Bath oils are scented oils added to bathwater. These oils, which are largely plant-based, have a wide range of benefits, including antibacterial and antioxidant properties [1], antifungal [2], antiviral [3], massage therapy, psychotherapy [4], sleep therapy [5], and pain management [6].
The active ingredients in bath oils are derived from flowers, leaves, stalks, fruits, roots, and resins. These ingredients are very concentrated [7].
Plant oils can be fixed or essential (carrier). The leaves, roots, bark, and other aromatic parts of a plant or botanical are used to distill essential oils. Compounds found in essential plant oils include alcohol, aldehydes, esters, ethers, ketones, oxides, phenols, and terpenes, as well as saturated and unsaturated hydrocarbons [8]. They resemble clear liquids and emit a pleasant aroma.
Because of their concentrated strength, these oils work on pressure points to elicit a relieving response. Essential oils are stored in different parts of plants, such as glandular hairs, specialized cells, spaces between cells, pockets, and reservoirs. By evaporating oils, which give off a warming aura, essences protect plants from microbial attacks and temperature changes [9].
Fixed oils are extracted from a plant’s fatty parts, such as seeds, nuts, or kernels. These fixed oils get their name because they do not evaporate at normal temperatures. Triglycerides, free fatty acids (FFAs), tocopherols, sterols, stanols, phospholipids, waxes, squalene, and phenolic compounds are some of the fixed plant oil constituents [10].
When administered topically, these substances affect the skin’s physiology, including its proliferation, inflammatory condition, antioxidant response, and skin barrier. Essential oils are not used directly in baths or on the skin due to their high volatility and strong concentration (potential for irritating effects). Instead, they are rather diluted with carrier oils if applied at all [11], [12].
These oils may be synthetic or natural. Natural oils are preferable since, compared to synthetic oils, they have a less irritating impact and cause little to no itching. On the other hand, synthetic fragrances fall short of natural or vital energy and are best avoided for skincare purposes [13].
Plant oils have been applied to the skin for cosmetic and therapeutic purposes for a long time and research has shown that they have many favorable physiological effects. For instance, applying plant oils to the skin may have an occlusive effect that serves as a protective barrier, allowing the skin to retain moisture and reduce transepidermal water loss (TEWL) levels.
Previous studies on plant oils have shown that when applied topically, almond, jojoba, soybean, and avocado oils typically remain on the skin’s surface without deeply penetrating into the skin’s outermost layers [14]. Glycerol helps hydrate the skin’s outer layer even when triglycerides cannot penetrate deeper into the skin. Free fatty acids (FFAs), particularly monounsaturated FFAs like oleic acid, can damage the epidermal barrier and increase the permeability of other plant oil-based substances [15].
Another component of plant oils called phospholipids mostly fuses with the skin’s outer lipid layer, potentially increasing chemical permeability [16].
Other substances, such as phenolic compounds and tocopherols, have an antioxidant impact and may control physiological processes like inflammation and the homeostasis of the skin barrier [17].
Additionally, when plant oil’s triglyceride and FFA content are applied to the skin, different physiological reactions occur as it relates to their TEWL and irritating reactivity [18].
For instance, SFA linoleic acid directly contributes to preserving the skin’s water permeability barrier [19]. In contrast, oleic acid, a UFA, harms the skin barrier function. Under continued topical administration, oleic acid disrupts the barrier and promotes dermatitis [20].
According to research, monounsaturated oleic acid oils, among which olive oil has the highest level of epidermal penetrance, improve skin permeability [21]. Linoleic acid has been demonstrated to marginally promote wound healing, while oleic acid has been linked to delayed wound closure [22].
It has been shown repeatedly that bath oils can help treat dry skin. Some evidence suggests that certain properties found in bath oils can help treat dry skin.
The bath oil is best absorbed within the first 20 minutes. Both the amount of oil in the water and the temperature of the water seem to affect how well the oil is absorbed [23]. There was a big difference between people with dermatoses that cause dry skin and healthy volunteers in how much oil they could absorb. After using bath oils, the skin took in more water (12 to 27 percent more).
When an oil bath is taken, the lipids on the surface of your skin will increase for at least three hours, just like they would after you put on a regular moisturizer. This increase in the lipids on the skin’s surface could have long-lasting effects, like making the skin less dry and flaky [24].
Due to the properties of the plant extracts they contain, some bath oils are better at relieving dry skin than others.
The olives used to produce olive oil are harvested from the Olea europaea tree. Oleic acid is its primary component. There are also small amounts of linoleic acid and palmitic acid in their fatty acids, but they are much less common. Not only does it have strong antioxidant and anti-inflammatory effects, but it also has some moisturizing effects that can be used to treat dry skin. However, research shows that when olive oil is put on the skin, it damages the integrity of the skin and the way the skin barrier works. There is evidence of increasing TEWL following its use in adults [25]. Caution should be exercised, especially for individuals with a history of atopic dermatitis (AD).
The kernel or meat of a ripe coconut, which grows on a palm tree, is crushed to make coconut oil, Cocos nucifera. Studies have shown that coconut oil is just as good and safe as mineral oil for moisturizing dry skin [26].
The study found that putting virgin coconut oil on children with mild to severe AD made the disease less severe, improved the skin’s barrier function, and lowered the disease severity [27].
Soybean oil comes from the Glycine max plant. Most scientific research has been done on extracts from soybean oil. Researchers have found that putting an extract of soybean oil on the skin of the forearms can reduce TEWL. Soy phytosterols have been shown to help heal the skin barrier, which may explain why they have this property. There is evidence that this makes the skin much less dry.
There is evidence that peanut oil helps keep the skin moist without significantly increasing the amount of water lost through the skin (TEWL) [14]. Peanut oil can help soothe and calm minor skin irritations like redness and itching caused by dry skin [28].
The plant that is used to make sesame oil is called Sesamum indicum. The oil’s mix of linoleic acid and fatty acids makes it one of the best natural moisturizers for dry skin. Using it helps create a thin barrier on the skin that helps retain moisture [14].
Avocado oil is made from the fruit of the Persea Americana tree. Because the oil comes from the pulp of the fruit, it has a lot of oleic acid (31.8 to 69.6 percent), linoleic acid (6.1 to 22.9 percent), and linolenic acid (0.4 to 4.0 percent). It also contains minerals, sitosterol, and vitamins A, C, D, and E. Using avocado oil is a great way to heal dry, cracked, or chapped skin [14].
The jojoba plant, called Simmondsia Chinensis, can grow in dry places and live for a long time. Jojoba oil is very stable and doesn’t oxidize or break down easily. The high concentration of wax ester in jojoba oil makes it a good choice for repairing dry skin with a compromised skin barrier caused by acne, eczema, seborrheic dermatitis, and atopic skin dermatitis (AD) [29].
Derived from the almond tree’s seed, called Oleum Amygdalus. Almond oil has been found to help with dry skin by helping to moisturize it. It has also been used to improve the tone and texture of the skin as a whole.
Evidence on the use of bath oils for eczema is conflicting. While it has been demonstrated that jojoba oil [29], rosehip oil [30], and oat oil [31] have alleviating effects when applied to the skin, other studies have found no evidence of clinical benefits from using bath oil additives in the treatment of eczema in children [32], [33].
However, anecdotal evidence has given weight to the use of certain bath oil additives like tea tree oil, peppermint oil, lavender oil, and chamomile oil. This may underlie the fact that these bath oils provide a moisturizing, anti-inflammatory, and antioxidant effect on the skin, inhibiting certain mechanisms through which dermatitis manifests. The use of non-scented bath oils is preferred for this as they may have less of an irritating effect on the skin.
Pouring a small amount of natural oils into bath water may offer a soothing feeling and relieve itching caused by eczema.
Bath oils provide a myriad of benefits. They aid skin rejuvenation, and moisturization, and provide an overall protective effect. While this is so, care must also be taken not to use bath oils that may possibly worsen an already existing skin condition or cause an irritant effect.
Seeking professional advice may also come in handy, and additional skincare routines may also need to be incorporated to achieve healthy skin.
References:
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500 Formulas for Aromatherapy: Mixing Essential Oils for Every Use
https://www.cabdirect.org/cabdirect/abstract/20013071731
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8001530/
https://link.springer.com/chapter/10.1007/978-94-017-2558-3_2
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