Semaglutide 5mg | GLP-1 Agonist Research

Zoom

29,00 €

Tax included • Free delivery from 99€

Unavailable

The 10mg is in stock, shipped on the next dispatch, at 49,00 €I take the 10mg

Semaglutide 5mg is the entry format of the peptide research GLP-1 range. This nominal dosage historically corresponds to the 0.25 to 0.5mg weekly dose used in the initial titration phase of the Ozempic/Wegovy clinical scheme, multiplied by a reconstitution factor allowing several weeks of cycle. The 5mg vial offers perfect granularity for short-medium research protocols (4-8 weeks), individual tolerance exploratory tests, or consolidation cycles after an initial weight loss phase with higher dosages.

Semaglutide is the pioneer and historical reference of the next-generation GLP-1 agonist class. Developed by Novo Nordisk and FDA-approved in 2017 (Ozempic for type 2 diabetes) then 2021 (Wegovy for obesity), it has radically transformed the therapeutic landscape of obesity and diabetes through the most impressive clinical trials of the past fifteen years: STEP-1 (Wilding 2021 NEJM) demonstrating mean -14.9% weight loss at 68 weeks, SELECT 2023 (Lincoff NEJM) documenting -20% cardiovascular risk reduction in secondary prevention in non-diabetics. Over 30 phase III trials and over 2 million patient-years of pharmacovigilance make it the best-documented peptide molecule worldwide.

Why choose the 5mg dosage: three use cases dominate. Exploratory research: testing individual tolerance and metabolic response before investing in a higher dosage (inter-individual responses vary significantly). Short consolidation cycle: after an initial cycle with 10-20mg having reached a desired weight loss plateau, maintenance with weekly micro-doses for 4-8 weeks. Sensitive tolerance profile: patients anticipating significant digestive effects who prefer to start at very low dose and titrate extremely gradually over several weeks.

Typical reconstitution of a 5mg vial with 2ml USP bacteriostatic water gives a final concentration of 2.5 mg/ml, ideal for U100 withdrawals of 10 to 25 units (0.1 to 0.25ml) corresponding to doses of 0.25 to 0.625mg per injection. With weekly single frequency, a 5mg vial covers 8 to 16 weeks of cycle depending on target dosage - a temporal density allowing serious evaluation of individual response curve before potentially moving to a more concentrated dosage (10mg or 20mg).

Science

01
Mechanism of action

Semaglutide is a complete and selective GLP-1 receptor agonist (Glucagon-Like Peptide-1 Receptor, GLP-1R), resulting from sophisticated molecular engineering carried out by Novo Nordisk on the native scaffold of endogenous human GLP-1. The base peptide is modified at three critical positions to simultaneously resolve the two major limitations of native GLP-1: plasma half-life of 1-2 minutes (rapid degradation by dipeptidyl peptidase-4, DPP-4) and weak albumin affinity compromising duration of action.

Semaglutide structural modifications (described by Lau et al 2015, J Med Chem):
1. Ala8 to Aib (alpha-aminoisobutyrate) substitution: totally blocks DPP-4 cleavage at the N-terminal site, primary cause of native GLP-1 inactivation.
2. Lys34 to Arg34 substitution: removes a potential glycation site and stabilises conformation.
3. Lys26 acylation with C18 diacid fatty chain (octadecanedioic acid) via glutamic linker: creates a highly lipophilic covalent anchor that reversibly binds to serum albumin.

This C18 diacid acylation is the heart of semaglutide's pharmacological innovation. Once subcutaneously injected and diffused into the vascular compartment, semaglutide binds mainly to serum albumin (> 99%) through hydrophobic interaction between the C18 chain and the albumin lipid pocket. This reversible binding serves as a plasma reservoir progressively releasing free peptide for action on GLP-1R. Result: plasma half-life of 155-180 hours (about one week), a 10,000-fold increase vs native GLP-1.

Cellular-level mechanism: once bound to GLP-1R (G-protein coupled receptor class B), semaglutide triggers a pleiotropic signalling cascade:
- Adenylate cyclase activation via Gs protein -> intracellular cAMP increase.
- PKA and EPAC2 activation -> potentiation of glucose-dependent insulin secretion by pancreatic beta cells (explaining the absence of iatrogenic hypoglycaemia except under concomitant insulin).
- Glucagon secretion inhibition by pancreatic alpha cells under hyperglycaemia (preserved in hypoglycaemia, counter-regulatory mechanism intact).
- Gastric emptying slowing via vagus nerve (central effect on dorsal vagal complex), prolonging satiety and flattening post-prandial glycaemic peaks.
- Central POMC neuron activation in hypothalamus (arcuate nucleus) and AgRP/NPY neuron inhibition -> drastic food intake and appetite reduction.
- Recently identified extra-metabolic effects: inflammatory modulation (CRP, TNF-alpha reduction), direct cardioprotective effects (experimental studies on cardiomyocytes), neuroprotective effects (studies on Alzheimer's and Parkinson's mouse models).

Semaglutide's GLP-1R selectivity distinguishes it from dual agonists (Tirzepatide GLP-1/GIP) or triple agonists (Retatrutide GLP-1/GIP/GCGR). This monospecificity offers a more predictable and better-characterised pharmacological profile (extensive clinical corpus SUSTAIN + STEP + SELECT), but limits metabolic amplitude vs more recent multi-receptor agonists. Semaglutide nevertheless remains the historical reference of the class and the best-documented GLP-1 molecule to date.

Clinical data

02Clinical studies

Semaglutide's clinical corpus is one of the most extensive of the entire modern peptide class, with more than 30 randomised controlled phase III trials published since 2016 and cumulative pharmacovigilance follow-up exceeding 2 million patient-years.

SUSTAIN program (type 2 diabetes, 8 main trials 2016-2020): evaluation of glycaemic efficacy and weight loss in type 2 diabetics.
- SUSTAIN-1 (Sorli et al 2017, Lancet Diabetes Endocrinol): HbA1c reduction -1.45% vs placebo over 30 weeks at 1mg/week dose.
- SUSTAIN-6 (Marso et al 2016, NEJM): major cardiovascular trial on 3297 high CV risk patients, significant reduction in composite CV mortality / non-fatal MI / non-fatal stroke endpoint (-26%, p=0.02), establishing semaglutide's cardiovascular benefit.
- SUSTAIN-7 (Pratley et al 2018, Lancet Diabetes Endocrinol): head-to-head comparison semaglutide 1mg vs dulaglutide 1.5mg, semaglutide superiority on HbA1c (-1.8% vs -1.4%) and weight (-6.5kg vs -3.0kg).

STEP program (non-diabetic obesity, 8 trials 2021-2023): weight loss evaluation at 2.4mg/week dose (obesity dose, higher than diabetes dose).
- STEP-1 (Wilding et al 2021, NEJM): flagship trial on 1961 non-diabetic overweight or obese adults, mean weight loss of -14.9% at 68 weeks (vs -2.4% placebo), -15% threshold reached in 50.5% of patients. Marking the greatest pharmacological anti-obesity advance since amphetamine derivatives of the 1970s.
- STEP-4 (Rubino et al 2021, JAMA): treatment cessation effect - mean weight regain of +6.9% over 48 post-cessation weeks, confirming the chronic nature required of treatment.
- STEP-5 (Garvey et al 2022, Nat Med): 2-year weight loss maintenance under continuous treatment, no early plateau, total mean loss -15.2%.

SELECT 2023 (Lincoff et al 2023, NEJM): major cardiovascular trial on 17,604 adults with established cardiovascular disease but without diabetes, randomised semaglutide 2.4mg vs placebo, mean 39.8 month follow-up. -20% reduction in primary composite endpoint (CV mortality, MI, stroke, p<0.001), demonstrating for the first time a GLP-1 cardiovascular benefit in secondary prevention in non-diabetics. Opening the way to a dedicated cardiovascular indication, distinct from the metabolic indication.

Detailed pharmacokinetics (Kapitza et al 2015, J Clin Pharmacol; Granhall et al 2019, Clin Pharmacokinet):
- SC bioavailability: 89%
- Tmax: 1-3 days after SC injection
- Distribution volume: 12.5 L
- Plasma protein binding: > 99% (mainly albumin)
- Half-life: 155-180 hours (7-8 days)
- Clearance: 0.05 L/h
- Metabolism: hepatic and renal proteolysis (comparable elimination to native GLP-1 once released from albumin)
- Excretion: 70% urinary, 30% faecal

Tolerance and adverse effects: cumulative SUSTAIN + STEP + SELECT data establish a well-characterised tolerance profile, dominated by digestive effects (nausea 15-44%, vomiting 5-25%, diarrhoea 15-30%, constipation 5-15%), generally transient during titration. Rare but serious effects: acute pancreatitis (< 0.5%), aggravated diabetic retinopathy in poorly controlled patients (SUSTAIN-6 weak signal), theoretical risk of medullary thyroid tumours (rodent signal unconfirmed in humans).

Post-marketing data 2022-2025: emergence of signals on concomitant muscle mass loss (up to 25% of weight loss is lean mass, Heymsfield 2023), persistent gastroparesis post-cessation in a few published cases, and glucagon-mediated peak recovery after abrupt cessation (rebound dumping). These observations reinforce the need for nutritional-muscular support and progressive cessation.

No references yet for this peptide — search PubMed for associated scientific literature.

The listed studies are provided for documentation and research purposes only. They do not constitute a therapeutic indication nor a recommendation for human use. This product is strictly for laboratory use only (RUO).

Lab workflow

03
Research protocols

Semaglutide 5mg reconstitution: recommended volume 2ml USP bacteriostatic water 0.9% benzyl alcohol, giving final concentration 2.5 mg/ml. Alternative: 1ml giving 5 mg/ml (more concentrated, more delicate U100 syringe reading for small doses).

U100 dosage correspondences (concentration 2.5 mg/ml):
- 4U = 0.04ml = 100 mcg (0.1 mg) — micro-test dose
- 10U = 0.1ml = 250 mcg (0.25 mg) — initial titration dose
- 20U = 0.2ml = 500 mcg (0.5 mg) — intermediate dose
- 40U = 0.4ml = 1000 mcg (1 mg) — high dose (SUSTAIN equivalent)
- 80U = 0.8ml = 2000 mcg (2 mg) — maximal dose (high Wegovy equivalent)

Recommended research titration schemes (single weekly SC injection):
- Week 1-4: 0.25 mg/week (10U per week)
- Week 5-8: 0.5 mg/week (20U per week)
- Week 9-12: 1.0 mg/week (40U per week, standard SUSTAIN dose)
- Week 13-16: 1.7-2.4 mg/week if obesity targets (68-96U, STEP/Wegovy dose)

The 5mg vial typically allows 8 to 20 weeks of cycle depending on target dose: at 0.25 mg/week, 20 weeks; at 2.4 mg/week, 2 weeks. For a complete STEP-like cycle, plan 2 to 3 5mg vials or move to the more economical 10mg/20mg format.

Injection timing: fixed day of the week (e.g. every Sunday morning), random relative to meals. Clinical trials showed no pharmacokinetic benefit of fasting vs post-meal injection thanks to long half-life. Day-to-day-week-to-week consistency matters more than precise time of day.

SC injection sites: systematic rotation between abdomen (fast absorption), anterior thigh (intermediate absorption), flank (slow absorption). No significant difference at long half-life but preserves local skin health.

Essential progressive titration: digestive effects (nausea, vomiting, diarrhoea) are maximal when transitioning to higher dose. Too rapid titration guarantees severe digestive intolerance and risks protocol abandonment. Conversely, too slow titration prolongs sub-therapeutic phase and delays weight loss. The 4-week-per-step compromise is well validated by trials.

Combinations and interactions: semaglutide can be combined with other research peptides (BPC-157 gastro-protective co-injection to reduce nausea, Cagrilintide amylin analogue to amplify weight loss). To avoid: co-administration with insulin without dose reduction (hypoglycaemia risk), with sulphonylureas (same reason), with other GLP-1s (redundancy without additional benefit).

Reconstitution for this format (5 mg)Standard volumes used in laboratory settings

Water added	Concentration	Reading marker
1 ml	5 mg/ml	40 UI = 2 mg
2 ml	2,5 mg/ml	40 UI = 1 mg

The volume of water does not change the product, only its concentration. Introduce the water slowly along the vial wall, never directly onto the lyophilisate, then swirl without shaking. Markers given on a 1 ml syringe graduated in 100 units.

Asepsis

Disinfect surfaces and stoppers (70% alcohol).

Solvent

Draw the required volume of bacteriostatic water.

Introduction

Inject gently against the vial wall (avoid direct jet on powder).

Solubilization

Roll the vial gently. Do not shake vigorously (degradation risk).

Solution storageOnce reconstituted: 2-8°C (refrigerator).

WarningTheoretical tool for chemical handling. Does not constitute medical advice.

I open the dilution calculator

What is normal on arrivalThe observations that worry customers, and are not defects

The amount of powder looks tiny. A lyophilisate takes up a few millimetres at the bottom of the vial, sometimes just a translucent film. The stated weight is there.
The powder is compact, stuck to the wall or to the stopper. Transport moves the freeze-dried cake around. It changes nothing to reconstitution.
The vial carries no individual label. That is our standard packaging, not a downgraded vial.
After reconstitution, deposits or filaments appear. This is common, especially with small molecules. Let it settle and roll the vial between your palms, never shake it.
The parcel is plain. Nothing on the outside indicates the contents or the brand name.

What is not normal: a cracked vial, an uncrimped cap or a stopper that moves, powder that has liquefied or changed colour. In those specific cases, write to us with a photo and we take the vial back.

Handling

04Storage & handling

Lyophilised semaglutide stores for 24 months in sealed vial at room temperature (15-25°C) protected from direct light. No pre-reconstitution refrigeration required. After reconstitution in USP bacteriostatic water, the solution peptide stores for 21-28 days at 2-8°C, beyond progressive chemical degradation by peptide hydrolysis measurable by HPLC.

Fragile chemical structure: despite stabilisation modifications (Aib8, Arg34, C18 diacid), semaglutide remains a long peptide (30 amino acids) with sensitivity sites:
- N-terminal amide bond: sensitive to acid or enzymatic hydrolysis.
- Methionine residue Met14: oxidation to methionine sulphoxide under prolonged dissolved oxygen exposure.
- Glutamic linker ester bond: possible hydrolysis in acidic solution (pH < 5).
- C18 acylated chain: chemically stable but can undergo progressive beta-oxidation over several weeks.

Optimal storage conditions:
- Unopened vial: 15-25°C, original cardboard packaging, protected from light, humidity < 60%.
- Opened reconstituted vial: strict 2-8°C, vertical position, vial covered or in cardboard box for light protection, do not freeze.
- Transport: refrigerated isothermal pack 2-8°C on trips > 2 hours. Temperatures > 30°C accelerate peptide degradation in solution.

Errors to avoid:
- Freeze-thaw: freeze-thaw cycles form ice crystals denaturing peptide tertiary conformation, 20-40% activity loss per cycle.
- Direct solar exposure: Met14 methionine and acylated Lys26 are photodegradable, 1-2 hour direct sun exposure can reduce activity by 5-15%.
- Vigorous agitation: semaglutide forms reversible oligomers in solution (dimers and trimers via C18), mechanical agitation can favour irreversible insoluble aggregates.
- Mixing with other peptides in same vial: unpredictable interactions with pH / ionic strength / other lipophilic residues. One vial = one peptide.

Recommended reconstitution with USP bacteriostatic water 0.9% benzyl alcohol. Typical reconstitution volume depending on nominal dosage (detailed below in Protocols section). Reconstituted peptide presents a clear solution, possibly slightly opalescent after a few hours (reversible C18 micro-oligomer formation), colourless. Any yellow or brown colouration signals oxidation or contamination -> rejection.

Alteration visual indicators: solution that remains turbid, appearance of floating particles, formation of deposit at vial bottom, perceptible odour (normally odourless), swollen vial (possible suspect internal pressure). Faced with any of these signs, discard the vial and use a new one.

01What is the fundamental difference between semaglutide and natural GLP-1?

Natural GLP-1 has a 1-2 minute half-life, degraded almost instantly by plasma DPP-4 enzyme. Semaglutide carries three key modifications: Aib8 blocks DPP-4 cleavage, Arg34 stabilises conformation, and a C18 diacid acylated chain on Lys26 creates reversible binding to serum albumin. Result: 155-180 hour half-life (7-8 days), a 10,000-fold increase. This half-life enables single weekly injection vs practical impossibility with native GLP-1.

02Why does semaglutide cause such significant weight loss?

Multiple mechanisms. (1) Centrally, POMC hypothalamic neuron activation and AgRP/NPY neuron inhibition drastically reduce hunger and appetite. (2) Vagal slowing of gastric emptying prolongs post-prandial satiety. (3) Indirect metabolic improvement: glycaemic control reduces insulin peaks favouring adipose storage. The STEP-1 trial (Wilding 2021 NEJM) showed -14.9% mean weight loss at 68 weeks in non-diabetics, with 50.5% of patients reaching -15%. Recent data also suggest systemic anti-inflammatory effects contributing to adipose remodelling.

03Does semaglutide cause hypoglycaemia?

No in monotherapy in non-diabetics or non-insulinised type 2 diabetics. The mechanism of action is **glucose-dependent**: semaglutide potentiates insulin secretion only when glycaemia is elevated, and inhibits glucagon only in hyperglycaemia. In hypoglycaemia, physiological counter-regulation remains intact. Increased hypoglycaemia risk only in combination with insulin or sulphonylureas, which then requires dose reduction of these concomitant drugs.

04What's the difference between semaglutide, tirzepatide and retatrutide?

Three successive generations of GLP-1 agonists. **Semaglutide** (2017): mono-GLP-1R agonist, -15% weight loss STEP-1. **Tirzepatide** (2022, Mounjaro): GLP-1R + GIPR co-agonist, adds GIP thermogenic arm, -20.9% weight loss SURMOUNT-1. **Retatrutide** (phase III ongoing): GLP-1R + GIPR + GCGR triple agonist, adds glucagon arm (thermogenesis + lipid beta-oxidation), -24.2% weight loss phase II Jastreboff 2023. Increasing metabolic amplitude, decreasing clinical corpus. Semaglutide remains best documented to date.

05What are the most frequent semaglutide side effects?

Digestive effect dominance, generally transient during titration (first 4-8 weeks). Nausea 15-44%, vomiting 5-25%, diarrhoea 15-30%, constipation 5-15%. Headaches, fatigue, excessive satiety sensations. Rare but serious effects: acute pancreatitis < 0.5%, persistent post-cessation gastroparesis (published cases), aggravated diabetic retinopathy in poorly controlled patients. Theoretical medullary thyroid tumour risk (rodent signal, unconfirmed in humans). Most digestive effects reduce with progressive titration and dietary adaptation (frequent small meals, avoid fat and fast sugars).

06How is semaglutide stored?

Unopened lyophilised vial: 24 months at 15-25°C protected from light, original cardboard packaging. After reconstitution: 21-28 days at strict 2-8°C (refrigerator), vertical position, protect from light. Never freeze (freeze-thaw cycles denature the peptide, 20-40% activity loss per cycle). Visually inspect before each use: solution should be clear or slightly opalescent (normal reversible C18 micro-oligomer formation), without yellow or brown colouration. Any lasting turbidity, particle, deposit or colouration = vial rejection.

07Should semaglutide be stopped progressively?

Recommended. Abrupt GLP-1 cessation after prolonged use can trigger a **metabolic rebound phenomenon**: accelerated weight regain (STEP-4 documents +6.9% over 48 post-cessation weeks), rapid recovery of central orexigenic signals, re-centring of hypothalamic set-point. Recommended scheme: progressive reverse titration over 4-8 weeks, dose reduction in 25% steps, nutritional support and physical activity to preserve the new metabolic set-point. Abrupt cessation does not neutralise effects but rapidly redeploys them.

08Does semaglutide cause muscle mass loss?

Yes, partially. Heymsfield 2023 data and STEP secondary analyses show that about 25% of weight loss under semaglutide is lean mass (muscle + organs + bone). It's a phenomenon common to rapid weight loss interventions (hypocaloric diet, bariatric surgery). Compensatory strategies: high protein intake (1.6-2.2 g/kg/day), 2-3x/week resistance training, progressive titration. New muscle-preservation targeted peptides (bimagrumab, experimental myostatin inhibitors) are emerging to counter this effect.

Benchmark

Similar peptides

Semaglutide vs native human GLP-1: native GLP-1 has a half-life of 1-2 minutes, unusable in therapeutic practice. Semaglutide, through its three structural modifications, reaches a half-life of 155-180 hours, a 10,000-fold increase. First synthetic GLP-1s (exenatide 2005, liraglutide 2010) progressed along this gradient without ever approaching semaglutide which remains the current mono-agonist class plateau.

Semaglutide vs Liraglutide (Victoza, Saxenda): liraglutide has a 13-hour half-life requiring daily injection, vs semaglutide once weekly. Comparable weight loss SUSTAIN/STEP (semaglutide -15% vs liraglutide -8% at obesity dose). Liraglutide retains niche utility (sensitive digestive profile patients tolerating lower peaks better). Semaglutide dominates on nearly all clinical criteria: efficacy, convenience (weekly), cardiovascular data, long-term cumulative tolerance.

Semaglutide vs Dulaglutide (Trulicity): direct SUSTAIN-7 comparison (Pratley 2018 Lancet Diabetes Endocrinol) on 1201 patients: semaglutide 1mg superior to dulaglutide 1.5mg on HbA1c (-1.8% vs -1.4%) and weight loss (-6.5kg vs -3.0kg). Same injection frequency (weekly). Dulaglutide retains marginal digestive tolerance advantage. Semaglutide = first choice if main objective is weight + glycaemia.

Semaglutide vs Tirzepatide (Mounjaro, Zepbound): tirzepatide is a GLP-1/GIP dual agonist from the next generation (approved 2022). SURMOUNT-1 trial (Jastreboff 2022 NEJM): mean weight loss at 72 weeks -20.9% at 15mg (vs -14.9% semaglutide STEP-1 at 2.4mg). Direct comparison SURPASS-2 (Frias 2021 NEJM, diabetics) shows tirzepatide 15mg superior to semaglutide 1mg on HbA1c and weight. Tirzepatide is mechanically more powerful thanks to GIP co-activation adding a thermogenic arm. Semaglutide retains the advantage of massive clinical corpus (> 10x longer) and specific SELECT cardiovascular data.

Semaglutide vs Retatrutide: retatrutide is an even more recent GLP-1/GIP/GCGR triple agonist (phase III ongoing late 2024-2025). Published phase II data (Jastreboff 2023 NEJM) suggest -24.2% weight loss at 48 weeks at 12mg - the highest ever observed in a peptide trial. The additional glucagon arm activates thermogenesis and lipid beta-oxidation. Semaglutide will remain relevant for its known profile and lower cost but will probably be surpassed in amplitude by retatrutide.

Semaglutide vs bupropion/naltrexone, orlistat, phentermine: older obesity pharmacological treatments typically reach -3 to -8% weight loss, largely inferior to semaglutide's -15%. Less favourable tolerance profiles (psychiatric bupropion/naltrexone effects, orlistat steatorrhoea, phentermine dependence). GLP-1s have redefined the obesity therapeutic standard starting with STEP-1.

Semaglutide oral (Rybelsus) vs Semaglutide SC (Ozempic, Wegovy): oral version (Rybelsus, approved 2019) available in 3, 7, 14 mg daily with absorption assisted by salcaprozate (SNAC). Oral bioavailability 1%, efficacy inferior to SC (-3 to -5 kg vs -15 kg). Practical interest (needle phobia) but unfavourable cost-efficacy ratio. Weekly SC form remains gold standard for peptide research and real practice.

Full guide: Semaglutide — mechanism, studies, dose comparison

Metabolism

Asepsis

Solvent

Introduction

Solubilization

Complementary reagents