7 Years of Supplements: 5 Mistakes I Made First

Mike HartnettEvidence-Based

7+ years researching longevity protocols. Runs a 20+ supplement daily stack. Built CoreStacks after losing his father to heart disease.

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I’ve spent 7 years and thousands of dollars on supplements. I’ve followed Huberman, read Attia’s book, tracked Sinclair’s stack, and gotten my blood drawn more times than I can count. I’ve made every beginner mistake possible. Some of them cost me money. One of them could have cost me my health. Here are the 5 things I wish someone had told me before I started.

This content is for informational purposes only. Consult your healthcare provider before starting any supplement protocol.

Mistake 1: I Didn’t Get Bloodwork First

This is the big one. I was taking 40,000 IU of Vitamin D every day. I felt completely fine — no symptoms, no warning signs, nothing. I’d been doing it for months. A routine blood panel through my doctor caught it: my levels were dangerously high, well above the 40-60 ng/mL range that experts target.

I cut to 10,000 IU immediately. That single blood test probably prevented kidney damage or worse. I wrote the full story here because it’s the most important thing I can share with anyone starting supplements.

The mistake wasn’t taking vitamin D. Vitamin D is important — most people are deficient. The mistake was supplementing blind. I had no baseline. I didn’t know where my levels were before I started, so I had no way to know when I’d overshot.

Most people start supplements and then maybe get bloodwork later. That’s backwards. Bloodwork should come first. A basic panel costs $30-100. That’s less than one month of supplements. Every longevity expert — Attia, Huberman, Stanfield — emphasizes testing. Attia’s entire medical practice is built on biomarker tracking.

Get a baseline before you take anything. Then test again at 3 months. You’ll know exactly what’s working instead of guessing.

Mistake 2: I Started With Too Many Supplements

When I first got into longevity supplements, I tried to build a complex stack immediately. I’d listen to a Huberman episode and order 3 new things. Read a Sinclair interview, add 2 more. See Bryan Johnson’s 100-pill protocol and feel like my 15 supplements weren’t enough.

The problem with starting 10+ supplements at once is simple: you have no idea what’s doing what. Feel better after a month? Great — was it the magnesium, the fish oil, the ashwagandha, or the placebo effect of spending $200? You’ll never know. Feel worse? Same problem. You can’t isolate the variable when you’ve changed 10 variables at once.

I should have started with the 4 supplements that every longevity expert agrees on:

1. Omega-3 Fish Oil — cardiovascular and brain support. Every expert takes it. The data goes back decades. (Carlson’s fish oil is what I use.)
2. Vitamin D3 + K2 — immune function, bone health. Just get your levels tested first. Learn from my mistake.
3. Magnesium Glycinate — sleep quality and muscle recovery. Most people are low in magnesium.
4. Creatine Monohydrate — brain and body support at $0.15 per day. Best value in supplements.

Total cost for those four: $50-60 per month. That covers roughly 80% of the benefit of a full longevity stack at a fraction of the price. I cover the math in detail in my budget stack guide. Add one new supplement at a time after that. Wait 4-6 weeks between additions so you can actually notice what each one does.

Mistake 3: I Didn’t Drop What Wasn’t Working

I took resveratrol for months because David Sinclair endorses it. He’s discussed taking 1g daily for years, and his research on sirtuins is fascinating. I bought in.

After months of consistent use: nothing. No change in energy. No change in sleep. No change in any bloodwork marker I was tracking. The clinical data in humans is mixed. I was paying $30-40 per month for something I couldn’t detect by any measure — subjective or objective.

Same thing with zinc. I added it because “everyone takes zinc.” Got bloodwork. I wasn’t deficient. No noticeable benefit. Cut it. If my zinc levels had been low, I’d have kept it. They weren’t.

The lesson isn’t that your stack should shrink over time. Mine didn’t. My current 31-supplement stack is larger than what I was taking two years ago — and I’m fine with that. I went from 0 to 31 over 7 years. Each one was researched, tested, and kept only because I could justify it through evidence or bloodwork. I also dropped things that didn’t work — resveratrol and zinc are gone.

Some people think 31 is excessive. I disagree. Every single one has a reason. The lesson is that your stack should grow with intention, not impulse. There’s a difference between adding a supplement because a podcast guest mentioned it and adding one because your bloodwork flagged a deficiency or a meta-analysis convinced you.

But if you asked me to start over with only 4, it would be Omega-3, D3+K2, Magnesium, and Creatine. Build from there.

Set a 3-month review for every supplement you add. If it doesn’t show up in your labs or how you feel, cut it and redirect that money to something with better evidence. My full 31-supplement stack breakdown shows every item, dose, cost, and the specific reason I kept it.

The Supplement Most People Are Sleeping On

The supplement I think most people should consider but aren’t? L-Cysteine. NAC gets all the attention as a glutathione precursor, but L-Cysteine does the same job at a similar price. Most people have never even heard of it. It supports glutathione production — your body’s primary antioxidant — without the occasional GI issues that NAC can cause. I added it after reading the research on age-related glutathione decline, and it’s stayed in my stack since.

Mistake 4: I Assumed Expensive Brands Are Always Better

I used to pay $40 for branded creatine because the marketing convinced me it was somehow superior. It’s not. Creatine monohydrate is creatine monohydrate. The $40 Thorne tub contains the same 5g of the same molecule as a $10 store brand. The difference is marketing budget, not molecular structure.

Vitamin D is similar. The D3 molecule in a $5 bottle is identical to the D3 molecule in a $25 bottle. Same with basic minerals like zinc and calcium.

Where brand quality DOES matter:

• Fish oil — purity matters. Heavy metals, oxidation, and actual EPA+DHA content vary significantly between brands. Third-party testing (IFOS certification) is worth paying for. See my omega-3 buying guide for tested brands.
• Magnesium form — glycinate and threonate cost more than oxide because they’re better absorbed. The premium is justified by bioavailability.
• NMN — purity testing matters for a compound this expensive. Third-party certificates of analysis from reputable brands are worth the price difference.
• CoQ10 — ubiquinol (reduced form) is more bioavailable than ubiquinone. The form difference justifies the cost.

The rule I follow now: pay for purity in fish oil, pay for form in magnesium and CoQ10, and save money on commodity molecules like creatine, vitamin D, and basic minerals. I spend about $200 per month on 31 supplements. Smart brand selection is how I keep it under $215. My analysis of expensive vs. cheap supplements breaks down exactly where the premium is worth it and where it’s not. The Cost Calculator can help you compare prices across brands.

Mistake 5: I Treated Expert Stacks Like Prescriptions

I tried to copy Huberman’s entire stack once. Ordered everything on his list. Took it for weeks.

Three problems became obvious fast. First, his recommendations change. What he takes in January isn’t always what he’s taking in June. I was chasing a moving target. Second, his context is completely different from mine — different age, different genetics, different health goals, different baseline bloodwork. Half his stack was addressing things I didn’t need to address.

Third, and this is the one that took me longest to accept: experts disagree with each other. Huberman takes NMN. Attia doesn’t. Sinclair takes resveratrol. Stanfield has questioned it. If you follow one expert blindly, you’re making a bet on one opinion. If you follow all of them blindly, you end up with 40 supplements and a confused body.

Expert stacks are research starting points. Not shopping lists. The expert comparison I put together shows where they agree and disagree. Use those agreements as your foundation. Use the disagreements as areas to research and make your own informed decisions based on your bloodwork, your family history, and your goals.

My dad died of heart disease. That’s why I take CoQ10 and prioritize omega-3. Not because an expert told me to — because my specific risk profile demands it. Your reasons should be just as personal.

What I’d Do Differently

If I could restart from zero with everything I know now, here’s the exact sequence:

1. Month 0: Get full bloodwork. Full lipid panel, metabolic panel, vitamin D, B12, iron, thyroid, inflammation markers (hsCRP). Cost: $100-200. My blood test guide covers every marker worth testing.
2. Month 1: Start the core 4 — omega-3, D3+K2, magnesium glycinate, creatine. Total: ~$50-60/month. Note how I feel. Track sleep and energy in a simple journal.
3. Month 4: Retest bloodwork. Compare to baseline. Add ONE supplement based on what the data shows. If everything looks good, maybe that’s CoQ10 for heart health or NAC for antioxidant support.
4. Month 7: Evaluate every supplement. Can I feel it? Do my labs support it? If no to both, drop it. Add the next one if there’s a reason.
5. Ongoing: Annual bloodwork. Quarterly self-assessment. Cut anything that isn’t earning its place.

My stack is 31 supplements now. It’s bigger than it was 3 years ago, and intentionally so. I spend about $200 per month. That puts me somewhere between Attia’s minimalism and Bryan Johnson’s maximalist approach. The expert cost comparison shows where each expert lands.

People look at the number 31 and assume I’m throwing pills at a wall. I’m not. Every supplement in my stack either shows up in my bloodwork, changes how I feel, or addresses a specific genetic risk I carry. Nothing survives on hype alone. I dropped resveratrol. I dropped zinc. I added L-Cysteine, TUDCA, and a dozen others that each earned their spot. My full 31-supplement stack breakdown shows every item, dose, cost, and reason.

The Stack Quiz can help you figure out where to start based on your goals and budget. The Interaction Checker catches potential conflicts before you start combining supplements. And the Cost Calculator shows you exactly what each expert’s stack costs per month.

Seven years of trial and error, boiled down: test first, start small, add slow, cut fast, and trust your own data over anyone else’s recommendations. Including mine.