Minoxidil Side Effects: Everything You Need To Know


Minoxidil is a common medication used to reduce hair loss in both men and women. It’s effective, and, along with finasteride, it’s used as a first-line hair loss medication.

Unlike other hair loss medications, like finasteride, you can buy minoxidil over-the-counter (without a prescription) in Canada. You can even buy minoxidil online

So it’s an effective and accessible medication for hair loss—but is it safe?

Yes, research consistently finds that minoxidil is safe and well-tolerated by most people. However, there are some minoxidil side effects that you should be aware of. In this article, you’ll find everything you need to know about the potential side effects of minoxidil, along with usage instructions. 

Minoxidil Uses

Minoxidil was first developed in the 1970s as a medication for the treatment of hypertension. However, researchers were surprised to find that patients who were given the medication experienced accelerated hair growth. 

Based on those observations, researchers developed a topical minoxidil solution for promoting hair growth and treating hair loss in the 1980s. That product was marketed as Rogaine. 

Since Rogaine’s development, research has consistently found that the medication, and its generic counterpart minoxidil, are effective at treating various forms of hair loss.

Minoxidil is approved for the treatment of male and female pattern hair loss in Canada. It is also sometimes used off-label as a treatment for alopecia areata, central centrifugal cicatricial alopecia, chemotherapy-induced alopecia, frontal fibrosing alopecia, telogen effluvium, and even for beard enhancement

Types of minoxidil

The two most common forms of minoxidil are as a topical liquid solution and as a foam. It can also be taken orally as a tablet in some circumstances, although this is uncommon. 

At Hair Supply, we only sell topical minoxidil solutions.

Minoxidil Side Effects—Topical Solution

Minoxidil topical solution is considered safe and well-tolerated by most people. While adverse side effects can occur, they are not common. 

Of the uncommon side effects, the most common is skin irritation, itching, and scaling. However, some research suggests that these side effects may actually be from other ingredients—propylene glycol—in the topical solution, rather than the minoxidil itself. Minoxidil foam is formulated without propylene glycol and is a good option for anyone that experiences skin irritation as a result of using minoxidil topical solution. 

Other side effects of minoxidil topical solution include:

  • Temporary hair shedding
  • Excessive hair growth, including on the face and body

Note that research has not found systemic side effects from twice daily application of topical minoxidil such as low blood pressure, abnormal heart rate, or weight gain. 

Minoxidil Side Effects—Foam Formula

The side effects of minoxidil foam are similar to side effects for the topical solution:

  • Temporary hair shedding
  • Excessive hair growth, including on the face and body

Like the topical solution, the foam formula is considered safe and well-tolerated. Research even suggests that the foam formula results in significantly fewer side effects than the topical solution.

Minoxidil Side Effects—Oral Tablets

Side effects of oral minoxidil are uncommon at the doses used for hair loss treatment. One study of 1,404 individuals found that only 2.5% of women and 0.5% of men had to stop treatment due to a side effect.

However, side effects of oral minoxidil tablets can occur. They include:

  • Skin rash
  • Itchy eyes
  • Temporary hair shedding
  • Excessive hair growth, including on the face and body
  • Fluid retention and swelling of the lower legs
  • Low blood pressure
  • Lightheadedness
  • Increased heart rate
  • Headaches
  • Weight gain

When to not use minoxidil

While minoxidil is safe for most people, avoid using a minoxidil topical solution or foam if the skin on your scalp is red, swollen, irritated, infected, or sunburned. Minoxidil may make these conditions worse.

Further, some groups of people should exercise caution when using minoxidil. If you fall into one of these groups, consider seeking guidance from a doctor before using it:

  • A skin condition
  • Irritated skin
  • Sunburn
  • Angina or recent heart attack
  • Heart disease
  • Heart failure
  • Hypertension
  • Pheochromocytoma
  • Liver impairment

Also, note that minoxidil has not been evaluated for or approved for use on children.

Proper use of minoxidil

Side effects of minoxidil are dose-dependent, meaning that applying excess minoxidil can increase your chances of experiencing side effects. To ensure you use minoxidil safely:

  • Follow your doctor’s directions or the manufacturer’s instructions included in the package label.
  • Do not apply more minoxidil than directed, and do not apply it more often than directed. Doing so could cause more minoxidil to be absorbed into the skin and increase the chance of experiencing negative side effects.
  • Do not use other skin products in the same area that you use minoxidil. 

Read more: Can I Apply Less Than The Recommended Dose Of Minoxidil?

Minoxidil Application instructions

To maximize the effectiveness of minoxidil, apply it correctly. To apply minoxidil:

  • Ensure your hair and scalp are clean and dry.
  • Apply minoxidil in the amount prescribed by your doctor or by the manufacturer. 
  • Wash your hands immediately after application to remove any excess medication.
  • Allow the medication to dry for 2 to 4 hours after application.
  • Do not blow-dry your scalp after application, as this can make the medication less effective.
  • Do not shampoo your hair for at least 4 hours after application, as this can remove the medication and make it less effective.
  • Avoid the use of aspirin with minoxidil, if possible. Aspirin appears to reduce the effectiveness of topical minoxidil.

Read more: Can Men Use Minoxidil Once Per Day?

Generic minoxidil vs. Rogaine

Are the side effects of Rogaine different from the side effects of generic minoxidil?

No, both generic minoxidil and Rogaine have the same side effect profile. 

In Canada, brand-name medications generally have the same side effects as their generic counterparts. That’s because Canada requires that drug manufacturers demonstrate that generic medications are pharmaceutically equivalent to the brand-name versions—including in terms of safety.

The only real difference between Rogaine and generic minoxidil is their price: the generic version is much cheaper. 

Where can I buy minoxidil in Canada?

In Canada, you can buy minoxidil over-the-counter at pharmacies or from online shops like Hair Supply

Hair Supply offers affordable hair loss treatment products for both men and women. You don’t even need a prescription.

Check out our popular Kirkland Minoxidil products—they’re super effective and the most affordable hair loss treatment option out there.