Fertirelin dosing & administration
A potent GnRH analog designed to support reproductive function in veterinary and research settings
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Dosing
How much do I take?
Intramuscular: An injection into a muscle, usually the thigh, shoulder, or buttock.
Bioavailability High — well absorbed into the bloodstream from the muscle.
50-100 mcg per animal
Frequency
Single injection at the defined point in the synchronization protocol
Duration
Single dose (repeated per breeding cycle as needed)
Timing
Best time to take
Administer Fertirelin 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?
Fertirelin 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
Fertirelin 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
Administration
How do I use it?
Reconstitution
What you need
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
Storage
Before reconstitution
Store Fertirelin 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.
After reconstitution
Once reconstituted, Fertirelin 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 — discard the vial
Sample daily schedule
As prescribed (once daily)
As prescribed by your healthcare provider injection
Site: Intramuscular injection—rotate sites if applicable
Maintain a consistent schedule for optimal results with Fertirelin. Set reminders if needed. If you miss a dose, follow your healthcare provider's instructions—do not double up on doses to compensate.
Safety
Is it safe?
Side effects
Commonly reported: Mild discomfort at treatment site, Transient hormone fluctuations, Temporary behavioral changes in animals, Mild injection site reactions, Short-term changes in appetite, Temporary mood variations, Minimal systemic effects at therapeutic doses
Less common: Occasional swelling at injection site
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 Fertirelin
- Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
- Abnormal lab results or clinical markers that suggest adverse effects
Fertirelin 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.
Flagged pairings
- Dopamine agonists — Use with caution—discuss with your healthcare provider.
- Other GnRH agonists without medical guidance — Use with caution—discuss with your healthcare provider.
- Certain anticonvulsants — Use with caution—discuss with your healthcare provider.
Published research
What the studies show
Chenault JR · 1990
Fertirelin acetate improved conception rates in lactating dairy cows when administered for timed insemination. The GnRH agonist effectively synchronized ovulation and improved fertility outcomes in breeding programs.
Kawakami E, Tonsho H, Tsutsui T · 1991
LHRH analogs improved sperm quality in dogs by temporarily raising testosterone and LH levels. Treatment restored fertility within 30 days, with sperm abnormalities decreasing from 19-32% to 10-16%.
Inaba T, Tani H, Gonda M · 1998
GnRH agonist depot formulations successfully induced fertile estrus in female dogs, allowing precise control of breeding timing. Long-acting formulations provided sustained hormone effects for reproductive management.
Yamada K, et al. · 2002
In lactating dairy cows, intramuscular fertirelin acetate at 50 mcg and 100 mcg both raised plasma LH above 5 ng/mL ~120 min post-injection with comparable conception rates (61.1% vs 59.5%), supporting 50-100 mcg IM for ovulation synchronization.
Head to head
Fertirelin compared
Want the full picture?
The complete Fertirelin research profile: mechanism of action, clinical studies, effectiveness timeline, and FAQ.