The Proof with Simon Hill

Peptides are being marketed as solutions for everything from injury recovery to longevity, but what does the science actually say?

In this episode, Dr Leigh Baxt joins me to break down what peptides are, how drug development really works, and why so many of the claims circulating online are running far ahead of the evidence. We explore the difference between approved peptide medicines and unregulated products sold online, why anecdotes are not enough, and what people should understand before putting these compounds into their bodies.

What We Cover

What peptides are and why they are not new

FDA-approved peptide drugs versus unregulated peptides sold online

Why scientists are concerned about the current peptide boom

How drugs are developed and why most ideas fail

Why animal and cell studies are not enough to establish safety and efficacy

The problem with using “natural” as a proxy for safe

How to think critically about peptide marketing and anecdotal claims

This is an important conversation for anyone trying to make sense of the peptide boom and separate genuine science from wellness hype.

To learn more from Dr Leigh Baxt, follow her on Instagram at @sciencemomscicomm. I also recommend exploring Unbiased Science, where science communication is made far more accessible for the public. You can follow the project on Instagram, Threads, Facebook, LinkedIn, X, subscribe on Substack, and watch on YouTube.

The views expressed are her own and she is not representing her employer.

Intro (00:00)

Stanford Expert Breaks Down the Peptide Hype (00:53)

The Skill Set Behind Real Drug Development (05:09)

FDA Approved vs Research Only Peptides Explained (08:03)

Why Most Drug Candidates Never Become Medicine (11:06)

Peptide Reclassification What Changes and What Doesn't (15:59)

The Biological Risks Nobody Mentions About Peptides (20:36)

Why Natural Peptides Are Not Necessarily Safe (23:00)

What Safety Tests Drugs Must Pass First (28:51)

Accepting Unknown Risk What That Actually Means (33:31)

How to Find Credible Health Experts Online (36:13)

Why Drug Development Always Requires A Team (39:19)

Want to support the show?

The best way to support the show is to use the products and services offered by our sponsors. To check them out and enjoy great savings, visit theproof.com/friends. You can also support the show by leaving a review on the Apple Podcast app and sharing your favourite episodes with friends and family.

This episode is brought to you by:

38TERA

Consider 38TERA's DMN prebiotic supplement a daily multivitamin for your gut. Formulated by yours truly and gastroenterologist Dr Will Bulsiewicz. Use code THEPROOF for a discount at checkout.

38Tera ships to the United States, Australia, and New Zealand.

Function Health

Take charge of your health with advanced blood testing and personalised insights. Function Health offers a practical way to track key health markers such as cholesterol, blood sugar, and more. Learn more and join at functionhealth.com/simonhill for a $25 credit toward your membership. Only available to those living in the United States.

Function Health ships to 48 U.S. states, excluding Rhode Island, Hawai‘i, and Puerto Rico.

Cozy Earth

Cozy Earth’s sheets are designed to keep you cool by wicking heat and moisture away from your body, helping you sleep deeper and wake less. Get up to 20% off at cozyearth.com with code THEPROOF.

Cozy Earth ships worldwide.

Eight Sleep

Upgrade your sleep with the Pod 5 Ultra by Eight Sleep. Clinically validated to deliver up to 1 extra hour of quality sleep per night through temperature control and biometric tracking. Use code THEPROOF for $350 off at eightsleep.com/theproof. Try it risk-free for 30 days, with worldwide shipping.

Eight Sleep ships to the U.S. (excluding Alaska, Hawaii, and territories), Canada, Mexico, most of the EU, the U.K., Australia, the UAE, Saudi Arabia, and Switzerland.

ProLon

Ready for your own reset? For a limited time, ProLon is offering The Proof listeners 15% off sitewide plus a $40 bonus gift when you subscribe to their 5-Day Program. Visit ProLonLife.com to claim your discount and bonus gift.

ProLon ships within the United States.

WHOOP

Whoop, the most advanced fitness and health wearable available. Your personalised fitness and health coach to recover faster, sleep better, and train smarter. Claim your first month free on join.whoop.com/simon.

Whoop ships to 56+ international markets, including the US, Canada, most of Europe, Australia, New Zealand, UAE, Singapore, and parts of Asia.

Simon Hill, MSc, BSc (Hons)

Creator of theproof.com

Host of The Proof with Simon Hill

Author of The Proof is in the Plants

Subscribe & Connect:

YouTube

Apple Podcasts

Spotify

Instagram: @simonhill

Twitter: @theproof

Facebook: The Proof with Simon Hill

In this episode, I’m joined by Dr Belinda Beck to challenge long-held beliefs about osteoporosis and bone health. We break down what actually works, what doesn’t, and why many people are being given outdated advice.

We explore the science of bone adaptation, the importance of heavy resistance training, and how to think about prevention and treatment across the lifespan.

What We Cover

Why walking is not enough for bone health

How heavy lifting changes bone strength

What DEXA scans can and cannot tell you

The impact of menopause on bone loss

Exercise vs medication for osteoporosis

Common myths and misleading advice

If you want to better understand how to build and protect your bones, this episode is a must-listen.

You can learn more about Dr Belinda Beck’s work via her website, follow updates on Facebook, or explore her clinical and training work at The Bone Clinic and ONERO.

Intro (00:00:00)

Why Your Doctor Is Wrong About Bone Exercise (00:01:44)

The Silent Fracture Crisis No One Is Catching (00:08:34)

How Much of Bone Loss Can You Actually Control? (00:14:23)

Why Your DEXA Score Misses the Bigger Picture (00:17:28)

What Blood Tests Actually Reveal About Your Bones (00:24:58)

The Trial That Changed Osteoporosis Exercise Guidelines (00:30:00)

The Exact Load Needed to Rebuild Bone (00:38:31)

Why Static Holds Won't Build Your Bones (00:43:47)

Strength Training Cuts Fracture Risk by 78% (00:47:57)

Why Osteoporosis Guidelines Are Still Getting It Wrong (00:51:03)

Should You Combine Bone Meds With Heavy Training? (00:55:45)

More Exercise + Meds = Better Bone Outcomes (01:02:47)

How Menopause Destroys Bone (And What Fights Back) (01:06:35)

The Hidden Bone Risk of GLP-1 Weight Loss Drugs (01:11:05)

Bone Gadgets and Gimmicks: What the Science Says (01:14:01)

This episode is brought to you by:

38TERA

Consider 38TERA's DMN prebiotic supplement a daily multivitamin for your gut. Formulated by yours truly and gastroenterologist Dr Will Bulsiewicz. Use code THEPROOF for a discount at checkout.

38Tera ships to the United States, Australia, and New Zealand.

Shopify

Shopify, the world's leading e-commerce platform, helps you turn browsers into buyers with the internet’s best-converting check out–up to 36% better compared to other leading e-commerce platforms. To boost your conversion rate, and grow your business, sign up for your one-dollar-per-month trial at shopify.com/proof.

IM8

With 92 nutrients, including Vitamin B12, Iodine, Selenium and Vitamin D, in highly absorbable forms, IM8 Daily Essentials is the perfect all-in-one daily multi-vitamin to ensure you meet your daily micronutrient needs. IM8 is offering an exclusive 10% off your first order with a free welcome kit when you enter the promo code SIMON at checkout on im8health.com.

IM8 ships to 27 countries including the U.S., Canada, the U.K., Australia, and many regions across Europe, Asia, and South America.

Momentous

My go-to supplement brand for protein and creatine is Momentous. Use code THEPROOF for up to 35% off your first order at livemomentous.com.

Momentous ships to many countries worldwide depending on local import regulations.

Caraway Caraway’s cookware set is a favourite for a reason. It can save you up to $190 compared to buying items individually, and The Proof listeners can take an additional 10% off at CarawayHome.com or by using code PROOF at checkout. Caraway. Non-toxic cookware made modern.

Caraway ships within the United States.

WHOOP

Whoop, the most advanced fitness and health wearable available. Your personalised fitness and health coach to recover faster, sleep better, and train smarter. Claim your first month free on join.whoop.com/simon.

Whoop ships to 56+ international markets, including the US, Canada, most of Europe, Australia, New Zealand, UAE, Singapore, and parts of Asia.

Simon Hill, MSc, BSc (Hons)

Creator of theproof.com

Host of The Proof with Simon Hill

Author of The Proof is in the Plants

Subscribe & Connect:

YouTube

Apple Podcasts

Spotify

Instagram: @simonhill

Twitter: @theproof

Facebook: The Proof with Simon Hill

In this episode, I return to a conversation I promised to continue - sitting back down with Prof Tim Spector, MD, to explore everything that has changed in microbiome science since Episode 224. Tim and the ZOE team have now published a landmark Nature paper with 34,000 microbiome samples, run a clinical trial comparing personalized nutrition against government guidelines, and Tim has published a book on fermentation science.

We cover why most probiotics are scientifically obsolete, a practical ranked guide to fermented foods, the TMAO pathway linking gut bacteria to cardiovascular risk, and the estrobolome - the gut bacteria that recycle estrogen in women. If you have the gut health basics in place, this conversation tells you what to prioritize next.

What We Cover

The ZOE Microbiome Health Ranking 2025: what 34,000 gut microbiomes revealed about the species that actually matter

A practical guide to fermented foods: how much, how often, and whether pasteurised versions count

The TMAO mechanism - how your gut bacteria may influence the cardiovascular risk of red meat

Why most probiotic supplements use strains that are 100 years out of date

The estrobolome: how gut bacteria control estrogen recycling in women

The menopause - microbiome connection and what ZOE's latest research shows

Building a healthier gut microbiome is less about one dramatic intervention and more about consistent, moderate changes compounding over time. This conversation gives you the clearest picture yet of which changes to prioritise.

To connect with the guest, follow Tim Spector on Instagram at @tim.spector and explore ZOE at zoe.com.

Intro (00:00)

Why Gut Diversity Is a Flawed Metric (01:58)

Does the Microbiome Actually Cause Disease? (15:23)

Vegan vs. Omnivore Microbiomes (26:52)

Why ZOE Made Their Research Public (31:49)

Prebiotics Beat Probiotics in RCT (39:46)

The Case for More Fiber (46:43)

How to Buy Fermented Foods (53:32)

Resistant Starch vs. Polyphenols (59:42)

Are "Natural" Sugars Any Different? (01:03:12)

Time-Restricted Eating & the Microbiome (01:11:21)

What's Next for Zoe Research (01:18:35)

Want to support the show?

The best way to support the show is to use the products and services offered by our sponsors. To check them out and enjoy great savings, visit theproof.com/friends. You can also support the show by leaving a review on the Apple Podcast app and sharing your favourite episodes with friends and family.

This episode is brought to you by:

38TERA

Consider 38TERA's DMN prebiotic supplement a daily multivitamin for your gut. Formulated by yours truly and gastroenterologist Dr Will Bulsiewicz. Use code THEPROOF for a discount at checkout.

38Tera ships to the United States, Australia, and New Zealand.

Eight Sleep

Upgrade your sleep with the Pod 5 Ultra by Eight Sleep. Clinically validated to deliver up to 1 extra hour of quality sleep per night through temperature control and biometric tracking. Use code THEPROOF for $350 off at eightsleep.com/theproof. Try it risk-free for 30 days, with worldwide shipping.

Eight Sleep ships to the U.S. (excluding Alaska, Hawaii, and territories), Canada, Mexico, most of the EU, the U.K., Australia, the UAE, Saudi Arabia, and Switzerland.

Function Health

Take charge of your health with advanced blood testing and personalised insights. Function Health offers a practical way to track key health markers such as cholesterol, blood sugar, and more. Learn more and join at functionhealth.com/simonhill for a $25 credit toward your membership. Only available to those living in the United States.

Function Health ships to 48 U.S. states, excluding Rhode Island, Hawai‘i, and Puerto Rico.

Pique Tea

Pique’s Pu’er Tea Duo brings ancient fermentation into a simple daily ritual, delivering living nutrients that support digestion, metabolism, and sustained energy from the inside out. Unlock 20% off and establish your powerful foundation for sustained well-being at Piquelife.com/SIMON.

Pique ships within the U.S. and to Australia, Canada, and select EU countries.

WHOOP

Whoop, the most advanced fitness and health wearable available. Your personalised fitness and health coach to recover faster, sleep better, and train smarter. Claim your first month free on join.whoop.com/simon.

Whoop ships to 56+ international markets, including the US, Canada, most of Europe, Australia, New Zealand, UAE, Singapore, and parts of Asia.

Simon Hill, MSc, BSc (Hons)

Creator of theproof.com

Host of The Proof with Simon Hill

Author of The Proof is in the Plants

Subscribe & Connect:

YouTube

Apple Podcasts

Spotify

Instagram: @theproof

Twitter: @theproof

Facebook: The Proof with Simon Hill

Nourish your gut with my Plant-Based Ferments Guide and download my Two-Week Meal Plan.

In this episode, I’m joined by Dr Kevin Hall from the NIH to unpack the science behind ultra-processed foods, energy balance, and the new U.S. Dietary Guidelines.

We explore what controlled feeding studies reveal about why people tend to eat more calories on ultra-processed diets, and whether it’s the foods themselves or the broader environment driving these effects.

What We Cover

Key takeaways from the new U.S. Dietary Guidelines

What ultra-processed foods actually mean in research vs policy

Why people eat more calories without noticing

The role of energy density and hyper-palatable foods

Whether ultra-processed foods can be improved rather than eliminated

Individual variability in response to diet

A fascinating look at the intersection of biology, behaviour, and the modern food system.

You can learn more about Dr Kevin Hall’s work at his website, follow him on X, or connect on LinkedIn. His book, Food Intelligence: The Science of How Food Both Nourishes and Harms Us, co-authored with Julia Belluz, explores the science of metabolism and ultra-processed foods.

Intro (00:00)

2025 Dietary Guidelines First Impressions (01:03)

Why They Avoided "Ultra-Processed" Language (04:11)

The UPF Definition Nobody Agrees On (09:59)

What Actually Makes You Overeat UPFs (19:08)

Two Food Properties That Hijack Your Calories (27:38)

What Happens When You Fix Ultra-Processed Food (34:28)

Why Big Food Won't Fix Its Own Products (45:08)

How We Went from Famine Fear to Calorie Glut (51:33)

Why Some People Overeat UPFs and Others Don't (58:12)

Is Obesity Actually Genetic? (1:01:22)

Carbs vs. Fat: What the Data Actually Shows (1:06:34)

Keto vs. Low-Fat: The Metabolic Ward Results (1:17:35)

A Top Nutrition Scientist's Honest Diet Advice (1:26:22)

Will Food Labels Actually Change What You Eat? (1:33:11)

"Am I a Food Industry Shill?" -Kevin Hall (1:41:36)

Why Kevin Hall Left the NIH for Drug Research (1:44:29)

The Study He'd Run With Unlimited Funding (1:47:49)

This episode is brought to you by:

38TERA

Consider 38TERA's DMN prebiotic supplement a daily multivitamin for your gut. Formulated by yours truly and gastroenterologist Dr Will Bulsiewicz. Use code THEPROOF for a discount at checkout.

38Tera ships to the United States, Australia, and New Zealand.

Mill

Mill is an odourless, fully automated food recycler that turns kitchen scraps into clean, dry grounds overnight with no smells or mess. Get $75 off and try it risk-free for 90 days at mill.com using code THEPROOF.

Mill ships within the United States.

IM8

With 92 nutrients, including Vitamin B12, Iodine, Selenium and Vitamin D, in highly absorbable forms, IM8 Daily Essentials is the perfect all-in-one daily multi-vitamin to ensure you meet your daily micronutrient needs. IM8 is offering an exclusive 10% off your first order with a free welcome kit when you enter the promo code SIMON at checkout on im8health.com.

IM8 ships to 27 countries including the U.S., Canada, the U.K., Australia, and many regions across Europe, Asia, and South America.

Momentous

My go-to supplement brand for protein and creatine is Momentous. Use code THEPROOF for up to 35% off your first order at livemomentous.com.

Momentous ships to many countries worldwide depending on local import regulations.

WHOOP

Whoop, the most advanced fitness and health wearable available. Your personalised fitness and health coach to recover faster, sleep better, and train smarter. Claim your first month free on join.whoop.com/simon.

Whoop ships to 56+ international markets, including the US, Canada, most of Europe, Australia, New Zealand, UAE, Singapore, and parts of Asia.

Simon Hill, MSc, BSc (Hons)

Creator of theproof.com

Host of The Proof with Simon Hill

Author of The Proof is in the Plants

Subscribe & Connect:

YouTube

Apple Podcasts

Spotify

Instagram: @simonhill

Twitter: @theproof

Facebook: The Proof with Simon Hill

In this episode, I speak with Dr Lora Giangregorio about how to train for stronger bones, better balance, and long-term independence. We break down what actually matters when it comes to preventing fractures and improving bone health.

We explore the role of resistance, balance, and impact training, and how to apply these in a practical, sustainable way.

What We Cover

Why starting where you are matters more than following a perfect plan

How balance, strength, and impact training work together

What progressive overload looks like in real life

Why effort matters more than the weight you lift

How to safely introduce impact training

The role of protein and energy intake in bone health

This episode is a practical guide to building strength and resilience for the long term.

To explore more of Dr Lora Giangregorio’s work, follow her on TikTok, connect with her on LinkedIn, and visit her University of Waterloo profile to learn more about her research in bone health, exercise, and fracture prevention.

Intro (00:00)

The Real Cost of Fractures (01:25)

Is Osteoporosis a Lifelong Process? (06:39)

Who Is Most at Risk for Fragility Fractures (09:32)

What Actually Determines Fracture Risk (12:49)

How a DEXA Scan Works and How to Read Your Results (26:30)

How to Monitor Bone Loss and Choose the Right Treatment (32:06)

How Menopause Accelerates Bone Loss (41:52)

Bone Health Myths Debunked (46:08)

Evidence-Based Exercise Guidelines for Bone Health (59:15)

The Three Pillars of Bone Health Exercise (1:04:15)

Why Specificity and Progressive Overload Matter (1:09:48)

How to Structure Your Weekly Bone Health Training (1:13:39)

Resistance Training for Bone Health (1:22:31)

How to Choose the Right Load and Effort (1:27:10)

Making Bone Health Exercise Accessible to Everyone (1:38:09)

High-Risk Exercises to Avoid with Low Bone Density (1:42:22)

Does Yoga, Swimming, or Cycling Help Your Bones? (1:47:18)

What Is Bone Fit and Who Is It For? (1:52:47)

How to Safely Build Up to Impact Training (1:55:57)

Free Resources for Fracture Recovery (2:02:06)

Nutrition for Bone Health (2:05:10)

GLP-1 Drugs and Bone Loss (2:12:48)

Future Research on Exercise, Creatine, and Bone Health (2:16:09)

Why Effort Matters More Than the Weight You Lift (2:22:15)

What Is Possible When You Commit to Bone Health (2:25:48)

This episode is brought to you by:

38TERA

Consider 38TERA's DMN prebiotic supplement a daily multivitamin for your gut. Formulated by yours truly and gastroenterologist Dr Will Bulsiewicz. Use code THEPROOF for a discount at checkout.

38Tera ships to the United States, Australia, and New Zealand.

Cozy Earth

Cozy Earth’s sheets are designed to keep you cool by wicking heat and moisture away from your body, helping you sleep deeper and wake less. Get up to 20% off at cozyearth.com with code THEPROOF.

Cozy Earth ships worldwide.

Function Health

Take charge of your health with advanced blood testing and personalised insights. Function Health offers a practical way to track key health markers such as cholesterol, blood sugar, and more. Learn more and join at functionhealth.com/simonhill for a $25 credit toward your membership. Only available to those living in the United States.

Function Health ships to 48 U.S. states, excluding Rhode Island, Hawai‘i, and Puerto Rico.

Simon Hill, MSc, BSc (Hons)

Creator of theproof.com

Host of The Proof with Simon Hill

Author of The Proof is in the Plants

Subscribe & Connect:

YouTube

Apple Podcasts

Spotify

Instagram: @simonhill

Twitter: @theproof

Facebook: The Proof with Simon Hill