Needle gauge and dead space — my results so far

Not a noob question at all — this trips up a lot of people. HPLC Purity (99.2%) — Of all the peptide-related material in the sample, 99.2% is the target semaglutide molecule. The remaining 0.8% are related impurities (truncated sequences, deamidation products, etc.) Peptide Content (97.8%) — Of the total powder in the vial (by weight), 97.8% is actual peptide material. The remaining 2.2% is non-peptide stuff: residual water, counter-ions (acetate/TFA), salts from the manufacturing process. So if you have a 10mg vial: - 9.78mg is peptide material (peptide content) - Of that 9.78mg, 9.70mg is actual semaglutide (HPLC purity applied) Both numbers being high is what you want. Some vendors have high purity but lower peptide content, meaning you're getting less active ingredient per vial than labeled.

That's an incredibly clear explanation, thank you. So WWB is basically giving you 9.7mg of real semaglutide in a 10mg labeled vial — that's 97% of what's advertised. Is that considered good?

That's considered excellent. Most research peptide suppliers are in the 85-95% range for effective yield when you combine both numbers. 97% effective yield is near pharma-grade. Some suppliers label "10mg" but you're really getting 7-8mg of actual target peptide after accounting for both purity and content. This is why third-party testing matters. The vial says 10mg but without testing you have no idea if that's 10mg of 99% pure sema or 10mg of 93% pure sema cut with 15% salts and water. 📉

I tested the same batch from WWB (#WS-SEM-2026-0118) and got 99.0% HPLC purity. So our results are within 0.2% of each other which is within normal analytical variance for HPLC testing. This is actually a great data point — two independent tests of the same batch showing consistent results means neither of us got a lucky/unlucky vial. The batch is genuinely high quality. I paid the extra $90 for endotoxin testing too: - Endotoxin (LAL): <0.5 EU/mg ✅ (specification: <5 EU/mg) Very low endotoxin levels. This batch is clean.

That's great to see independent confirmation. And the endotoxin result is exactly what I was hoping someone would test — <0.5 EU/mg is excellent. For anyone keeping score, that's two independent Janoshik tests on batch WS-SEM-2026-0118: - Test 1 (mine): 99.2% HPLC - Test 2 (QualityQueen): 99.0% HPLC + <0.5 EU/mg endotoxin Batch is certified clean. I'll be reordering from WWB with confidence. 🔬