The Science of Supplements: What Works, What's Hype, and What Could Actually Harm You | Dr. Mahtab Jafari
10% Happier with Dan Harris
10% Media, LLC
4.6 • 12.9K Ratings
🗓️ 11 May 2026
⏱️ 70 minutes
🧾️ Download transcript
Summary
Creatine, melatonin, peptides, protein powders, green powders, probiotics, multivitamins, and much more: A pharmaceutical scientist breaks down the evidence and busts the myths.
Dr. Mahtab Jafari is a Professor of Pharmaceutical Sciences and Ecology & Evolutionary Biology at the University of California, Irvine, and the Founding Director of the UC Irvine Center for Healthspan Sciences. She is the author of the award-winning book, The Truth About Dietary Supplements: An Evidence- Based Guide to a Safer Medicine Cabinet.
In this episode we talk about:
- Product quality, safety, and regulation
- The most important thing to do before starting dietary supplements
- Vitamins B, C, and D (and the multivitamin debate)
- The research on amino acids and peptides
- The truth behind sleep supplements
- The efficacy of herbs, botanicals, and green powders
- Heavy metal risk factors
- Supplements for brain health and muscle growth
- Probiotics and gut health
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Transcript
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| 0:00.0 | This is the 10% Happier Podcast. I'm Dan Harris. |
| 0:07.8 | Hello, everybody. Today we're talking about one of the most confusing and controversial areas of wellness and fitness, and that is supplements. Should you be taking them? Which ones should you be taking? How do you know? How do you separate fact from fiction in the midst of this multi-billion dollar, almost entirely unregulated business where people are making |
| 0:39.4 | all sorts of wild health claims. So what to do about all this? We brought in a ringer, an expert, Dr. Matab Jafari. |
| 0:47.1 | She's a professor at the University of California, Irvine, and she's also written a book called |
| 0:52.1 | The Truth About Dietary Supplements, an evidence-based |
| 0:55.2 | guide to a safer medicine cabinet. |
| 0:57.8 | Real quick, as many of you know, one of the major use cases for supplements is, of course, |
| 1:02.9 | sleep, which is why we are this week over on the 10% app adding a ton of new sleep content. |
| 1:09.6 | We've just added 10 new sleep meditations. We're also |
| 1:13.0 | going to be doing a live session tomorrow where our teacher of the month, Kar Lai, is going to talk |
| 1:18.0 | about how to use meditation for sleep. And alongside all of this, we'll be doing some sleep-centric |
| 1:23.6 | content here on the pod. The sleep, as you know, is the apex predator of healthy habits. |
| 1:28.7 | Nothing works without it. By the way, if you sign up for the app, which you can do over at |
| 1:33.8 | Dan Harris.com, you will also get this podcast without any ads. So head on over to danharis.com. |
| 1:41.8 | Okay, enough out of me. We're going to get started with Dr. Matab Jafari right after this. |
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... |
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