TestoPlex C 300 from XtLabs is an injectable anabolic steroid—each 10 ml vial packs 300 mg/ml of testosterone cypionate.

what’s inside:
Testosterone cypionate (C27H40O3) is a long-acting, single-ester testosterone. It sticks around, with a half-life of 8 to 12 days, so you get a steady release after each shot (usually in the glutes or thighs). Because it’s oil-based and pretty concentrated, you don’t need to inject as often as you would with lower-dose options.

What’s it for?
Doctors use it for TRT in guys with low testosterone. In bodybuilding, it’s the go-to base for bulking—think more muscle, more strength, and quicker recovery. It stacks well with other XtLabs gear, like DecaPlex for lean bulks, DianaPlex if you want to gain fast, or ParaPlex for recomp phases.

How much do you take?
Most men use 300–600 mg per week—so, one to two milliliters, split into one or two weekly injections (like Monday and Thursday). If you’re new, 250–400 mg is plenty; advanced users sometimes go up to 1000 mg. Cycles usually last 10 to 16 weeks. You’ll need an aromatase inhibitor (like Arimidex) and PCT (Clomid, Nolva, HCG) to keep your hormones in check.

Why pick it?
It’s a reliable mass builder with a slow, steady release. Levels stay stable, and you don’t have to inject as often as you would with blends like SustaPlex. People stick with it for a reason—it works for size and strength.

What’s the catch?
It turns into estrogen in your body, which can mean gyno or water retention. It’ll shut down your natural testosterone hard. Some people get post-injection pain at this dose, and with underground labs, purity or dosing isn’t always guaranteed.

Side effects to watch for:
Estrogenic stuff like gyno and water retention (keep Arimidex handy), plus acne, hair loss, high blood pressure, and thickened blood. There’s also the risk of aggression or prostate issues. Keep an eye on your bloodwork—lipids, liver enzymes, estrogen levels—all of it.