As a ghrelin receptor agonist, MK-677 works by attaching itself to the ghrelin receptor in the brain and signaling the secretion of GH and IGF-1. It doesn’t have androgenic properties, nor does it increase serum testosterone by lowering SHBG, as SARMs do. Despite this, you can find countless cases of users who developed gyno after their MK-677 cycle.
MK-677 has the potential to cause gyno by increasing prolactin, though very, very rarely. The prolactin increase it causes is not strong enough to cause gyno by itself. Those who are naturally prone to gyno and have an imbalance between testosterone and estrogen are already more likely to develop it on MK-677.
Keep on reading for a more detailed answer. This article is based on the latest academic data, the analysis of thousands of anecdotal reports online, as well as my own experiments on myself and over 500 lifetime clients in conditions deemed as controlled as possible.
One of the side effects of MK-677 is a slight increase in prolactin. High prolactin levels can lead to the development of gyno in some men.
The extent of the increase in prolactin that MK-677 causes is not by itself enough to cause gynecomastia. However, if you have had gynecomastia in the past or during puberty, you are at a greater risk of developing it again if you take MK-677.
If you want to be 100% on the safe side, get your prolactin levels checked by doing bloodwork. If your baseline prolactin levels are over the reference range, I would suggest taking measures to bring them down before taking MK-677.
If you want to take MK-677, or any research chemical including SARMs, safely and as effectively as possible you can do so by getting The SARMs Wiki. There’s a whole multi page section for bloodwork, which is why I’m plugging it here.
To prevent this side effect, take 100mg of Vitamin B6 (P5P form) before bed during your MK-677 cycle. Do this even if you’re not prone to gyno, as this dose of P5P doesn’t have side effects and will improve your health and sleep.
Again, it is extremely unlikely if you are not prone to it, but if you feel any early symptoms of gyno like nipple pain or swelling, you can also take:
Prolactin-induced gyno from MK-677 is rare, and if you follow these instructions, it will not happen to you.
MK-677 is cheap to manufacture, but despite that, it’s still not uncommon to get an underdosed bottle or a completely different chemical that can cause gyno among other equally bad or worse side effects.
I’m certain that 99%, if not all, of the anecdotal reports of MK-677 causing gyno involve a tainted and fake product.
High-quality MK-677 is not hard to come by, and opting to buy from a shady merchant that offers suspiciously cheaper prices can bite you back.
Even though fake chemicals are not as common as they once were, only shop from reputable sources that have a good reputation in the community. My recommended sources are:
If you have a family history of gynecomastia or developed gyno during puberty, you have a risk of redeveloping it if you take any kind of drug that alters your hormonal balance.
To be safe, have Raloxifene at your disposal whenever taking things that might provoke the development of gyno (or just skip the PED train and stay natty forever).
If you have gyno, MK-677 can make it worse by increasing prolactin. Before taking any kind of gyno-provoking PED, get rid of your existing gynecomastia first.
Stacking multiple SARMs can lead to gyno, and MK-677 can exacerbate this by increasing prolactin.
NOTE: If you’ve had gyno before during puberty, you are at a much higher risk of redeveloping it again if you take SARMs.
A lot of users have the misconception that stacking 2 SARMs of the same kind will lead to better results. When you take two SARMs of the same kind (e.g., RAD 140 and LGD 4033), they end up fighting over the same androgen receptors. The SARM with the higher binding affinity always wins, leaving the other one in your bloodstream, giving you little additional benefit while exacerbating the side effects of both compounds.
Always stack a SARM with a research chemical or PED that works through a different pathway to achieve synergy between the compounds like:
Also, keep in mind that SARMs like YK11 and S23 are known to cause androgenic side effects, which could lead to the development of gyno if one is prone to it.
Real, high-quality MK-677 is very unlikely to cause gyno unless you’re someone who has had it during puberty or are taking MK-677 with other AAS and SARMs. To be safe, get your prolactin levels tested, have Raloxifene at hand, and get high-quality MK-677.
premium resources
Everything you would ever want or need to know about SARMs to use and recover from them. Also includes other research chemicals.
An all-in-one guide that will teach you how each of the peptides works, how you can use them and find the perfect one (or stack) to reach your goals.
Wish there was ONE comprehensive, easy-to-read guide to get you fully informed on the safe and effective use of anabolic steroids?
Improve penile function, get harder fuller and longer-lasting erections, increase stamina in bed and last longer, go more rounds. All the good stuff.
A summary of everything you NEED to know about using PHs as safely as possible, supplements to stay as healthy as possible during cycles and how to recover (PCT).
A document I originally made for my clients. A neat map to the sphere of PEDs and supplements.
You'll receive the link and a once-a-week PED-related article in your inbox upon subscribing.
A special gift to all my email subscribers. The PED Dictionary is a DOC designed to help you navigate the world of enhanced bodybuilding. A game changer for beginners that want to learn more but don't know where to start, and a must-have handbook for even the most advanced enhanced researchers.
