Adrian Crook Quit Retatrutide After 6 Months: What He Learned

In late 2026, content creator Adrian Crook posted "I Quit Retatrutide: My Final Verdict After 6 Months" — one of the most detailed first-person accounts of long-term grey market retatrutide use available on YouTube. Crook documented his experience from March through September 2026, using low doses (1–3mg per week) and sharing his weight loss, side effects, craving elimination, muscle loss measured by DEXA scan, and a dangerous PPI drug interaction.

This page breaks down what Crook reported, where his experience aligns with clinical data, and where it diverges. Crook is not a physician and used unregulated grey market retatrutide without clinical trial oversight.

His Starting Point and Dosing

"I started Retatrutide back on March 1st"

0:41

Crook started at 200 lbs, 5'10", roughly 19% body fat. His dosing was notably conservative:

"I started doing every other day, 0.33 milligrams. So about a milligram a week roughly. And I noticed it right away. Certainly within 24 hours, I noticed the appetite suppression."

— Adrian Crook

His peak dose of 3mg per week is still far below the Phase 3 target doses of 9–12mg. In the Phase 2 trial, the 4mg dose produced 17.9% weight loss at 48 weeks, while 1mg produced only 3.19%. Crook's aggressive weight loss at very low doses is noteworthy — though the potency and actual content of grey market products is unverifiable.

For clinical dosing data, see Retatrutide Dosage. For sub-clinical dosing context, see Microdosing Retatrutide.

Weight Loss: 25 Pounds in 6–8 Weeks

"Within 6 to 7 weeks I had lost 25 pounds"

1:31

Crook reports losing 25 lbs in approximately 6–8 weeks at roughly 1mg per week:

"Probably within 6 to 7 weeks at the most 8 weeks I had lost 25 lbs. I'm not someone who enjoys eating at the best of times... I really leaned into the lack of appetite. And way too much. Obviously, that amount of weight loss in that short of time is not really healthy and it definitely ate into my muscle mass."

— Adrian Crook

He eventually stabilized around 175–176 lbs — a total loss of roughly 25 lbs from his 200 lb starting weight. That is a 12.5% reduction over 6 months.

His rate of loss is much faster than the Phase 2 trial showed at 1mg — where participants averaged only 3.19% at 48 weeks. This could reflect his intentional caloric restriction ("I really leaned into the lack of appetite"), individual variation, or differences in the grey market product. He honestly acknowledges the speed was unhealthy and cost him muscle.

Craving Elimination: Cigars and Alcohol

"My cigar habit went to zero"

3:09

One of Crook's most interesting observations was the elimination of non-food cravings:

"My cigar habit went to zero as well. I don't think this is a fluke. Those sort of dopaminergic loops... reta really short-circuits that across the board. So it's not just food or sweets — it can be smoking cigars in my case, it can be alcohol consumption."

— Adrian Crook

This aligns well with published GLP-1 research. A randomized controlled trial in JAMA Psychiatry (2025) found semaglutide users achieved zero heavy drinking days at twice the rate of placebo, and a retrospective study found semaglutide users had a 56% lower risk of new alcohol use disorder diagnoses. The mechanism — GLP-1 receptor activation in the brain's reward pathways attenuating dopamine release — would logically extend to other craving-driven behaviors beyond food and alcohol.

For retatrutide specifically, one preclinical study (Windram et al., 2025) showed it blunts subjective alcohol effects in rats, but no human data exists yet.

For the full analysis, see Retatrutide and Alcohol.

Muscle Loss: DEXA-Confirmed

"I had lost like 10 pounds of muscle"

4:59

Unlike most anecdotal reports, Crook actually measured his body composition:

"I had a DEXA scan in the summer, and the last DEXA scan I had was the summer before, and I had lost like 10 pounds of muscle in that time. Pretty horrifying."

— Adrian Crook

He attributes this partly to retatrutide-induced undereating and partly to a shoulder injury that prevented upper body training for two months. He estimates retatrutide contributed roughly half of the muscle loss (~5 lbs), with the remainder due to training limitations.

This is consistent with clinical data. The Phase 2 DXA substudy found that the ratio of lean mass loss to total weight loss was similar to semaglutide and tirzepatide — meaning retatrutide does not uniquely spare muscle. Crook's admission is valuable because it demonstrates what happens when someone "leans into the deficit" without prioritizing protein intake and training — the muscle loss concern that clinical data flags is real.

For the body composition data, see Retatrutide and Muscle Loss.

PPI Interaction: A Dangerous Combination

"The combinatorial effect of the two"

6:19

Crook shared a concerning drug interaction experience:

"Because the PPI slows your stomach acid production and because rea slows gastric emptying, the combinatorial effect of the two meant that I woke up the next day and nothing was moving and it felt horrible and everything just came up the other way."

— Adrian Crook

He was taking pantoprazole (a proton pump inhibitor) for acid reflux while on approximately 3mg/week of retatrutide. After eating popcorn, he experienced a complete gastric blockage that nearly sent him to the hospital.

This interaction is not well-documented in retatrutide literature specifically, but it is mechanistically logical. All GLP-1 receptor agonists slow gastric emptying, and PPIs reduce stomach acid — combining the two creates a compounded slowing of digestion. The FDA has issued warnings about delayed gastric emptying with GLP-1 drugs (particularly around anesthesia timing), and this real-world report adds to the picture.

Crook eventually discontinued the PPI after viewer advice, using apple cider vinegar to manage acid reflux instead. He reports no further issues since stopping the PPI.

For related safety data, see Retatrutide Side Effects.

Half-Life and Tapering

Crook references retatrutide's half-life multiple times:

"If you look at the 6 day half-life of retatrutide... you can see that when you drop under that sort of average, you can feel it quite frankly — your appetite spikes up."

— Adrian Crook

The approximately 6-day half-life is confirmed by Phase 1 pharmacokinetic data. His observation about feeling appetite return as drug levels drop below a threshold is consistent with the pharmacology — and is a common report in GLP-1 communities.

He also describes tapering before stopping rather than quitting abruptly, which is reasonable practice even though no formal discontinuation protocol has been published for retatrutide.

For half-life data, see Retatrutide Half-Life.

Frequently Asked Questions

Sources

• Crook, A. (2026). "I Quit Retatrutide: My Final Verdict After 6 Months." YouTube. Watch on YouTube
• Jastreboff, A.M., et al. (2023). Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial. New England Journal of Medicine. DOI: 10.1056/NEJMoa2301972
• Semaglutide and alcohol use disorder RCT. JAMA Psychiatry. (2025).
• Coskun, T., et al. (2025). Body composition substudy. The Lancet Diabetes & Endocrinology.

Medical Disclaimer

The content on glp3.wiki is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Retatrutide is an investigational drug that has not been approved by the U.S. Food and Drug Administration (FDA) or any other regulatory agency.

Adrian Crook's video documents his personal experience and is not medical advice. He is not a physician and used unregulated grey market retatrutide without clinical trial oversight. His results — including the rapid weight loss, DEXA-confirmed muscle loss, and PPI interaction — reflect his individual experience and may not be typical.

Do not use this information to make decisions about your health without consulting a qualified healthcare provider. Do not purchase or self-administer grey market peptides based on YouTube videos or any information on this site.

This site is not affiliated with Adrian Crook, Eli Lilly and Company, or any pharmaceutical manufacturer.