In this video, board‑certified dermatologist Dr. Jane Yoo addresses the widespread online fear that hyaluronidase can “ruin” a face. She explains that hyaluronidase is an enzyme that breaks down hyaluronic acid, including HA fillers, but does not dissolve collagen, fat, or muscle. She outlines why patients may look hollow or dramatically different after filler dissolution: (1) seeing their unfilled face for the first time after years of masking age‑related changes, (2) tissue adaptation to long‑term filler volume, and (3) temporary changes in hydration and inflammation caused by the enzyme and injection trauma. Dr. Yoo discusses safety considerations—dose, injection technique, and the importance of targeting the correct area, often using ultrasound to locate filler. She notes the rare but real risk of allergic reactions, especially with animal‑derived or recombinant formulations. The video introduces “post‑hyaluronidase syndrome,” an emerging term describing persistent hollowing after dissolution, and cites a 2024 retrospective study of 90 periorbital cases that linked poorer outcomes to the amount and duration of prior filler rather than hyaluronidase dose. She emphasizes that there is no evidence hyaluronidase permanently destroys facial structure, nor should patient concerns be dismissed. Dr. Yoo provides practical post‑treatment guidance: expect swelling and bruising in the first days, a flatter appearance over weeks, and the need to allow tissue to settle before judging results. She recommends standardized photography, avoiding immediate re‑filling, and seeking assessment from an experienced practitioner—potentially using ultrasound—to determine residual filler before any further intervention. The overall message balances the utility of hyaluronidase with thoughtful, evidence‑based use and patient education.
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Hi everyone, I'm Dr. Jane Yoo, board-certified dermatologist and Mohs surgeon. Today I want to talk to you about something I see discussed constantly online: the fear that hyaluronidase can ruin your face. If you search hyaluronidase ruin my face, you'll find thousands of people describing their experiences, and I don't think those experiences should simply be dismissed. So I want to take them seriously while also explaining what we actually know about how hyaluronidase works and what may be happening after filler is dissolved. Hyaluronidase is an enzyme that breaks down hyaluronic acid. That includes hyaluronic acid filler, but it can also temporarily affect some of the naturally occurring hyaluronic acid in your own tissue. Your natural hyaluronic acid, however, is not cross-linked the way the filler is, and it is continuously being broken down and replaced as part of normal physiology. Hyaluronidase does not work by dissolving your own collagen, fat, muscle, or Those are completely different tissues. But that doesn't mean people who say they look dramatically different after dissolving are imagining it. The change can be very real. The question is what is actually causing it. Why can someone look hollow or different after having filler dissolve? There are a few things that may be happening. First, you may be seeing your unfilled face for the first time in years. If you've had filler continuously since 2019, for example, you haven't really seen your face without the additional volume since 2019. Your face has continued to age during that time. Changes in facial fat, bone, skin, and soft tissue happen whether or not you're getting filler, but filler may have been masking some of those changes. When the volume is removed relatively quickly, the difference can feel dramatic because you're seeing several years of change all at once, rather than gradually. Second, if you've had a significant amount of filler for a long period of time, the surrounding tissues may also have adapted to that additional volume. When the filler is removed, the area can initially look looser or more deflated than you expect. And third, there can be temporary changes in hydration and inflammation after hyaluronidase. Your naturally occurring hyaluronic acid helps bind water in the tissue, and hyaluronidase can temporarily affect the hyaluronic acid as well. You're also injecting into the tissue, which causes swelling, bruising, and inflammation. So what you see immediately after dissolving is not necessarily what the area is going to look like once everything has settled. Now, I want to be fair about the other side of this conversation, because hyaluronidase is still a medication and there are real risks. Dose, location, technique matter, particularly in a thin, delicate area like the under eye. I want to be as targeted as possible rather than unnecessarily exposing a large area to hyaluronidase. If the person treating you doesn't know where the filler is located, they may also dissolve filler that was actually providing useful structure while leaving the product that was causing the original problem behind. This is one reason I use ultrasound in complicated filler cases. I want to know what I'm targeting before I start dissolving. There are also true allergic reactions to hyaluronidase. They're uncommon, but they can happen. Hyaluronidase products may be animal-derived or recombinant human formulations, and hypersensitivity reactions have been reported. Any medical practice administering hyaluronidase should be prepared to recognize and manage an allergic reaction. Now, let's talk about something called post-hyaluronidase syndrome, because if you've been researching this online, you may have come across that term. This is actually an area where the medical literature is evolving. Post-hyaluronidase syndrome has been used to describe patients who report changes such as hollowing or an altered facial appearance after filler dissolution. A 2024 retrospective study looked at 90 patients treated with hyaluronidase around the eyes and found that some patients did report these types of changes afterwards. Interestingly, these poorer outcomes were associated with how much filler patients had previously received and how long that filler had been present, rather than the concentration or dosage of hyaluronidase used. That doesn't prove exactly what causes every case, But we still need more research. But it does suggest that the experience some patients are describing deserves to be studied rather than simply dismissed. What I would not say is that we have evidence that hyaluronidase permanently destroys the entire facial structure. We don't. And I also wouldn't tell someone who feels like their face changed dramatically after dissolving that nothing happened. Both of those positions are more certain than the evidence allows. So what should you expect after dissolving? During the first few days, you may have swelling or bruising. This is one of the least useful times to judge your appearance. Over the next couple of weeks, that swelling begins to settle, and you may feel like the treated area looks flatter or more hollow than you expected. After that, I want to give the tissue time. Hydration changes settle, your naturally occurring hyaluronic acid continues to turn over and you get a much clearer idea of what your baseline actually looks like. The exact timeline is different for everyone, which is why I don't like giving patients a specific week and promise that everything will look a certain way by then. I also recommend taking standardized photographs in the same lighting, from the same angle, and with the same facial expression. When you're looking at yourself every day and understandably worried About a change, it can be very difficult to objectively remember what you looked like a week or a month earlier. And if you're unhappy with how you look shortly after dissolving, I would be very cautious about immediately adding more filler to try to correct it. You don't want to make a long-term treatment decision based on a temporary stage of healing. Give the area time to settle. If you're still concerned, get an assessment from someone experienced in filler complications. In complicated cases, ultrasound can also determine whether any filler is actually still present. And only after you understand what you're looking at should you decide what, if anything, needs to be treated. The most important thing I want patients to understand is that we don't need to choose between dismissing people who have had a difficult experience with hyaluronidase and claiming that the enzyme permanently destroys The evidence doesn't support either extreme. Hyaluronidase is an incredibly useful medication when it's used appropriately, but it should still be used thoughtfully. The goal should always be to understand what filler is present, where it is, and how much actually needs to be treated before you start dissolving.
