PT-141 from Sixpex is a synthetic peptide, also known as Bremelanotide. Each vial contains 10mg. It’s a research chemical that acts as a melanocortin receptor agonist.

What It Is
Bremelanotide is a seven-amino acid peptide (C50H68N14O10) made from the alpha-MSH hormone. It comes as a freeze-dried powder—you mix it with bacteriostatic water before use. People inject it under the skin. It doesn’t last long in your system (about 66 minutes) and works by stimulating the central nervous system, not by targeting blood flow like PDE5 inhibitors do.

Uses
Doctors use PT-141 by Sixpex to treat hypoactive sexual desire disorder (HSDD) in premenopausal women and erectile dysfunction (ED) in men. It ramps up arousal and desire. Some bodybuilders also use it off-label—to boost libido during cycles, lift their mood, improve workout endurance, and help with recovery thanks to effects similar to endorphins.

Benefits
PT-141 goes straight to the brain’s centers for sex and motivation, often kicking in within 30 to 60 minutes. People notice a quick mood lift, less fatigue, faster recovery, and better intensity at the gym. It boosts sexual satisfaction without relying on blood flow. Bodybuilders often mention stronger pumps and an increase in IGF-1, which helps with muscle growth and repair.

Drawbacks and Side Effects
Nausea is the most common side effect, and it usually depends on the dose. Other issues include flushing, headaches, redness where you inject, and sometimes a small bump in blood pressure. Overusing it can cause dark patches on your face or gums and leave you feeling wiped out. It’s not safe for people with high blood pressure. Plus, your body can get used to it fast, so regular use isn’t a good idea.

How to Take It
To prepare, mix the 10mg vial with 2ml of bacteriostatic water (that’s 5mg/ml). Both men and women usually inject between 0.5mg and 2mg (100-400mcg) under the skin of the abdomen or thigh, about 45 to 60 minutes before they want it to work. Don’t use it more than once or twice a week. Start with a low dose (250mcg) to see how you react. There’s also a nasal spray version if you don’t like needles. Most people use it for 4 to 8 weeks, then take 4 weeks off. No post-cycle therapy needed.