Diethylamino Hydroxybenzoyl Hexyl Benzoate
Also known as: DHHB, Hexyl 2-[4-(diethylamino)-2-hydroxybenzoyl]benzoate, Diethylamino Hydroxybenzoyl Hexyl Benzoate
Overview
Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) is a synthetic organic compound primarily used as a UVA filter in sunscreen formulations. It is chemically synthesized and not naturally derived. Its main purpose is to protect the skin from harmful ultraviolet A (UVA) radiation, which contributes to skin aging and damage. DHHB is valued for its strong UVA absorption capabilities, excellent photostability, and low phototoxicity, making it a reliable component in broad-spectrum sunscreens. It is often combined with other UV filters, such as avobenzone, to enhance overall UV protection. While several in vitro and formulation studies exist, large-scale clinical trials specifically on DHHB alone are limited. The evidence quality for DHHB's efficacy and safety largely stems from in vitro photostability and phototoxicity studies, as well as safety evaluations conducted by regulatory bodies.
Benefits
DHHB offers significant benefits primarily as an effective UVA filter in sunscreen formulations, contributing to the prevention of UV-induced skin damage, including photoaging. Its demonstrated photostability under UV exposure ensures that its protective function is maintained throughout sun exposure, providing sustained defense against UVA rays. In vitro studies have indicated a low phototoxic potential, suggesting a favorable safety profile for topical application. While some research suggests it might contribute to the photostabilization of other UV filters, the evidence for this specific effect is mixed. DHHB is suitable for general population use in sunscreens, with no specific subgroup data indicating differential benefits. Quantitative UV absorption data confirm its strong UVA filtering capacity, though clinical effect size data from randomized controlled trials (RCTs) are not available. The immediate UV protection upon application and sustained effect due to photostability are key practical benefits.
How it works
Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) functions by absorbing UVA radiation, specifically within the 320-400 nm range. Upon absorbing UV energy, DHHB converts it into less harmful forms, primarily heat, thereby preventing the radiation from penetrating and damaging skin cells. This mechanism protects against UV-induced cellular damage and photoaging. DHHB primarily acts on the skin surface, with safety evaluations indicating minimal percutaneous absorption and low systemic exposure. It does not target specific biochemical pathways or molecular targets within human cells but rather interacts directly with UV photons to neutralize their harmful effects.
Side effects
Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) is generally considered safe for topical use in sunscreens by regulatory bodies, such as the European Scientific Committee on Consumer Products (SCCP). Common side effects are rare, with minimal reports of irritation or sensitization. Uncommon and rare side effects are not well-documented in the existing literature, and no significant adverse effects have been reported in comprehensive safety assessments. There are no known drug interactions associated with DHHB. Contraindications are not specific to DHHB, but general caution applicable to all sunscreen ingredients should be observed. While some in vitro studies have suggested potential progesterone-mimicking effects, the clinical relevance of these findings is currently unclear and requires further investigation. DHHB is generally regarded as safe for all skin types, with no specific data indicating concerns for special populations.
Dosage
The minimum effective dose for Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) is not standardized as it is typically used as part of a multi-filter sunscreen formulation. Sunscreen products commonly contain DHHB at concentrations ranging from 2% to 10% by weight, depending on regulatory limits and desired protection levels. The optimal dosage range is formulation-dependent, as DHHB is usually combined with other UV filters (e.g., UVB filters) and photostabilizers to achieve broad-spectrum coverage. The maximum safe dose is guided by regulatory opinions, with the European SCCP suggesting concentrations up to 10% are safe for cosmetic use. DHHB should be applied topically to the skin prior to sun exposure, and reapplication is recommended according to general sunscreen guidelines (e.g., every two hours, or after swimming/sweating). It is stable in various cosmetic forms, including emulsions, lotions, and creams, and its photostability ensures it does not degrade significantly under UV exposure.
FAQs
Is DHHB photostable?
Yes, studies confirm that Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) is highly photostable under UV exposure, meaning it maintains its protective function without significant degradation.
Does DHHB enhance the photostability of avobenzone?
Evidence suggests that DHHB does not significantly photostabilize avobenzone, although it also does not negatively affect avobenzone's stability. Their interaction occurs via static quenching.
Is DHHB safe for sensitive skin?
In vitro phototoxicity tests show low phototoxic potential for DHHB, indicating it is generally well-tolerated and safe for use on sensitive skin.
How quickly does DHHB work?
DHHB provides immediate UVA protection upon topical application, as it functions by absorbing UV radiation directly on the skin's surface.
Is DHHB absorbed systemically?
Minimal systemic absorption of DHHB has been reported, indicating a low risk of systemic effects and confirming its primary action is localized to the skin surface.
Research Sources
- https://ec.europa.eu/health/ph_risk/committees/04_sccp/docs/sccp_o_130.pdf – This European SCCP Opinion from 2008 provides a safety evaluation of Diethylamino Hydroxybenzoyl Hexyl Benzoate (DHHB) for cosmetic use. Based on toxicological data and in vitro tests, the committee concluded that DHHB is safe for use in cosmetic products at recommended concentrations, observing no genotoxicity or significant toxicity. The assessment primarily relied on in vitro and animal studies.
- https://pubmed.ncbi.nlm.nih.gov/28042100/ – This study by Kawakami et al. (2017) investigated the in vitro photostability and phototoxicity of DHHB, particularly in formulations with avobenzone. It found that DHHB is photostable and does not induce phototoxicity in fibroblast cultures. The research also indicated that DHHB does not significantly increase the photostability of avobenzone, with their interaction occurring via static quenching.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11121922/ – Breakell et al. (2024) published a review article on various UV filters, including DHHB. The review concluded that DHHB shows no significant adverse effects, though it noted some in vitro reports of progesterone-mimicking effects with unclear clinical relevance. The article emphasizes DHHB's role in modern sunscreens for effective UV protection and prevention of skin aging.