melanotan studies from 1989 to 2026 found benefits and harms
This guide explains 26 findings about skin color, erections, hunger, and harm. MT-I became an approved drug, but MT-II didn't.
Melanotan was made to help skin grow darker
In the late 1980s, Hruby and Hadley made melanotan at an Arizona university. They hoped to darken skin by increasing its pigment [1].
MT-I is also known as afamelanotide and has thirteen linked protein pieces. MT-II has seven pieces set in a ring [1].
Researchers hoped darker pigment might protect DNA, the instructions inside your cells, from sunlight. Their work led to two approved drugs, MT-I and PT-141, but MT-II still isn't approved [2].
MT-II reaches receptors, the small parts of cells that take orders. In the published work, 1 skin receptor starts dark pigment [4].
Researchers tested the drug in 4 main areas. In 3 early papers, men had erections and side effects linked to brain receptors [5][6][7].
Across those areas, 5 changes stand out: darker skin, erections, less hunger, nausea, and yawning. The melanotan research studies, melanotan dosage studies, melanotan side effects, and /references pages tell you what each finding means.
Melanotan II reaches more body parts than Melanotan I
MT-I has thirteen protein parts in a straight row. MT-II has seven set in a ring and reaches more receptors [2].
MT-I works mostly on the receptor that darkens your skin. MT-II also reaches brain receptors tied to hunger, erections, heat, and unwanted effects.
That narrower reach suited MT-I to a rare illness caused by light. The EU approved MT-I in 2014.
The US approved MT-I in 2019 [15]. Neither approval nor the safety record covers MT-II.
Researchers also made PT-141 from MT-II. The US approved that related drug in 2019 [19].
MT-II still has no approved use. Keep the Melanotan I and Melanotan II difference in mind when you compare their results.
Melanotan II is made from protein parts joined in a ring
Scientists build Melanotan II from basic parts in a lab; no living source is used. Seven amino acids, the small pieces of protein, make its closed ring.
Its round shape keeps MT-II whole better than a straight row would [1]. This helps you understand why the drug can last longer inside your body.
Researchers often began with dry MT-II powder. In rats, only 4.6% reached the blood by mouth, so a shot placed the drug beneath the skin [1].
Your body normally breaks small drugs into pieces. The ring slows that work and leaves the drug whole for longer.
Melanotan studies found changes in skin, erections, hunger, and nerves
Researchers tested MT-II in four main areas. The clearest human findings for you concern skin color and erections.
Skin color. some men grew darker without planned sun in an early study [3]. A receptor on pigment-making skin cells began that change [4].
Erections. Three early papers describe men receiving shots under the skin [5][6][7]. The brain started the erections rather than the skin.
Hunger and body fat. Rats ate less and lost body fat after a brain receptor was reached [8][9]. In 2022, mice ate less without fear or a faster burn of calories [10].
Nerve healing. In rats, 20 millionths of a gram for each kilogram of weight helped a crushed leg nerve heal. Smaller and larger amounts didn't help [21].
The melanotan questions page gives you short answers. The melanotan research page names the study group and the change.
Small Melanotan studies found erections in many men
In the first 1996 study, 3 healthy men received 5 shots. The amount rose each day.
Skin grew darker in 2 of 3 men, and unplanned erections began. Those erections lasted 1–5 hours after a shot [3].
In 1998, researchers studied 10 men whose erection trouble was linked to mental causes. Erections occurred in 8 of 10 men.
A gauge found the head of the penis at least 80% firm for 38 minutes. After a placebo, an inactive comparison shot, firmness lasted 3 minutes [5].
One 2000 study followed 20 men whose trouble came from a body cause. Erections occurred in 17 of 20 men [6].
The men reported more sexual desire after 68% of MT-II shots. They reported it after 19% of placebo shots.
Another 2000 study tested 10 men with the same kind of trouble. Erections lasted about 45 minutes with MT-II and 1.9 minutes with placebo [7].
The erections began without sexual pictures. That finding points to the brain rather than the penis's blood vessels.
These small studies tell you what happened to those men. They can't predict what would happen in your body.