What Is Japanese Indigo, and Should You Add It to Your Skin-Care Routine?

Over the past few years, Japanese indigo has been gaining popularity in skin-care products because of its purported soothing, anti-inflammatory effects — particularly for people who experience psoriasis, eczema, and rosacea.

But does research support these claims, and do dermatologists recommend using this ingredient in your skin-care routine? Here’s the lowdown on this ingredient.

Also known as Indigo naturalis and qing dai, Japanese indigo “is a botanical extract [from an herb] that’s been used in traditional Chinese medicine [as well as in Japan and Korea, per research] for centuries,” says Joshua Zeichner, MD, an associate professor of dermatology and the director of cosmetic and clinical research in dermatology at Mount Sinai Hospital in New York City. “It has been used as a blue dye in [both Eastern and] Western societies, but has recently gained popularity as an ingredient in skin-care products.”

While Japanese indigo is still relatively rare in mass-market topical skin-care products, when you do come across it, you’re likely to find it in moisturizing serums, oils, and creams that are formulated to reduce irritation and sensitivity.

“It pairs well with other calming ingredients and ingredients that support and protect the skin’s barrier,” says Howard Sobel, MD, a dermatologic surgeon at Lenox Hill Hospital in New York City and the founder of Sobel Skin Rx. Dr. Zeichner concurs, saying that “Japanese indigo is commonly paired with skin-hydrating ingredients like natural oils, oat extract, or ceramides” to provide well-rounded support to heal inflamed skin.

Japanese indigo is touted for its calming, anti-inflammatory effects, and it may provide benefits for people managing certain skin conditions, though research is limited and emerging.

May Help Manage Psoriasis

Most of the existing research on the topical skin-care benefits of Japanese indigo addresses psoriasis, an autoimmune disorder where skin cell growth goes into overdrive, leading to inflammatory plaques and scales on the skin, according to the National Psoriasis Foundation.

One review and meta-analysis of preliminary research, which analyzed a variety of plant extracts in the management of psoriasis, found that certain compounds in Japanese indigo may reduce inflammation and suppress cell growth, which may be helpful in psoriasis treatment.

It’s possible that benefits for psoriasis can be traced back to the two active compounds, indirubin and tryptanthrin. “Studies have shown that indirubin can improve psoriasis without serious adverse side effects by reducing the size and density of patches on the skin,” Dr. Sobel says. “It works to block and inhibit the communication between cell activity that causes moderate plaque psoriasis.”

Meanwhile, tryptanthrin “works to decrease the molecules in the body that promote inflammation, [which is] the root cause of psoriasis,” Sobel adds. “Together, these ingredients address the cause and effect of inflamed skin conditions,” he explains.

As the authors of the aforementioned review and meta-analysis note, Japanese indigo evidence from clinical trials is “limited but consistent.” And since the publication of that research, a more recent review on the ingredient came to similar conclusions: Japanese indigo acts on specific pathways that decrease inflammation and cell proliferation, and suppress new blood cell growth in similar ways to drug treatments. (This is not to say that it’s as effective, or a substitute for, drug treatments.) Still, as the review authors point out, despite its potential promise, the ingredient is still being explored as a theoretical treatment for psoriasis, and much more research needs to be done.

May Help Soothe Eczema

While Japanese indigo is commonly used to help treat eczema, there are fewer studies suggesting its efficacy on this skin condition than psoriasis.

That said, one small randomized, double-blind clinical trial found that topical application of Japanese indigo ointment helped treat atopic dermatitis — the most common form of eczema — in 48 participants ages 6 to 65 when used twice daily over six weeks. Those who received the Japanese indigo (32 people) saw their eczema severity decline by about 50 percent, while the placebo cream group (16 people) had a reduction of about 20 percent. In addition, the Japanese indigo group also had a smaller body surface area affected with dermatitis and reported a higher quality of life after the six weeks.

One popular skin-care product containing this ingredient, the Indigo Soothing Triple Recovery Cream by Tatcha, has a Seal of Acceptance from the National Eczema Foundation indicating its suitability for eczema-prone skin, though Japanese indigo is not an FDA-approved treatment for eczema or any dermatological conditions yet.

May Calm Rosacea

Clinical studies supporting the use of Japanese indigo for rosacea are scarce, so more research is needed to provide conclusive evidence on this front.

Right now, the ingredient provides theoretical benefits for rosacea. “Tryptanthrin has been shown to exhibit antioxidant, anti-inflammatory, and antimicrobial effects on the skin. This may explain any [possible] benefits in treating rosacea,” says Zeichner. “We also know that mites that live on the skin as part of the normal microbiome contribute to inflammation and bumps,” he adds. Tryptanthrin may lower levels of these skin mites and calm inflammation, which is how rosacea is biomedically treated.

Zeichner recommends sticking to conventional prescriptions for rosacea treatment. You can certainly use a cream containing Japanese indigo, he says, but at this time, it’s not recommended to abandon current, doctor-recommended prescriptions in favor of one of these products.

Additional Possible Benefits of Japanese Indigo for Skin

Zeichner says this ingredient “may also be helpful in protecting the skin against environmental-induced free radical damage,” which some research supports. Such sources of skin damage include exposure to UV rays, pollution, smoke, and even stress, so Japanese indigo may be a worthy addition to your skin-care regimen to ward off dullness and signs of premature aging.

Last, Sobel says Japanese indigo boasts antibacterial properties, “making it a good addition to anti-blemish products.” This additional benefit to clear up breakouts isn’t too surprising, since acne is also an inflammatory skin condition; but there is no research yet to substantiate this potential benefit.

There are few skin-care products that contain Japanese indigo. Among those that do, it’s most commonly found in moisturizers, oils, and serums, particularly those that claim to calm and soothe the skin and repair the skin barrier.

Aforementioned research on Indigo naturalis and psoriasis notes that there are no serious side effects when it comes to topical use of the ingredient or its active compounds, however, GI bleeding and liver damage can occur from oral intake and is not recommended. Another trial on atopic dermatitis found that while longer trials were needed to determine long-term risks, the ingredient had a history of topical use on skin disease in traditional Chinese medicine, dating back hundreds of years.

Zeichner agrees that Japanese indigo is generally safe and well-tolerated. But allergies may emerge. It’s always a good idea to monitor your skin for a reaction — red, burning, stinging, or peeling. Stop use immediately and consult your dermatologist if you experience discomfort.

Japanese indigo can be safely layered on other active ingredients when treating skin conditions such as psoriasis, eczema, or rosacea.

Much of the research on psoriasis that analyzed Indigo naturalis excluded pregnant or lactating women.

The most popular brand that uses Japanese indigo in their products, Tatcha, maintains that their products are pregnancy-safe because they do not use retinols. Avoidance of retinoids (retinols are a weaker version of retinoids) is recommended by the American College of Obstetricians and Gynecologists (ACOG) during pregnancy. Currently, ACOG also recommends avoiding phthalates, parabens, oxybenzone, and triclosan if you are pregnant or breastfeeding. Products contain a range of ingredients, so look at the label and ingredients on yours or ask your ob-gyn for safe product recommendations.

Japanese indigo hasn’t gone mainstream in the United States skin-care market. If you’re having trouble finding it, Gretchen Frieling, MD, a triple board-certified dermatopathologist and the founder and owner of GFaceMD in Wellesley, Massachusetts, says you have several alternatives at your disposal.

Kale Surprise! This veggie isn’t just for salads. “Kale is an amazing ingredient that has antioxidant and anti-inflammatory properties that helps reduce redness,” says Frieling. In a very small clinical study of 10 participants, a topical cream containing kale (as well as apple and green tea) extracts was found to improve symptoms, including itching, when used on people with moderately severe atopic dermatitis for four weeks, compared with a control cream. Kale contains kaempferol, a flavanol that has anti-inflammatory properties. “It also contains vitamin C and lutein, which are both brightening,” Frieling explains. The only catch is that if you’re allergic to kale, you should avoid this one.

Aloe A classic skin-care ingredient, aloe offers nice soothing properties, says Frieling. That may be why aloe has been used to treat burns, wounds, and eczema, according to a review. Another plus, Frieling says, is that it’s inexpensive and easy to find.

Oral collagen Although it’s not a topical product, a collagen supplement “can help with skin quality and moisture retention,” says Frieling. An improvement in skin hydration has been shown in a meta-analysis published in May 2023.

It’s tough to provide specific parameters, since this ingredient is niche and found in few products. But Frieling mentions that Japanese indigo — given its soothing properties — would best be used in a moisturizer or cream, serum, oil, or — if you can find it — a creamy cleanser, which all help add moisture alongside the calming properties of Japanese indigo, in order to potentially help restore or maintain the skin’s barrier.

When you’re planning out your skin-care routine and have a skin condition, such as eczema, your first step is to determine the order of application of your treatments versus soothing creams, says Frieling.

“I recommend putting your [treatment] products on first, and then using a soothing cream,” Frieling says. For example, if you have eczema, this might mean you apply a topical steroid first (or whatever is prescribed or recommended by your dermatologist), allowing it to absorb into your skin, and then cover it with a soothing product, potentially one that contains Japanese indigo.

What’s important to remember is that Japanese indigo is not going to cure a skin condition like eczema or psoriasis, but it may be used as an added layer to calm skin and promote moisture.

Bottom line: Is Japanese indigo worth seeking out and using in your skin-care routine if you struggle with inflammation?

Possibly. This ingredient may appeal to people with chronic inflammatory skin conditions and other sensitivities. “From what I have seen, and my personal [clinical] experience, yes,” Sobel says. All things considered, he gives Japanese indigo the green light because it’s “a long-standing, natural ingredient that has been shown to offer multiple benefits to all skin types without notable side effects.”

That said, it’s important to remember Japanese indigo is not a substitute for dermatological treatments for skin conditions, and you should always consult your dermatologist before starting to use any new ingredient.