July 13, 2020
KumiTominaga, Nobuko Hongo, Mariko Karato and Eiji Yamashita
Aesthetics and cosmetics is a lucrative field of medicine and billions of dollars are being spent by consumers to get a taste from the fountain of youth. Companies have founded research on compounds that make people at least hopeful to be forever young. One of those compounds is astaxanthin, a potent carotenoid antioxidant. Astaxanthin is derived from the microalgae Haematococcus pluvial, one of the oldest carotenoids isolated and identified from crustaceans.
Astaxanthin was suggested to be free from pro-oxidative effects unlike other carotenoids. In terms of its benefits for the skin, it has shown suppression of hyperpigmentation, improvement in moisture and elasticity, and inhibition of melanin synthesis and photoaging.
This technical review articlediscusses the findings fromtwo studies on astaxanthin. Study 1 is an open-labeled, non-controlled clinical study combining both oral supplementation and topical treatment with astaxanthin among healthy female subjects and study 2 has a randomized, double-blind,placebo-controlleddesign using astaxanthin oral supplementation in36 healthy male subjects.
Method and Materials
The oral supplementation contained 3mg of astaxanthin and canola oil in soft gel capsules. Identical placebo capsules for control were prepared with canola oil in soft gel capsules. For topical applications, a solution containing 78.9 micromolar (μM) astaxanthin without any other active ingredients and base materials was used.
Subjects and Study Design
Study 1 is an open-label, non-controlled clinical trial. Thirty healthy Japanese women aged 20 to 55 participated in this study. An astaxanthin wash-out period of 1 week was done before the start of the 8-week trial. One capsule of astaxanthin was administered twice daily (breakfast and dinner) and 1ml of topical application was applied on the whole face every morning and night. Measurement of each test item was performed at three points: at the beginning of the study, after four weeks, and after eight weeks.
Study 2 is a randomized double-blind placebo-controlled study using oral astaxanthin among 36 healthy Japanese male subjects aged 20 to 60 years old. Eighteen participants took the oral active form of astaxanthin (breakfast and dinner) for 6 weeks. The remaining 18 took the placebo form also for 6 weeks twice daily. Measurements of each test item were performed at the beginning of the study and after six weeks.
Conditions of Measurements
The measurements were performed 15 minutes after the subjects were allowed to rest in a seated position after washing their faces in an environmental test room conditioned to 20±2°C (or 68±3.6°F) room temperature and 45±10% relative humidity in both studies.
Measurement of Parameters
Skin surface photographs for crow’s feet condition evaluation were recorded using the Facial Stage. Wrinkle topography measurements were made from negative skin replicas of the left crow’s feet and calculated by image analysis based on six parameters (deepest point, mean depth and maximum width of the deepest wrinkle, area ratio, mean depth and volume ratio of all wrinkles).
Skin elasticity of the left crow’s feet area was measured.
Comparison of the most outstanding age spot on the left cheek between 0 and 8 weeks were determined by image analysis using ImageJ. Skin surface photographs were also recorded using the Facial Stage with normal and ultraviolet (UV) lamps.
Skin topography for left cheek evaluation were determined with replicas by the image analysis based on 4 parameters— number, mean depth, volume ratio of texture and projection number of texture. Corneocyte of the left cheek was collected by Scotch tape stripping and was applied to hematoxylin-eosin stain. The area was calculated by ImageJ analysis on a prepared slide at a magnification of 200 times.
Skin moisture contents of the left crow’s feet for wrinkle evaluation and cheek for skin texture evaluation were recorded.
Skin sebum oil content at the left cheek was measured by the SEBU sheet around the nose.
Transepidermal Water Loss (TEWL)
TEWL at the left cheek was measured.
Wrinkle, elasticity, age spots, skin texture and moisture content were measured for Study1 whereas, wrinkle, elasticity, moisture content, sebum oil and TWEL were measured for Study 2.
Visual wrinkle reductions on the crow’s feet were seen among subjects in study 1. Significant improvements on four parameters were also observed (deepest point, mean depth, maximum width of the deepest wrinkle and mean depth of all wrinkles). Moisture content of corneocyte layer in the left crow’s feet did not show any significant differences before and after the treatment. Elasticity of crow’s feet area significantly improved at weeks 4 and 8.
Visual age spot reductions were observed among subjects. The age spot area was significantly treated at week 8. Improvements on skin texture were observed in both subjects. Total area of the corneocyte at week8 significantly improved from the start period. Moisture content of corneocyte layer in the cheek among all subjects did not show any significant differences. However, those with dry skin had a significant improvement in moisture.
Significant improvements in two parameters “area ratio of all wrinkles” and “volume ratio of all wrinkles” was seen. Moisture content at the crow’s feet did not show any significant differences before and after the administration. However, the moisture content of the cheek did show a tendency to increase among the selected subjects who had dry skin at the beginning of the study. Elasticity of crow’s feet area significantly improved at week6 compared from the area at the start of the trial. Total epidermal water loss also showed significant improvement at week 6 compared from the start.
Astaxanthin was studied in 2 viewpoints, route of administration and gender. Study 1 is an open-label, non-controlled trial involving female test subjects. It was administered through oral and topical form. Significant improvements were observed in skin wrinkle (crow’s feet at week-8), age spot size (cheek at week-8), elasticity (crow’s feet at week-8), skin texture (cheek at week-4), moisture content of corneocyte layer (cheek in 10 dry skin subjects at week-8) and corneocyte condition (cheek at week-8). Combination technique may be much beneficial for the skin.
Study2 was performed to evaluate the efficacy in male subjects by oral supplementation under a randomizeddouble-blind placebo-controlled design. Significant improvements were observed in wrinkle and elasticity of crow’s feet and TEWL at cheek at week6 compared from the start. Tendencies of improvement in moisture content and sebum oil at cheek were also observed. Astaxanthin supplementation exhibited cosmetic benefits not only among female subjects but in male subjects as well.
The Japanese Cosmetic Science Society (Task Force Committee for Evaluation of Anti- aging Function) prescribes that a product can be effective in wrinkle reduction if there is a significant improvement from at least one parameter. Significant improvements from four parameters in study1 and from two parameters in study2 were observed respectively. The mechanism of action of wrinkle reduction by astaxanthin could be explained as an improvement in the condition of the dermis through collagen fiber recovery. Astaxanthin promotes collagen fiber recovery by protecting the dermal layer from singlet oxygen damage which has been substantiated by an in vitro study using human dermal fibroblasts.
Elasticity was also improved as a result of collagen fiber recovery in both studies.There was a significant inhibition of melanogenesis in age spots through the suppression of the oxidative polymerization in melanocytes and inflammation in the epidermis in study1.
The mean moisture content in the all subjects at the start was approximately 20 μS in study1. In general, the range of moisture content of dry skin is 12-15 μS. A significant increase was observed in ten subjects whose moisture content was less than 17 μS at the start. In study2 moisture content of the cheek showed a strong tendency to increase among the selected subjects less than 17 μS at the start. Topical treatment might be more deeply involved in the improvement of rough skin than oral supplementation.
Corneocyte consists of the dead epidermal cells. Astaxanthin treatment might normalize the corneocyte conditions protecting the keratinocyte differentiation and cornification from oxidative damages such as inflammation in epidermis. Excess oxidized sebum oil causes rough skin and aging odor. Astaxanthin supplementation may help to reduce rough skin and aging odor protecting the sebum oil from peroxidation. TEWL is a marker for the barrier functions in corneocyte layer. It also seems that the significant TEWL improvements resulted in normalizing the corneocyte condition. Patients with an atopic skin who have high TEWL may be treated by astaxanthin supplementation.
In conclusion, these results may suggest that astaxanthin derived from H. pluvialiscan improve skin condition in all layers such as corneocyte layer, epidermis, basal layer, and dermis by combining both oral supplementation and topical treatment and oral supplementation of astaxanthin can improve the skin condition in both men and women.
K. Tomiga et al. Cosmetic benefits of Astaxanthin on Human Subjects. Acta Biochimica Polonica. 2012.