Peptide profile · Hormone Support
Buserelin
A synthetic GnRH agonist that suppresses hormones to help treat prostate cancer, endometriosis, and infertility
Written & reviewed by Michael Carroll · Research, Peptide Initiative
Typical dose
200 mcg
Half-life
2-4 hours (subcutaneous), 30-60 minutes (intranasal); longer for depot formulation (28-40 days)
Bioavailability
~1% (oral); ~10-15% (intranasal); ~95% (subcutaneous)
Molecular weight
1239.4 g/mol
Evidence level
Strong human trials
01 · Compound profile
Scientific & efficacy data
Molecular formula
C60H86N16O13
Primary benefits
Reversible hormone suppression after treatment stops
Suppresses testosterone to near-castrate levels for prostate cancer management
Improves fertility outcomes when combined with IVF protocols
Hoechst AG (now Sanofi)
Amino acid sequence
pGlu-His-Trp-Ser-Tyr-D-Ser-Leu-Arg-Pro-NHEt02 · Dosing
How much do I take?
200 mcg · once daily
Subcutaneous: A small injection into the fatty layer just under the skin — the same way insulin is given.
Bioavailability High — most of the dose reaches your bloodstream, just more gradually than an IV.
Best time to take
Administer Buserelin 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?
Buserelin 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
Buserelin 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.
＋ 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
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03 · Suitability
Is this right for me?
Best for managing advanced prostate cancer & treating endometriosis and reducing associated pain
Best for
Managing advanced prostate cancer
Buserelin is particularly well-suited for individuals focused on managing advanced prostate cancer. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Treating endometriosis and reducing associated pain
Buserelin is particularly well-suited for individuals focused on treating endometriosis and reducing associated pain. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Optimizing ovarian response during fertility treatments
Buserelin is particularly well-suited for individuals focused on optimizing ovarian response during fertility treatments. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Consider alternatives if
Do not use if
Use with caution if
Not sure?
Compare Buserelin with similar peptides to find the best fit for your goals.
04 · Administration
How do I use it?
Subcutaneous injection · Intranasal spray
Reconstitution — what you need
Example
Add the recommended volume of bacteriostatic water to the Buserelin vial. Gently swirl (do not shake) until the powder is fully dissolved. The resulting solution should be clear. Calculate your individual dose based on the concentration and your prescribed amount.
Your dose of Buserelin is determined by your healthcare provider. Using an insulin syringe marked in units, draw up the exact amount prescribed. For example, if the reconstituted concentration is 1mg/mL and your dose is 0.5mg, draw up 0.5mL (50 units on an insulin syringe). Always double-check calculations before 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
Technique
- 01Wash your hands thoroughly with soap and water before handling supplies
- 02Clean the injection site with an alcohol swab and let it air dry completely
- 03Pinch a fold of skin at the chosen injection site
- 04Insert the needle at a 45-90 degree angle (depending on needle length and body composition)
- 05Inject the medication slowly and steadily over 5-10 seconds
- 06Release the skin fold and remove the needle, applying gentle pressure with a clean swab
- 07Rotate injection sites to prevent tissue irritation or lipodystrophy
- 08Dispose of the needle safely in a sharps container—never recap or reuse needles
Storage · before reconstitution
Store Buserelin in the refrigerator at 36-46°F (2-8°C) in its original packaging. Protect from light and moisture. Do not freeze. Check the expiration date before use. Some formulations may be stored at room temperature for limited periods—check your specific product labeling.
Storage · after reconstitution
Once reconstituted, Buserelin should be kept refrigerated at 36-46°F (2-8°C) and used within the timeframe specified on your product labeling (typically 14-28 days). Label the vial with the reconstitution date. Do not use if the solution appears cloudy, discolored, or contains particles.
Signs of degradation
Sample daily schedule
05 · Safety
Is it safe?
Buserelin is an FDA-approved GnRH agonist with safety data from Phase 3 trials and decades of clinical use, but carries well-documented risks from intentional testosterone/estrogen suppression. The initial testosterone flare (first 2-3 weeks) can worsen prostate cancer symptoms and cause tumor flare pain in 10-20% of patients. Long-term use causes bone density loss of 2-3% annually, with vertebral fractures in 10-20% of long-term users. Cardiovascular risks include increased MI and stroke in men over 65. Hot flashes affect 40-80%, erectile dysfunction is nearly universal, and liver enzyme elevations occur in 5%. Nasal spray formulation causes local irritation in 20-30% of users.
Buserelin was studied through Phase 3 clinical trials before FDA approval, with decades of post-market pharmacovigilance data. The flare phenomenon, bone loss, cardiovascular effects, and endocrine complications are well-characterized from long-term studies spanning over 30 years. Comparative safety data with GnRH antagonists demonstrates buserelin's disadvantage regarding initial flare effect but similar long-term side effect profiles.
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 Buserelin
- ×Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
- ×Abnormal lab results or clinical markers that suggest adverse effects
Buserelin 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.
With other peptides
- ✓Anti-androgens (like bicalutamide) for prostate cancer—provides additional tumor control — May be used together under medical guidance.
- ✓Gonadotropins during IVF—enhances ovarian response and timing — May be used together under medical guidance.
- ✓NSAIDs—helps manage pain and inflammation from endometriosis — May be used together under medical guidance.
With medications
- !Other GnRH agonists—redundant and increases side effects — Use with caution—discuss with your healthcare provider.
- !Alcohol in excess—may worsen hot flashes and mood changes — Use with caution—discuss with your healthcare provider.
With supplements
- ✓Multivitamins — Generally safe to take alongside Buserelin. 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.
06 · Effectiveness
How do I know it's working?
Strong human trials
Evidence level
Strong human trials
(Phase 3 or FDA approved)
How it works
Buserelin is a GnRH agonist that first stimulates hormone release, then shuts down the whole system. For endometriosis, this lowers estrogen dramatically, reducing tissue growth and pain. Available as injections or nasal spray for flexibility.
Buserelin is a nonapeptide GnRH agonist with D-serine substitution at position 6. Initial agonistic activity causes FSH/LH release (flare, 7-14 days), followed by receptor desensitization and downregulation, achieving 90%+ suppression of testosterone and estrogen within 3-4 weeks.
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 Buserelin over time
- ✓Reduction in symptom frequency or severity
Signs it's working · 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
07 · Questions
Frequently asked
How quickly does buserelin work?+
You'll see some effects within 1-2 weeks, but full benefits take 4-6 weeks. For fertility, timing is precise—ovulation is prevented within days. For cancer, it takes several weeks to see tumor response.
Is buserelin reversible?+
Yes! Once you stop taking it, your hormone levels return to normal within 4-8 weeks. Sexual function, mood, and energy improve as hormones bounce back.
Does buserelin hurt when injected?+
Most people say the injection is a quick pinch, similar to other shots. Some experience minor bruising or redness at the injection site. Your doctor can show you proper injection technique to minimize discomfort.
Can I use buserelin if I want kids later?+
For men with prostate cancer: fertility may be affected, but hormones usually recover after treatment stops. For women with endometriosis: buserelin actually improves fertility by reducing pain and improving egg quality during IVF. Talk to your doctor about your specific situation.
What about the nasal spray—does it work as well as injections?+
Yes, the nasal spray works just as well if you use it correctly. You need to spray more frequently (usually 3 times per day), but hormone suppression is equally effective. Some people prefer it because there are no needles.
Will my hair fall out?+
Hair loss is not a common side effect of buserelin. You might notice some thinning due to hormone suppression, but it's usually temporary and mild compared to chemotherapy.
How long can I take buserelin?+
For endometriosis, doctors typically limit it to 6-12 months due to bone loss risk. For prostate cancer, you might take it indefinitely. For fertility, it's only a few weeks. Your doctor will determine what's safe for your situation.
Is buserelin available in the United States?+
Not under the brand name Suprefact. However, similar GnRH agonists like leuprolide (Lupron) and goserelin (Zoladex) are available in the US and work similarly.
08 · Further reading
History & related research
History · since 1982
The first GnRH agonist that taught doctors how to turn off hormone signals to fight cancer and help couples have babies
Buserelin is a man-made copy of a natural hormone that controls sex hormones in your body. It was one of the first drugs in its class, developed by Hoechst in the 1980s.
Read the full history of Buserelin