Saxenda (liraglutide) is a glucagon-like peptide-1 (GLP-1) receptor agonist used for weight management in adults with obesity or overweight with weight-related comorbidities. Administered via subcutaneous injection, Saxenda can occasionally cause localised lumps or nodules at the injection site. These reactions range from benign, self-limiting swelling to lipohypertrophy (tissue thickening) from repeated injections in the same area. Understanding the causes, recognising normal versus concerning reactions, and employing proper injection technique are essential for minimising complications and ensuring safe, effective treatment. This article provides evidence-based guidance aligned with UK clinical practice to help patients manage injection site reactions confidently.

What Causes a Lump Under the Skin After Saxenda Injections?

Saxenda (liraglutide) is a glucagon-like peptide-1 (GLP-1) receptor agonist administered via subcutaneous injection for weight management in adults with obesity or overweight with weight-related comorbidities. When injected beneath the skin, Saxenda can occasionally cause localised lumps or nodules at the injection site. Understanding the underlying mechanisms helps patients recognise normal reactions and identify when medical review may be warranted.

Common causes of lumps following Saxenda injection include transient injection-site reactions and bruising. Lipohypertrophy (tissue thickening) can occur with repeated injections into the same area, though this is less commonly reported with liraglutide than with insulin. This presents as firm, painless lumps that develop gradually. These areas may affect medication absorption, potentially reducing effectiveness.

A localised inflammatory response to the injection itself is frequently observed. The subcutaneous tissue may react to the needle trauma or the medication volume, resulting in temporary swelling, redness, or a small, tender lump. This reaction usually resolves within a few days without intervention. In some cases, injecting too rapidly or using cold medication directly from the refrigerator can exacerbate tissue irritation.

Bruising and haematoma formation can also create palpable lumps when small blood vessels are inadvertently damaged during injection. These typically appear as discoloured, tender areas that gradually fade over one to two weeks. Rarely, an injection site abscess may develop if bacteria are introduced during injection, though this is uncommon with proper technique and hygiene. Such infections present with increasing pain, warmth, redness, and sometimes purulent discharge, requiring prompt medical assessment.

Importantly, do not inject into areas that are hard, bruised, tender, inflamed, infected, or have existing lumps.

How to Identify Normal vs Concerning Injection Site Reactions

Distinguishing between expected injection site reactions and those requiring medical attention is essential for patient safety. Most lumps following Saxenda injections are benign and self-limiting, but certain features warrant clinical review.

Normal injection site reactions typically include:

• Mild swelling or firmness that usually subsides within a few days, gradually diminishing without treatment

• Slight redness (erythema) around the injection point, typically limited in size

• Minimal tenderness that does not interfere with daily activities

• Small bruises that change colour from red-purple to yellow-green as they resolve

• Lipohypertrophy lumps that are painless, non-inflamed, and develop slowly over time

These reactions are documented in Saxenda's Summary of Product Characteristics, with injection site reactions categorised as 'common' (affecting up to 1 in 10 people).

Concerning features that should prompt contact with your GP or healthcare provider include:

• Increasing pain, warmth, or swelling beyond a few days post-injection

• Expanding redness spreading beyond the immediate injection site

• Fever or systemic symptoms such as chills, malaise, or feeling generally unwell

• Purulent discharge or abscess formation at the injection site

• Hard, persistent lumps that do not resolve after several weeks

• Severe allergic reactions including widespread rash, difficulty breathing, or facial swelling (anaphylaxis—call 999 or go to A&E immediately)

Patients should also be aware that lipodystrophy (tissue changes including both lipohypertrophy and lipoatrophy) can affect medication absorption. If you notice lumps developing at injection sites, inform your healthcare provider, as this may necessitate adjusting your injection rotation pattern. You can report suspected side effects via the MHRA's Yellow Card scheme (yellowcard.mhra.gov.uk), contributing to ongoing medication safety monitoring.

Preventing Lumps and Skin Reactions with Saxenda

Preventing injection site complications requires consistent adherence to best practice guidelines and patient education. Several evidence-based strategies significantly reduce the risk of developing lumps and other skin reactions with Saxenda.

Systematic injection site rotation is the cornerstone of prevention. The abdomen, thighs, and upper arms are approved injection sites for Saxenda. Patients should rotate between these areas and, within each area, use different spots for each injection. A practical approach involves dividing the abdomen into quadrants and systematically moving through them, ensuring at least 1-2 cm distance between injection points. Avoid injecting into areas with existing lumps, bruising, or irritation.

Proper medication handling also plays a crucial role:

• Allow Saxenda to reach room temperature before injecting (remove from refrigerator 15–30 minutes prior)

• Inspect the solution for particles or discolouration before each use

• Do not use if the solution is not clear and colourless or almost colourless

• Store unopened pens in the refrigerator (2–8°C) and in-use pens below 30°C for up to 1 month

• Do not freeze Saxenda or expose to extreme heat

Skin preparation and hygiene are essential:

• Cleanse injection sites with an alcohol wipe and allow to dry completely before injecting

• Avoid injecting through clothing or into areas with skin conditions, scars, or existing lumps

• Do not massage the injection site immediately after administration, as this may increase local irritation

Needle management contributes to tissue preservation. Always use a new needle for each injection, as reusing needles causes tissue trauma and increases infection risk. A 4 mm pen needle is suitable for most adults regardless of body size. Never share pens or needles with others, and always dispose of used needles in an approved sharps container.

Proper Saxenda Injection Technique to Minimise Side Effects

Mastering correct injection technique is fundamental to minimising lumps and other injection site complications. Healthcare professionals should provide initial training, with periodic technique review to reinforce best practices.

Step-by-step injection technique:

1. Wash hands thoroughly with soap and water
2. Prepare the pen: Attach a new needle, perform the flow check before first use of each new pen as per manufacturer instructions
3. Select and prepare the site: Choose an injection area following your rotation schedule, cleanse with alcohol wipe, and allow to dry
4. Pinch technique: With a 4 mm needle, a skinfold is usually not needed; however, if you are very thin or concerned about injecting into muscle, gently pinch a fold of skin between thumb and forefinger
5. Insert the needle: Hold the pen at a 90-degree angle to the skin surface and insert the needle fully with a swift, smooth motion
6. Inject the medication: Press the dose button completely and hold for 6 seconds (count slowly: "one-thousand-one, one-thousand-two..." up to six) to ensure full dose delivery
7. Withdraw the needle: Remove the needle at the same angle it was inserted, release the skin pinch if used, and dispose of the needle safely in a sharps container

Common technique errors that increase lump formation include:

• Injecting too rapidly without the 6-second hold, causing medication to leak back out

• Incorrect angle (too shallow or into muscle rather than subcutaneous tissue)

• Injecting into lipohypertrophic areas, which impairs absorption and perpetuates tissue changes

• Reusing needles, which become blunted and cause increased tissue trauma

Note that upper-arm injections may require assistance from another person. Patients experiencing persistent injection site reactions despite proper technique should consult their prescriber. Alternative GLP-1 receptor agonists with different formulations or injection frequencies may be considered if local reactions significantly impact treatment adherence. NICE guidance (TA664) emphasises that weight management medications should be continued only if clinically beneficial and tolerable, making injection technique optimisation essential for treatment success.

Frequently Asked Questions