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- 2025 Research on Kisspeptin
Happy Wednesday!
If you follow my personal life, you probably know that Taylor and I got married this year.
In the very near future, we hope to start a family.
As you can probably imagine, in my free time, I have been digging up any peptide data I can get my hands on to help facilitate the birth of our future children.
And recently, I came across a scientific review in The Journal of Clinical Endocrinology & Metabolism (June 2025) that examines the use of kisspeptin.
Although kisspeptin doesn’t get much love in the peptide world, some of the data this review compiled changed my thinking on it.
Sure, there are documented reproductive uses for kisspeptin, but this review also explored its benefits for mood, motivation, bone health, and more.
Today, I’ll summarize the data from this review on kisspeptin and discuss why it might be more beneficial for things other than baby-making (although I’ll be using it for that too 😉 ).
Let’s jump in.
FYI, BioLongevity Labs is running their Halloween Sale this week. Until Friday at midnight PST, you can get 20% off any product in the store, and an additional 15% off when you use code HUNTERW at checkout.
What Is Kisspeptin?
Kisspeptin is a small protein made naturally in your brain and body.
It acts as a major “on-switch” for your hormone system, specifically for the hypothalamic-pituitary-gonadal (HPG) axis.
In simpler terms, your brain’s hypothalamus releases a signal (GnRH) when kisspeptin activates it. The pituitary gland then releases LH and FSH, which tell your ovaries or testes to produce sex hormones like testosterone and estrogen.
In addition to reproduction, kisspeptin also connects to parts of the brain involved in emotion, attraction, motivation, and bonding.
So it helps link what you feel with how your body responds hormonally.
Age matters too.
Studies show that as people age, the expression of endogenous kisspeptin neurons and their receptors declines.
One human plasma study found that kisspeptin concentrations peak around ages 9-12, then decline with age.
This decline suggests there may be an argument for supplementing with kisspeptin periodically as we age.
The Benefits
The review brings together human studies showing practical benefits of kisspeptin.
Here are the top ones:
Hormone Activation: Kisspeptin reliably stimulates the HPG axis. In men, it increases LH and FSH, which can lead to increased testosterone (though I wouldn’t say it replaces TRT). In women, it’s being used in fertility settings to trigger ovulation more naturally.
Better Sexual Desire and Function: Human brain imaging trials show that after kisspeptin administration, the brain responds more strongly to sexual, romantic, and bonding cues. For example, men showed greater arousal and better penile rigidity when exposed to erotic stimuli under kisspeptin vs placebo. The review reports that such neural effects correlate with reported desire.
Improved Mood and Motivation: Studies show that kisspeptin may reduce negative mood states (such as anxiety and irritability) and enhance reward/motivation circuits in the brain. That means this peptide could also help with emotional and psychological well-being.
Bone Health Support: Early human data show that kisspeptin boosts osteocalcin (a bone formation marker) and suppresses osteoclast (bone breakdown) activity. This suggests potential value for bone integrity, especially in aging or hormone-deficient states.
Good Safety/Tolerability: In a large crossover human study, a biologically active dose of kisspeptin did not raise anxiety, heart rate, or blood pressure in healthy men and women.
From a practical point of view, kisspeptin gives you a tool for fertility support, libido enhancement, mood/emotional balance, and possibly bone health.
Who Is a Good Candidate for Kisspeptin?
While kisspeptin is exciting, it’s not for everyone. Here are the profiles that make the most sense:
Men with low testosterone from central causes: If the brain/pituitary is under-signalling (low LH/FSH) rather than the testes being totally dysfunctional, kisspeptin may help “turn the system back on” naturally. To me, this means men on TRT without HCG would be a good candidate.
Women with irregular cycles or fertility issues: Kisspeptin is being studied for ovulation triggers and for restoring natural HPG rhythm in women with hypothalamic amenorrhea or IVF contexts.
Individuals with low libido or sexual desire problems: Especially when typical labs (testosterone, estradiol) look okay, but desire remains low. The brain/emotion link matters, and kisspeptin may help.
Aging men or post-menopausal women concerned about bone health and hormone mitigation: Because the peptide supports bone markers and upstream hormone drive, kisspeptin assists with bone density.
If someone has primary gonadal failure (ovaries/testes simply cannot respond), kisspeptin won’t solve the downstream organ issue, which means that it is a poor substitute for testosterone replacement.
However, if testosterone is optimized, there is evidence to suggest it could enhance sexual desire or improve interest in sexual activity.
How to Mix and Dose
Kisspeptin’s half-life is short, so smaller, more frequent injections work best. I recommend 125 mcg twice daily for maximum effect.
Once in the morning and once in the evening to maintain steady signaling and natural hormone rhythm.
Mixing:
Add 3 mL of bacteriostatic water to your 10 mg (10,000 mcg) vial of kisspeptin.
This creates a concentration of 3,333 mcg per mL.
Gently swirl (don’t shake) until dissolved.
Dosing:
125 mcg ÷ 3,333 = 0.037 mL per injection.
Inject 0.04 mL (4 units) SubQ twice per day into the abdomen, about 8–12 hours apart.
Cycle and monitoring:
Continue for 8–12 weeks, tracking libido, mood, sleep, and hormone labs (LH, FSH, testosterone/estradiol).
If tolerated but results plateau, you may titrate up slightly under medical guidance.
For advanced stacks, kisspeptin can pair well with PT-141 and oxytocin for improved sexual desire.
This twice-daily micro-pulsing mimics natural kisspeptin rhythms and supports smoother HPG activation without receptor fatigue associated with higher bolus doses.
Summary
The 2025 JCEM review on kisspeptin really brought my attention to some of its ancillary benefits.
The more I study how endogenous peptides decline as we age, the more I become a fan of replacing peptides like kisspeptin to physiological levels as a common practice.
In addition to reproductive health, it serves as a node connecting hormones, brain/emotion, sexual desire, and even bone health.
It’s NOT a generic “boost testosterone overnight” hack.
However, based on the data, it gives you a controlled way to reset or enhance the body’s natural systems and rhythms.
Best,
Hunter Williams