Hair is one of the few physical features of the body whose length, shape and color we can determine, and which distinguishes the person from other individuals. Hair, which constitutes an important part of the body image, can also reflect the personality structure.
A healthy hair is defined as vibrant, colorful, shiny, durable, sufficient volume and smooth1. Throughout history, people have used various care methods as well as treatments defined as complementary and alternative medicine (CAM) in order to have healthy hair.
Although interest in CAM practices varies according to age, gender, geographical region and ethnicity, it is increasing every year2. CAM is classified in five main groups, one of which is biologically based therapies that include natural products. Various cultures such as Ayurveda in India, Kampo in Japan and traditional Chinese medicine widely use natural products in the treatment and prevention of diseases.
It is known by many dermatologists that many patients try complementary or alternative therapies other than such methods because many chronic skin diseases, which are emotionally exhausting for the patient, cannot be treated with conventional methods.
In this review, natural products that have been used for thousands of years by trial and error for hair care and diseases will be examined. While there are scientific studies on some of these products, there are no studies on many of them. Especially the lack of clinical trials naturally causes reservations in their recommendation by scientists.
Natural Products
Garlic (Allium sativum L)
In a 2007 study conducted in Iran, half of 40 alopecia areata patients were treated with topical corticosteroids (betamethasone valerate) and garlic (one hour off), while the other half were treated with topical corticosteroids (betamethasone valerate) and placebo. As a result of the treatment, statistically significant improvement was found in the garlic group compared to the control group. There were no complications in the patients. The researchers stated that garlic may increase the effect of topical steroid in patients with alopecia areata.
Onion (allium cepa L)
In a study published in 2002, 38 patients diagnosed with alopecia areata were treated with onion juice and tap water (onion juice n=23, tap water n=15) twice daily for two months. After four weeks, 73.9% of the patients had new hair growth and after 8 weeks, 86.9% had new hair growth (13% after 2 months with tap water). The mechanism of the effectiveness of onion juice in the treatment of alopecia areata is not fully known. However, it is thought that it may be due to irritation or an immunologic reaction due to the sulfur and phenol compounds in its content and is recommended as an effective topical agent in the treatment of alopecia areata in the same study.
Capsaicin
Capsaicin is one of the most bitter substances found in cayenne pepper. It relieves pain by inhibiting neurotransmitter stimulation in nerve endings. Burning and stinging sensation are among the most common side effects. In a study conducted in alopecia patients in Turkey, capsaicin was used topically for 3 weeks, it was reported to be effective in treatment and no relapse was seen in the 3-month follow-up period. It is thought that the mechanism of action of capsaicin in alopecia may be related to increased synthesis of insulin-like growth factor or increased blood flow in the scalp due to irritation caused by skin contact.
Saw palmetto
Saw palmetto is a commonly used herb in the treatment of androgenetic alopecia. However, its mechanism of action is not fully known. It is thought to block the conversion of testosterone hormone to dihydrotestosterone hormone by inhibiting the five alpha reductase enzyme. Like other herbal treatments, some side effects can be seen in the use of saw palmetto. Constipation, diarrhea, nausea, vomiting, erectile dysfunction and bad breath have been reported. There is insufficient information on its use in pregnant women, breastfeeding, children, kidney and liver diseases.
Gooseberry (Indian gooseberry)
It is used as an effective treatment for the prevention of hair graying. However, it also provides hair growth and darkening of hair color. One tablespoon is applied as a scalp massage every evening. It is also used for its anti-aging effects8. Sanctuary tree (ginkgo biloba)
Ginkgo biloba
It is very popular among herbal therapies and is thought to regulate blood flow and therefore cure many health problems. A significant number of herbalists believe that by increasing blood flow to the brain and skin in hair loss, more nutrients can be delivered to the hair follicle and thus the hair will grow again. It is used in the treatment of alopecia due to its vasodilator and anti-edema effects.
Green tea
Green tea, a widely used herb all over the world, has potential antioxidant and anti-cancer effects due to epigallocatechin-3-gallate (EGCG)10. Recently, it has been reported that EGCG can be used to prevent androgenetic alopecia by inhibition of 5a-reductase11. In addition, green tea also provides dandruff loss without dehydration of the skin.
Çin melekotu
Dong Quai is used in Chinese herbal medicine to stop hair loss and restore hair growth. Dong Quai contains phytoestrogens that prevent the formation of dihydrotestosterone.
Oriental thuja
Another of the plants traditionally used in the treatment of hair loss in Asia is Oriental marigold. In a 2013 study in which the hair cycle was evaluated after topical application to telogenic guinea pigs with shaved back, it was observed that Eastern mazu induced hair growth by inducing the anagen phase in telogenic guinea pigs. It was determined histomorphometrically that it affected the early anagen phase and prolonged mature anagen phase, especially compared to the control group treated with 1% minoxidil. In addition, the number and volume of hairs increased. These results support that Eastern mazu can be used as a potential hair growth agent by inducing anagen phase in resting hair follicles.
Henna
Lawsonia inermis is a plant in the Lawsonia inermis family that contains Lawsone, a red-orange colored molecule that is made into henna powder. It has been used to dye hair, skin and nails for more than four thousand years. Henna, which has a natural affinity for proteins in the hair, dyes the hair shaft but has no effect on hair growth. Henna also has the properties of a good conditioner. It can repair defects in the hair shaft by filling them in and protects against loss of shine and breakage. So-called “neutral” or “black” henna products do not actually contain henna, but are derived from other plants. Natural henna only gives a strong red-brown color.
False chamomile
Eclipta Alba is an Ayurvedic plant used in hair growth. It is included in hair lotions due to its black color and hair growth inducing effect. In a study on shaved albino guinea pigs, it was reported that hair growth was more abundant and faster in those treated with the extract than in the control group using 2% topical minoxidil solution. This plant is also called “Kesharaja” in Sanskrit, which means “king of hair revitalizing plants”.
Pansy flower
Pansies (V. tricolor hybrids) is one of the plants recommended for the treatment of seborrheic dermatitis in newborns. 1-2 teaspoons of pansy flowers are mixed in a glass of water and applied as a wet dressing. This application also has softening and moisturizing properties.
Rooster crest flower (amaranth)
Rooster ibis flower is another herb used in hair care and diseases. Applying the leaf juice of the fresh plant to the scalp helps the hair regain its color and prevents premature graying. It also induces hair growth and makes it soft and smooth.
Indian spices (curry leaves)
It has nothing to do with curry, which is a spice mix. Consumption of Indian spice helps prevent premature hair graying. The use of its leaves helps to give vitality to the hair follicles. The new hair follicles are of normal color and grow healthier than the old ones. The leaves can also be used as a spice or in buttermilk. It supports hair growth and color gain. These effects are believed to be mediated by its main ingredients: carbohydrate, fiber, calcium, phosphorus, iron, magnesium, copper, minerals, nicotinic acid, C, A, B, E, antioxidants, plant sterols, amino acids and flavonoids.
Isırgan otu (stinging ısırgan, urtica diocia)
Nettle inhibits the conversion of testosterone to dihydrotestosterone DHT, which is the main cause of hair loss in men. It can be taken as a capsule or in combination with the more effective saw palmetto. In one study, it was stated that it may play a strengthening role in hair growth by increasing the proliferation of dermal papilla cells when applied in combination with platelet-rich plasma (PRP).
Biberiye (rosmarinus officinalis linn.)
Topical application of rosemary extract promotes hair growth in guinea pigs whose hair growth was stopped by testosterone. It was also found to have an effect on the shaved back areas of guinea pigs.
Sage (salvia officinalis)
Sage is known as one of the best methods that can be used to darken and tone the hair. The infusion solution of fresh leaves is used topically. It is also applied to the scalp to darken the hair. It is also said to be effective in cases of alopecia. Sage is a good hair tonic and its application to the scalp gives shine and vitality to the hair. For this purpose, some sage and rosemary are thrown into cold water and boiled for 3 minutes and after 3 minutes of infusion, it is used by massaging the scalp.
Aloe vera
Aloe vera is used in the treatment of hair loss. It has been reported to positively affect hair growth when used frequently23. There are also studies reporting that the application of aloe vera lotion to the skin in patients with seborrheic dermatitis treats seborrheic dermatitis23,24. Aloe vera contains many vitamins, minerals, enzymes, amino acids, natural sugars and some anti-inflammatory and antimicrobial agents. This combination may play a role in its healing effects.
Vegetable Oils
Jojoba oil
Jojoba oil regulates the activity of sebaceous glands and helps oily hair to be free of excess sebum and to look vibrant and healthy. It is also a good moisturizer for dry hair. Jojoba oil is a natural product and not very intense. It is especially used for hair prone to breakage, split ends, dry and damaged hair. Since its molecule is small enough, it can easily penetrate the hair cuticle and thus has a moisturizing effect. Therefore, products containing this oil give the hair a healthy shine and order.
Coconut oil
Coconut oil is extracted from the fruit or seed of the coconut tree. It has a melting point of 24 -25 °C and can be easily obtained in liquid and solid form. Coconut oil helps damaged hair to regrow. It provides essential proteins for hair and softens the scalp and hair. Coconut oil is an excellent moisturizer. In a study using coconut oil, it was observed that its application to the scalp prevented protein loss in the hair for 14 hours and did not have any side effects27. It has also been reported to be safe for use in cosmetics.
Argan oil
It contains high levels of oleic and linoleic acids and is rich in phenols. Its clinical effects in hair care are difficult to demonstrate scientifically, but sebum-regulating effects have been reported. It is not a cheap oil, but its effects are reported to be quite satisfactory and its use has recently increased considerably. Many famous cosmetic companies have patent applications for products containing argan oil29. The problems of dry, dull and frizzy hair have been reported to be considerably reduced with the use of this hair oil. It gives the hair its natural clear color and protects it from the harmful effects of UV and other environmental factors.
Almond Oil
Almonds contain 44% fat. Of this, 62% is monosaturated oleic acid (omega-9 fatty acid), 29% is linoleic acid (polyunsaturated omega-6 essential fatty acid) and 9% is saturated fatty acid31. Almond oil, which has been recommended for centuries for hair growth among the people, is frequently used by those who have hair loss and brittle hair problems and those with dandruff problems.
Olive oil
Only the so-called “pure olive oil” comes from cold-pressed olives and is chemical-free. Pure olive oil is green in color and is of better quality than the yellow-green colored one. Olive oil applied regularly to the scalp is thought to prevent hair loss by preventing DHT formation, repair scalp damage, strengthen the hair cuticle, remove roughness and provide a shinier appearance.
Castor oil
It is pale yellow in color, a dense oil and has no taste or smell. It is rich in ricinoleic acid and is used to treat fungal infections of the skin. It nourishes the hair and prevents dryness by moisturizing the scalp. Although it is claimed to thicken hair, there is no scientific data available.
Avocado oil
It is rich in mono saturated fats and vitamin E32. Avocado oil is claimed to promote hair growth and moisturize dry, damaged hair, making it look more vibrant and shiny. Soybean oil MEL-A (mannosylerythritol), derived from soybean oil, has been shown to stimulate papilla cells, potentially promoting new hair growth.
Such products, which have been used by the public for centuries, are actually recommended to the public by herbalists or similar persons who have no scientific knowledge in this field. The purpose of this review is to provide preliminary information for scientific investigation of whether such products, which have been used for many years, have the claimed effects. There may be more products than the ones reviewed here.
It is a long process to standardize the products that are considered to be useful to make them into medicines. The dermatology-related issues of natural products should be examined within the positive science of dermatology, and serious evidence-based studies and research should be conducted to ensure that patients are informed about such products, some of which have proven to have serious side effects, and that they are first prevented from being harmed and then benefit from evidence-based effects34-36. Otherwise, in the hands of unauthorized and uninformed people, such treatment and care methods may increasingly harm our patients, continue to interact with the conventional treatment and care methods they use, and may be completely out of scientific control.