Is applying minoxidil once a day enough?

People on the internet often debate if it’s better to apply minoxidil once, or twice daily. Let’s just say that the science is not conclusive, and opinions are divided. People have gotten great results with applying minoxidil once a day, just as people have applying twice daily.

Let’s find out if applying minoxidil once a day is enough, or if two times is the most optimal way.

 

Can I apply minoxidil once a day?

It is perfectly fine to use minoxidil just once a day. You will still get great results applying once daily.

A lot of people, especially women who are more weary of possible side effects, apply only once daily and notice very good results. Some people even remark getting the same results as they would apply twice a day.

 

Is applying minoxidil once a day enough or not?

Mental representation of Kirkland minoxidil liquid.

So can we apply minoxidil once a day to get the best results?

Well, it’s complicated. The truth is rarely black or white. To get the best results, it is generally agreed upon that you should apply minoxidil twice daily.

The following study confirms that the absorption of topical minoxidil was more or less 50% complete by 1 hour, and greater than 75% by 4 hours. This means that topical minoxidil gets absorbed rather rapidly through the skin.

Absorption was approximately 50% complete by 1 h and greater than 75% complete by 4 h.

This suggests that minoxidil absorption from the vehicle into skin occurs rapidly relative to diffusion through skin.[1]https://pubmed.ncbi.nlm.nih.gov/2395092/

Another study confirms that the half life of topical minoxidil is about 4.2 hours.[2]https://www.sciencedirect.com/topics/medicine-and-dentistry/minoxidil

However, some other studies say that the half life of topical minoxidil is about 22 hours. If this is indeed the case, then theoretically, applying once or twice daily would make little to no difference.

Can I use minoxidil 2% once a day?

It should be pointed out that Rogaine specifically states in their FAQ that the 2% minoxidil topical solution for women should be applied twice daily.

This product should be used twice daily, every day.

To be effective, it is important to apply the product directly to your scalp and not to your hair so that it can easily get to your hair follicles to help regrow your hair.

Still, applying minoxidil 2% topical solution only once a day can still yield considerable results.

Can I use minoxidil 5% once a day?

Rogaine notes that the 5% minoxidil topical aerosol for women should only be applied once daily.

This is probably due to the increased strength of the 5% product and, thus, the increased risk for negative side effects such as growing unwanted body hair in women.

This is what Rogaine had to say about the 5% minoxidil topical aerosol product:

This product should be used once daily, every day.

To be effective, it is important to apply the product directly to your scalp and not to your hair so that it can easily get to your hair follicles to help regrow your hair.[3]https://www.rogaine.com/faq.html

Rogaine Canada states that men should use 5% Rogaine foam twice daily

Use only the recommended dosage of half a capful twice a day.[4]https://www.rogaine.ca/mens-rogaine/how-to-use-rogaine-for-men-foam

Largely speaking, applying minoxidil once a day is enough to get noticeable results.

Still, even the supplier sometimes recommends applying twice daily, which seems to indicate some form of benefit from applying more than just once a day.

 

Is applying Rogaine once a day enough?

Image of women's Rogaine 5% foam.

The same rules apply to Rogaine than to every generic brand of minoxidil. It is by and large considered the most optimal practice to apply minoxidil twice daily.

It should be noted that Rogaine specifically states on their website that the 5% minoxidil topical aerosol for women should be applied just once daily. Possibly to reduce the chance for annoying side effects such as the growth of unwanted body hair.

Nevertheless, that doesn’t mean that applying Rogaine once a day doesn’t yield excellent results.

 

Conclusion

Applying minoxidil once a day will get you great results most of the time. It can even be beneficial to use minoxidil after you’ve got a hair transplant.

Some people notice little difference between applying just once, and twice a day.

Applying Rogaine once a day or two times daily depends on the strength of the product, and if it’s designed for women or not.

Evidence is not conclusive about if it’s better to apply once or twice daily. If you do decide to apply twice daily, then leave at least 4 hours between your first time applying in order to give your skin the necessary time to absorb the product and to reduce the risk for side effects.

 

References

References
1 https://pubmed.ncbi.nlm.nih.gov/2395092/
2 https://www.sciencedirect.com/topics/medicine-and-dentistry/minoxidil
3 https://www.rogaine.com/faq.html
4 https://www.rogaine.ca/mens-rogaine/how-to-use-rogaine-for-men-foam