The first thing Sofie Pavitt, NYC esthetician also known as the “acne whisperer,” asks her clients who come in with persistent breakouts is what their skincare and makeup routine looks like. This is so she can identify and remove all the potentially comedogenic products.

Pavitt explains that comedogenicity, the measure of how likely an ingredient is to clog your pores, is less about specific ingredients and more a reflection of the formulation of a product — which makes buying beauty products both a risk and a headache. Moreover, there’s a lot of contrary information. For example, certain ingredients touted as “natural” and “good for your skin’s microbiome” are also the same ones that Pavitt will look at and say: Actually, that could be what’s breaking you out. Algae extracts, in particular, require a slight disclaimer: If you’re acne prone, proceed with caution.

The benefits of algae in skincare

Let’s start by addressing the benefits of using algae on your skin. For many people, it’s fantastic and there’s no cause for any concern when consuming seaweed or spirulina (a type of blue-green algae in greens powder), or using a topical skincare product that has algae on the label. “Algae extracts are rich in vitamins, minerals, and antioxidants,” explains dermatologist Divya Shokeen Khalsa, MD, FAAD. The antioxidant properties in algae are particularly impressive — and we know antioxidants are like bubble wrap for your skin, helping protect against environmental damage and reduce inflammation. Moreover, while there are hundreds of different types of algae, Pavitt says that in general, most will act as a humectant, bringing hydration to the skin, which is great, especially if you’re dry.

Algae is also a player in the conversation around microbiome-friendly skincare. “The impact of algae on the skin’s microbiome is still an area of ongoing research,” explains Dr. Shokeen Khalsa. “It is thought that certain compounds present in algae may have antimicrobial or prebiotic properties [prebiotics are a source of food for bacteria], which may help balance the microbiome and promote a healthy skin environment.”

Why algae is controversial for acne-prone skin

Now, algae sounds like a great addition to a skincare routine. But some people have to be careful with it. Nikki DeRoest, makeup artist and the co-founder of a new SPF-makeup brand called Ciele, self-identifies as very acne-prone. DeRoest explained that when creating a skincare product that would sit on people’s skin, it was imperative she remove all potentially comedogenic ingredients. One ingredient she was adamant about removing, you guessed it, algae. “It’s very popular in beauty products — both algae and coconut oil derivatives — but I can’t put those on my face or I’ll break out,” DeRoest tells me.

Commonplace comedogenic ingredients include isopropyl alcohol, cocoa butter, coconut oil, synthetic perfumes, and essential oils. But algae surprised me. “Yes, some types of algae can be comedogenic, meaning they have the potential to clog pores and contribute to the formation of acne,” explains Dr. Shokeen Khalsa. “While it is difficult to generalize, certain types of algae and certain formulations that involve heavy oils or emollients may have a higher comedogenic potential than others. Especially formulations with castor or coconut oil.”

According to dermatologist Brendan Camp, MD, the comedogenic potential of algae is controversial, which is likely why there’s not a lot of information about it. “There are reports that suggest [algae] can help reduce inflammation associated with acne, and others that suggest it can encourage the production of acne because of its high iodine content,” explains Dr. Camp. His general guidance: “If you have acne-prone skin and you are using an algae containing product that does not exacerbate your acne, you do not need to discontinue use of it,” offers Dr. Camp. “Tread carefully if you have acne-prone skin and are starting a new product that contains algae, as some reports suggest it can contribute to acne formation.”

The problem with algae supplements

In Dr. Shokeen Khalsa’s practice, adverse acne reactions specifically attributed to topical forms of algae are relatively rare. Pavitt says that spirulina supplements or greens powder containing blue-green algae can commonly trigger acne, due to the aforementioned high iodine content. “Although algae is touted as a highly nutritious food and ingredient with anti-inflammatory attributes and antioxidants, it’s also packed with iodine, which can absolutely break you out,” Pavitt explains. “Excessive iodine, when consumed in foods or supplements, gets excreted through the pores which causes irritation.” Iodine, a trace mineral commonly found in seaweed, seafood, iodized salt, vitamin supplements, and greens powder has been linked to acne.

It’s ironic, too, because Pavitt explains that many people who come to her with acne are taking a greens powder to try and clear their skin, when it’s actually doing the opposite. “One of the first questions I ask someone with a persistent breakout is if they are using greens powder supplements,” Pavitt says. “So many of them [contain] spirulina, which is algae. That can cause breakouts. Taking them off the greens powders that contain algae can be really helpful in clearing them up.”

If you’re acne prone, the skin experts recommend avoiding algae in skincare and supplements, considering its potential comedogenicity. “When I’m working with a client with active acne, it’s definitely an ingredient I tell them to avoid,” offers Pavitt. It’s not a huge dermatological concern but more like food for thought, and probably a topic we’ll hear more about in the future. As Dr. Shokeen Khalsa notes, “A lot of research is still pending in this area.”