Minoxidil

An unexpected effect during tension treatment

Minoxidil was not originally developed as a hair product. Administered orally, it is a powerful vasodilator used in certain hypertensions that are difficult to treat. Patients develop an increase in hair growth, called hypertrichosis. This undesirable effect attracts attention: a molecule used to act on the vessels also seems capable of modifying hair growth.

However, observation is not enough to treat baldness. Stimulating hair growth all over the body is not the desired result, and a cardiovascular drug exposes you to significant constraints. The idea then consists of applying the molecule directly to the scalp. It must be verified that it produces a useful effect, at a dose and in a form compatible with prolonged use.

Moving from observation to comparative trials

Work published in the early 1980s explored this skin application, notably a regrowth trial published in 1984. This is a different stage from the initial observation: the product is evaluated as a local treatment, on people with hair loss. Research is gradually seeking to distinguish a real improvement from an impression linked to lighting, hairstyle or spontaneous variations in the hair cycle.

Controlled studies provide this comparison using a vehicle without minoxidil, similar to the active product. Hairs are counted in a defined area and photographs are examined, while collecting feedback from participants. This work explains why a promise of regrowth benefits from being supported by several measurements: the number of hairs and the impression of density complement each other, but do not tell exactly the same thing.

Compare the concentrations then the textures

In 2002, a 48-week trial involving 393 men compared 5%, 2% solutions and placebo. The 5% obtains better results on several criteria and an earlier response, with more local irritations than the 2%. This study helps to establish the benefit of the 5% dosage in humans, while showing that effectiveness must be considered alongside tolerance.

The question then shifts to comfort of use. A study published in 2007 in 352 men evaluated a 5% foam in front of their vehicle and observed an improvement in growth after 16 weeks. The change in texture responds to a very concrete issue: a daily treatment must be able to find its place between washing, styling and going to bed, without becoming an impossible constraint to maintain.

The return of the oral route, in another context

More recently, clinicians have explored low-dose oral minoxidil for some forms of hair loss. This returns the medicine to its original route of administration, with a different aim from treating high blood pressure. Approval for hair loss and prescribing arrangements depend on local rules. Oral treatment requires clinical assessment and is not an automatic substitute for a scalp lotion.

A randomized trial published in 2024 in 90 men did not demonstrate overall superiority of oral minoxidil studied over topical after 24 weeks. This recent step reminds us of a lesson from all this history: a simpler route of administration does not guarantee a better compromise. The effect on hair, adverse reactions and monitoring constraints must be compared together.