Skingredient: Retinyl Palmitate

What is Retinyl Palmitate

Retinyl palmitate is a form of vitamin A. It is a stabilized and ester form of retinol. Retinyl palmitate is one of the most commonly used vitamin-based ingredients in sunscreens.^[1]

 

What Does Retinyl Palmitate Do?

When retinyl palmitate is applied to the skin, it can penetrate into the upper layers of the skin and then undergoes a series of reactions so that it is eventually converted into the active form, retinoic acid (Figure 1). In the first step of this pathway, retinyl palmitate is converted into retinol by retinyl palmitate hydrolase, an enzyme that is normally found in the skin. Eventually, both retinyl palmitate and retinol are converted into the active retinoic acid (tretinoin) to perform its function in the skin.

Figure 1: Retinoid chemical synthesis pathways 

Retinyl palmitate requires one extra step in the conversion pathway before it becomes tretinoin, (Figure 1) prior to exerting effects similar to retinol. Retinyl palmitate can deliver similar benefits to the skin as tretinoin, but is in a more gentle way with less irritation. Retinyl palmitate exerts its effects similar to other retinoids by improving the appearance of fine lines and the skin tone on the face.^[2] However, higher doses of retinyl palmitate are needed, probably due to the extra chemical conversions that are needed before it is in an active form (Figure 1).^[2]

Since retinyl palmitate is more stable than retinol, it is more commonly used in over the counter care products.^[3] Here is a comparison of how retinyl palmitate and retinol compare against each other since they are commonly used in over the counter products.

Table – Characteristics of retinyl palmitate, retinol, and tretinoin

Effect	Retinyl Palmitate	Retinol	Tretinoin (All-trans-retinoic acid)
Appearance of wrinkles and dark pigmentation	+	++	+++
	Improves wrinkles and pigmentation, but need higher concentrations than retinol[2]	Improves wrinkles and pigmentation, but need lower concentrations than retinyl palmitate[2]	Improves wrinkles and pigmentation and more potent than retinol[14]
Skin penetration	++	+++	++
	Slower than retinol[4]	Fastest at penetration [4]	Slower than retinol[4,15]
Direct skin irritation	+	++	+++
	Less irritating than retinol[4]	Less irritating than tretinoin[4]	More irritating than retinol[4,16]
Stability in cream formulation	+++	++	++
	More stable than retinol	Less stable than retinyl palmitate	Less stable than retinyl palmitate
Stability against UV and fluorescent light induced breakdown	++	+++	+
	Less stable than retinol to both fluorescent and UV light[5,6]	More stable than retinyl palmitate to both fluorescent and UV light[5,6]	Less stable than retinyl palmitate to sunlight and non-micronized form breaks down within hours[17,18]

 

What Are the Potential Side Effects of Retinyl Palmitate?

Retinyl palmitate can potentially cause similar side effects that commonly occur with retinoids such as redness, irritation, and scaling. However, one study in humans showed that retinyl palmitate did not cause redness normally associated with tretinoin and did not cause the skin’s superficial layer to thicken as much as when it was exposed to retinol.^[4] This study implies that retinyl palmitate may be less irritating than tretinoin. 

 

Sunscreen Controversy

Retinyl palmitate has been the subject of controversy as it is widely used in sunscreens.^[1] The central issue is whether or not retinyl palmitate can accelerate the formation of skin cancers.

Here is what is known about retinyl palmitate: 

• Although retinyl palmitate is considered a more stabilized form of retinol, this is only in topical formulations. However, retinyl palmitate breaks down more quickly that retinol when exposed to ultraviolet light and visible light.^[5,6]
• When retinyl palmitate breaks down after exposure to ultraviolet light (both ultraviolet A and ultraviolet B), it leads to the formation of free radicals including superoxides and singlet oxygen.^[7-9] Free radicals are very reactive molecules that can cause damage to surrounding cells and tissues.
• In mice, topical application of retinyl palmitate in combination with ultraviolet light exposure led to skin cancers forming more quickly and in greater numbers, ^[10] although these results have been debated.^[11,12] 

Theoretically, it is concerning that the breakdown of retinyl palmitate in the presence of ultraviolet light can generate reactive oxygen species, which is associated with faster growth of squamous cell carcinoma skin cancers in mice. However, at this time there is no evidence showing that retinyl palmitate can promote skin cancers in humans.

 

Using Retinyl Palmitate During the Day

Regardless of the skin cancer and sunscreen controversy, retinoids are not used during the day because they break down after ultraviolet light exposure, increase sun sensitivity, and can be irritating when exposed to daylight and sunlight. Retinyl palmitate is no exception as studies have shown that it is efficiently metabolized into retinol and tretinoin.^[4,13] Therefore, retinyl palmitate is likely to increase the risk of sun sensitivity and irritation. It will also break down if used during the day. As such, it may be smarter to use retinyl palmitate containing products in the evening (similar to how other retinoids are used) instead of daytime. For those that would like to avoid retinyl palmitate altogether, there are many options for skin care products and sunscreens without retinyl palmitate.

 

Please consult a qualified healthcare provider/physician to discuss how the information discussed here may be appropriate for your skin care.