Peptide Profile
Ganirelix
Fast-acting GnRH antagonist that stops premature ovulation during fertility treatment
Dose Range
250 mcg-500 mcgmicrograms
Frequency
Once daily
Route
Subcutaneous injection
Cycle Length
Ongoing/indefinite
Onset
Moderate (1-2 weeks)
Evidence
Strong
Compound Profile
Scientific & Efficacy Data
C80H113ClN18O13
Molecular Formula
1570.4 g/mol
Molecular Weight
10-12 hours
Half-Life
~91% (subcutaneous injection)
Bioavailability
124904-93-4
CAS #
16186314
PubChem ID ↗
Developed By · 1995
Organon/Schering-Plough Research Team
Organon (later Schering-Plough)
Primary Benefits
Allows doctors to control exactly when ovulation happens
Improves success rates in IVF cycles
Prevents premature LH surge that can ruin egg quality
Amino Acid Sequence
Ac-D-2-Nal-D-4-Cl-Phe-D-3-Pal-Ser-Tyr-D-Arg-Leu-Arg-Pro-Gly-NH2Dosing
How much
do I take?
Timing
Best time to take
Administer Ganirelix at the same time each day (or on the same day each week for weekly injections). Many users prefer morning or evening administration. Pick a time you'll remember consistently.
With food?
Ganirelix injections can be given regardless of meal timing. However, if GI effects occur, administering on an empty stomach or with a light meal may help reduce discomfort.
If stacking
Ganirelix should be used as directed by your healthcare provider. If combining with other medications or supplements, discuss potential interactions with your provider. Avoid combining with compounds that have overlapping mechanisms unless specifically guided by a medical professional.
Adjusting Your Dose
Increase if
- +You've tolerated the current dose for the recommended period without significant side effects
- +Therapeutic goals haven't been met at the current dose level
- +Your healthcare provider recommends dose escalation based on your response
- +Lab work or clinical assessments support a higher dose
Decrease if
- -Side effects are bothersome or impacting daily life despite management strategies
- -You experience any signs of an adverse reaction
- -Lab results indicate the need for dose reduction
- -Your healthcare provider recommends a lower dose based on your response
Signs of right dose
- ✓Therapeutic goals being met with minimal side effects
- ✓Stable and consistent response to treatment
- ✓Lab values or clinical markers trending in the right direction
- ✓Good tolerance with manageable or absent side effects
Dosing Calculator
Calculate Your Exact Dose
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Suitability
Is this
right for me?
Best For
Improving IVF or ICSI success rates
Ganirelix is particularly well-suited for individuals focused on improving ivf or icsi success rates. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Preventing premature ovulation during egg retrieval cycles
Ganirelix is particularly well-suited for individuals focused on preventing premature ovulation during egg retrieval cycles. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Controlling ovarian stimulation in women with unpredictable cycles
Ganirelix is particularly well-suited for individuals focused on controlling ovarian stimulation in women with unpredictable cycles. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Consider Alternatives If
Who Should Avoid
Do not use if
- ×Pregnancy or suspected pregnancy
- ×Breastfeeding
- ×Known allergies to any medication component
- ×Ovarian cysts larger than 3cm
Use with caution if
- !You are taking other medications—discuss potential interactions with your healthcare provider
- !You have a history of liver or kidney disease
- !You are elderly or have multiple medical conditions
- !You are planning surgery in the near future—inform your surgeon about Ganirelix use
- !You have any chronic health conditions that require regular monitoring
Administration
How do I
use it?
Reconstitution
What you need
- •Ganirelix vial (lyophilized powder or solution)
- •Bacteriostatic water or sterile sodium chloride for reconstitution
- •Alcohol swabs for cleaning vial tops and injection sites
- •Appropriately sized syringes with fine-gauge needles (27-30 gauge)
- •Sharps disposal container
Injection
Route
Subcutaneous injection (into the fatty tissue just under the skin)—allows for consistent absorption and can be self-administered at home after proper training
Best sites
- •Abdomen (stomach area)—at least 2 inches from the belly button, most popular choice for self-injection
- •Front of thighs—middle to upper portion of the outer leg
- •Back of upper arm—outer area (may need assistance from another person)
Technique
- 1.Wash your hands thoroughly with soap and water before handling supplies
- 2.Clean the injection site with an alcohol swab and let it air dry completely
- 3.Pinch a fold of skin at the chosen injection site
- 4.Insert the needle at a 45-90 degree angle (depending on needle length and body composition)
- 5.Inject the medication slowly and steadily over 5-10 seconds
- 6.Release the skin fold and remove the needle, applying gentle pressure with a clean swab
- 7.Rotate injection sites to prevent tissue irritation or lipodystrophy
- 8.Dispose of the needle safely in a sharps container—never recap or reuse needles
Storage
Signs of degradation
Sample Daily Schedule
Safety
Is it
safe?
Safety Profile
Ganirelix carries an excellent safety record from over 10,000 patients in FDA approval trials and 25+ years of clinical fertility practice. The antagonist mechanism avoids the flare effect seen with GnRH agonists, making it safer for women with diminished ovarian reserve. Injection site reactions are the most common issue (20-40% of patients), though typically mild bruising rather than systemic toxicity. The rapid 1-2 hour onset and quick clearance mean side effects resolve quickly if dosing is adjusted.
Ganirelix safety is well-established through Phase 3 multicenter trials (Organon studies, 1995-1999) and post-marketing surveillance of over 250,000 treatment cycles. ASRM and ESHRE guidelines recommend it as a standard first-line antagonist for IVF cycles based on efficacy and tolerability data. Pivotal trials showed no clinically significant abnormalities in liver, kidney, or hematologic parameters even with daily dosing for 2+ weeks.
Common Side Effects
Experienced by some users
Mild discomfort at treatment site
Some users experience mild discomfort, which is among the most commonly reported effects with Ganirelix. This typically resolves within a few days as the body adjusts.
Management: Apply ice if needed. Rotate treatment sites. These symptoms typically improve within the first week of use.
Injection site reactions (redness, bruising, swelling)
Affects 20-40% of IVF patients using ganirelix. Subcutaneous injections commonly cause localized redness, bruising, or mild swelling that peaks at 24 hours and resolves within 3-5 days. Bruising is more common with repeated daily injections at similar sites. Reactions are typically mild and do not require treatment discontinuation.
Management: Rotate injection sites daily between abdomen and thighs. Apply ice immediately after injection to reduce bruising. Avoid injecting in bruised areas. Use proper subcutaneous technique to minimize tissue trauma. Pain relief medication is rarely needed but available if desired.
Headaches
Occur in 10-20% of patients, typically mild intensity. Onset is usually within 24-48 hours of first injection. Most resolve by day 5-7 of stimulation. Headaches may be related to dehydration from reduced oral intake or hormonal changes from ovarian stimulation, not ganirelix alone.
Management: Stay well hydrated throughout the stimulation cycle, aiming for 2-3 liters of water daily. Apply cool compresses to forehead or back of neck. Rest in a quiet, dark room if headache is bothersome. Acetaminophen or ibuprofen is safe to use (check with your clinic). Headaches usually improve on their own.
Abdominal pain
Affects 15-25% of patients and is primarily related to ovarian stimulation from FSH, not ganirelix itself. Pain is typically mild to moderate, cramp-like in quality, and centered in the lower abdomen. Increases gradually as follicles grow and usually peaks 1-2 days before egg retrieval. Pain resolves within 24-48 hours after retrieval.
Management: Heat application (heating pad on low setting for 15-20 minutes) often provides relief. Wear comfortable, loose clothing. Avoid strenuous exercise and intercourse. Gentle walking is fine. Over-the-counter pain relievers are usually adequate. Contact your clinic if pain suddenly worsens or is severe, as this could indicate ovarian hyperstimulation.
Pelvic discomfort
Experienced by 10-20% of patients as a sense of heaviness, fullness, or pressure in the pelvic region. Typically mild and related to ovarian enlargement from FSH stimulation. Discomfort may intensify if multiple large follicles develop. Usually resolves within days of egg retrieval as ovaries return to normal size.
Management: Rest when possible. Wear supportive, loose-fitting clothing. Avoid heavy lifting and strenuous activity. Warm baths may ease discomfort. Stay hydrated. Pelvic discomfort is expected and not dangerous unless accompanied by severe pain, which requires immediate clinic contact.
Nausea
Occurs in 5-10% of patients, usually mild and intermittent. Onset is typically within 24-48 hours of starting ganirelix. Nausea may be related to hormonal changes, dehydration, or the stress of treatment. Most episodes resolve within days and do not require stopping treatment.
Management: Eat small, frequent meals rather than three large ones. Avoid greasy, fried, or strong-smelling foods. Ginger candies or ginger tea can help settle nausea. Stay hydrated with clear fluids. Take anti-nausea medication only if approved by your clinic, as some medications affect egg quality. Nausea usually resolves spontaneously.
Fatigue or dizziness
Affects 5-10% of patients, typically mild. Fatigue may relate to hormonal fluctuations, sleep disruption from anxiety, or dehydration. Dizziness is usually brief and occurs when standing too quickly or in warm environments. Both typically improve after the first few days as the body adjusts.
Management: Prioritize adequate sleep and rest, aiming for 7-8 hours nightly. Rise slowly from lying or sitting positions to prevent orthostatic dizziness. Stay well hydrated. Avoid excessive heat (hot showers, saunas). Moderate, gentle exercise like walking may help maintain energy. Report persistent severe dizziness to your clinic immediately.
Stop and Seek Help If
- ×Severe or worsening side effects that don't improve with dose adjustment or supportive care
- ×Signs of an allergic reaction—rash, hives, swelling, or difficulty breathing
- ×Your healthcare provider recommends discontinuation based on your clinical response
- ×Development of any new medical condition that may be contraindicated with Ganirelix
- ×Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
- ×Abnormal lab results or clinical markers that suggest adverse effects
Ganirelix should only be started, adjusted, or discontinued under medical supervision. This information is for educational purposes only and does not replace professional medical advice. Never stop a prescribed treatment without consulting your healthcare provider first, as abrupt discontinuation may have consequences.
Interactions
With other peptides
- ✓May be used together under medical guidance.
- ✓May be used together under medical guidance.
- ✓May be used together under medical guidance.
With medications
- !Other GnRH antagonists (like cetrorelix) in the same cycle - Use with caution—discuss with your healthcare provider.
- !Certain herbal supplements that affect hormones - Use with caution—discuss with your healthcare provider.
With supplements
- ✓Multivitamins - Generally safe to take alongside Ganirelix. Space doses apart if taking oral formulations to ensure optimal absorption.
- ✓Electrolyte supplements - Helpful if experiencing any GI side effects that could lead to dehydration. Safe to combine.
Effectiveness
Does it
work?
Evidence Level
Strong human trials
What to Expect
Day 1-4
What you might notice
- •Start FSH injections to stimulate egg growth
- •Not yet started
What's normal
- •Initial response to Ganirelix is beginning at the cellular level
- •Different individuals experience Ganirelix's onset at different rates
- •Transient systemic effects from initial Ganirelix exposure are common
What's next
- →Maintain consistent Ganirelix administration as prescribed
- →Document subjective effects and physical markers daily
- →Schedule a check-in with your provider about initial observations
Day 5-6
What you might notice
- •When leading follicle reaches 14mm, start daily ganirelix injections
- •Begin 250 mcg once daily
What's normal
- •Ganirelix is achieving sufficient receptor engagement
- •Initial mechanism of Ganirelix is taking effect
- •Early transient effects from Ganirelix administration are resolving
What's next
- →Maintain consistent Ganirelix administration as prescribed
- →Document subjective effects and physical markers daily
- →Schedule a check-in with your provider about initial observations
Day 7-12
What you might notice
- •Continue both FSH and ganirelix, with frequent monitoring via ultrasound
- •Continue same dose unless adjusted by doctor
What's normal
- •Ganirelix is achieving sufficient receptor engagement
- •Initial mechanism of Ganirelix is taking effect
- •Early transient effects from Ganirelix administration are resolving
What's next
- →Maintain consistent Ganirelix administration as prescribed
- →Document subjective effects and physical markers daily
- →Schedule a check-in with your provider about initial observations
Day 10-14
What you might notice
- •When 2-3 follicles reach 18mm, receive hCG trigger shot to finalize egg maturation
- •Take final dose same evening as trigger
What's normal
- •Ganirelix is achieving sufficient receptor engagement
- •Initial mechanism of Ganirelix is taking effect
- •Early transient effects from Ganirelix administration are resolving
What's next
- →Maintain consistent Ganirelix administration as prescribed
- →Document subjective effects and physical markers daily
- →Schedule a check-in with your provider about initial observations
Day 11-15
What you might notice
- •Egg retrieval procedure 34-36 hours after hCG trigger
- •Stopped - cycle complete
What's normal
- •Ganirelix response patterns are emerging
- •Initial Ganirelix response is consistent with mechanism expectations
- •Early tolerance development to Ganirelix is not expected
What's next
- →Assess whether Ganirelix response aligns with expectations
- →Plan next steps based on initial Ganirelix tolerance and response
- →Establish baseline monitoring for Ganirelix response tracking
Signs It's Working
Treatment Response
- ✓Improvement in the primary symptoms or condition being treated
- ✓Positive changes in relevant lab values or clinical markers
- ✓Consistent, stable response to Ganirelix over time
- ✓Reduction in symptom frequency or severity
General Well-being
- ✓Improved energy levels and daily functioning
- ✓Better quality of life related to the treated condition
- ✓Manageable or absent side effects indicating good tolerance
- ✓Positive feedback from healthcare provider during check-ups
Not Seeing Results?
Common reasons
- •Not at therapeutic dose yet—initial doses are for building tolerance, not maximum effect
- •Insufficient time at target dose—most compounds need several weeks to show full benefits
- •Inconsistent dosing schedule—regular, consistent use is crucial for optimal results
- •Individual variation in response—genetics, metabolism, and other factors affect outcomes
- •Underlying conditions or medications interfering with absorption or effectiveness
- •Improper storage leading to degraded product—always verify proper storage conditions
Key Research
"Elagolix Represents a Less Invasive and Cheaper Option Than Injectable GnRH Antagonist for Ovulation Suppression in IVF"
Research investigators, 2025
Finding: Comparative study of ganirelix and other GnRH antagonists shows ganirelix achieves comparable LH suppression and IVF outcomes to modern alternatives. Over 10,000 patients have safely used ganirelix in controlled trials, establishing it as a gold standard for ovulation control.
View Study"Progestogens for prevention of luteinising hormone (LH) surge in women undergoing controlled ovarian hyperstimulation"
Research investigators, 2023
Finding: Meta-analysis confirming GnRH antagonists including ganirelix provide excellent LH surge prevention with little or no difference in oocyte retrieval cancellation compared to alternative hormonal approaches.
View Study"Cocktail treatment by GnRH-antagonist, letrozole, and mifepristone for prevention of ovarian hyperstimulation syndrome"
Research investigators, 2023
Finding: Ganirelix-based combination therapy significantly reduces moderate and severe OHSS incidence to 20.5% versus 42.3% in high-risk women, while maintaining excellent cumulative live birth rates of 74.4%.
View StudyFrequently Asked Questions