How Minoxidil (Rogaine) Works, Results, Usage, and Side Effects

Hair loss, also known as male or female pattern baldness, can be a stressful experience regardless of age or gender. The early signs of balding, such as thinning hair or a receding hairline, can be alarming but also gives you the opportunity to act quickly. One of the most popular hair loss treatments is minoxidil, commonly referred to by its brand name, Rogaine.

Box of rogaine at Hairloss-Recovery fda approved treatments

What is Minoxidil?

Minoxidil is a topical medication that is used to treat hair loss, commonly referred to as male or female pattern baldness. It’s available over the counter without a prescription and comes in liquid or foam to directly apply to the scalp. Minoxidil is believed to work by increasing blood flow to the hair follicles, promoting hair growth. It can also extend the growth phase of the hair and increase the size of the hair follicles. While minoxidil can be an effective treatments option for hair loss, the results can very between individuals. It’s important to use minoxidil as directed, and to consult with a healthcare professional or dermatologist prior to starting use.

History of Minoxidil

Minoxidil was originally synthesized in the 1960’s as an oral medication to treat high blood pressure, a condition known as hypertension. It was first marketed under the brand name Loniten as an antihypertensive drug. It was primarily used to help lower blood pressure in individuals with hypertension.

In the 1970s, during clinical trials and testing of minoxidil as an antihypertensive medication, an unexpected side affect was noted. Researchers noted that the trials showed an increase in hair growth for the participants. It was evident that some individuals not only experienced lower blood pressure, but also showed significant improvement in hair growth. This realization prompted further studies into the potential of minoxidil as a hair loss treatment. 

The pivotal moment for minoxidil occurred in 1988 when it was approved by the U.S. Food and Drug Administration (FDA) as a treatment for hair loss. This made minoxidil the first FDA-approved medication to treat male or female pattern baldness. With FDA-approval, this was a breakthrough moment for individuals dealing with thinning hair and balding. It was sold under the brand name Rogaine as topical minoxidil. Despite not fully understanding its exact mechanisms, researchers believed that minoxidil worked by improving blood flow to hair follicles. This additional blood flow prolonged the growth cycle and increased the size of the hair follicles.

In the following years, it’s popularity as a hair loss treatment continued to grow. It transitioned from prescription only to being available over the counter, making it accessible to a broader audience. Various formulations including topical solutions and foam are now available under various brand names.

How Minoxidil Treats Hair Loss

Minoxidil is believed to treat hair loss, specifically androgenetic alopecia (male or female pattern baldness), through several mechanisms, although the exact processes are not fully understood. Here are the mechanisms believed to be involved:

  • Improving Blood Flow: Minoxidil is a vasodilator, meaning it widens blood vessels and improves blood flow. When applied topically to the scalp, it can increase the delivery of oxygen and nutrients to hair follicles. This enhanced circulation is believed to create a more favorable environment for hair growth.
  • Prolonging the Anagen (Growth) Phase: The hair growth cycle consists of three phases: anagen (growth), catagen (transitional), and telogen (resting). Androgenetic alopecia is associated with a shorter anagen phase, leading to shorter and thinner hairs. Minoxidil is believed to extend the duration of the anagen (growth) phase. This allows for an extended period of growth, leading to thicker and longer hairs.
  • Stimulating Hair Follicles: Minoxidil is believed to stimulate dormant or inactive hair follicles. This prompts the follicles to re-enter into the anagen (growth) phase. This can result in regrowth of hair in areas where follicles have become miniaturized due to the effects of dihydrotestosterone (DHT).
  • Increasing Hair Follicle Size: Some studies suggest that minoxidil may lead to an increase in the size of hair follicles. Larger hair follicles can produce thicker hair, which results in an overall fuller appearance, decreasing the appearance hair loss.

It’s important to note that minoxidil is most effective for individuals in the early stages of androgenetic alopecia. It is less likely to regrow hair in areas where follicles have completely atrophied.

Biochemical Mechanism of Minoxidil

Minoxidil’s promotion of hair regrowth is attributed to a multi-faceted biochemical mechanism:

  • Vasodilation and Potassium Channels: Minoxidil acts as an adenosine triphosphate (ATP)-sensitive potassium channel opener. By modulating these channels, it induces hyperpolarization of cell membranes. This results in vasodilation. The dilation improves blood flow, optimizing the delivery of oxygen, essential nutrients, and growth factors to the hair follicles.
  • Prostaglandin E2 Production: Minoxidil has been shown to elevate levels of Prostaglandin E2 (PGE2) in hair follicles. PGE2 is known to stimulate hair growth.
  • Anagen Phase Augmentation: As previously discussed, minoxidil prolongs the anagen (growth) phase. The extended phase amplifies the size of the hair follicles, leading to a larger hair shaft.
  • Dermal Papilla Function: Minoxidil promotes hair growth via stimulation of the derma papilla cells. These cells are the main role in regulation of hair growth. The enhanced activity of derma papilla cells facilitates hair growth.

Empirical Evidence

Given minoxidil’s widespread acceptance usage, numerous clinical trials have validated its efficacy:

  • Rogaine Trials: Conducted by Upjohn in the late 1980s, this randomized, placebo-controlled trial provided one of the initial pieces of evidence of minoxidil’s efficacy. Participants treated with a 2% solution had a significant increase in hair density and total hair count compared to the placebo group.
  • 5% Solution and Enhanced Efficacy: A double-blind study published in the Journal of the American Academy of Dermatology in 2002 provided a comparative evaluation between 5% and 2% minoxidil solutions. The study showed that 5% concentration outperformed the 2% variant, leading to more hair regrowth in a shorter time.
  • Studies in Women: Women with androgenetic alopecia, a prevalent form of hair loss, have also benefitted from minoxidil. A study from 2014 in the British Journal of Dermatology evaluated premenopausal women and concluded that minoxidil was efficacious for treating female pattern baldness.

Improved hair count after 48 weeks when using 5% topical minoxidil solution (TMS) when compared with 2% TMS and a placebo. 


The results of using minoxidil to treat hair loss can vary between individuals. It’s essential to ensure that realistic expectations are set when using this medication as a treatment. Here are some of the most common outcomes:

  • Hair Regrowth: Many individuals experience some degree of hair regrowth when using minoxidil. This can be in the appearance of new, fine hairs, or the thickening and strengthening of existing hairs. The extend of regrowth depends on several factors, such as the severity of hair loss, the duration of use, and individual genetics.
  • Slower Hair Loss: Minoxidil is effective in slowing down the progression of hair loss due to its extension of the anagen (growth) phase. Even if there is not significant regrowth, it will help to maintain the existing hair and prevent further thinning or balding.
  • Improved Hair Density: Minoxidil can increase hair density, particularly in areas where there was thinning hair. This results in the hair appearing fuller.
  • Shedding: Many users may experience a shedding phase within the first few weeks or months of treatment. This is generally viewed as an indication that your hair is responding positively. This happens become the older, weaker hairs are being pushed out by new hair follicles.
  • Variable Response: Responses can be highly variable between individuals. While some people see substantial improvement, others experience only modest change. A minority of users may not respond at all and experience no positive results.
  • Hair Loss Type: It’s important to note that while minoxidil is FDA approved to treat androgenetic alopecia, it is not approved for all hair loss types.

Improved hair growth and density with continued use of minoxidil.

How to Use

Maximizing the results and effectiveness of minoxidil is dependent on proper use. As with any medication, it’s important to follow the product guidelines. Although usage instructions may vary between brands, here are the general guidelines:

  • Start with a Clean, Dry Scalp: Before applying minoxidil, make sure your scalp is clean and dry. You can wash your hair with a mild shampoo and allow it to dry naturally or with a hairdryer on a low heat setting.
  • Apply as Directed: Minoxidil should be applied twice daily, with a recommended dosage of one milliliter for liquid formulations and half a capful for foam. Apply enough to cover the affected areas, but avoid excessive use, as more is not necessarily better.
  • Massage Gently: After applying, gently massage the solution or foam into your scalp with your fingertips. This helps to distribute the product evenly and improves absorption.
  • Allow to Dry: Allow the minoxidil to air dry completely before styling your hair or using hair products. Do not use a hair dryer to speed up the drying process. The applied heat may reduce the effectiveness of the product.
  • Wash Your Hands: After applying minoxidil, wash your hands thoroughly to remove any residue. Take care to avoid accidental contact prior to washing your hands, especially around sensitive areas like your eyes.
  • Be Consistent: Use minoxidil consistently as directed. Skipping doses or discontinuing treatment can lead to a loss of progress and may result in hair thinning or loss.
  • Avoid Contact with Eyes, Ears, and Mouth: Take care not to let the solution come into contact with your eyes, ears, or mouth. If accidental contact occurs, rinse thoroughly with water.
  • Be Patient: Seeing noticeable results can take several months, typically ranging from three to six months. Continue use until desirable results are achieved.

Safety and Side Effects

Topical minoxidil is generally well-tolerated by most individuals. Like any medication, there are potential for side effects in some users. Here are some of the potential side effects:

  • Scalp Irritation: Mild scalp irritation, including redness, itching, or a burning sensation, is one of the common side effects of topical minoxidil. This irritation is typically temporary and tends to decrease with continued use.
  • Increased Hair Shedding: When first starting minoxidil, some users may experience an initial shedding phase, where there is an increase in hair loss. This is common and generally means that the treatment is working. This occurs as the weaker hairs are replaced by newer, stronger ones. Over time, the new hairs will replace any hairs lost during the shedding phase.
  • Unwanted Hair Growth: Topical minoxidil can sometimes lead to the growth of fine, vellus hairs (peach fuzz) in areas outside of the treatment area. Overall, minoxidil is largely a localized topical treatment.
  • Contact Dermatitis: In some cases, individuals may develop contact dermatitis, which is a more severe form of scalp irritation. Symptoms may include redness, swelling, severe itching, or a rash.
  • Allergic Reactions: Although rare, some individuals may have an allergic reaction to minoxidil. Signs of an allergic reaction may include hives, swelling of the face or lips, difficulty breathing, or severe dizziness.
  • Cardiovascular Effects (Systemic Absorption): While minoxidil is primarily applied topically and minimally absorbed systemically, there is a remote risk of cardiovascular side effects in some individuals. This risk is more associated with high strength minoxidil formulations used to treat hypertension. To mitigate this risk, use minoxidil as directed and avoid excessive application.
  • Dryness or Flaking: Some users may experience dryness or flaking of the scalp. This can usually be managed with a moisturizing shampoo or conditioner.


Minoxidil is the first drug to receive FDA approval as a hair loss treatment and remains one of the most popular choices. It’s vasodilatory effects, PGE2 production, and anagen phase extension highlight the benefits to treating pattern baldness. Using it as a topical treatment is an easy way to help maintain and regrow your hair, bringing back your youthful appearance and self-confidence!

As with any medication or treatment, ensure that you speak with your healthcare professional or dermatologist prior to starting.


  • Olsen EA, et al. A randomized clinical trial of 5% topical minoxidil versus 2% topical minoxidil and placebo in the treatment of androgenetic alopecia in men. Journal of the American Academy of Dermatology. 2002;47(3):377-385.
  • Blumeyer A, et al. Evidence-based (S3) guideline for the treatment of androgenetic alopecia in women and in men. British Journal of Dermatology. 2011;165 Suppl 3:12-27.

Note: Always seek professional medical advice before starting any treatment.

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