The first FDA-approved peptide that works through your brain to reignite sexual desire—think of it as flipping the 'on' switch for arousal rather than just boosting blood flow like traditional ED meds.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Subcutaneous
Route
3 recommended
Sites
As needed
Frequency
Preparation
Bacteriostatic water (BAC water)—contains preservative for multi-dose use
Insulin syringes (29-31 gauge) for injection
Alcohol swabs for cleaning vial tops and injection sites
Your PT-141 powder vial
Pro tip
Prepare all supplies on a clean surface before you begin. Having everything ready makes the process smoother and more sterile.
Mixing
Wash your hands thoroughly with soap and water. Gather all supplies on a clean, flat surface.
Remove the plastic cap from the peptide vial and wipe the rubber stopper with an alcohol swab. Let it air dry.
Draw the appropriate amount of bacteriostatic water into a sterile syringe.
Insert the needle into the vial at an angle, aiming at the inside wall of the vial. Slowly push the plunger to let the water trickle down the glass wall -- do NOT squirt directly onto the powder.
Once all water is added, gently swirl the vial in a slow circular motion. Never shake the vial, as this can damage the peptide bonds.
Continue swirling until the powder is completely dissolved and the solution is clear. If particles remain, let the vial sit for a few minutes and swirl again.
Label the vial with the date of reconstitution, the peptide name, and the concentration (e.g. 250mcg per 0.1mL).
Example calculation
For a 10mg vial: add 2mL of BAC water to get 5mg/mL concentration. For the standard 1.75mg dose, you'd draw 0.35mL (35 units on an insulin syringe). For 2mg, draw 0.4mL (40 units).
Dose calculation
At 5mg/mL concentration: 1mg = 0.2mL (20 units); 1.75mg = 0.35mL (35 units); 2mg = 0.4mL (40 units). The FDA-approved Vyleesi autoinjector comes pre-dosed at 1.75mg and doesn't require reconstitution.
Pro tip
Always add the bacteriostatic water slowly, letting it run down the side of the vial. Never shake the vial -- swirl gently to avoid damaging the peptide.
Location
Site 01
Abdomen
Pinch the skin 2 inches from navel. Avoid the area directly around the belly button. Rotate between left and right sides.
Site 02
Outer Thigh
Middle third of the outer thigh. Keep at least 4 inches above the knee and below the hip. Alternate legs each injection.
Site 03
Upper Arm
Back or outer area of the upper arm. This site may require assistance from another person for proper technique.
Rotate between 3 sites to prevent tissue buildup and ensure consistent absorption.
Pro tip
Rotate your injection sites with each dose to prevent lipohypertrophy (buildup of fatty tissue). Keep a simple log of where you last injected.
Step by step
Wash your hands thoroughly with soap and water
Clean the injection site with an alcohol swab and let it dry completely
If using a syringe: pinch about an inch of skin to create a fold
Insert the needle at a 45-90 degree angle (45 if lean, 90 if more tissue)
Inject slowly and steadily over a few seconds
Wait 5 seconds before withdrawing the needle
Apply light pressure with a clean cotton ball if needed—don't rub
Pro tip
This peptide uses subcutaneous injection (just under the skin)—this is how the fda-approved vyleesi autoinjector delivers the dose. Inject at a 45-90 degree angle into pinched skin. Aspirate before injecting to ensure you haven't hit a blood vessel.
Timing
Optimal timing
Best time
Take PT-141 at least 45 minutes before anticipated sexual activity. Effects typically begin within 45-60 minutes and can last several hours. Some people find it works better with 60-90 minutes lead time.
With food?
Taking PT-141 on an empty stomach may increase nausea. A light meal or snack beforehand can help reduce stomach upset without significantly affecting absorption.
Stacking notes
PT-141 is typically used as a standalone treatment. Its unique mechanism of action through melanocortin receptors means it doesn't directly interact with most other peptides, but consult your healthcare provider before combining with other treatments.
Sample daily schedule
45-60 minutes before anticipated intimacy
1.75 mg (standard FDA-approved dose) injection
Site: Abdomen or thigh
PT-141 is used on-demand, not on a daily schedule. Effects begin within 45-60 minutes and can last several hours. Do not take more than one dose in 24 hours, and limit to 8 doses per month maximum.
Dosing tiers
Dose
1 mg
Frequency
As needed, ~45 min before sexual activity; no more than once per 24 h
Duration
Trial period (assess response/tolerability)
Lower 1 mg trial dose used in practice to gauge nausea tolerance before moving to the FDA dose [6]. Inject into abdomen or thigh.
Dose
1.75 mg
Frequency
As needed, ~45 min before sexual activity; max once per 24 h and 8 doses per 28 days
Duration
Ongoing as needed
FDA-approved Vyleesi dose for hypoactive sexual desire disorder in premenopausal women; efficacy shown in the RECONNECT phase 3 trials [1][6].
Preservation
Before mixing
Keep your PT-141 powder in the refrigerator (36-46°F / 2-8°C) for short-term storage or in the freezer (-4°F / -20°C) for long-term storage. Store in the original sealed vial away from light. Properly stored powder remains stable for 2+ years when frozen.
After mixing
Once mixed with bacteriostatic water, refrigerate at 36-46°F (2-8°C). Never freeze the reconstituted solution—freezing destroys the peptide. Keep away from light and use within 30 days. The FDA-approved Vyleesi autoinjector should also be refrigerated.
Shelf life after mixing
30 days
Signs of degradation
Discard the vial immediately if you notice any of these:
Cloudy or hazy appearance (should be crystal clear)
Visible particles floating or settled at the bottom
Color changes—any yellowing or discoloration
Unusual smell—fresh solution should have little to no odor
Important
When to stop
Severe nausea that makes the experience unpleasant or affects your health
Significant blood pressure increases, especially if you feel chest discomfort or severe headache
Noticeable skin darkening that concerns you (may be irreversible)
Any signs of allergic reaction—hives, swelling, difficulty breathing
The medication isn't providing the desired effect after multiple attempts
You become pregnant or are trying to conceive
PT-141 (Vyleesi) is an FDA-approved medication, but it should be used under healthcare provider supervision. This information is educational—always consult your doctor about starting, stopping, or adjusting any medication. Report any unexpected side effects to your healthcare provider.
Clean technique checklist
Wash hands thoroughly with soap and water before handling supplies
Swab vial tops and injection site with alcohol and let dry
Never touch the needle tip or allow it to contact non-sterile surfaces
Use a new syringe and needle for each injection
Dispose of used sharps in a proper sharps container
Store reconstituted peptides according to the storage instructions above
Published research
Kingsberg SA, Clayton AH, Portman D · 2019
The landmark RECONNECT trials that led to FDA approval. Over 1,200 premenopausal women with HSDD showed statistically significant improvements in sexual desire and reduction in distress compared to placebo. The 1.75mg dose delivered real benefits where it mattered most.
Simon JA, Kingsberg SA, Portman D · 2019
The 52-week extension study showed PT-141 maintained its effectiveness over time without developing tolerance. No new safety signals emerged with long-term use, and improvements in desire and reduced distress persisted throughout.
Dhillon S, Keam SJ · 2019
This comprehensive review covered PT-141's journey from lab to FDA approval. It explained how the drug works on MC4 receptors in the brain's desire circuits—a completely novel mechanism compared to existing sexual health treatments.
Pfaus JG, Sadiq A, Spana C · 2022
Deep dive into how PT-141 actually works in the brain. It activates MC4 receptors in the hypothalamus, triggering dopamine release in areas that control sexual motivation. This explains why it enhances desire itself, not just physical response.
Koochaki P, Revicki D, Wilson H · 2021
Real-world feedback from clinical trial participants. Women reported meaningful improvements in their sexual experiences and quality of life. Most felt the benefits outweighed the side effects, particularly nausea.
AMAG Pharmaceuticals (FDA) · 2019
Head to head