minoxidil twice a day experienced less average hair loss than subjects who applied 3% minoxidil once a day ().
Minoxidil, while in many cases a very effective treatment for hair loss, is not a miracle drug. While it can restore some hair density, it will probably not return your hair to its original state if you’ve experienced extensive hair loss.
Research also seems to suggest that minoxidil isn’t consistently effective when applied over a long-term period. In other words, it’s not a linear pattern of regrowth. The efficacy of topical minoxidil on the scalp seems to peak at the one-year mark of treatment (22).
Nevertheless, research has demonstrated definitively that minoxidil is an effective treatment overall.
Concentration of Minoxidil: 2% or 5%?
Not all minoxidil is created equal. Generally, 5% topical minoxidil has been shown to be more effective than either 2% or 3% minoxidil. One study showed that response to 5% topical minoxidil yielded more regrowth and was faster than response to 2% topical minoxidil (26).
However, the same study also showed that treatment with the 5% solution led to increased irritation and itchiness in the area of application. Neither solution led to any severe side effects in subjects besides the irritation.
The verdict on minoxidil concentration? If you value effectiveness, try the 5%. If you would rather not risk the discomfort of an itchy, irritated scalp, try a lower concentration.
Kirkland Minoxidil Versus Rogaine: What’s the Difference?
Kirkland Minoxidil and Rogaine are two prominent pharmaceutical brands which contain the active ingredient minoxidil. This part of the article will cover the similarities and differences to help you decide which brand may be right for you.
Both treatments contain 5% minoxidil, which means that clinically speaking they should have the same efficacy.
However, they have slight differences in their inactive ingredients, which may make your experiences with the two medicines different.
Inactive Ingredients and Absorption
Which inactive ingredients might make a difference? It depends on which product we’re talking about.
Rogaine has four products containing 5% minoxidil. They are:
- Men’s Rogaine Unscented Foam
- Men’s Rogaine Solution (liquid)
- Women’s Rogaine Unscented Foam
- Women’s Rogaine Solution (liquid)
Kirkland Minoxidil has only one version of the medication, a liquid.
The liquid version of Rogaine and Kirkland Minoxidil actually contain the same ingredients, which are just alcohol, propylene glycol, and purified water. Therefore, there should not be any practical difference between the Rogaine liquid solutions and the Kirkland Minoxidil solution.
Where the difference really comes into play is with the Rogaine foams. The Rogaine unscented foam for men and women have the same ingredients. In the order they are listed on the label, they are:
Butane, Butylated hydroxytoluene (BHT), Cetyl alcohol, Citric acid, Glycerin, Isobutane, Lactic acid, Polysorbate 60, Propane, Purified water, SD alcohol 40-B, Stearyl Alcohol.
The fact that butane is the first ingredient may be alarming to you. In fact, butane and propane are commonly used in other aerosol beauty products, such as hairspray.
How dangerous can they be for your skin? Well, the FDA has reviewed them as GRAS, which means Generally Recognized as Safe. As such, butane and propane are unlikely to harm your skin because they evaporate quickly.
Research has also found that long-term, low-dose exposure to butane doesn’t lead to adverse effects in humans (28). However, inhalation of butane in high doses can be lethal. But as long as you’re not breathing in the foam, you should be safe.
So what about the other ingredients?
BHT is used as an antioxidant in medicines, and is sometimes added to cosmetics and food in small amounts (30). Although some suspect that it is a carcinogenic, there is no solid evidence that it causes cancer, and most research has been inconclusive. So while it’s probably safe to use, people who are worried about BHT in any product should avoid the Rogaine foam treatment.
Alcohol, citric acid, polysorbate 60, and glycerin are all used commonly in beauty products and don’t typically cause irritation unless your skin is already dry and irritated.
So which product should you choose?
In the end, it all comes down to preference. Kirkland Minoxidil and the liquid Rogaine solutions are effectively the same. If you feel comfortable with the extra inactive ingredients in the foam and value the ease of application that a foam applies, you should buy the Rogaine foam version. If not stick with the liquid solutions.
There’s one more factor to this decision we haven’t mentioned yet: Price!
Which product is better for your wallet?
If that’s your main concern, go with the Kirkland Minoxidil. The price varies depending on where you get it, but at the time this article was written, you could buy a one-month supply on Amazon for about $23.
In contrast, all versions of the Rogaine treatment cost $27.49 for a one-month supply. So if you would like to use the liquid version anyway, it makes sense for you to buy the Kirkland Minoxidil. If your heart is set on the foam version, Rogaine is the better brand.
Let’s go over the application techniques of the topical treatment. They are essentially the same for any version of the product (31):
- Make sure your hair is dry.
- Apply onto the entire affected area.
- Wash your hands to remove remaining solution.
- Allow minoxidil to dry for two to four hours before shampooing.
Because the 5% solution is relatively strong, we don’t recommend applying it more than once a day. If you apply it more often, you may experience irritation.
If you’re experiencing areas of thinning or hair loss, minoxidil may be worth a try. It may make a difference in reversing, stopping, or slowing your hair loss, and it does not usually have long-term negative effects on the body.
To summarize the important points about this drug:
- Minoxidil has been proven a fairly effective treatment for hair loss.
- It helps stimulate hair growth by lengthening the active anagen phase of hair and shortening the resting telogen phase.
- It may cause irritation, but this is not common and other side effects are even rarer.
- The exact mechanism of action isn’t clearly understood by scientists.
- A higher concentration is typically more effective.
- Kirkland Minoxidil and Rogaine are similar in effect, but the Rogaine foam may make application easier and Kirkland is more economical.
Does all of this mean that minoxidil is right for you? Certainly not. There are many other treatment options to consider, and you may also want to consider taking a more natural route.