Circulation Support While on GLP-1s (Zepbound / Tirzepatide): What We Know and What We Don't

Justin Eaton Blood Pressure and Circulation
October 23rd, 2026 9 minute read

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What Are GLP-1 Drugs, and How Many People Take Them?
What Do Clinical Bodies Actually Recommend Nutritionally on a GLP-1?
Do GLP-1 Drugs Hurt Cardiovascular Health? The Evidence Says the Opposite
Where Do Nattokinase and Vitamin K2 Fit In?
What to know about drug absorption on GLP-1s
What Are the Safety Boundaries Before Adding Nattokinase?
The Bottom Line
FAQs

Key Takeaways:

GLP-1 drugs do not cause circulation problems that a supplement needs to fix. In the SELECT trial, semaglutide reduced major cardiovascular events by 20% in adults with preexisting cardiovascular disease.
The 2025 joint clinical advisory on GLP-1 nutrition prioritizes protein (1.2 to 1.6 g/kg/day during active weight loss), strength training, fluids, and fiber from foods. Supplements are framed as something to "consider" for at-risk nutrients like vitamin D, calcium, and B12, individualized to each person.
There are no published studies of nattokinase or vitamin K2 taken alongside GLP-1 drugs. We sell a nattokinase and K2 product, and we are telling you that directly.
GLP-1 drugs slow gastric emptying, which the Zepbound label says can affect the absorption of oral medications. Bring your full supplement list to your prescriber or pharmacist.
Never stop or adjust a GLP-1 medication because of anything you read in a supplement article, including this one.

If you searched "what supplements should I take with tirzepatide," most of what you found was probably a product page wearing a lab coat. This article takes a different approach: we’re talking about what clinical bodies actually recommend, what the cardiovascular evidence really shows, and where research on ingredients like nattokinase and vitamin K2 simply doesn’t exist just yet.

What Are GLP-1 Drugs, and How Many People Take Them?

GLP-1 drugs are prescription medications that regulate appetite and blood sugar, and their use is now mainstream. By late 2025, 18% of US adults reported having taken one, with 12% currently taking one, according to KFF's health tracking poll. Among adults with diagnosed diabetes, CDC data show 26.5% used GLP-1 injectables in 2024, roughly 6.9 million people.

Tirzepatide, sold as Zepbound for weight management, is technically a dual GIP/GLP-1 receptor agonist. It is FDA-approved for chronic weight management in adults with obesity, or overweight plus a weight-related condition, and for moderate-to-severe obstructive sleep apnea in adults with obesity. The results behind that approval are substantial: in the SURMOUNT-1 trial, tirzepatide produced 16.0 to 22.5% mean body-weight reduction over 72 weeks, compared with 2.4% for placebo.

Weight loss at that scale changes what your body needs nutritionally. That is where the supplement question starts, and where the honest answers get thinner than the marketing suggests.

The clearest guidance comes from a 2025 joint clinical advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society.

In order:

Protein: 1.2 to 1.6 g/kg of body weight per day during active weight reduction, or roughly 80 to 120 g/day in absolute terms
Strength training 3x weekly, plus 150 minutes per week of aerobic activity
Adequate fluids
Adequate fiber, from foods

The protein and resistance-training emphasis exists because a meaningful share of GLP-1 weight loss is lean mass. DXA data from STEP 1 found that about 6.9 kg of the 15.2 kg lost was lean mass, and SURMOUNT-1 showed about 5.3 kg of 15.3 kg. That said, it’s worth knowing that a 2026 Cell Reports Medicine analysis argues that this loss is not disproportionate to non-drug weight loss. Either way, the clinical response is the same: eat enough protein and lift.

Specifically regarding supplements, the advisory highlights that supplements can be proactively considered for specific nutrients that are considered at-risk, like vitamin D, calcium, and B12. At the end of the day, though, this should come down to your specific needs.

The at-risk framing is grounded in data. A 2026 study in Clinical Obesity documented vitamin D deficiency in 7.5% of GLP-1 users at 6 months and 13.6% at 12 months, and found more than 60% falling below estimated calcium and iron requirements. Those are reasons to get levels checked and talk to your clinician, not reasons to buy a shelf of bottles.

Do GLP-1 Drugs Hurt Cardiovascular Health? The Evidence Says the Opposite

Here is the part of the honest answer that costs supplement brands money: GLP-1 drugs have demonstrated cardiovascular benefit on their own.

In the SELECT trial, 17,604 adults with preexisting cardiovascular disease and overweight or obesity (without diabetes) took semaglutide or placebo. Semaglutide reduced major adverse cardiovascular events by 20%. This matters for how you should read supplement marketing aimed at GLP-1 users. Nobody needs a supplement to fix a circulation problem GLP-1 drugs cause, because the evidence doesn’t show them causing circulation problems in the first place. If a product pitch implies your GLP-1 is quietly harming your heart and their formula is the antidote, close the tab.

Circulation support on a GLP-1 is, therefore, the same question it is for anyone else: is this ingredient worth it for me, given my health, my medications, and my goals? Which brings us to our own ingredients.

Where Do Nattokinase and Vitamin K2 Fit In?

There are no published studies examining nattokinase taken with GLP-1 receptor agonists. The same is true for vitamin K2: no published research on K2 co-administered with GLP-1 drugs.

We make Toku Flow, a powder combining 10,800 FU nattokinase with vitamin K2 (MK-7) and oat beta-glucan, so we have every commercial incentive to blur that gap. We would rather state it plainly, because you cannot make a good decision with your clinician if a brand hides what is unknown.

Here is what nattokinase's evidence does show, outside any GLP-1 context. A 2023 meta-analysis of 6 randomized controlled trials (546 participants) found a modest reduction in systolic blood pressure, about 3.45 mmHg on average, with no notable adverse events reported in the trials themselves. The authors flagged small sample sizes, and case reports of bleeding events are present in the broader literature. That is a real but modest evidence base, and none of it involved people on tirzepatide or semaglutide.

What to know about drug absorption on GLP-1s

One practical consideration is drug absorption. The Zepbound label states the drug "delays gastric emptying and thereby has the potential to impact the absorption of concomitantly administered oral medications." In studies, the acetaminophen peak concentration fell 55% after the first 5 mg dose, an effect that diminishes with continued dosing, and users of oral contraceptives are advised to switch or add a barrier method for 4 weeks after starting and after each dose escalation.

It’s worth specifying that GLP-1 labels address oral medications, not supplements. Whether slowed gastric emptying meaningfully changes how a supplement is absorbed is a logical extension for your pharmacist or prescriber to weigh, not a label statement. It’s exactly the kind of question worth asking at your next appointment, with your full supplement list in hand.

What Are the Safety Boundaries Before Adding Nattokinase?

Keep the following in mind before adding nattokinase to your routine if you’re on a GLP-1:

On any anticoagulant or antiplatelet drug? Nattokinase can have drug interactions. If you’re taking anticoagulent or antiplatelet medications, do not add nattokinase without explicit physician or pharmacist approval. A 2008 case report described a cerebellar hemorrhage in a patient combining nattokinase 400 mg/day with aspirin, in the setting of existing cerebral microbleeds.
Bleeding disorder, or surgery coming up? Same rule: clinician first.
On warfarin? Know that routine INR monitoring does not capture nattokinase's fibrinolytic activity, so a "normal" INR is not reassurance here.
Never stop or adjust your GLP-1, or any prescription, on your own. Supplements are a conversation to have with your prescriber, not a substitute for one.

The Bottom Line

If you are on Zepbound or another GLP-1, the evidence-backed priorities are protein, strength training, fluids, fiber, and individualized attention to vitamin D, calcium, and B12 with your clinician. The drugs themselves showed cardiovascular benefit in a major trial. Nattokinase and K2 have their own evidence base, but none of it yet includes GLP-1 users, and any brand that claims otherwise is ahead of the science. Bring your supplement list to your prescriber, ask about timing, and make the call together.

FAQs

What vitamins should I take while on Zepbound?

There is no universal vitamin list for Zepbound. The 2025 joint clinical advisory says supplements "can be proactively considered for at-risk nutrients, such as vitamin D, calcium, and B12, tailored to each person's needs." The higher-priority basics in that advisory are protein (1.2 to 1.6 g/kg/day during active weight loss), strength training, fluids, and fiber from foods. Ask your prescriber whether testing your levels makes sense before supplementing.

What supplements should I take with tirzepatide?

Clinical guidance does not name any supplement that everyone on tirzepatide should take. The honest framework is: cover protein, resistance training, fluids, and fiber first; then discuss individualized supplementation for at-risk nutrients like vitamin D, calcium, and B12 with your clinician. Be skeptical of any product marketed as necessary "for GLP-1 users." No supplement has that evidence.

Can I take nattokinase with a GLP-1?

There are no published studies of nattokinase taken with GLP-1 drugs, in either direction, so nobody can honestly claim the combination is proven safe or proven problematic. Ask your prescriber or pharmacist before adding it, and treat that as non-negotiable if you take any blood thinner or antiplatelet medication, have a bleeding disorder, or have surgery scheduled.

Do GLP-1 drugs cause circulation problems?

There is no evidence that GLP-1 drugs cause circulation problems. The opposite has been demonstrated: in the SELECT trial, semaglutide reduced major adverse cardiovascular events by 20% in over 17,000 adults with preexisting cardiovascular disease. Any supplement pitch built on the idea that your GLP-1 is harming your heart is not supported by the evidence.

*The information provided in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives. This content has not been evaluated by the Food and Drug Administration and is not intended to diagnose, treat, cure, or prevent any disease.

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