Two generations of the same design
Liraglutide and semaglutide are both Novo Nordisk peptides built from human GLP-1, the gut hormone released after a meal. Native GLP-1 is destroyed by the enzyme DPP-4 within minutes. Both drugs solve that the same way: a lightly altered sequence plus a fatty acid chain that grips albumin in the blood, so the peptide is shielded and cleared slowly.
Liraglutide, approved first, gets a half-life of about 13 hours from that design, long enough for one injection a day. Semaglutide pushes the same trick further, with additional changes that stretch the half-life to about a week. That single difference, daily versus weekly, turns out to carry a difference in effect size as well.
They are the two GLP-1 peptides you can actually buy in a Philippine pharmacy, which is why they get compared here.
Side by side
| Liraglutide | Semaglutide Stocked locally | |
|---|---|---|
| Brands | Victoza (diabetes), Saxenda (weight) | Ozempic (diabetes), Wegovy (weight), Rybelsus (oral, diabetes) |
| Half-life | About 13 hours | About 1 week |
| Dosing | Once daily | Once weekly |
| Weight-management dose | 3.0 mg | 2.4 mg |
| Pivotal weight trial | SCALE, 3,731 adults, 56 weeks | STEP 1, 1,961 adults, 68 weeks |
| Mean weight change vs placebo | 8.4 kg vs 2.8 kg | 14.9% vs 2.4% |
| Cardiovascular outcome trial | LEADER, type 2 diabetes | SELECT, obesity without diabetes |
| Head-to-head | STEP 8: 6.4% at 68 weeks | STEP 8: 15.8% at 68 weeks |
| Generic | US generics approved 2024 and 2025 | None |
| PH availability | Prescription, Victoza and Saxenda in pharmacies | Prescription, Ozempic and Wegovy in pharmacies |
The head-to-head: STEP 8
Cross-trial comparisons of GLP-1 drugs are unreliable because populations, durations and analysis rules differ. STEP 8 removed that problem. Published in JAMA in 2022, it randomised 338 adults with overweight or obesity and no diabetes at 19 US sites to weekly semaglutide 2.4 mg, daily liraglutide 3.0 mg or matching placebos, all with diet and physical activity counselling, for 68 weeks. The two active arms were open label against each other; each was blinded against its own placebo.
- Mean weight change was 15.8% on semaglutide and 6.4% on liraglutide, a difference of 9.4 percentage points. Pooled placebo lost 1.9%.
- 70.9% on semaglutide lost at least 10% of body weight, against 25.6% on liraglutide. For 15% or more the figures were 55.6% and 12.0%; for 20% or more, 38.5% and 6.0%.
- Gastrointestinal adverse events were almost identical: 84.1% and 82.7%.
- Discontinuation for any reason was 13.5% on semaglutide and 27.6% on liraglutide.
The participants were 78% women with a mean weight of about 104 kg, and the trial was funded by the manufacturer of both drugs. With those caveats, the result is about as clean a comparison as the class has: the weekly drug produced roughly two and a half times the weight loss of the daily one, with similar gut effects and fewer dropouts.
Their separate trial records
SCALE (2015) put liraglutide 3.0 mg against placebo in 3,731 adults without diabetes for 56 weeks. Mean loss was 8.4 kg versus 2.8 kg. 63.2% lost at least 5% of body weight against 27.1% on placebo, and 33.1% lost more than 10% against 10.6%. Serious adverse events were 6.2% versus 5.0%.
STEP 1 (2021) put semaglutide 2.4 mg against placebo in 1,961 adults without diabetes for 68 weeks. Mean change was 14.9% versus 2.4%, or 15.3 kg versus 2.6 kg. 86.4% lost at least 5%, 69.1% at least 10% and 50.5% at least 15%. Discontinuation for gastrointestinal events was 4.5% versus 0.8%.
Both drugs have also been tested on hard outcomes. LEADER (2016) followed 9,340 adults with type 2 diabetes and high cardiovascular risk for a median 3.8 years: the composite of cardiovascular death, heart attack or stroke occurred in 13.0% on liraglutide versus 14.9% on placebo, a hazard ratio of 0.87, and cardiovascular death fell from 6.0% to 4.7%. SELECT (2023) followed 17,604 adults with established cardiovascular disease and overweight or obesity but no diabetes for a mean 39.8 months: the same composite occurred in 6.5% on semaglutide versus 8.0% on placebo, a hazard ratio of 0.80.
These are different populations and not a comparison of the two drugs. What they establish is that both have outcome data beyond weight, which almost nothing else on this site can claim.
Side effects reported
The pattern is the same for both: nausea, diarrhoea, vomiting and constipation, mostly mild to moderate, concentrated during dose escalation and easing with time. In the Wegovy label the most common reactions were nausea (44% vs 16% placebo), diarrhoea (30% vs 16%) and vomiting (25% vs 6%). The Saxenda adult trials saw about 10% stop for side effects versus 4% on placebo.
Both labels carry the class boxed warning: thyroid C-cell tumours in rodents, human relevance undetermined, and a contraindication for anyone with a personal or family history of medullary thyroid carcinoma or MEN 2. Both list pancreatitis and gallbladder disease among the warnings. The side effect management guide covers what the trials report and when to see a doctor.
Status in the Philippines
Both are registered prescription medicines. Ozempic has been registered with FDA Philippines since 2022, and Wegovy is registered and on sale at Watsons since late 2025. Victoza and Saxenda are sold on prescription through Philippine pharmacies. Prescribing, dose selection and monitoring belong with a licensed Philippine physician.
Pharmacy prices checked on the pharmacies' own pages on 26 August 2026:
| Product | Pen | PHP | Source |
|---|---|---|---|
| Saxenda | 6 mg/mL pen | 3,380 | Southstar, MedsGo |
| Victoza | 6 mg/mL pen | 3,300 promo, 4,400 list | MedsGo |
| Ozempic | 0.25 or 0.5 mg | 7,650 | Watsons |
| Ozempic | 1 mg | 8,734 | Watsons |
| Wegovy | 0.25, 0.5 or 1 mg | 9,900 | Watsons |
| Wegovy | 1.7 mg | 11,600 | Watsons |
| Wegovy | 2.4 mg | 12,650 | Watsons |
Weekly pens hold four doses. Saxenda is daily, so one pen lasts about six days at the 3 mg maintenance dose. Those two facts matter more than the sticker price when comparing the drugs over a month; cost reality in the Philippines does that arithmetic. Enforcement has tightened in 2026: the Philippine College of Physicians issued an advisory on 14 March against compounded and non-registered Ozempic and Mounjaro, and the NBI and FDA Philippines raided a Pasig clinic on 27 May.
Where the class went next
Liraglutide is the first generation, semaglutide the second. The third adds receptors: tirzepatide adds GIP, CagriSema adds an amylin analogue, and retatrutide adds glucagon, covered on GLP-3 and retatrutide explained. Orforglipron takes a different route, a non-peptide pill. Semaglutide's STEP 8 margin over liraglutide is the reason the class kept moving.
Storage
Unopened pens of either drug go in the refrigerator at 2 to 8°C. The Wegovy label allows an unused pen up to 28 days between 8 and 30°C before the cap is removed; the Saxenda label allows an in-use pen 30 days at 15 to 30°C. Manila afternoons regularly pass 30°C, so an in-use pen belongs in the fridge or an insulated case, not a bag or a parked car. Do not freeze either, and do not use a pen that has frozen.
