MK-677 user experiences: what users themselves report
Users’ own accounts, not research. The accounts are self-selected and prove neither that it works nor that it is safe.
This page does not list users’ doses or sellers, and no figure on it is a recommendation. Doses used in studies, with sources: MK-677 dosage in studies.
In short
Of 80 people, 43 (54%) said MK-677 brought some benefit and 50 (63%) some harm.
- An AI model read and classified 300 public Reddit posts one by one, following written instructions. Leaving out posts that looked like marketing, 87 were first-hand accounts, from 80 different people.
- Benefits mentioned most often: better sleep (20, 25%), more appetite or weight gain (wanted) (11, 14%) and muscle or strength (11, 14%).
- Harms mentioned most often: higher blood sugar or insulin resistance (12, 15%), strong hunger (unwanted) (11, 14%) and nausea or stomach upset (7, 9%). In addition, 12 (15%) described some other, rarer harm. People tend to post when something goes wrong, so this share does not tell how common harms are.
- MK-677 is taken by mouth, and only 8 of 80 people (10%) used other substances at the same time, so the accounts describe this substance more clearly than most other summaries. 63 of 87 accounts came from the users' own forum r/mk677.
- The accounts cannot separate the substance from placebo or other causes. What the research shows: MK-677: what the research shows.
Where the accounts come from and how we read them
Sources: the Reddit forums r/mk677 (63 accounts), r/Peptides (12), r/Biohackers (10) and r/Nootropics (2), 17 Oct 2024 to 10 Sep 2026. The posts were retrieved from a public Reddit archive. From first-person posts about MK-677, 300 were picked at random, and every one was read.
Coding: for each account we recorded the route, reported benefits and harms, how strong a harm was, whether and why the person stopped, length of use and other substances used at the same time. We kept accounts that reported some effect, some harm, or no effect. Questions and plans were left out. A harm was recorded when the person reported it during use, even if the cause was uncertain. Several posts by one person count as one person. One person can mention several things, so the shares in the tables do not add up to 100.
Check: an AI model read and classified the posts following written instructions. A second, separate AI run classified a random tenth (30 posts) again without seeing the first classification. The main fields matched: 28/30 (93%). One post looked like marketing and is not in the figures.
Whose accounts these are: routes mentioned: by mouth 80; the others did not say. The figures describe the writers and are not a recommendation. The products were not verified, so we do not know what people actually took.
Did MK-677 help? The overall picture
Of 80 people, 25 (31%) reported benefit only, 18 (23%) both benefit and harm, 32 (40%) harm only and 5 (6%) neither.
Stopping. 3 people (4%) said they stopped or paused: 3 because of harms and 0 because they noticed no effect or for another reason.
| Overall picture: benefit, harm or neither | People | Share |
|---|---|---|
| Benefit only | 25 | 31% |
| Both benefit and harm | 18 | 23% |
| Harm only | 32 | 40% |
| Neither benefit nor harm | 5 | 6% |
Most common reported benefits
Of 80 people. 43 (54%) mentioned some benefit; the table lists every benefit reported.
| Reported | People | Share |
|---|---|---|
| Better sleep | 20 | 25% |
| More appetite or weight gain (wanted) | 11 | 14% |
| Muscle or strength | 11 | 14% |
| Faster recovery | 9 | 11% |
| Energy or alertness | 4 | 5% |
| IGF-1 rose on a lab test | 3 | 4% |
| Mood or wellbeing | 3 | 4% |
| Less joint or other pain | 2 | 3% |
| Other benefit | 8 | 10% |
Share = people / 80.
Most common reported harms
Of 80 people. 50 (63%) mentioned some harm; 4 said explicitly they had none.
| Reported | People | Share |
|---|---|---|
| Higher blood sugar or insulin resistance | 12 | 15% |
| Strong hunger (unwanted) | 11 | 14% |
| Nausea or stomach upset | 7 | 9% |
| Fatigue or lethargy | 6 | 8% |
| Water retention or swelling | 6 | 8% |
| Sleep problems | 5 | 6% |
| Anxiety, irritability or low mood | 4 | 5% |
| Joint or muscle pain | 3 | 4% |
| Heart or blood pressure | 2 | 3% |
| Headache | 1 | 1% |
| Prolactin, cortisol or breast tissue symptoms | 1 | 1% |
| Other, rarer harm | 12 | 15% |
Share = people / 80.
How severe were the harms?
Of the 50 people who described how strong a harm was, 35 (70%) described it as mild, 13 (26%) as clearly bothersome and 2 (4%) as severe. The strength is the writer's own description, not a doctor's assessment.
| Strength of the harm as the writer described it | People | Share |
|---|---|---|
| Mild: minor and manageable | 35 | 70% |
| Clearly bothersome: several days, sleep or work affected | 13 | 26% |
| Severe: emergency visit, hospital or unable to function | 2 | 4% |
Harms known from research and regulators: What side effects does MK-677 have?
How long did people use MK-677?
59 of 80 people (74%) said how long they had been using it at the time of writing. Where one person wrote several posts, the longest stated time counts.
| Stated length of use | People | Share |
|---|---|---|
| Under a week | 22 | 37% |
| 1-4 weeks | 22 | 37% |
| 1-3 months | 11 | 19% |
| Over 3 months | 4 | 7% |
Many people post partway through, often in the first days or as soon as harms start, so short times are over-represented. The numbers describe the writers; they do not say how long it should be used.
Other substances at the same time
8 of 80 people (10%) used other substances at the same time. The most common: testosterone therapy (2), arimistane (1), BPC-157 (1), cardarine (1), enclomiphene (1) and 5 more equally common. Then the account cannot tell which substance had the effect.
About dosing
We do not repeat the amounts or ways of use people mention, and we give no dosing or how-to instructions. A safe dose is not known. Doses used in studies, with sources: MK-677 dosage in studies. Legal status: Is MK-677 legal in Finland?
What can be concluded?
The most common reported benefit was better sleep and the most common harm a rise in blood sugar, and many also reported unwanted hunger. Because other substances were rarely used, the accounts describe this substance more clearly than most other summaries.
The accounts prove neither that it works nor that it is safe. The writers are self-selected, the product contents are unknown, many used several substances at once, and placebo effects can be large. The research and its evidence levels: MK-677: what the research shows.
Quotes
Short excerpts in the writers’ own words. Writers’ names and links are not shown. We picked quotes from every group: benefit, both benefit and harm, no effect, harms and people who stopped.
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"I used to sleep 12+ hours, now I feel perfect off of 6.5, sleep study scores have tripled"
r/Biohackers, 2026-06, By mouth, in very small amounts for about two months for severe chronic fatigue. Sleep was the most common benefit reported in the sample. The writer says he does not know the cause of his symptoms.
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"What it did do if heal my joints and improved my recovery time."
r/mk677, 2025-08, A three-month course by mouth. The writer reported no side effects and no direct strength gain, but recovered from training faster.
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"i can lift more than before and i eat more but the sleep was good only in my first week, now i have problems with sleeping"
r/mk677, 2025-02, Three weeks by mouth. Strength and appetite rose as hoped, but sleep got worse after the first week.
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"No increased hunger, no sleep changes, no lethargy, no water retention"
r/mk677, 2025-07, A month of capsules. The writer noticed no effect at all and suspects the product contained too little active ingredient.
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"My heart started pounding really hard and fast and it was hard to catch my breath. I got dizzy and fell."
r/mk677, 2025-01, About a month by mouth. Symptoms began after a large meal; paramedics measured high blood pressure and blood sugar. Whether MK-677 caused it is uncertain.
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"So i got scared and didn’t used it no more"
r/mk677, 2025-01, About a week by mouth. Fasting blood sugar rose clearly on day six and stayed raised a week after stopping. Higher blood sugar was the most common harm in the sample.
Other summaries made with the same method: BPC-157 user experiences, Ipamorelin user experiences, CJC-1295 user experiences, Tesamorelin user experiences, Sermorelin user experiences, AOD-9604 user experiences, CJC-1295 + ipamorelin blend user experiences and user experiences with collagen and skin peptides.
Content is general information about research, not medical advice. If you have symptoms, contact a healthcare professional.