Is it better to use rosemary in shampoo or as a natural oil?

Rosemary (Rosmarinus officinalis), a Mediterranean herb with a long history in natural medicine, has gained significant popularity in hair care. Its presence in shampoos and essential oils is marketed as a solution for strengthening hair and reducing hair loss, making it a star ingredient in hair cosmetics. But how much truth is there to these claims? To understand which of these formulations is more effective, we will analyze both the available scientific evidence and the influence of marketing on its popularity.

Rosemary in hair care: myth or reality?

The promotion of rosemary in hair products is based on its supposed ability to improve blood circulation in the scalp, strengthen hair follicles, and stimulate hair growth. Traditional medicine supports this belief, as rosemary has been used for centuries as a remedy for scalp problems. However, the actual effectiveness of this ingredient depends on several factors, such as its concentration in the product, the frequency of application, and the way it is administered.

Rosemary's antioxidant and anti-inflammatory properties have been studied, and some research suggests that it may help reduce hair loss and improve hair quality. However, not all forms of rosemary provide the same benefits, as the absorption of its active compounds varies significantly depending on whether it is used in a shampoo or an oil.

Rosemary shampoos: marketing or real solution?

Shampoos with rosemary extract are marketed as natural options for improving hair health. Their popularity is largely due to their image as a natural alternative to conventional treatments.

However, the effectiveness of these products has been questioned by experts due to the way they are used. The key to their limited action lies in the short contact time with the scalp, as shampoo is rinsed off after just one or two minutes, reducing the absorption of rosemary's active compounds.

Additionally, many shampoos contain only trace amounts of rosemary extract, suggesting that its inclusion is more about marketing strategies than proven benefits. For an ingredient to have a real impact, it must be applied in adequate concentrations and remain on the scalp long enough to be absorbed.

Strengthening Hair vs. Reducing Hair Loss

In contrast to treatments like minoxidil, whose effectiveness has been supported by multiple clinical studies, rosemary faces limitations in its ability to penetrate hair follicles and exert a significant effect on hair growth stimulation.

While minoxidil works directly on follicles by prolonging the anagen phase of the hair cycle and increasing blood flow in the scalp, rosemary relies on less efficient absorption and less thoroughly studied mechanisms. Additionally, the dosage and application frequency of minoxidil are clearly established in clinical studies, whereas the use of rosemary still lacks a consensus on the ideal concentration for optimal benefits.

According to dermatologists, shampoos primarily serve a cleansing function, and while some ingredients may provide additional benefits, the absorption of active compounds is minimal compared to other formats. Moreover, many commercial shampoos contain only small amounts of rosemary extract, reinforcing the idea that its inclusion in these products is more related to marketing strategies than to scientifically proven benefits.

A study published in Skin Pharmacology and Physiology in 2015 compared the effectiveness of rosemary essential oil with 2% minoxidil in patients with androgenetic alopecia.

A clinical trial was conducted with 100 participants, divided into two groups: one applied 2% minoxidil, while the other used rosemary essential oil diluted in a carrier oil. For six months, participants applied the treatment twice daily. The results showed that both groups experienced similar hair growth, but those who used rosemary reported fewer side effects, such as scalp itching and irritation.

However, it is important to highlight that this study used rosemary essential oil in direct applications, not in shampoos, which indicates that including rosemary in rinse-off products may not provide the same benefits due to the brief contact time with the scalp.

Rosemary oil: a more potent option?

Rosemary essential oil, applied directly to the scalp, has a greater chance of being absorbed and exerting a prolonged effect. It has been suggested that this oil may stimulate hair growth by improving scalp microcirculation and providing antioxidant compounds that protect hair follicles.

A 2013 study published in Phytotherapy Research analyzed the effects of rosemary extract on the inhibition of 5-alpha reductase, the enzyme responsible for converting testosterone into dihydrotestosterone (DHT), a key factor in hair loss. The results indicated that rosemary has an inhibitory effect on this enzyme, which could explain its potential to prevent hair loss. However, this study was conducted on animal models and in vitro cells, so further research in humans is needed to confirm these findings.

Despite its potential, rosemary oil must be used with caution. Essential oils are highly concentrated compounds that can cause irritation if not properly diluted in a carrier oil, such as coconut or jojoba oil. Additionally, its application requires consistency and time for effects to become visible.

User Experiences

Community feedback on the effectiveness of rosemary for hair loss suggests that using it as a natural oil may be more beneficial than incorporating it into shampoo. Many users on the r/tressless forum reported that applying rosemary oil directly to the scalp allowed for better absorption, as it had more time to interact with the hair follicles compared to being briefly rinsed out in shampoo. Several individuals who used diluted rosemary essential oil with a carrier oil, such as coconut or jojoba oil, mentioned seeing improvements in hair thickness and reduced shedding over time. Some even incorporated microneedling into their routine to enhance penetration, believing this helped maximize rosemary oil’s effectiveness.

On the other hand, users who used rosemary-infused shampoo generally found it to be a convenient option but were divided on its results. Some believed it contributed to scalp health and improved circulation, but others felt that since the shampoo was washed out quickly, the rosemary had little time to exert its potential benefits. A few users suggested leaving the shampoo on the scalp for a few minutes before rinsing to increase its effectiveness, while others combined both approaches—using rosemary oil treatments a few times a week while also using a rosemary-infused shampoo for maintenance.

There were also discussions about irritation and sensitivity. A small number of users reported scalp irritation from undiluted rosemary essential oil, emphasizing the importance of proper dilution. In contrast, rosemary shampoo was generally tolerated well, but some noted that commercial formulations might contain additional ingredients that could counteract rosemary's natural benefits.

Overall, the consensus leaned toward using rosemary oil directly on the scalp for better absorption and potency, with rosemary shampoo serving as a supplementary option rather than a primary treatment.

Conclusion: Which to Choose?

While rosemary oil appears to have greater potential effectiveness compared to shampoo, scientific evidence is still inconclusive. The choice between the two depends on individual needs and patience in applying the treatment. Those looking for a quick solution may find rosemary shampoo a convenient option, although its actual effectiveness may be limited. On the other hand, those willing to follow a more consistent and prolonged treatment may achieve better results with rosemary essential oil.

It is important not to be swayed solely by marketing strategies and to pay attention to ingredient concentrations in chosen products. In any case, consulting a dermatologist remains the best option to determine which treatment is most suitable based on hair type and individual conditions.

References

Panahi, Y., Taghizadeh, M., Marzony, E. T., & Sahebkar, A. (2015). "Rosemary oil vs. 2% minoxidil for the treatment of androgenetic alopecia: a randomized comparative trial." Skin Pharmacology and Physiology. Retrieved from https://pubmed.ncbi.nlm.nih.gov/25842469/

Murata, K., Noguchi, K., Kondo, M., & Onishi, J. (2013). "Promotion of hair growth by Rosmarinus officinalis leaf extract." Phytotherapy Research. Retrieved from https://pubmed.ncbi.nlm.nih.gov/24360091/

El País. (December 13, 2024). "The tricks that actually stop hair loss in women." Retrieved from https://elpais.com/salud-y-bienestar/2024-12-13/tengo-la-casa-llena-de-pelos-y-es-horroroso-los-trucos-que-si-frenan-la-caida-capilar-en-mujeres.html

AS. (December 7, 2024). "If you have this 'sacred herb' in the kitchen, you have a treasure: it improves digestion, strengthens hair, and reduces stress." Retrieved from https://as.com/tikitakas/estilo/si-tienes-esta-hierba-sagrada-en-la-cocina-tienes-un-tesoro-mejora-la-digestion-fortalece-el-pelo-y-reduce-el-estres-n/