Balding is a natural part of aging for many men. Between 30% to 50% of men experience hair loss by age 50. Genetics, hormones, stress, and medical conditions can all predispose to baldness.

As science has advanced over the years, baldness is no longer a life sentence. Several different medical procedures and drugs of varying success are on the market to help men manage hair loss. Topical minoxidil, belonging to a class of drugs called vasodilators, is a common medication approved by Health Canada to treat hair loss.

To understand the treatment of hair loss or alopecia, it’s important to first understand the process of hair growth.

Hair Growth Cycle

Human hair grows in four stages:

1. Anagen

This is the active growth phase of hair follicles. It lasts between 3 and 10 years, making it the longest phase of hair growth. During the anagen phase, rapid cell division occurs in the hair bulb and dermal papilla, and new hairs begin to protrude from the scalp.

2. Catagen

The second phase of hair growth is catagen or regression. It is a transitional phase that lasts 2 to 3 weeks. During this phase, cell division stops, and melanocytes stop producing pigment.

3. Telogen

The third phase, telogen, is the resting phase. It lasts 3 to 4 months during which hair follicles are dormant and the shaft does not grow.

4. Exogen

Exogen is a relatively recently accepted fourth phase in hair growth. It lasts between 2 to 6 months. This phase relates to any signaling or structural changes preceding the loss of hair from the follicle, and subsequent shedding.

Minoxidil: What is it?

In scientific terms, minoxidil (C9H15N5O) is an adenosine 5′-triphosphate-sensitive potassium channel opener. The oral form of the medication was introduced as a treatment for high blood pressure in the 1970s. During the course of therapy, doctors discovered that the drug also led to the regrowth of hair in balding men, and thus, tropical minoxidil entered the market as an alopecia treatment.

It is applied directly to the scalp and is available in different strengths and formulations: gel, foam, or solution. It works by increasing blood flow to the hair follicles, which can stimulate hair growth. The drug may also prolong the anagen phase of the hair growth cycle.

According to reviews of clinical trials, 62% of the patients on minoxidil therapy showed a significant decrease in the affected area of the scalp when treated with 5% topical minoxidil twice daily and 84.3% of patients reported hair regrowth.

Mechanism of Action: How Minoxidil Works

The drug widens blood vessels and opens potassium channels, allowing more oxygen, blood, and nutrients to the hair follicles.

In the body, minoxidil is converted by the enzyme sulfotransferase into minoxidil sulfate, the active ingredient that promotes hair growth by prolonging anagen and shortening the telogen phase, stimulating new hair production as the next anagen phase begins.

According to some theories, minoxidil might also act as a nitric oxide agonist. This may cause hair follicles in the telogen and exogen phases to shed, which are then replaced by thicker and stronger hairs in a new anagen phase. Minoxidil induces cell growth factors such as the vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and insulin-like growth factor 1 (IGF-1), which results in increased growth and development of hair follicles.

Efficacy of Minoxidil in Studies:

In a study of 904 men with androgenetic alopecia treated with 5% topical minoxidil twice daily, 62% of the patients showed a significant decrease in the affected region of the scalp and 84.3% of patients reported varying degrees of hair regrowth.

In a 16-week, multi-center, double-blind, placebo-controlled trial of 5% minoxidil topical foam in 352 men, 18 to 49 years old, the 5% minoxidil solution elicited a statistically significant improvement in mean hair density compared with a placebo.

Another study demonstrated the effectiveness of 5% topical minoxidil compared to 2% topical minoxidil and placebo in 393 men, aged 18-49, with androgenetic alopecia. After 48 weeks of therapy, 5% topical minoxidil was significantly superior to 2% topical minoxidil and placebo in terms of hair regrowth (45% more), change from baseline in hair count, patient rating of scalp coverage and treatment benefit, and investigator rating of scalp coverage.

Minoxidil Side Effects

Generally, tropical minoxidil is well tolerated by patients. Some side effects that have been observed during trials and clinical treatment include:

  • changes in the color, length, or thickness of body or facial hair
  • headache
  • allergic or application site dermatitis
  • pruritis (itching)

Sometimes, treatment with minoxidil can lead to a temporary increase in hair shedding at the start of therapy, which may negatively impact physical appearance and discourage patients from continuing with the treatment plan. This shedding phase is caused by changes in the hair cycle which trigger the hair follicle to enter the anagen phase prematurely, after passing through a shorter telogen phase, resulting in a period of hair shedding before clinical improvement can be seen.

Minoxidil Formulations

Topical minoxidil 5% gel:

  • effective medication delivery into the skin
  • easy clean-up
  • hypoallergenic

How to use: Before and after applying minoxidil gel, wash your hands. Apply the gel to clean and dry hair and scalp.

Apply 1 ml of the drug to the affected areas of the scalp twice a day (morning and evening), or as prescribed by your doctor.

After application, let it air dry. Make sure to avoid washing or rinsing your hair immediately afterwards and keep the gel out of fabrics and associated hair accessories.

Minoxidil foam:

  • Better for straighter hair with more open areas of scalp
  • Less messy to apply
  • Does not contain propylene glycol, for those men allergic or sensitive to it

How to use: Match the arrow on the can ring with the arrow on the cap to open the container. Remove the cap.

Part your hair into one or more rows to see the thinning hair on your scalp more clearly. The foam can be applied on damp hair as well as dry hair.

Turn the can upside down and press the nozzle to transfer the foam to your fingertips. Spread the foam with your fingers over the hair loss area and gently massage it into your scalp.

Wash your hands immediately after to remove any medicine that may have gotten on them. Keep the foam container away from heat, open flames, and smoke. The aerosol can should not be punctured, broken, or burned.

Minoxidil Topical Solution:

  • Faster and more precise application using the dropper
  • Better for thicker, longer, or wavier hair

How to use:
Before application, make sure your hair and scalp are fully dry. Apply the recommended dosage to the affected area of the scalp, commencing in the center. Follow your doctor’s instructions for applying the solution with the provided applicator. One dose is 1 ml of the solution in the dropper.

After using minoxidil, wait 4 hours before shampooing your hair. Wash your hands immediately afterwards to eliminate any medicine residue.

Using a hairdryer to dry the scalp after applying minoxidil solution may reduce the effectiveness of the treatment.

Allow 2 to 4 hours after application, including before going to bed, for the minoxidil to thoroughly dry. If your hair or scalp is not completely dry after using the medication, it may discolor clothing, caps, or bed sheets.


  • Use minoxidil only on the affected area of the scalp and keep it away from other body parts, particularly the eyes, nose, mouth, ears, or broken skin.
  • In case you miss a dose, do not apply two doses to make up for it.
  • Avoid washing your scalp for at least 4 hours after applying the medication.
  • If you plan to get a hair procedure, stop using minoxidil 24 hours before and after the procedure to avoid any chemical interactions.
  • Avoid using minoxidil if the skin on your scalp is red, inflamed, irritated, or infected.
  • Check the medication label to ensure that the medication will treat your specific kind of hair loss.
  • Only use the formula designed for your gender. Women should avoid using minoxidil products designed for men.
  • If you have other medical issues, such as heart disease, consult your healthcare provider about whether it is safe for you to use this medication.
  • If you are pregnant or breastfeeding, do not use this medication without seeing your doctor.
  • Without medical advice, do not use minoxidil on anyone under the age of 18.
  • If you do not see any improvement in hair loss after 4 months of use, get in touch with your healthcare provider.

If you’re looking to start your minoxidil treatment, start your consultation with one of our physicians today.



The opinions shared in this article belong to the author and, like all content on Gambit’s Health Hub, should not be considered a replacement for professional medical advice, diagnosis, or treatment. If you have any health-related inquiries, consult with your preferred healthcare professional or visit a licensed, Canadian physician through Get Gambit for a supported condition.

This article has been medically reviewed by:

Dr. Taneer Ahmed, MBBS, MS


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