Side Effects of Minoxidil

Minoxidil has been the gold standard for topical hair loss treatments since the Food and Drug Administration (FDA) first approved the treatment for men’s hair loss in 1988.

While the 5 percent solution does offer male users up to 40 percent regrowth, there are side effects that should be considered before adding Minoxidil to your hair loss regimen (1).

Minoxidil therapy is a bit less effective for women with androgenetic alopecia, with approximately 50 percent of female users seeing minimal hair regrowth and only 13 percent experiencing moderate hair regrowth (2)

To make it easy for you to decide whether or not Minoxidil is right for you, we’ve compiled a comprehensive overview of the product, including both common and rare side effects.

The History of Minoxidil

When drug manufacturer Upjohn created Minoxidil to treat ulcers, they found that a side effect of the drug was that it effectively lowered blood pressure (3).

Found to be a powerful vasodilator — a drug that widens, or dilates, your blood vessels — Minoxidil was approved by the FDA in 1979 as an oral treatment for high blood pressure. It was then released in prescription-only tablets marketed under the name Loniten.

Soon afterward, patients taking Loniten for high blood pressure noticed increased hair growth and thickness as a side effect of the drug, so Upjohn undertook research to see if the product might be used to treat hair loss (4).

By 1988, the FDA had approved a 1 percent solution of Minoxidil, trade-named Rogaine, to treat hair loss in men. The 1 percent solution was approved for women in 1991, and a stronger 5 percent formula was approved for both men and women in 1997.

How Minoxidil Works

Currently, there’s no real consensus on how Minoxidil contributes to hair regrowth.

Some hypothesize that as a vasodilator, Minoxidil increases blood flow and circulation to the scalp, bringing necessary nutrients and oxygen to hair follicles.

A diagram of the hair follicle

Other researchers think that minoxidil inhibits prostaglandins, thereby slowing or reversing hair loss. Prostaglandins, specifically the prostaglandin D2, have been shown to inhibit hair growth and are found in elevated levels in the scalps of men with androgenetic alopecia (5, 6).

Some scientists theorize that Minoxidil works directly to block androgens from androgen-sensitive hair follicles and it may also delay the aging of matrix cells to prolong the anagen phase of hair growth (7).

No matter what the mechanism, Minoxidil can provide hair regrowth for up to 40 percent of users, and studies show it is dose-dependent — meaning higher doses (5 percent versus 1 percent) result in more hair growth in individuals that respond well (1, 8).

The Side Effects of Minoxidil

The fact that Minoxidil is a topical drug, applied to your largest organ, your skin — specifically, the skin of your scalp — means you should be aware of potential side effects.

Your skin is a conduit — and barrier — to many substances (9).

In fact, the Center for Disease Control (CDC) notes that most dermal absorption of substances centers on the outer skin layer, the stratum corneum, which is where you apply most topical products, including Minoxidil (10).

Chemicals and other substances absorbed by skin travel from areas of high concentrations to areas of lower concentrations, which means anything absorbed by your skin might have systemic effects.

Most people tolerate Minoxidil well, although there are a number of common — and some severe — side effects associated with short- and long-term use (4, 7).

So let’s take a look at the wide range of side effects associated with Minoxidil.

General Side Effects

The most common side effects of Minoxidil use include (4):

  • Burning
  • Stinging
  • Scalp redness
  • Itching

These side effects are mostly associated with contact dermatitis, a condition brought about when a hazardous or allergy-causing substance causes an inflammatory response in your skin (11).

Contact dermatitis is characterized by redness and itching and generally goes away once you stop using whatever is causing the rash — in this case, Minoxidil. It will take about two to four weeks after you discontinue use for your body to clear the rash and return to normal.

An example of contact dermatitis, which can be caused by minoxidil use
An example of contact dermatitis, which can be caused by minoxidil use.

Normally, contact dermatitis is aggravated by an allergen — a substance that causes your immune system to react strongly. In the case of Minoxidil, both the drug and its carrier substance, a mixture of alcohol and propylene glycol, can be the culprit.

Propylene glycol is considered to be a skin irritant, and alcohol has known skin-drying properties (12). Propylene glycol has also been shown to have the potential to cause renal toxicity and liver damage (13, 14).

These two substances, alcohol and propylene glycol, can also contribute to the increase of seborrheic dermatitis some people experience when using Minoxidil (6).

Minoxidil foam does not contain propylene glycol, so it’s a good choice for those that experience an allergic reaction to the serum formula.

Seborrheic dermatitis shows up as greasy, red skin patches that are covered by white scales or yellowish crusts. These scaly changes in the skin of your scalp are often accompanied by itching and flaking, both of which can range from mild to severe.

Like the other common side effects, seborrheic dermatitis disappears within weeks of discontinuing use of topical Minoxidil.

Hypertrichosis

Another common side effect of topical Minoxidil, hypertrichosis, is most often seen in women and adolescents, although it appears in men as well (15). Hypertrichosis is the excessive growth of hair, and it normally appears where you don’t want it.

With topical Minoxidil use, the excess hair is most common on the face — cheeks, chin, and forehead — although it can become generalized, with hair spreading down the back and limbs (16).

Fortunately, the excess hair growth will go away once you’ve stopped using Minoxidil, although not for several weeks.

Facial Swelling and Water Retention

Edema, or swelling of the face can occur with topical Minoxidil use. While this side effect has been studied, no conclusion was reached regarding danger associated with its occurrence (17).

However, given that edema can be connected with adverse cardiac events, it’s best to seek a doctor’s advice if you are having swelling of any kind after beginning Minoxidil therapy (18).

Minoxidil can also cause overall water retention by causing your body to retain sodium (19). This retention can manifest as a puffy face, more pronounced eye bags, bloated hands and feet, or overall body swelling and weight gain.

Cardiovascular Side Effects

Patients with heart disease or underlying cardiovascular conditions should not use Minoxidil, as it is associated with several negative cardiovascular side effects (20).

Always talk to your physician before beginning topical Minoxidil therapy to avoid hazardous side effects and discontinue therapy immediately if you experience any serious adverse reaction.

Left Ventricular Enlargement

In some patients with high blood pressure, treatment with Minoxidil resulted in left ventricular hypertrophy, meaning an enlarged and thickened wall of your left ventricle (21).

This enlargement, in turn, can contribute to shortness of breath, syncope, palpitations, and even heart attacks. Eventually, left ventricular hypertrophy affects the heart’s ability to function normally.

Increased Heart Rate

Minoxidil has been shown to increase the average beats per minute as well as the volume of blood flow through the arteries (20). While this may not impact someone with a healthy heart, those with cardiac disease might want to steer clear.

Pericarditis/Pericardial Effusion/Tamponade

This is a very serious side effect, and involves an inflammation of the membrane surrounding the heart (22). As it progresses, the lining can fill with fluid, leading to pericardial effusion.

Eventually, the fluid interferes with the heart’s ability to effectively pump to circulate blood and requires immediate emergency treatment by withdrawing the fluid from the sac with a needle.

This is why you must see a physician immediately if you experience any heart-related symptoms while using topical Minoxidil. If you think you may be experiencing an adverse side effect, discontinue use of Minoxidil immediately.

Other Systemic Side Effects

There are conflicting studies that both prove, and disprove, the systemic side effects of topical Minoxidil (23, 8). It’s important to note that there have been documented instances of systemic problems directly connected to the use of the topical formula.

While rare, sudden weight gain, swelling in the legs or ankles, local or all-over swelling, racing heart, dizziness, chest pain, or fainting all point to a severe systemic reaction and should be reported to a doctor immediately (23).

Other potential areas of concern are:

Ocular

Minoxidil has been tapped as a possible contributor to ischemic optical neuropathy resulting in blurred vision that was corrected once the topical Minoxidil was discontinued (24).

This is an extremely rare side effect.

Hepatic

Increased aminotransferase numbers have been seen in patients using topical Minoxidil (19). Elevated liver enzymes like aminotransferase are markers for increased inflammation of — or damage to — the cells in your liver (25).

However, this damage is dose-dependent, so it’s possible that it can be slowed or even stopped by using a different Minoxidil formulation (26).

Gastrointestinal

There have been cases of gastrointestinal distress relating to the use of topical Minoxidil (27). The most common side effect is nausea, but diarrhea and vomiting were also noted.

Neurological

Topical Minoxidil therapy has been associated with dizziness, numbness, and syncope (becoming off-balance).

A recent case study conducted by researchers in the U.K. noted that topical Minoxidil can cause hypotension — low blood pressure — with resulting syncope, causing potential falls (28).

The researchers conclude that this study proves that topical Minoxidil does have systemic effects.

Cosmetic Side Effects — Hair Loss

Besides the cosmetic issues that could occur with cases of dermatitis, facial swelling, and excess hair growth, there’s one side effect that most hair loss sufferers using topical Minoxidil should be aware of — hair loss (4).

A man suffering from minoxidil shedding

It seems counterintuitive that a product design to help you regrow your hair would cause hair loss, but in most people, that is exactly what happens when beginning topical Minoxidil.

Minoxidil’s ability to open potassium channels and widen blood vessels causes oxygen, blood, and nutrients to saturate hair follicles (4).

This mechanism can promote shedding of follicles that are in the telogen phase of growth. In effect, Minoxidil re-synchronizes hair phases, which can result in sudden, but hopefully temporary, thinning.

The shedding generally begins in the first two to eight weeks, but begins to slow shortly thereafter, once your hair is acclimated to the therapy.

If you are concerned, or your shedding does not subside after two months, you’ll want to see an expert in hair loss and/or your physician to rule out other causes of hair loss such as endocrine disorders, autoimmunity, or other underlying diseases.

Still, it’s important to be aware, and prepared, for your hair to look thinner at the beginning of Minoxidil therapy.

Side Effects of Stopping Minoxidil

If you need to stop using Minoxidil due to allergic reactions or other health concerns, you may experience the side effect of hair loss.

Minoxidil, while stimulating hair growth, does not reduce dihydrotestosterone (DHT) or 5-alpha reductase,the enzyme responsible for the accumulation of DHT around the hair follicle (29).

Since these substances are the primary cause of male pattern baldness, once Minoxidil treatment is stopped, all the hair growth that was being stimulated by the drug will be lost to acute telogen effluvium (30).

Acute telogen effluvium can be devastating, as it is a severe shed of short duration. This sudden loss of hair can cause extreme psychological stress and contribute to depression and a decline in mental health (31).

Preventing Minoxidil Side Effects

Minoxidil is generally well-tolerated, but it still has a range of side effects from mild discomfort to serious heath issues.

In fact, it’s contraindicated for many populations, such as (32):

  • Pregnant and nursing mothers;
  • Children and adolescents;
  • People over the age of 65 (as it’s not been studied);
  • Those with poor cardiac health, including high blood pressure, low blood pressure, or heart disease;
  • Anyone with an allergy to propylene glycol or alcohol. People with other allergies should consult a physician first;
  • Those with kidney or liver disorders; and
  • Anyone with irritated, broken, inflamed, or sunburned skin on the scalp.

For those who prefer not to take the risk of adverse affects, research has provided a number of viable alternatives to Minoxidil which have performed well in preliminary studies

There are several safe, effective ways to create your own substitute “Minoxidil” formula at home to regrow hair as well as — and maybe even more effectively than — Minoxidil itself.

Let’s explore the possibilities.

Oleuropein

The most recent addition to the arsenal of natural Minoxidil substitutes is oleuropein, a substance produced from the unprocessed olive fruits and leaves of Olea europaea. 

In a recent study, topically-applied oleuropein was found to positively regulate the anagen phase of the hair growth cycle in mice — producing even better results than Minoxidil therapy (33):

The results of a scientific study showing the efficacy of oleuropein and minoxidil
Credit.

In fact, oleuropein was significantly more effective than Minoxidil in all of the elements measured by the researchers. These included:

  • Hair follicle length
  • Hair follicle diameter
  • Number of follicles
  • Dermal papilla cell proliferation

While most oleuropein is available in capsule form for ingestion, as it has many significant health benefits, there are some liquid brands on the market that may be useful as a topical hair formula, although this has not been studied.

Peppermint Oil

What could be sweeter than using peppermint oil to boost your hair’s thickness?

A topical mix of jojoba and peppermint oils was found to be more effective (95 percent versus 55 percent) than Minoxidil in encouraging hair growth without any toxic side effects (34):

The results of a scientific study showing the efficacy of peppermint and minoxidil
Credit.

This study found this combination of 3 percent peppermint oil plus jojoba oil as a carrier to be effective in increasing:

  • Hair follicle length
  • Hair follicle diameter
  • Follicle depth
  • Dermal papilla cell proliferation
The development of hair follicles are seen in the use of peppermint essential oil and minoxidil
Credit. Histological observation of hair follicle length and depth.

The study was conducted over a four-week period on mice. However, the researchers’ conclusion recommends the use of peppermint oil for humans suffering from androgenic alopecia.

Magnesium Oil

Magnesium oil is a good replacement for the jojoba oil in the above study.

Magnesium oil can be substituted because studies show that hair miniaturization can be caused in part by scalp calcification and magnesium oil reduces calcification in the scalp (35).

Rosemary Oil

The efficacy of peppermint oil has already been explained, but another natural oil, rosemary oil, can be added to your hair regrowth arsenal to provide extra benefit.

One study has shown rosemary oil to be as effective as 2 percent Minoxidil in promoting hair growth, in part through increased blood circulation (36).

Pumpkin Seed Oil

Pumpkin seed oil has been found to have a positive effect on hair growth in people with mild to moderate male pattern hair loss possibly due to its ability to inhibit 5-alpha-reductase.

A spoonful of pumpkin seeds and pumpkin seed oil

In addition to its effects on 5-alpha-reductase, pumpkin seed oil also provides anti-inflammatory benefits that can help calm the scalp inflammation that contributes to hair loss (37, 38).

Lavender Oil

In other research, lavender oil proved to be as effective as Minoxidil in regrowing hair on mice in a four-week study (39). Researchers believe the operative component of lavender oil is its ability to increase follicles and follicle depth and decrease the number of mast cells present in the scalp.

Mast cells are markers of an allergic or histamine reaction, and it’s possible that lavender oil’s potent antimicrobial effects could contribute to its ability to repress mast cell activity (40).

Supercharging Your Homemade Minoxidil

One of the best ways to get an extra boost of effectiveness from your homemade topical hair regrowth treatment is to encourage better absorption.

And one of the simplest ways to get better absorption is through a process called microneedling. According to studies, microneedling significantly increases the effectiveness of topical hair growth solutions (41).

This article can give you a more in-depth description of the procedure and its effectiveness.

Microneedling can be done at home with an inexpensive device called a dermaroller. It’s a hand-held device with a roller “drum” that is studded with tiny, micro-fine needles that roll across your skin, causing tiny perforations.

A simple dermaroller

Despite how it sounds, if used correctly, the dermaroller causes minimal pain.

According to studies, microneedling works by stimulating collagen and growing new blood vessels for increased circulation to hair follicles. (42)

In addition, the sizes of the needles appear to be critical for success. One study showed that a .25 mm needle followed by a .5 mm needle for ten cycles each provided the most optimal results for hair regrowth. (43)

Both needle sizes are easily available online in home-use dermarollers.

Why Minoxidil Might Not Be the Answer

Besides its potential for adverse side effects, Minoxidil doesn’t address the root cause of much hair loss, inflammation, scalp calcification, and scalp tension.

DHT, which has long been targeted as a cause of male pattern hair loss, is definitely a factor. But it’s the inflammation that DHT causes that is the instrument behind the miniaturization, and eventual loss, of your hair (44).

And studies have shown that cytokines, the pro-inflammatory substances our bodies produce in response to stress — whether physical or mental — are a significant contributing factor to hair loss (45).

And this stress can contribute to tension in the scalp muscles, which further inhibits the growth of hair by promoting androgen sensitivity in the dermal papilla surrounding hair follicles (46).

This means that slathering a chemical on your scalp, while it may help in the short term, is not a long-term treatment for androgenetic alopecia, particularly if you are concerned about potential health consequences.

Conclusion

Topical Minoxidil can regrow your hair, but it’s not without side effects. Although most are considered mild and will go away once you’ve stopped using Minoxidil, there are some severe — and dangerous — side effects.

Plus, if you stop using Minoxidil, you’ll lose any regrowth you’ve experienced.

As discussed previously, some studies have shown Minoxidil to be a toxic substance with the potential for widespread systemic side effects. In layman’s terms, these cautions indicate Minoxidil has the potential to adversely affect your health.

And Minoxidil does not address all causes of hair loss, like stress or underlying diseases, such as hypothyroidism, among others.

While it may help some people regrow hair, you should always consult your physician before beginning Minoxidil topical therapy.

If you’ve experienced adverse results with Minoxidil or are looking for safe, effective, natural hair regrowth, take a careful look at the natural alternatives in this article. Each of these ingredients are scientifically proven to regrow hair without the toxic side effects of Minoxidil.

No amount of hair growth is worth a serious health side effect, especially since you can get the same — or better — using easily available natural alternatives.

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