Rejuran injections, while generally considered safe when administered by qualified professionals, can cause a range of side effects from common, mild reactions to rare, more serious complications. The procedure involves injecting polynucleotide (PN) gel derived from salmon DNA into the skin to stimulate collagen production and improve skin texture. Understanding these potential side effects is crucial for anyone considering the treatment.
The vast majority of side effects are temporary and resolve on their own within a few days to a week. These are typically a direct result of the injection process itself and the body’s initial inflammatory response to the healing stimulus.
Common and Temporary Side Effects
These are the reactions most people experience to some degree. They are signs that the healing process has begun.
Injection Site Reactions (ISRs): This is the most predictable category. Immediately after the procedure, you can expect:
- Redness (Erythema): The skin will appear red and flushed, similar to a sunburn. This is caused by increased blood flow to the area and the mild trauma of the needles. It usually subsides within 12-24 hours.
- Swelling (Edema): Swelling is very common, especially when treating larger areas like the entire face. The PN gel attracts water molecules as part of its mechanism, which contributes to a temporary, mild puffiness. This typically peaks within 24-48 hours and resolves significantly by day 3.
- Pain and Tenderness: The injection process itself can be uncomfortable. Most practitioners use a topical numbing cream for 30-45 minutes before the procedure to minimize this. After the anesthetic wears off, the area may feel tender to the touch for a day or two, similar to the sensation after a vigorous facial treatment.
- Bruising (Ecchymosis): Bruising occurs when a needle nicks a small blood vessel under the skin. The likelihood depends on the individual’s skin fragility and the practitioner’s technique. Bruises can range from small red pinpricks to larger purple patches and usually fade within 3-7 days.
- Itching: As the skin heals and the PN material is metabolized, some patients report mild, transient itching. This is generally not a cause for concern unless it is severe or persistent.
The following table summarizes the common temporary side effects, their typical duration, and management tips:
| Side Effect | Frequency | Typical Duration | Management Tips |
|---|---|---|---|
| Redness | Very Common (>90%) | 12-24 hours | Apply a cool compress; avoid hot showers/saunas. |
| Swelling | Common (70-80%) | 24-72 hours | Sleep with head elevated; gentle cool compresses. |
| Tenderness | Common (60-70%) | 1-2 days | Avoid touching or applying pressure to the area. |
| Bruising | Common (30-50%) | 3-7 days | Arnica cream or gel can help speed up resolution. |
| Itching | Less Common (10-20%) | 1-3 days | Keep skin moisturized; avoid scratching. |
Less Common and Procedure-Related Side Effects
These side effects occur less frequently and are often related to the injection technique, the product, or an individual’s unique physiological response.
Lumps and Nodules: Small, palpable lumps under the skin can sometimes form. There are two primary causes:
1. Technique-Related: If the PN gel is injected too superficially or in too concentrated a bolus, it can clump together. These lumps are usually temporary and can be massaged gently (as advised by your practitioner) to disperse the material.
2. Product Clumping: If the product is not properly reconstituted or handled, it may not have a smooth consistency, leading to uneven injection. A skilled practitioner minimizes this risk.
Skin Discoloration: Hyperpigmentation (darkening of the skin) can occasionally occur, particularly in individuals with darker skin tones (Fitzpatrick skin types IV-VI). This is often a response to the inflammation caused by the needles. Hypopigmentation (lightening of the skin) is much rarer.
Infection: Any procedure that breaks the skin barrier carries a risk of infection. This is why it is critical that the procedure is performed in a sterile clinical environment. Signs of infection include increasing redness, warmth, pain, and pus formation days after the procedure. Strict adherence to aseptic technique by the practitioner is the best prevention. If you suspect an infection, contact your provider immediately.
Allergic Reaction: Although the PN in rejuran is highly purified to remove proteins and allergens, there is still a minute risk of an allergic reaction, especially for individuals with a known allergy to salmon or fish products. Reactions can range from localized increased redness and swelling to a systemic response (like hives or difficulty breathing), though the latter is extremely rare. A patch test is often recommended for those with significant allergies.
Rare and More Serious Complications
These are very uncommon but represent the more significant risks associated with any injectable procedure. They often underscore the importance of choosing an experienced, medically-qualified injector who understands facial anatomy.
Vascular Complications: This is the most serious potential risk. It occurs when the needle accidentally enters and blocks a blood vessel. There are two main types:
1. Arterial Embolization: If the material is injected into an artery, it can block blood flow to the surrounding tissue, potentially leading to skin necrosis (tissue death). This can result in scarring and permanent changes in skin appearance. The risk is higher in areas with dense vasculature, like the glabella (between the eyebrows) and the nasal ala (nose wings).
2. Venous Compromise: If a vein is blocked, it can cause a backflow of blood, leading to bruising and swelling that is more severe and prolonged.
A skilled practitioner uses techniques like aspirating (pulling back on the syringe plunger to check for blood) and has an in-depth knowledge of safe injection planes and high-risk zones to avoid these events. They are also trained to recognize the signs immediately (intense pain, blanching of the skin, mottled discoloration) and initiate emergency treatment.
Granuloma Formation: This is a rare, delayed complication where the body’s immune system walls off the injected material, forming a persistent, firm, inflammatory nodule. These can appear months after the injection and may require medical intervention, such as corticosteroid injections, to resolve. The risk is lower with PN-based fillers like Rejuran compared to some permanent or semi-permanent fillers.
Underlying Medical Conditions: Individuals with certain autoimmune conditions (e.g., lupus, rheumatoid arthritis), active skin infections in the treatment area, or a history of keloid scarring may be at a higher risk for adverse events. A thorough medical consultation before the procedure is essential to screen for these contraindications.
Minimizing Your Risk: The Importance of the Practitioner
The single most significant factor influencing your risk profile is not the product itself, but the expertise of the person holding the syringe. A qualified medical professional—such as a dermatologist or plastic surgeon—brings a critical understanding of facial anatomy, sterile technique, and complication management. They can properly assess your skin, determine if you are a good candidate, use the correct injection depth and pattern, and provide realistic expectations. They are also equipped to handle any adverse reactions should they occur. Choosing a reputable clinic based on the practitioner’s credentials and experience, rather than price, is the most effective strategy for ensuring a safe outcome and maximizing the benefits of the Rejuran procedure.