Cynthia Sass is a nutritionist and registered dietitian with master's degrees in both nutrition science and public health. Frequently seen on national TV, she's Health's contributing nutrition editor and counsels clients one-on-one through her virtual private practice. Cynthia is board certified as a specialist in sports dietetics and has consulted for five professional sports teams, including five seasons with the New York Yankees. She is currently the nutrition consultant for UCLA's Executive Health program. Sass is also a three-time New York Times best-selling author and Certified Plant Based Professional Cook. Connect with her on Instagram and Facebook, or visit www.CynthiaSass.com.

As a registered dietitian, I'm often asked about nutrition trends that become popular on TikTok, from apple cider vinegar (never take straight, undiluted shots) to "what I eat in a day" videos (many of which feature menus that aren't balanced or nutritionally adequate). One of the latest trends to bubble up is chlorophyll, sold in liquid form, with a dropper for dispensing the green solution. You may see fans of the supplement swirl it into water and claim that it does everything from boost energy to reduce skin redness to detoxify the body. If you're tempted to try it yourself, here are a few things to know before you jump on the liquid chlorophyll bandwagon.

You may remember from science class that chlorophyll is the most abundant pigment in plants, including those we eat. Green veggies, like kale and green beans, are rich natural sources, so if you eat your greens, you'll get plenty of chlorophyll. For example, 1 cup of raw spinach provides 23.7 mg of chlorophyll, about half the amount in 15 drops of some liquid supplements.

According to the Centers for Disease Control and Prevention, just 9% of Americans eat the minimum recommended 2 to 3 cups of veggies daily. Upping your intake to at least 3 cups (although I typically recommend five), and choosing green varieties, provides not only chlorophyll but also a wide array of other important vitamins, minerals, antioxidants, and fiber. In other words, eating more green plants is a much better way to get this pigment; and if you do that, you don't need a supplement.

Because natural chlorophyll is not very stable, most over-the-counter chlorophyll supplements actually contain chlorophyllin, a semi-synthetic mixture of water-soluble sodium copper salts derived from chlorophyll. In addition to its role in supplements, chlorophyllin can be used as a color additive in foods, drugs, and cosmetics.

There are some studies about the use of chlorophyllin in animals and on laboratory cells, but not much in humans. One older study in nursing home patients found that chlorophyllin tablets helped control body and fecal odors, eased chronic constipation, and reduced flatulence. No toxic or other unwanted side effects were observed, but there were limitations to the study, including the lack of a control group, the small number of study subjects (just 62 participants), and no comparison to a diet-based change.

While the topical use of chlorophyll has been studied in people with acne, human studies aren't available to support many of the outcomes people link to oral chlorophyllin supplements. These supposed benefits include skin health, immune function, and weight loss.

A lack of research on any supplement means an absence of knowledge about its effectiveness, the precise amount to use, and potential side effects or interactions. While some nutrients are beneficial in one form or amount, they may become dicey when taken in higher concentrations. For example, zinc helps support immune function, but too much zinc can trigger digestive upset, suppress immune function, and reduce blood levels of "good" heart-protective HDL cholesterol.

Antioxidants are another example. They're protective in the amounts found in fruits and veggies, but when taken in supplement form, antioxidants can act as pro-oxidants and potentially increase health risks.

In regards to chlorophyllin specifically, the Natural Medicines Comprehensive Database (NMCD) states that the supplement has been used with apparent safety at doses of up to 300 mg daily for up to three months. But this was primarily for therapeutic purposes, such as in patients exposed to aflatoxins, poisonous substances produced by certain kinds of fungi.

The NMCD notes that while no general adverse effects are reported, a thorough evaluation of chlorophyllin's safety outcomes has not been conducted. Some known possible mild effects include increased sensitivity to sunlight (and therefore increased sunburn risk), loose stools, and green-colored urine or feces.

I'm not anti-supplement, but I'm cautious about liquid chlorophyll simply because there's a lot we don't know due to the lack of research. The supplement may not be appropriate for people with certain medical conditions, and there's no established ideal dose or length of use. Potential interactions with prescription and over-the-counter medicines, vitamins, and herbal products are also unknown. And if you're pregnant or breastfeeding, keep this in mind: It shouldn't be used without medical supervision.

If you've been using liquid chlorophyll and feel like you're seeing benefits, talk to your doctor about its pros and cons, based on your personal health status and history. And if you're looking for benefits with more science backing, your best bet is to get your greens from fresh veggies rather than a dropper.

Cynthia Sass, MPH, RD, is Health's contributing nutrition editor, a New York Times best-selling author, and a private practice performance nutritionist who has consulted for five professional sports teams.

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