Statins Slash GLP-1 Levels: Human Controlled Trial
Norwitz walks through a 2024 Cell Metabolism paper reporting that statins lowered GLP-1 levels, and a small pilot in which a bile acid supplement reversed it.
Key moments
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- 0:00Statins, insulin resistance, and GLP-1Norwitz introduces the paper and says statins are linked to insulin resistance and a substantial drop in GLP-1 levels in humans. He connects this to the popularity of GLP-1 receptor agonist drugs.
- 1:18Why the paper upset himHe notes the findings appeared in Cell Metabolism in February 2024 and says nobody around him at Harvard mentioned them. He treats this as a sign of an overlooked issue.
- 2:05Informal poll of 12 physiciansNorwitz says seven doctors did not know the effect of statins on GLP-1 and five guessed, with four guessing correctly that levels fall.
- 2:40The 16-week human trialHe describes 30 patients starting atorvastatin 20 mg versus 10 controls. He reports higher HbA1c, insulin and HOMA-IR, and GLP-1 down nearly 50%.
- 4:04Gut bacteria and the UDCA bile acidHe explains that statins depleted Clostridium species, lowering their conversion of a precursor bile acid into UDCA. He links this to insulin resistance and reduced GLP-1.
- 5:24Preclinical and transplant experimentsNorwitz describes preclinical studies where statins reproduced the pattern and transplanted microbiomes from statin users worsened insulin resistance. Restoring the bacteria or giving UDCA reversed it, he says.
- 6:41Five-patient UDCA pilotHe reports that five long-term statin users took UDCA at 500 mg per day. According to him, blood sugar, insulin and insulin resistance improved and GLP-1 was restored.
- 7:12Incentives and the silenceNorwitz argues that health care incentives favor protocols and profit over simple, cheap options. He stresses that he is not blaming individual physicians.
- 9:07TUDCA on Amazon, with a caveatHe mentions that a taurine-conjugated version, TUDCA, is sold as a supplement. He says the video is not medical advice and the choice is the viewer's.
- 9:56Call to actionHe asks patients to share the information and ask questions, and asks clinicians and students to read the study and raise it in journal clubs.
What the video says
Nick Norwitz presents a single paper, published in Cell Metabolism in February 2024, on how statins affect insulin resistance and the gut hormone GLP-1. He opens by saying he found the work annoying as well as exciting, because he thinks it received almost no attention. He reports an informal poll of 12 physicians, including four cardiologists, none of whom knew the answer to what statins do to GLP-1 levels.
He describes the first experiment: 30 patients starting atorvastatin 20 mg were compared with 10 controls over 16 weeks. According to Norwitz, the statin group had higher HbA1c, insulin and insulin resistance, and GLP-1 fell by nearly 50% by the end. He then explains the proposed mechanism. Statins depleted Clostridium species in the gut, which reduced production of a bile acid called UDCA, and he says this led to the metabolic changes and lower GLP-1.
To test causality, he says the researchers ran preclinical studies. Statin-treated subjects showed the same pattern, microbiome transplants from statin-taking patients worsened insulin resistance, and restoring the bacteria or giving UDCA reversed the damage. He then describes a small human pilot of five long-term statin users given UDCA at 500 mg per day, in which he says HbA1c, insulin and insulin resistance improved and GLP-1 was restored.
The second half is commentary. Norwitz argues that incentives in health care keep inexpensive options from being discussed, and notes that a taurine-conjugated form, TUDCA, is sold as a supplement. He states that the video is not medical advice and that he is not telling anyone to stop a statin. He closes by asking patients and clinicians to share the paper and raise it with colleagues.
What this video doesn’t settle
- The human UDCA result comes from a pilot of only five patients, with no control group described in the video.
- The video discusses UDCA, and mentions TUDCA only as an online supplement, without showing that TUDCA gives the same effects as the dose tested.
- Norwitz does not say whether the lower GLP-1 levels led to measurable changes in weight, diabetes outcomes or heart outcomes for statin users.
Questions this video answers
Do statins lower GLP-1 levels?
Norwitz reports that in a 16-week study of patients starting atorvastatin 20 mg, GLP-1 fell by nearly 50% by the end, compared with 10 controls not taking statins. He says this came from a 2024 Cell Metabolism paper.
How do statins affect the gut microbiome, according to Norwitz?
He says statin-treated patients had fewer Clostridium bacteria, which convert a precursor bile acid into UDCA. Less UDCA, he explains, was tied to insulin resistance, higher blood sugar and lower GLP-1.
What was the UDCA pilot trial in this video?
Norwitz describes a small pilot of five patients who had taken statins for at least 6 months and were given UDCA at 500 mg per day. He says HbA1c, insulin and insulin resistance improved and GLP-1 was restored.
Does Norwitz tell people to stop taking statins?
No. He says he is not prescribing or suggesting that patients stop statins and describes the video as informed consent and information. He adds that it is not medical advice and the decision is up to each person.
What does Norwitz say about TUDCA supplements?
He notes that TUDCA, a version of the bile acid conjugated to taurine, is sold on Amazon. He says it could in effect raise the same bile acid, but he frames this as information rather than a recommendation.
Video by Nick Norwitz MD PhD on YouTube, embedded as published. The summary is written by PeptidesDNA from the video; every claim in it is the speaker’s. Not affiliated with or endorsed by the creator. Not medical advice.
