Short answer: No. Let me explain why. This post is for educational and research purposes only. This is not medical advice. This is one of the most common questions I get, and I totally understand the concern. You spend your hard-earned money on a peptide, you reconstitute it, administer it, and... nothing. No sting. No burn. Meanwhile someone else is posting about how theirs lit them up like a campfire. So what gives? Let's walk through what's actually happening here. Why GHK-Cu stings in the first place GHK-Cu is a copper peptide. That copper component gives the solution a slightly acidic pH, usually somewhere around 4.5 to 5.5 once reconstituted. Your body's tissues, specifically the fluid between your cells (called interstitial fluid), sit right around a pH of 7.4. That's slightly alkaline. So when a mildly acidic solution meets tissue that's slightly alkaline, the body notices. That mismatch is what creates the sting. It's essentially a mild chemical irritation, not damage, just nerve endings going "hey, that's different." Think of it like squeezing lemon juice on a paper cut. The lemon juice isn't destroying your hand. Your nerves are just reacting to the pH difference on exposed tissue. So why do some people feel nothing? This is where it gets interesting, and why you can't use sting as a quality check. Individual pH varies. Not everyone's tissue pH is identical. Things like hydration levels, what you've eaten recently, your body's acid-base balance, even how much you've been exercising that day can slightly shift your local tissue pH. A person who's very well hydrated might have tissue that buffers that acidity faster, meaning less sting. Administration site matters a lot. Subcutaneous tissue isn't the same everywhere on your body. Your lower belly has a different nerve density and blood supply than, say, your upper arm or your love handle area. More nerve endings in an area means more sensation. Better blood supply means the solution gets absorbed and buffered faster. Same peptide, same concentration, two totally different experiences depending on the site.

I just wanted to run something by the community because I'm seeing more and more new third-party testing labs pop up due to the demand in the industry and the slow turnaround time from the most popular ones. After doing some more vetting for new websites and current companies on the price tool, there are a couple of new labs that look very reputable. However, they are newer to the space. Would you guys care if a company third-party tested with a newer lab vs some of the most popular ones like Chromate, Freedom Diagnostics, Janoshik, MZ BioLabs, Vanguard, etc.? If I ever went this route, and a company was using a newer lab, I would do my own research into them, get in contact, and make sure they were truly a reputable third-party testing facility. It's inevitable to happen at some point. However, I just wanted to get the community's thoughts.

I want to make sure the content I'm creating actually helps with YOUR goals, so I'm curious—where are you at right now? Drop your answer below, and if you want to share more about your journey so far, I'd love to hear it. As for me: Started at 250, got down to 170 without peptides, and maintained for about four years. Now I'm in a new chapter—intentionally trying to add muscle for the first time. It's 100% a mental game. Yes, I've put on some body fat in the process, but muscle takes way longer to build than fat takes to lose. You have to commit to the long game. And honestly? Muscle mass is the real key to longevity. The other piece I don't talk about as much: I dealt with binge eating for years. That maintenance phase wasn't just about weight—it gave me the foundation to finally have a healthy relationship with food. I still enjoy eating. But now I understand that the daily habits are what separate fat gain from muscle gain. So—where are you at? 👇

Quick background for those new here: Most peptides should be stored in the fridge after you reconstitute them (mix them with bacteriostatic water). Cold temps help keep them stable longer. But tesamorelin might be different. The FDA-approved version (EGRIFTA WR) actually says to store it at room temperature — not in the fridge. Josh Holyfield, a creator in this space, argues that research-grade tesamorelin should follow the same rule because the molecule itself doesn't like cold temperatures. Something about its structure causes it to clump up and degrade when it gets cold. I pushed back on this in an earlier post. Josh responded with some solid points about the science behind it. Honestly? I don't know who's right. And I'd rather have real data than keep guessing. So here's what I'm going to do: When I get back to Denver, I'm sending a vial of tesamorelin to Freedom Diagnostics for a 4-week degradation study. This will show us exactly what happens to research-grade tesamorelin under different storage conditions. No more theories. Just actual results. I'll keep you all posted.

Quick heads up for the researchers here — Purus is running 30% off sitewide right now. Sale runs: February 1st through February 6th Code: DEREK Shop here: https://puruspeptides.com/?ref=ntwggrnk This is a great chance to pick up the NAD+ 5-Amino Acid & MOTS-C blend if you've been eying it for your research. If you've been following along with my recent posts on MOTS-C timing and energy peptides, you know why this one's been getting attention. https://puruspeptides.com/product/nad-mots-c-5amino-1mq-blend/?ref=ntwggrnk Compare Before You Buy As always, you can compare pricing across 20+ vendors at peptideprice.store to make sure you're getting the best deal for your research. Even with a 30% discount, it's worth double-checking — that's what the site is there for. Questions? Drop them below. 👇 Research use only. Not for human consumption.