Vitamin A
A fat-soluble vitamin essential for vision, immune function, skin integrity and cell differentiation.
Both deficiency and toxicity cause real problems. Fat-soluble vitamins accumulate, so this is one where over-supplementation is a genuine risk — particularly relevant with high-dose retinol or cod liver oil.
Optimal ranges, root causes, and the complete correction protocol — nutrition, supplements, lifestyle, hormones and peptides — plus 100+ other markers.
Unlock everything — $10/mo →📚 Institute of Medicine DRI for vitamin A, including the tolerable upper intake level.
🩸 Test your Vitamin A
Order directly through Marek Diagnostics — no doctor's visit needed, drawn at any Quest location in the US. Code CAMERON applies 10% off automatically.
Order this test — 10% off → Browse all 102 markers →What Vitamin A is usually tested alongside
On its own, one marker is a data point. These panels include Vitamin A plus the markers that make it interpretable — each names every test, why it is on the list, and loads the whole set into your cart in one click at 10% off.
includes this + 10 more markers — Restrictive diet, plant-based, post-bariatric, on a GLP-1, heavy training load, or you just want to stop guessing which supplements you actually need.
What moves your Vitamin A
1 supplement in the Vault have a documented effect on this marker, or are a reason to have measured it first:
Browse all 237 compounds & 350 supplements →
Would you feel it? Symptoms Vitamin A helps explain
People rarely search for a marker — they search for how they feel. These are the complaints where this marker is worth checking, and whether it is a first-line test or a follow-up once the obvious causes are ruled out.
Why your Vitamin A might be wrong
Most abnormal results are interference, not disease. These are the things that measurably move this specific marker — check them before you change anything. Each one says whether the number is wrong and should be repeated, badly timed and should be redrawn, or real with a cause worth explaining.
This is an acute-phase reactant — it moves substantially during any infection, injury or inflammatory episode, and the change has nothing to do with your baseline.
Wait two weeks after any illness, vaccination or injury before drawing or interpreting.
The liver holds most of the body's vitamin A and defends serum retinol hard, so it stays normal until stores are substantially depleted — and falls with inflammation regardless.
A normal retinol does not exclude low stores. Read with CRP.
Recent supplementation raises measured retinol above your steady state, and isotretinoin is itself a retinoid that alters the whole picture.
Stop supplements a week before. Retinoid medication changes the interpretation entirely — flag it.
What Vitamin A means in combination
A single marker tells you a little. Combinations tell you the story — these are the named patterns this marker takes part in, and what each one points at.
That is a malabsorption pattern, not a diet pattern. Coeliac disease, atrophic gastritis, H. pylori, pancreatic insufficiency and inflammatory bowel disease all present this way, and correcting the individual nutrients without finding the cause is a treadmill.
Investigate why absorption is failing rather than supplementing indefinitely. Coeliac serology must be done before removing gluten. Any neurological symptom with low B12 or copper needs urgent attention.
What to test next
Markers rarely answer alone. These are the ones that put Vitamin A in context — each with its own full breakdown.
Frequently asked questions
20–80 µg/dL Ranges vary by laboratory and assay — always compare to the range printed on your own report.
Optimal ranges, root causes and the full correction protocol are available inside Coach Cam's Peptide Academy.
See the full breakdown inside the Academy.
See the full breakdown inside the Academy.
You can order Vitamin A directly through Marek Diagnostics without a doctor's visit — drawn at any Quest Diagnostics location in the US. Code CAMERON applies 10% off automatically.