Guide
Sore joints and back pain when you start lifting on Saxenda: what is normal
Some soreness in the first two or three weeks of strength work is expected, and on Saxenda it tends to be a little worse because you are recovering on much less food. The line we use: soreness in the muscle that fades within a day or two is adaptation; pain in a joint that is still there the next morning, or that swells, locks or gives way, is a signal to change the movement and see a physiotherapist. Nearly all early joint and back complaints come from too much load, too much range or too little warm-up in week one, and all three are fixable without stopping. Stopping is the expensive option, because the deficit keeps taking muscle whether or not you train.
Your number, before anything else
Protein is what decides whether the weight you lose is fat or muscle. Work your number out once and we will keep it with you on every page here. No account, no email.
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Why the first month hurts more than it should
Three things arrive at once. Muscles that have not been loaded for years are being asked to work, and they answer with soreness that peaks a day or two after the session. Joints that have carried extra weight are now moving through ranges they have not used, which is stiff at first. And you are doing all of it on Saxenda, eating far less than your body is used to, so repair is slower and the soreness lasts longer. Liraglutide's appetite effect is milder and steadier than the weekly medications. Most people we coach on Saxenda can eat a normal small meal; the risk is subtler, because the appetite that remains is often for toast rather than for chicken.
The temptation is to stop until it settles. That is where the muscle goes. Pooled across 20 randomised trials, 26.8% of the weight lost on liraglutide was lean mass, against 26.2% when the same weight came off by diet alone, and 17.5% when resistance training was added. A back or a knee that is sore from a badly chosen exercise gets better in a week with a different exercise; a body that stops training for two months in a large deficit loses tissue it does not easily get back. The fix is nearly always the movement, the range or the load, and rarely the decision to train at all.
Saxenda's effect is milder and steadier than the weekly medications, so there is no obvious bad day to avoid. Train outside the daily peak, eight to twelve hours after the injection, and keep the two sessions two days apart.
What to measure instead of trusting the scale
Soreness makes it feel as though nothing is working. The strength test settles that argument inside a month.
One strength test, same way every week
Goblet squat reps at a fixed weight, push-ups, or the 30-second sit-to-stand for beginners. Fat loss does not make you weaker, so a number that drops three or four weeks running is a real signal, and it is fixable. It measures what you can do, not how much muscle you have.
Average protein a day, whole week
Not your best day. 1.2 to 1.6 g per kg of goal body weight (0.55 to 0.7 g per lb), floor 1.2, protein first at every meal.
Upper arm tape, same spot, relaxed
Centimetres or inches. The waist shrinks whatever you do; if the arm shrinks as fast, that is muscle. Weight is number four, same day and time. The scale tells you what you lost. These tell you what you kept.
Fixing the pain without stopping
Halve the load and shorten the range
A squat to a high chair instead of a deep one, a hinge to a box instead of the floor, a push-up against a bench instead of the floor. The pattern is the same and the joint does less of the work.
Warm up for five minutes, every time
Two minutes of walking, then one easy set of each movement with no weight. Cold joints on a body with less padding than it had are where most week-one back tweaks come from.
Brace, do not crunch
Back pain from lifting is usually a rounded lower back on the hinge. Keep the chest up, push the hips back, stop the range where the back begins to round. Swap sit-ups for a plank or a dead bug.
Feed the repair
Soreness that will not fade is often protein and sleep, not the exercise. 1.2 to 1.6 g per kg of goal weight (0.55 to 0.7 g per lb), with 25 to 30 g inside two hours of the session, and two full days between sessions.
Train outside the daily peak
Saxenda peaks eight to twelve hours after each injection. A session in the hours furthest from the peak is easier to fuel and easier to recover from.
A joint-friendly session for the first month
- Sit-to-stand from a high chair or bench, 2 sets of 8, holding a light dumbbell of 2 to 4 kg (4 to 9 lb) if the bodyweight version is easy
- Hip hinge to a box or a chair seat, 2 sets of 8, then a glute bridge, 2 sets of 10
- Push-up against a kitchen bench, 2 sets of 8, and a band row with the band looped around a door handle, 2 sets of 10
- Carry a shopping bag in each hand for 20 metres (22 yards), twice, then a 20-second plank on the knees
About twenty minutes, twice a week, two days apart, with a shake or 200 g (7 oz) of Greek yoghurt afterwards. Add a set in week three and a little weight in week five. Any movement that hurts in the joint rather than the muscle comes out and gets replaced, not pushed through.
Work out your own target on SaxendaSee a physiotherapist or your doctor if
- A joint swells, locks, gives way, or is still painful the morning after two sessions in a row
- Back pain that runs down a leg, comes with numbness or tingling, or changes your bladder or bowel control, which needs same-day attention
- Pain in a joint that has been replaced, or that you have been told to protect after an injury or surgery, before you load it at all
Dose and timing on Saxenda are your prescriber's decisions; we coach the food and the strength.
Questions people ask
Is it normal to be sore after starting strength training on Saxenda?
Yes, in the muscles, for two to five days after the first few sessions, and a little longer than usual because you are recovering on less food. Pain inside a joint that lasts into the next day is not normal adaptation and means the movement or the load needs changing.
Should I stop lifting if my knees or back hurt?
Change the movement rather than stopping. Shorten the range, lower the load, warm up, and swap the exercise that hurts for another in the same pattern. Stopping altogether in a deficit is what costs muscle. See a physiotherapist for pain that persists.
Does Saxenda affect recovery from exercise?
Indirectly, through lower food and fluid intake. Protein at the floor or above, 2 litres (68 fl oz) of fluid a day and two days between sessions cover most of it. Persistent joint pain belongs with a physiotherapist.
The evidence, and how current it is
Soreness in the first fortnight is the cost of entry. This is what is being bought with it.
Supervised resistance training for longer than 10 weeks has produced gains of around 3 kg (6.6 lb) of lean mass and around 25% in strength in adults. Locatelli JC et al, Diabetes Care 2024
In 191 older adults, higher protein was associated with more preserved lean tissue but not with better grip strength, walking speed or chair-stand scores. Protein looks after the material. Training is what turns it into function. Eglseer D et al, Nutrition Journal 2026
The papers these numbers come from
- Locatelli JC, Costa JG, Haynes A, et al. Incretin-Based Weight Loss Pharmacotherapy: Can Resistance Exercise Optimize Changes in Body Composition? Diabetes Care, 2024. Narrative review. doi:10.2337/dci23-0100
- Eglseer D, Reiter L, Schoufour JD, et al. Is higher protein intake during weight loss interventions in older adults associated with improved outcomes? A secondary data analysis of three randomised controlled trials. Nutrition Journal, 2026. 191 adults, mean age 65.1 years. doi:10.1186/s12937-025-01279-2
- Eisa N, Barood O. Lean Mass Changes With Incretin Therapy Versus Lifestyle Intervention: A Systematic Review and Meta-Analysis of Randomised Controlled Trials. Diabetes, Obesity and Metabolism, 2026. 20 randomised controlled trials, 15,782 participants. doi:10.1111/dom.70666
- Arslan S. Medical nutrition in the glucagon-like peptide-1 (GLP-1) era: Protein strategies, micronutrient monitoring, and lean mass preservation. Clinical Nutrition ESPEN, 2026. Narrative review, guideline-informed targets. doi:10.1016/j.clnesp.2026.103305
Last reviewed 18 September 2026. We update these figures when a larger or better study replaces them, and we say what changed. How we handle evidence.
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EverStrong provides nutrition and strength coaching and education. It is not medical advice and does not replace your prescribing doctor. Consult your doctor before starting a new exercise or nutrition plan, especially with a heart, kidney, liver or metabolic condition, if pregnant, or with a history of disordered eating.