Astaxanthin: Which other active ingredients should it be combined with?

Derived from the fermentation of wheat, hyaluronic acid is known for its highly moisturising properties. Indeed, depending on its molecular weight, it can retain up to 1,000 times its weight in water. However, the production of hyaluronic acid in the body tends to decrease with age, which contributes to the appearance of the first signs of ageing. The application of hyaluronic acid helps to reduce dehydration fine lines and make the skin more supple. Combining hyaluronic acid with astaxanthin is an interesting approach: while hyaluronic acid retains water in the horny layer, astaxanthin indirectly supports the cohesion of the skin barrier. Indeed, by limiting lipid peroxidation and stabilising cell membranes, astaxanthin helps to slow down transepidermal water loss.

The combination of astaxanthin and karanja oil provides the skin with enhanced protection against UV rays. Karanja oil, extracted from the seeds of Pongamia glabra, is rich in pongamol and karanjin, two molecules with natural photoprotective properties. These compounds are capable of absorbing a portion of UVA and UVB radiation, while exerting an antioxidant activity complementary to that of astaxanthin. A study has indeed shown that karanja oil has an SPF ranging from 15 to 30 depending on the experiments and a UVA-PF of about 9.5. The synergy between astaxanthin and karanja oil therefore seems particularly relevant for limiting the effects of photoaging, a phenomenon describing the premature ageing of the skin caused by repeated exposure to sunlight or artificial sources of UV.

However, combining astaxanthin and karanja oil is not sufficient to protect the skin from the sun. This is merely beneficial to supplement the protection provided by a sunscreen.

Combining astaxanthin with other carotenoids, such as beta-carotene, lutein or zeaxanthin, creates a wider antioxidant defence network, due to the diversity of their tissue locations, their chemical structures, and their respective affinities for different forms of free radicals. Unlike other water-soluble antioxidants, carotenoids embed themselves in cell membranes, but their exact position varies. Lutein and zeaxanthin, for example, are primarily located in the centre of the lipid bilayer, while astaxanthin adopts a transmembrane orientation, interacting with both the inner and outer layers. This three-dimensional arrangement allows for a more uniform antioxidant coverage within cell membranes.

A clinical study examined the effects of a nanoemulsion containing astaxanthin and zeaxanthin. For context, a nanoemulsion is a specific type of emulsion characterised by the fineness of its droplets, with diameters of a few tens or hundreds of nanometres. This type of formulation promotes the spread of the product on the skin and its sensory properties. The study was conducted with fifteen women with an average age of 42 who applied the nanoemulsion twice a day for four weeks. After 28 days, a reduction in wrinkles of 80% to 93% was measured. This decrease was observed in both younger and older subjects, demonstrating the effectiveness of the astaxanthin/zeaxanthin combination for all age groups.

Pairing astaxanthin with vitamin C broadens the antioxidant scope of astaxanthin. Indeed, the vitamin C is a potent antioxidant capable of neutralising various types of free radicals, including superoxide anion and hydroxyl radicals. Additionally, it promotes the regeneration of other antioxidants, such as vitamin E. It's also worth noting that vitamin C acts as an enzymatic cofactor in the hydroxylation of proline and lysine, a crucial step in collagen synthesis. To maintain skin firmness to the maximum extent, it may be beneficial to combine vitamin C with astaxanthin, which can reduce the expression of matrix metalloproteinases, enzymes that degrade collagen.

Furthermore, a study conducted on human retinal cells (ARPE-19) exposed to sources of oxidative stress, such as hydrogen peroxide (H₂O₂) or UVB rays, demonstrated that each molecule has a distinct antioxidant effect. Ascorbic acid, at high concentrations (500–750 µM), improved cell viability in both models of oxidative aggression. Astaxanthin, on the other hand, proved to be effective primarily against damage induced by UVB rays. However, it was the combination of the two active ingredients that yielded the best results: a more pronounced reduction of intracellular oxidative stress and improved cell survival, highlighting a synergistic effect between these two antioxidants.

Vitamin E is a fat-soluble molecule that is a component of sebum. In skincare, it is used for its antioxidant properties, which are beneficial for protecting the skin and the product from oxidation. This is why vitamin E is sometimes referred to as a preservative. Combining astaxanthin and vitamin E is particularly beneficial for acne-prone skin, which often suffers from dysseborrhea. Dysseborrhea is a change in the composition and quality of sebum, characterised by a deficiency in vitamin E. In the absence of vitamin E, squalene, another component of sebum, easily oxidises into squalene peroxide, a comedogenic compound. The sebum then changes texture, becomes thick and eventually clogs the pores. Using vitamin E, especially when combined with astaxanthin, which has strong antioxidant properties, could help to compensate for the vitamin E deficiency in acne-prone skin and protect squalene from oxidation, thus limiting the formation of comedones.

A recent study in vitro has demonstrated the synergy between astaxanthin and tocotrienols, a form of vitamin E. Indeed, when these actives were used together, an increased elimination of hydroxyl radicals and singlet oxygen was measured. It is hypothesised that these two molecules interact through hydrogen bonds, promoting a better spatial organisation between their respective polyenic chains.

Astaxanthin can also be combined with retinol to enhance its preventive action on skin ageing. Indeed, retinol is a derivative of vitamin A known for its ability to stimulate the proliferation of keratinocytes, increase the production of type I and III collagen, and improve skin texture. Astaxanthin can supplement these effects by protecting the proteins of the extracellular matrix, particularly collagen and elastin fibres, against alterations caused by oxidative stress. Retinol and astaxanthin thus work in a complementary manner: while retinol acts dynamically by promoting cell renewal, astaxanthin stabilises and protects the results achieved, thus both contributing to slow down skin sagging.

A clinical case study demonstrated this synergy in two women showing advanced signs of photoaging. The first patient had visible wrinkles at rest, while the second showed wrinkles only when moving. Both followed a skincare routine combining an astaxanthin-based gel and sun protection in the morning and a 0.1% retinol serum in the evening, for six weeks. At the end of this period, researchers noted a significant improvement in the texture and elasticity of the skin of both participants, as well as a marked reduction in the depth of wrinkles.

These findings suggest that the combined use of astaxanthin and retinol can effectively act on skin ageing, provided it is paired with photoprotection.

The combination of astaxanthin and collagen could represent another interesting synergy for maintaining skin firmness and elasticity. While astaxanthin, with its powerful antioxidant properties, helps to neutralise free radicals responsible for oxidative stress, the topical application of collagen can help to preserve skin hydration and, in some cases, to rekindle the endogenous production of collagen. Indeed, some studies have shown that collagen hydrolysate can boost the synthesis of collagen by skin fibroblasts. The combination of astaxanthin and collagen could therefore be another interesting combination to preserve the support fibres of the dermis and limit skin ageing.

In cosmetics, spirulina is primarily valued for its nutrient richness: this micro-algae is packed with proteins, vitamins, particularly vitamin B12, essential amino acids, and minerals. It is also a source of phycocyanin, a pigment with antioxidant and anti-inflammatory properties. Spirulina is often compared to chlorella, another freshwater algae with which it shares similar cosmetic properties. Skincare products based on spirulina and/or chlorella help revitalise dull skin and support the skin barrier. Combining them with astaxanthin could enhance their effectiveness and protect the skin more efficiently from oxidative stress.

Quercetin is a flavonoid naturally found in apples, red onions, and green tea. In skincare, it is increasingly used for its antioxidant potential, as well as its soothing and protective properties. It helps neutralise free radicals, calm inflammation, and strengthen the skin barrier. The idea of pairing it with astaxanthin is intriguing as these two active ingredients share commonalities, while also complementing each other. Where quercetin acts more on the surface, astaxanthin penetrates deeper into the lipid membranes. Together, they could offer a dual antioxidant protection, both hydrophilic and lipophilic, with an enhanced effect against oxidative stress. This is a promising avenue, which still needs to be confirmed by scientific studies.

Resveratrol is a natural polyphenol found in the skin of black grapes, certain berries, and red wine. In skincare, it is valued for its antioxidant, protective, and anti-inflammatory properties. It works by modulating certain cellular mechanisms related to skin ageing, such as the activation of sirtuins or the neutralisation of free radicals. The idea of combining it with astaxanthin is based on a complementary action. Both are powerful antioxidants, but with different profiles: the resveratrol is water-soluble and acts primarily in the aqueous compartments of the cell, while astaxanthin, being lipophilic, protects the membrane structures. Together, they could therefore cover a wider spectrum against oxidative stress.

Glutathione is often cited as a key player in cellular detoxification. This naturally occurring tripeptide in the body plays a significant role in neutralising free radicals and recycling other antioxidants, such as vitamin C or vitamin E. Glutathione is gradually being incorporated into skincare products where it is used to protect the skin from oxidative stress. It could be relevant to pair it with astaxanthin, again with the aim of strengthening the skin's antioxidant defences. However, the potential synergy of this duo of active ingredients has not yet been studied.

At first glance, the combination of astaxanthin and capsaicin, the compound found in chilli peppers, may seem unusual, but it could enhance their respective antioxidant effects. Indeed, while astaxanthin is known for its ability to stabilise cell membranes and neutralise free radicals through its polyene chain, capsaicin could modulate the electronic state of astaxanthin's polyene chain. This rearrangement could amplify the antioxidant response and better protect cells from free radicals. This hypothesis has been confirmed by a recent study on liposomes encapsulating both astaxanthin and capsaicin. These liposomes demonstrated a synergistic antioxidant activity superior to the sum of the individual effects of each of the two active ingredients.

Capsaicin is seldom used in skincare due to its high potential for irritation.

The zinc is a trace element well known in skincare for its purifying and soothing properties, particularly for oily or blemish-prone skin. It also plays a key role in wound healing and enzymatic function, particularly in cellular defence mechanisms against oxidative stress. Combining zinc and astaxanthin could potentially enhance the overall protection of the skin and could be particularly relevant for simultaneously combating blemishes and signs of ageing.

The turmeric, due to its main active ingredient, curcumin, is recognised for its potent anti-inflammatory and antioxidant properties. In skincare, it is often used to soothe redness, even out skin tone, and combat oxidative stress. It could be beneficial to pair it with astaxanthin to enhance cellular protection against external aggressors, such as pollution or UV rays. While turmeric acts on the pathways of inflammation, astaxanthin strengthens the stability of cell membranes. Concurrently, these two active ingredients neutralise free radicals and delay skin ageing.

The dihydroxyacetone, or DHA, is a sugar of plant origin commonly used in self-tanners to give the skin a gradual tan without UV exposure. It reacts with the amino acids in the stratum corneum in a process called the Maillard reaction, producing temporary brown pigments on the skin's surface. The astaxanthin, on the other hand, is believed to be able to stimulate the production of tyrosinase, a key enzyme in the synthesis of melanin. This characteristic suggests that the combination of DHA and astaxanthin could be interesting to enhance and prolong the tanning effect, by combining the immediate colouring action of DHA and the natural stimulation of tanning by astaxanthin. However, scientific studies on this subject are necessary.

Biotin, or vitamin B8, plays a key role in the synthesis of keratin, a glycoprotein vital for the structure and strength of hair. It also participates in the metabolism of fatty acids and amino acids in the hair follicle. This vitamin is often used to reduce hair loss, typically taken orally but sometimes also applied topically. It could be beneficial to combine it with astaxanthin as this pigment neutralises free radicals in the scalp, thus protecting the hair against accelerated loss due to oxidative stress.

Scientific studies are necessary to confirm this, but astaxanthin and biotin could potentially exhibit a beneficial synergy for hair growth.

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• OH S. & al. Antioxidative effects of ascorbic acid and astaxanthin on ARPE-19 cells in an oxidative stress model. Antioxidants (2020).

• FLORENCIA D. & al. Effectiveness of 0.1% retinol serum and astaxanthin gel on skin photoaging. Biological Science (2022).

• VIRGIANTI D. P. & al. Formulation and evaluation of radiance serum containing astaxanthin–zeaxanthin nanoemulsions as an anti-wrinkle agent: Stability, ex vivo, and in vivo assessments. Cosmetics (2024).