What is the difference between Mounjaro and Zepbound?

Mounjaro and Zepbound contain the identical molecule — tirzepatide — manufactured by Eli Lilly. Mounjaro is approved for type 2 diabetes, while Zepbound is approved for chronic weight management in adults with obesity or overweight with at least one weight-related comorbidity. The dosing, delivery device, and available strengths are the same. The distinction is purely regulatory, affecting insurance coverage and prescribing indications.

How much weight can I lose on tirzepatide?

In the SURMOUNT-1 clinical trial, average weight loss was 15.0% at 5mg, 19.5% at 10mg, and 20.9% at 15mg over 72 weeks. Individual results vary significantly — some participants lost over 25% of their body weight, while others lost less than 10%. Factors that influence response include starting BMI, adherence to dose titration, diet, physical activity, and individual metabolic factors.

Is tirzepatide better than semaglutide?

In the only head-to-head trial (SURPASS-2), tirzepatide produced significantly greater weight loss and HbA1c reduction than semaglutide 1mg. However, this comparison used semaglutide at the diabetes dose, not the higher weight-management dose (2.4mg). Cross-trial comparisons suggest tirzepatide 15mg produces approximately 5-6 percentage points more weight loss than semaglutide 2.4mg, but direct head-to-head data at the obesity doses is lacking.

How long does tirzepatide take to work?

Most patients begin noticing appetite changes within the first 1-2 weeks. Clinically meaningful weight loss (5% or more of body weight) typically occurs by weeks 8-12, though the dose-titration schedule means patients are still at lower doses during this period. Maximum weight loss generally occurs at 9-12 months of treatment at the maintenance dose.

Can I get compounded tirzepatide?

Compounded tirzepatide is available from compounding pharmacies when the drug is listed on the FDA Drug Shortage List. Compounded versions are significantly less expensive than brand-name Mounjaro or Zepbound but carry greater quality variability. TriedRx tracks 136 vendors and 1,748 samples of compounded tirzepatide — check our vendor testing data for purity and potency information before selecting a supplier.

What are the most common side effects of tirzepatide?

The most common side effects are gastrointestinal: nausea (24-33%), diarrhea (17-21%), vomiting (6-12%), constipation (6-11%), and decreased appetite (13-21%). These effects are most pronounced during dose escalation and typically improve at a stable dose. Approximately 4-7% of clinical trial participants discontinued due to adverse events. Serious but rare side effects include pancreatitis, gallbladder events, and injection site reactions.

Does tirzepatide cause muscle loss?

Yes, approximately 30-35% of total weight lost with tirzepatide is lean mass (primarily muscle), based on body composition sub-study data. This is a concern across all GLP-1 agonists and weight-loss interventions generally. Resistance training at least 2-3 times per week and protein intake of 1.2-1.6g per kilogram of body weight per day are widely recommended to mitigate muscle loss during therapy.

Can I take tirzepatide if I don't have diabetes?

Yes. Zepbound (tirzepatide) is FDA-approved specifically for chronic weight management in adults without diabetes who have a BMI of 30 or greater, or BMI of 27 or greater with at least one weight-related condition such as hypertension, dyslipidemia, or obstructive sleep apnea. You do not need to have diabetes to receive a prescription for tirzepatide for weight management.

Vendor Rankings

Independent rankings of peptide vendors based on aggregated lab data, COA transparency, community sentiment, and verified pricing. We publish everything — including the failures.

2,433+ samples tracked 429 vendors ranked 15 peptides tracked

All BPC-157 Tirzepatide Semaglutide CJC-1295 Ipamorelin GHK-Cu Retatrutide Tesamorelin

AGreat

B+Very Good

BGood

COkay

DPoor

EBad

FFraud

Tirzepatide Rankings

FDA-APPROVED

2,433 samples across 429 vendors · Updated weekly from independent lab testing

#	Vendor	Avg score	Purity range	Tests	Verified $/mg	Grade	Profile
Grade A — Great
1	SRY Labs	9.4	—	36	—	A	review →
2	Andy Peps Studio	9.3	—	19	—	A	review →
3	Yiwu Aozuo Trading Co	9.2	—	31	—	A	review →
4	Aavant Research	9.1	—	15	—	A	review →
Grade B+ — Very Good
5	Nantong Guangyuan Chemical GYC	9.0	—	23	—	B+	review →
6	Guangzhou Jeep Biotechnology JEEP	9.0	—	16	—	B+	review →
7	Reta-Peptide	9.0	—	36	—	B+	review →
8	PeptiSlim	9.0	—	32	—	B+	review →
9	SaiyanMed	8.8	—	7	—	B+	review →
10	Jinan Elitepeptide Chemical JEC JCE	8.8	—	7	—	B+	review →
11	ZLZ Peptide	8.8	—	96	—	B+	review →
12	Peptide-S	8.8	—	41	—	B+	review →
13	Shanghai Wibson Biotechnology WBS	8.8	—	12	—	B+	review →
14	Noble Dragons	8.8	—	9	—	B+	review →
15	Wuhan Wansheng Biotechnology	8.7	—	53	—	B+	review →
16	Shanghai ERP peptide Biotechnology	8.7	—	23	—	B+	review →
17	Paradigm Peptide	8.7	—	10	—	B+	review →
18	Huayi Biotechnology	8.7	—	10	—	B+	review →
19	Cellupep	8.7	—	7	—	B+	review →
20	DAHAN Peptide	8.7	—	6	—	B+	review →
21	HK Peptides	8.7	—	130	—	B+	review →
22	Xianhong Tong XHT Peptides	8.7	—	6	—	B+	review →
23	Qianmiao Peptide	8.6	—	5	—	B+	review →
24	Expert Peptide	8.6	—	4	—	B+	review →
25	Golden Eagle	8.6	—	9	—	B+	review →
26	TSC Top Supplements China	8.6	—	31	—	B+	review →
27	Peptide Pole Hongkong	8.6	—	4	—	B+	review →
28	GrayPep	8.6	—	4	—	B+	review →
29	LN Peptides	8.6	—	14	—	B+	review →
30	M-Peptides	8.6	—	13	—	B+	review →
31	Shandong Shengyuan Peptide Technology	8.6	—	19	—	B+	review →
32	TP Peptide	8.6	—	4	—	B+	review →
33	Zhejiang Jiuzhou Chem Co	8.5	—	4	—	B+	review →
34	LMR	8.5	—	6	—	B+	review →
35	QH Peptide	8.5	—	3	—	B+	review →
36	Peptides Book	8.5	—	3	—	B+	review →
37	Yidan Biotech	8.5	—	7	—	B+	review →
38	Shanxi Qianyecao Biotech QYC	8.5	—	22	—	B+	review →
39	Hunan GoodPeptides Biotech Co	8.5	—	3	—	B+	review →
40	LiliPeptide	8.5	—	41	—	B+	review →
41	Shandong Yixin Peptide	8.5	—	3	—	B+	review →
42	Lipeptides	8.4	—	11	—	B+	review →
43	Cactus Peptides	8.4	—	2	—	B+	review →
44	Shandong Aishi Biotechnology	8.4	—	30	—	B+	review →
45	Chimera Peptides	8.4	—	9	—	B+	review →
46	Evolve BioPep	8.4	—	6	—	B+	review →
47	Oupeptide	8.4	—	61	—	B+	review →
48	Qingfuji Trading	8.4	—	3	—	B+	review →
49	Qing Li Peptide	8.4	—	44	—	B+	review →
50	Baohua Dongnuo Biotechnology BHD	8.4	—	6	—	B+	review →

Verified $/mg = list price ÷ (avg tested qty / labeled qty). Vendors below the cutoff omitted from view.