Weight-Loss Injections : What GLP-1 Medicines Achieve, What They Cost and Who They Are For

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You get the market in Germany with prices and reimbursement, the most important studies with their real numbers, an honest answer to the question of safety, how such a medicine gets approved, and a clear line on who the injection is made for and who it is not, plus what needs to be clarified before a decision. On top of that : what happens to muscle and weight, and why protein and resistance training play a role.

TL;DR

The essentials

GLP-1-based medicines such as semaglutide and tirzepatide reduce weight in studies far more than lifestyle counselling alone : on average by around 15 to 21 percent over a little more than a year. They are approved from a BMI of 30, or from 27 with a weight-related condition, always on top of diet and exercise, and have been studied in many thousands of people. Safe in the sense of free of side effects they are not : gastrointestinal complaints are common, biliary disease more frequent, in the weight-loss trials more than twice as often as on placebo, and some serious side effects very rare. After stopping, much of the weight returns. They are not approved for cosmetic weight loss, and the EMA explicitly advises against it.

1. What the injections are

How they work

GLP-1 is a hormone the gut releases after eating. It dampens appetite, slows gastric emptying and helps regulate blood sugar. The medicines mimic this hormone but act much longer : semaglutide is injected once a week or taken daily as a tablet, liraglutide is injected daily. Tirzepatide also acts on a second gut-hormone receptor (GIP). What they all share : you eat less because you feel full sooner and are less hungry. The active substances were first developed against type 2 diabetes ; approval for weight management came only later.

Small plate with a little vegetables and lentils, a glass of water beside it — Satiety and appetite are at the core of how these medicines work.· Image AI-generated

2. The market in Germany

Products, prices, reimbursement

Approved products in Germany

Active substance	Product	Approved for	Use	Out-of-pocket cost per 4 weeks, rounded (as of 5 October 2026)
Liraglutide	Saxenda	Weight management, EU since 2015	daily	–
Semaglutide	Wegovy (injection)	Weight management, EU since 2022	weekly, dose escalated in steps ; since February 2026 also a higher maintenance dose	around €170 to €280 depending on dose ; highest dose not checked
Semaglutide	Wegovy (tablet)	Weight management, EU since July 2026	daily, on an empty stomach	around €170 to €235 depending on dose (pack of 30 tablets)
Tirzepatide	Mounjaro	Type 2 diabetes, since 2023 also weight management	weekly	around €205 to €490 depending on dose
Semaglutide	Ozempic, Rybelsus	type 2 diabetes only	weekly or daily	– (not approved for weight management)

Prices are the same in every pharmacy ; anyone with statutory health insurance pays them out of pocket, for a long-term therapy over years.

Three points that often get mixed up in everyday life :

Same active substance does not mean same product. Ozempic and Wegovy both contain semaglutide, but Ozempic is approved only for type 2 diabetes. Using it for weight loss is use outside its approval (off-label).
Statutory health insurance does not pay. Under Section 34(1) of the German Social Code Book V (SGB V), medicines for weight management are excluded from reimbursement by statutory health insurance (GKV) ; Annex II of the Pharmaceutical Directive (Arzneimittel-Richtlinie) explicitly lists semaglutide and tirzepatide for this. The disease management programme for obesity that has existed since July 2024 does not change this : the Federal Joint Committee (G-BA, the body that decides what statutory insurance covers) has no leeway to include weight-loss medicines in it. With private health insurance, it depends on the tariff terms and on whether the treatment is medically necessary in the individual case.
Counterfeit products are real. In 2023 the BfArM (Germany's Federal Institute for Drugs and Medical Devices) warned of counterfeit Ozempic pens that contained insulin instead of semaglutide, with the risk of severe hypoglycaemia. In 2025 the EMA and national authorities warned of a sharp rise in illegal online offers. Offers without a prescription, via social media or with a supposed authority logo are warning signs.

Further active substances are in development, such as retatrutide, the combination of cagrilintide and semaglutide, and the tablet orforglipron. None of them has EU approval as of the cut-off date ; orforglipron has been under review by the EMA since January 2026, and no opinion has been issued yet.

3. What the studies show on effect

Approval trials versus placebo

All the large approval trials studied adults with a BMI from 30, or from 27 with a comorbidity, without diabetes, and all groups also received diet and exercise counselling. The placebo group therefore shows what this counselling achieved on its own.

Weight change in the large trials

Study	Product	Duration	Weight change, product versus placebo
SCALE (Pi-Sunyer 2015)	Liraglutide 3.0 mg daily	56 weeks	−8.0 % versus −2.6 %
STEP 1 (Wilding 2021)	Semaglutide 2.4 mg weekly	68 weeks	−14.9 % versus −2.4 %
STEP 5 (Garvey 2022)	Semaglutide 2.4 mg weekly	104 weeks	−15.2 % versus −2.6 %
SURMOUNT-1 (Jastreboff 2022)	Tirzepatide 5, 10 or 15 mg weekly	72 weeks	−15.0 / −19.5 / −20.9 % versus −3.1 %
SURMOUNT-5 (Aronne 2025)	Tirzepatide versus semaglutide, head to head	72 weeks	−20.2 % versus −13.7 %
STEP UP (Wharton 2025)	Semaglutide 7.2 mg weekly	72 weeks	−18.7 % versus −3.9 % (2.4 mg : −15.6 %)

The higher dose is approved only for adults with a baseline BMI from 30, and only after at least four weeks on 2.4 mg ; if it brings no additional weight loss, the dose should go back to 2.4 mg.

The effect varies widely. In STEP 1, 86.4 percent reached at least 5 percent weight loss and 32.0 percent at least 20 percent. So some lose hardly anything, others a great deal. The average does not predict where you yourself will end up.

Losing little at first does not mean it has failed. In a post-hoc analysis of SURMOUNT-1, 18 percent of those treated regularly who stayed until the end of the study had lost less than 5 percent after twelve weeks of tirzepatide, that is, still during dose escalation ; 90 percent of them did reach at least 5 percent by week 72, 11 percent on average (Ard 2025, funded by the manufacturer).

All the large trials were funded by the manufacturers. That does not make the numbers wrong, but it belongs in the assessment.

4. Is it safe?

Benefits and risks

The honest answer : for the approved groups, authorities consider the benefit greater than the risk. “Safe” in the sense of free of side effects it is not.

Safety at a glance

Topic	What has been shown
Gastrointestinal	Most common side effect. In STEP 1, on semaglutide 44.2 percent had nausea (placebo 17.4), 24.8 percent vomiting (6.6) and 31.5 percent diarrhoea (15.9). Overall, 7.0 versus 3.1 percent stopped because of side effects, 4.5 versus 0.8 percent because of gastrointestinal complaints.
Gallbladder	In a meta-analysis of 76 trials, the risk of gallbladder and biliary disease was 37 percent higher (RR 1.37 ; 1.23 to 1.52), in absolute terms about 27 additional cases per 10,000 person-years (He 2022). In the weight-loss trials the signal was stronger (RR 2.29 ; 1.64 to 3.18). For tirzepatide, a meta-analysis of twelve trials, mostly in type 2 diabetes, shows a similar signal (RR 1.52 ; 1.17 to 1.98 ; Gong 2025).
Pancreas	Acute inflammation of the pancreas is a known warning. In the trials without diabetes it was rare, with no significant difference from placebo, on tirzepatide 4 of 2,183 versus 2 of 935 (Safwan 2025). Persistent severe upper abdominal pain needs to be checked by a doctor immediately.
Optic nerve (NAION)	Since June 2025, the EMA has classified a circulatory disorder of the optic nerve as a very rare side effect of semaglutide, roughly one additional case per 10,000 person-years, derived from data in type 2 diabetes. For tirzepatide there is no separate EMA assessment so far. A sudden deterioration in vision needs to be checked by a doctor immediately.
Mental health	In 2024 the EMA found no causal link with suicidal thoughts. In the pooled approval trials, new suicidal thoughts occurred in 0.4 versus 0.6 percent on semaglutide (Wadden 2024) and in 0.6 versus 0.6 percent on tirzepatide (Wadden 2026) ; on tirzepatide there were two suicide attempts, on placebo none, and the authors call for further monitoring. People with severe mental illness were excluded. Observational studies contradict each other : one found fewer suicidal thoughts (Wang 2024), another more depression diagnoses (Kornelius 2024) ; neither proves a cause. Anyone who has had depression should discuss this with their doctor before starting.
Thyroid	C-cell tumours occurred in rodents. In a large Scandinavian registry study, thyroid cancer was not substantially more frequent under GLP-1 treatment (HR 0.93 ; 0.66 to 1.31) ; for semaglutide, however, follow-up there averages only about one year (Pasternak 2024).
Bone	Bone density falls along with weight. On liraglutide alone it decreased more than on placebo after a diet ; on liraglutide plus exercise it did not fall significantly more than on placebo, but it did fall in absolute terms (Jensen 2024, exploratory analysis). In SELECT, fractures occurred in 1.5 versus 1.7 percent. For tirzepatide, randomised bone data in people without diabetes are lacking.
Skin and hair	On 7.2 mg semaglutide in STEP UP, 21.6 percent reported abnormal skin sensations such as burning or sensitivity to touch, versus 0.3 percent on placebo ; most complaints subsided with continued treatment. Hair loss occurred in 5.3 versus 1.0 percent, more often with large weight loss (Wegovy summary of product characteristics).
Anaesthesia	Because the stomach empties more slowly, food may still be present in it during anaesthesia ; cases in which it was inhaled have been reported. The German specialist societies recommend pausing weekly products one week before a procedure ; this belongs in the conversation with the anaesthesia team.

5. What happens after stopping

Weight after stopping

Wooden hourglass beside a bowl of fresh herbs — For many a long-term therapy : the effect lasts as long as treatment continues.· Image AI-generated

A large part of the weight comes back. Three studies show this consistently :

STEP 4 : Those who switched to placebo after 20 weeks of semaglutide regained 6.9 percent by week 68 ; those who continued treatment lost a further 7.9 percent.
SURMOUNT-4 : After 36 weeks of tirzepatide (−20.9 percent), the placebo group regained 14.0 percent by week 88.
STEP 1, follow-up : One year after stopping, about two thirds of the lost weight had returned on average ; the accompanying lifestyle support ended at the same time.

In everyday life, many stop earlier. In Denmark, where people pay for the injection for weight loss themselves, as in Germany, 49 percent of almost 158,000 people without diabetes had stopped it for at least two months within a year ; about one in four of them started again a few months later (Mailhac 2026). A US cohort shows how large the difference is : those who stayed on for a year without a longer break had lost 11.9 percent on average, those who stopped in the first three months 3.6 percent (Gasoyan 2025). With continued treatment, the effect holds : in SELECT, weight on semaglutide fell until about week 65 and then remained stable ; among the roughly 900 people per group who were still weighed after four years, it was 10.2 percent below baseline, versus 1.5 percent on placebo (Ryan 2024).

So the injection treats a chronic tendency for as long as it is taken. Anyone who starts it should know that for many it is a long-term therapy, with the costs from section 2.

6. Who the injection is made for, and who it is not

Approval and limits

Approved are semaglutide and tirzepatide for weight management in adults with a baseline BMI from 30, or between 27 and 30 with at least one weight-related condition such as high blood pressure, prediabetes or sleep apnoea, and always in addition to a reduced-calorie diet and more physical activity. Semaglutide is also approved for adolescents from 12 years of age with obesity. The German S3 guideline on obesity says medicines may be considered in these groups, and only together with the basic therapy of diet, exercise and behaviour. The guideline (as of October 2024) has not yet assessed tirzepatide or the higher semaglutide dose.

The injection is not made for :

Normal weight and cosmetic weight loss. The EMA states explicitly that GLP-1 medicines are not approved for this and should not be used for it. The European Association for the Study of Obesity notes that evidence for using the medicines below a BMI of 27 is entirely lacking.
Pregnancy and plans to conceive. According to the product information, semaglutide should be stopped at least two months before a planned pregnancy, tirzepatide at least one month before. Semaglutide should not be used while breastfeeding ; for tirzepatide, the product information considers use acceptable, which is for the doctor to decide.
People with an eating disorder, as long as it has not been recognised and treated. The S3 guideline recommends recognising and treating an accompanying eating disorder.
Type 1 diabetes and previous pancreatitis are not formal contraindications, but have not been studied or hardly at all and need particular medical consideration.

Competitive sport : Semaglutide and tirzepatide are not on the WADA Prohibited List in 2027 either, but in the Monitoring Program. Unapproved substances from illegal online offers, such as retatrutide, on the other hand fall under the ban on non-approved substances. This concerns only the anti-doping rules : the medicines are not approved for athletes of normal weight.

Answered briefly

How much weight do you lose with a weight-loss injection?

In the approval trials STEP 1 and SURMOUNT-1, on average around 15 percent with semaglutide and 15 to 21 percent with tirzepatide over a little more than a year, each on top of diet and exercise counselling. The effect varies widely between people.

Who is the injection approved for?

For adults with a BMI from 30, or from 27 with a weight-related condition, always on top of diet and exercise. Semaglutide is also approved for adolescents from 12 years of age with obesity. It is not approved for cosmetic weight loss.

Is the weight-loss injection safe?

For the approved groups, the authorities consider the benefit greater than the risk. It is not free of side effects : gastrointestinal complaints are common, biliary disease more frequent, in the weight-loss trials more than twice as often as on placebo, and some serious side effects very rare (STEP 1 ; He 2022). Data on more than four years of continuous treatment in people without diabetes are lacking.

What happens when you stop?

A large part of the weight comes back. One year after stopping, about two thirds of the lost weight had returned on average in the STEP 1 follow-up.

Does health insurance pay?

German statutory health insurance (GKV) does not pay for weight-management medicines (Section 34 of the Social Code Book V, SGB V). With private insurance, it depends on the tariff and on whether the treatment is considered medically necessary in the individual case.

How much protein do I need on the injection?

We found no completed study comparing different protein amounts on the injection. US professional societies refer to a proposed 1.2 to 1.6 grams per kilogram per day, without clarifying which body weight this refers to. According to the same advisory, more protein alone is probably not enough without resistance training. Clarify the amount with your doctor or a nutrition professional.

This article is for information within the scope of lifestyle coaching. It is not medical advice, not a diagnosis and not a recommendation for or against any medicine. The medicines mentioned are prescription-only ; whether treatment is an option for you is decided by your doctor. Amounts mentioned come from studies and professional recommendations and are not individual instructions. Felix Baier is neither a physician nor a German-licensed Heilpraktiker ; StoaVita does not prescribe, does not arrange prescriptions and does not sell medicines or dietary supplements.

In the largest heart trial, the protection did not follow the amount of weight lost.

Beyond the scales

The effect on the scales is one thing. In the largest trial in people with cardiovascular disease and without diabetes, with 17,604 participants, heart attack, stroke or cardiovascular death occurred less often on semaglutide. A difference in protection between weight classes was not detectable, and it could not be explained statistically by the amount of weight lost ; about a third went along with the smaller waist circumference. For healthy people and people of normal weight, such a benefit has not been shown.

How such an injection gets approved and how extensively it was tested in humans, where a benefit beyond weight has been shown, what happens to muscle and why more protein without resistance training is probably not enough, what to clarify before a decision and where StoaVita comes in : that is the second part, along with the poster that puts the whole topic on one page.

Blurred preview of the poster with the core numbers

Continues in the client area

The second part is for clients : the approval route, added benefits, muscle and training, and where StoaVita comes in.

Up to this point the article covers the mechanism. What follows moves from the mechanism to your own values, and that part we keep for the people we work with.

Approval route : the three trial phases, central EU authorisation via the EMA, monitoring afterwards and how extensively the medicines were tested in humans
Added benefits beyond weight : cardiovascular disease, heart failure, sleep apnoea, and for whom they have not been shown
Muscle, protein and resistance training : how much lean mass is lost and what the professional societies advise
Rating matrix and what to clarify before a decision
Where StoaVita comes in, the open questions and the whole topic on one poster

There is no self-service sign-up. Access comes with working together ; the first conversation is free and non-binding.

Training, with or without the injection

Decisions about medicines are made by your doctor. Our field is training : we measure endurance and performance with cardiopulmonary exercise testing and lactate diagnostics and build a plan from it in which resistance training has a fixed place.

All services

Sources (primary literature, guidelines and agency information)

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Weight-loss injections :what they do and who they are for.