Restylane is an injected gel that contains an active ingredient called hyaluronic acid. A Restylane injection is designed to work like this natural hyaluronic acid in the body to fill in creases to improve the appearance of fine lines and wrinkles. Restylane is FDA approved and is considered to be a safe method of smoothing skin. If you are concerned about the effects of medical treatments in relation to the environment, you can rest assured that Restylane is biodegradable and is not sourced from animals. Restylane treatments are generally safe for patients, but rare restylane side effects can occur in a small percentage of people. Rare Restylane side effects include allergic reactions marked by severe swelling and shortness of breath; anaphylactic shock; severe erythema, a redness of skin; skin necrosis or permanent dark spots; and infection. Common side effects are mild and short-term in nature. You can discuss your concerns with a medical spa professional before having a treatment completed. Some people are more susceptible to these side effects because of their medical history, and a professional can advise you on whether restylane treatments are appropriate in your unique situation.