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Photoprotective agents
Medical expert of the article
Last reviewed: 08.07.2025
Photoprotection is a broad concept that implies a set of measures aimed at reducing the impact of UV radiation. First of all, the use of exogenous and endogenous photoprotectors is indicated.
Exogenous photoprotectors, or sunscreens, are available in the form of emulsion (cream), spray, and oil. Modern requirements for an “ideal” photoprotective agent include good tolerability, non-toxicity, effective protection from UVA and UVB simultaneously, high sun protection factor (at least 40), photostability, water resistance, and ease of use. Many researchers emphasize the importance of using chemical filters over screens.
Modern sunscreens are divided into those with predominant protection from UVB, from UVA and combined (UVA+UVB).
Products with preferential protection against VVB were the first at the disposal of dermatologists. They began to be produced industrially in the world since the end of the 30s of the last century. At present, this group includes PABA (PABA, or PABA) and its derivatives, esters of salicylic acid (salicylates), esters of cinnamic acid (cinnamates) and other compounds. Salicylates include the long-known compound phenyl salicylate (salol), as well as trimethyl cyclohexyl salicylate (homosalate, Neo Heliopan HMS, etc.), octyl salicylate (Neo Heliopan OS), methyl anthranilate (Neo Heliopan MA), 4-methylbenzylidene camphor (Emolex 6300, Uvinul MBC 95, etc.), benzaliden camphor sulfonic acid (Mexoryl SL), octyl triazone (Uvimtl E-150). Cinnamates are represented by ethylhexyl methoxycinnamate - EMC (Parsol MCX, Neo Heliopan AV, Escalol 557, etc.), octocrylene (Neo Heliopan 303, Parsol 5000, etc.), isoamyl-n-methoxycinnamate (Neo Heliopan E-1000).
Products with predominant protection from UVA are represented by butyl methoxydibenzoylmethane (avobenzone, or Parsol 1789. Eusolex 9020, Uvinul BMBM). Among them, such recently synthesized agents as terephthalidene dicamphor sulfonic acid - TDSA (Mexoryl SX, etc.) deserve special attention.
Combination preparations mainly include various benzophenones (hydroxybenzone, dioxybenzone, benzophenone, etc.). Recently, new highly effective compounds with combined protection have appeared on the market: drometrizole trisiloxane (DTS) - Mexoryl XL, as well as bis-ethyl-hexyloxyphenolmethoxyphenyltriazine (BF.MT) - Tinosorb S and methylene-bis-benzotriazolyl tetramethylbutylphenol (MBBT) - Tinosorb M.
To assess the effectiveness of protection from UVB, an indicator such as sun protection factor (SPF) is used. The SPF assessment method is standardized and is carried out in accordance with the strictly established rules of the international organization COLIPA, EC (The Buropean Cosmetic Toiletry and Perfumery Association). It is expressed in the form of simple numbers and demonstrates the degree of protection from the corresponding rays. SPF is the ratio of the minimum erythemal dose (ED, J/cm2), which arose during irradiation of the skin with a photoprotector, to the minimum erythemal dose without a photoprotector:
SPF = min ED with photoprotector / min ED without photoprotector
According to the new classification of photoprotective products approved by COLIPA, there are products with ultra-protection (SPF> 50, designated 50+), with increased protection (SPF = 30-50) and with high protection (SPF = 20-30).
At the same time, studies in recent years have shown that sunscreens with a high SPF do not provide an equivalent degree of protection from UVA rays. The importance of using products with high protection factors from UVA rays has already been proven. Since UVA rays are not erythemogenic, the degree of protection from UVA cannot be determined by the sun protection factor. Currently, several indicators are used, based on the severity of immediate and delayed skin pigmentation that occurs in response to the action of these rays on skin protected and unprotected by a photoprotector (1PD - immediate pigment darkening, PPD - persistent pigment darkening).
Modern photoprotectors are divided by the mechanism of action into chemical (filters) and mineral (screens). Chemical filters provide photochemical protection by absorbing certain types of energy, and screens reflect it, partially adsorbing (especially, B radiation). In this regard, chemical filters are currently the most preferred. This group includes para-aminobenzoic acid, salicylates, cinnamates, benzophenones, avobenzone (Parsol 1789), DTS (Mexoryl XL) and other compounds. Screens include titanium dioxide, zinc oxide, red iron oxide and other compounds.
Sunscreens are included in day creams for the face and body. There are also sunscreens for the lips and eye contour. In recent years, sunscreens have become widely added to various cosmetic products for hair care. As a rule, they are intended for hair care during a seaside vacation and are designed to protect hair from both ultraviolet exposure and contact with salt water. They are added in the form of gel, aerosol, foam, and hair cream.
It is also worth remembering that wearing a hat or panama on sunny days provides hair and scalp with protection similar to a sun protection factor (SPF) of 5-7.
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