Bremelanotide
(Vyleesi)

1980s-1990s

The Tanning Quest

Seeking Sun Without the Damage

Skin cancer rates were rising. Dermatologists knew that sun exposure was dangerous, but people loved their tans. What if you could make skin darken without UV rays?

Researchers at the University of Arizona studied melanocortins — hormones that control pigmentation. They created a peptide called Melanotan that could darken skin when injected. Clinical trials began.

But strange reports emerged from the trials. Male volunteers were experiencing spontaneous erections. Women reported increased sexual desire. The tanning drug was doing something unexpected in the brain.

1998-2005

Following the Side Effect

From Bug to Feature

Palatin Technologies licensed the technology and began exploring the sexual effects. They developed PT-141 (later named bremelanotide) — a modified version of Melanotan optimized for arousal rather than tanning.

The science was fascinating. Unlike Viagra, which works by increasing blood flow to genitals, PT-141 worked in the brain. It activated melanocortin receptors in areas controlling desire and arousal. The drug created the wanting — the psychological component of sexual response.

Early trials in both men and women showed the approach worked. People given PT-141 reported genuine increases in desire, not just the ability to perform. This was a fundamentally different kind of sexual medicine.

2006-2008

The First Setback

Blood Pressure Concerns

Palatin's first attempt to gain FDA approval hit a wall. The nasal spray formulation they'd developed caused blood pressure increases in some patients. The FDA raised safety concerns.

The company had to go back to the drawing board. They reformulated PT-141 as an injection — a less convenient delivery method but one that avoided the blood pressure issues. It was a costly setback that delayed approval by years.

Meanwhile, the debate about female sexual dysfunction continued. Some argued that low desire in women wasn't a medical condition but a normal variation. Others insisted that women deserved the same treatment options as men. PT-141 was caught in the crossfire.

2009-2019

The Long Road

Proving Desire Can Be Treated

Palatin ran new clinical trials with the injectable formulation, focusing on women with hypoactive sexual desire disorder (HSDD) — a condition where lack of desire causes significant distress.

The trials faced unique challenges. How do you measure desire? Researchers developed questionnaires tracking 'satisfying sexual events,' desire levels, and relationship distress. The results showed PT-141 helped — not dramatically, but meaningfully.

In June 2019, after more than two decades of development, the FDA approved bremelanotide as Vyleesi. It became the first FDA-approved drug to treat low sexual desire in women by acting on the brain.

2019-Present

The New Frontier

Desire as Medicine

Vyleesi entered a complicated market. It requires self-injection 45 minutes before anticipated activity — not exactly spontaneous. Side effects include nausea and flushing. Insurance coverage remains limited.

But for women who had tried everything else — therapy, hormone treatments, relationship counseling — Vyleesi offered something new: direct action on the brain's desire circuitry. For some, it was life-changing.

Research continues on melanocortin-based treatments. Scientists are exploring whether similar approaches could help with other conditions involving desire, motivation, and reward. The accidental discovery in a tanning trial opened a window into how the brain creates wanting — and how medicine might enhance it.