Why We Require Bloodwork Before Certain Therapies
If you've asked about a higher-dose therapy — high-dose vitamin C, glutathione above 2 grams, or a few other options on our menu — you may have been surprised to hear "we'll need recent bloodwork first." We know that can feel like an extra hurdle when you just want to feel better. Here's exactly why we don't skip it.
It's Not About Bureaucracy — It's About Individual Variation
Two people can look equally healthy and still respond very differently to the same dose of a nutrient. Kidney function, certain enzyme deficiencies, and underlying conditions you might not even know about can all change how safely a higher dose is processed. A basic metabolic panel and complete blood count give our providers a real picture of how your body is currently functioning — not a guess based on how you look or feel that day.
For high-dose vitamin C specifically, we also screen for G6PD deficiency, an enzyme condition that can cause a serious reaction to high-dose vitamin C in the small percentage of people who have it. Most people have never been tested for this and have no way of knowing their status without a simple blood test.
Why We Draw the Line Where We Do
This is also why you'll see specific thresholds on our menu — for instance, glutathione doses above 2 grams require a recent blood panel. That's not an arbitrary number. It reflects the point where the margin for individual variation starts to matter more, and where having real data beats relying on assumptions.
The Same Principle Applies to Vitamin D
Vitamin D deserves its own callout here, because it's one of the most common requests we get — and it's a good example of how we balance convenience with safety rather than picking one or the other.
Here's how it actually works: your first Vitamin D boost is available as a single injection, no bloodwork required upfront. But before we give you a second one, we require lab work — drawn at least a week after that first shot, so we can actually see what it did. Vitamin D directly affects how your body absorbs and regulates calcium, and repeat dosing without checking that response first means guessing at exactly the mechanism most likely to cause a problem if something's off.
So once you're a week or more past your initial boost, before any additional vitamin D injections, we require four specific labs:
25-hydroxy vitamin D — your actual current vitamin D status, and how much that first shot moved the needle
Phosphate
Ionized calcium
Alkaline phosphatase
The first test tells us where you landed after that initial dose. The other three are a bone and calcium metabolism profile — they tell us whether it's safe to continue, and at what dose.
Our Optimization Protocol
From there, we don't just give a generic dose and hope for the best. We have a specific protocol designed to bring guests into an optimal range — 50–80 ng/mL, which is higher than the bare minimum "sufficient" threshold most standard labs flag, but reflects the range we target for genuinely optimal function — safely and efficiently, typically within 4–5 weeks of starting that protocol.
We can order all four labs for you directly, so this isn't an extra errand on top of your visit — it's built into how we approach vitamin D the right way after that first boost.
Questions about a specific therapy?Reach out to our team
Replenish is Atlanta's original iV therapy boutique, located in Old Fourth Ward since 2012.
