O óleo de alecrim realmente ajuda o cabelo a crescer?

What is rosemary oil?

Rosemary oil comes from the rosemary plant, a fragrant herb that grows as an evergreen shrub. It’s known as a food seasoning, but is used in herbal medicines and cosmetics too.

Using rosemary oil as a hair product has fast-become a hit on social media, with many claiming it has helped treat hair loss and promote growth. There is some evidence to support this.

One study found rosemary oil to be as effective at encouraging hair regrowth as minoxidil, a medicine to treat male pattern hair loss (androgenic alopecia)¹ - however this study was small and it is difficult to make any conclusions from it.

Calvície masculina is a form of hair loss that happens when a by-product of testosterone called dihydrotestosterone attacks the hair follicles. It’s thought that rosemary oil helps to prevent this hormone from attacking the follicles, which allows the hair to grow. The rosemary oil also reduced scalp itchiness too.

Dr Sharon Wong, Consultant Dermatologist and Hair Specialist, the MW Clinic, London says: "Rosemary oil is being lauded as a miracle hair growth product, with very little data to back this claim up.

"One study looked at comparing the effects of rosemary oil versus common medical treatment on male pattern baldness," she says. "However there are several flaws with the study that raise the question of its reliability. Furthermore, there is currently no data that can confirm if rosemary oil works on any other forms of hair loss."

Rosemary oil is a natural remedy, but that does not mean it is safe for everyone. As with any product, some people may be allergic to rosemary oil. Those with sensitive skin may get irritation, rashes or other skin issues when using it.

You should not apply rosemary oil directly to your scalp. Always dilute it with a carrier oil - such as coconut or jojoba oil. For example, mix a few drops of rosemary essential oil with around a tablespoon of your chosen carrier oil.

Before applying, always do a test patch beforehand to check for any allergic reactions, and wash your hair thoroughly afterwards with shampoo.

The treatments available for hair loss depend on the causes of the problem. Some types of hair loss may be genetic - such as male and female pattern baldness. Other causes include illness, stress, cancer treatment, weight loss or iron deficiency. Some treatments may not be available on the NHS.

Minoxidil

Minoxidil and finasteride are the main treatments for male pattern baldness. Minoxidil can also be used to treat female pattern baldness, but women should not use finasteride.

Esteroides

Steroids in the form of creams or injections may help control alopecia areata by reducing the inflammation and suppressing the immune system. This stops the body from attacking the hair follicles.

Imunoterapia

Immunotherapy - the topical application of a chemical to bald areas of the scalp - may help those with alopecia areata³. It aims to alter the immune system so that it stops attacking the hair.

Low-level light therapy

Low-level light therapy, otherwise known as laser therapy, involves using different wavelengths of light to stimulate the hair follicles and promote hair growth. It may help hair loss caused by male and female pattern baldness, alopecia areata and queda de cabelo caused by quimioterapia⁴.

Eat healthily

Eating a varied diet which is full of vitamins, minerals and other nutrients is important for healthy skin and hair. A lack of vitamina D, folate and zinc may contribute to alopecia areata⁵. Vitamin D can be found in supplements, sunlight, oily fish and eggs - but it is often added to cereals, plant milks and fat spreads.

Green, leafy veg like spinach, broccoli and sprouts contain folate, while zinc can be found in meat, beans, nuts, wholegrains such as wholemeal bread, cereals and dairy products. You can find iron in red meat and green vegetables like broccoli.

Hair volumising products

While these products won't make hair regrow or grow back, it can enhance the look of the hair you have and make it appear thicker. Being gentle with your hair - and avoiding using heat from hairdryers or straighteners on it - will also keep it looking healthier. Avoid brushing it when it's wet or vigorously towel drying it, as this can lead to the strands breaking. Also, try not to style your hair in a tight ponytail or bun, as this can pull the hair.

Get help for stress

Psychological stress can lead to hair loss. If you're struggling with stress, ansiedade, low mood or any other saúde mental issue, it's important to speak to your doctor - they can advise on the right treatment and support.

1. Panahi et al: Rosemary oil vs minoxidil 2% for the treatment of androgenetic alopecia: a randomised comparative trial.

2. De Oliveira: Biological activities of Rosmarinus officinalis L. (rosemary) extract as analysed in microorganisms and cells.

3. Singh et al: Topical immunotherapy in alopecia areata.

4. Pillai et al: Role of low-level light therapy (LLLT) in Androgenetic Alopecia.

5. Thompson et al: The role of micronutrients in alopecia areata: A review.