If you have ever stood in a feed store comparing two vitamin E labels and wondered whether the difference between “natural” and “synthetic” was just marketing, the answer is no — and the research behind that distinction is more consequential than the supplement industry typically makes it sound. For horses on hay-only diets, dry lots, or heavy stall time, vitamin E is one of the nutrients most likely to be genuinely short, and the form you choose affects how much your horse actually absorbs. Here is what the research says and how to think through the buying decision.
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Natural vs. Synthetic Vitamin E: What the Research Actually Shows
Vitamin E is a fat-soluble antioxidant, and in horses — as in most species — the biologically active form is alpha-tocopherol. The distinction between natural and synthetic comes down to molecular structure. Natural vitamin E is derived from plant oils and exists as a single stereoisomer: RRR-alpha-tocopherol. Synthetic vitamin E is chemically produced and contains a mixture of eight stereoisomers — only one of which is RRR.
That structural difference is not trivial. The liver preferentially selects RRR-alpha-tocopherol for incorporation into lipoproteins and transport to tissues. The other stereoisomers in synthetic vitamin E are absorbed but cleared more rapidly. Multiple studies in horses and other species have documented that natural vitamin E raises plasma alpha-tocopherol concentrations more effectively than an equivalent dose of synthetic — some research suggesting roughly twice the bioavailability in horses, though the exact ratio varies by study design, diet, and individual.
The practical upshot: if you are feeding synthetic vitamin E and measuring against a target plasma concentration, you need more of it to achieve the same tissue status as natural. And plasma alpha-tocopherol testing is how you actually confirm status — symptoms alone are not a reliable guide, and I want to be direct about that. If you suspect your horse is low in vitamin E, the right first step is bloodwork through your vet, not a supplement purchase. Deficiency in horses has been associated with conditions including equine motor neuron disease (EMND) and nutritional myodegeneration, both of which are serious and veterinary in nature. A supplement is not a substitute for diagnosis.
What supplementation with a high-bioavailability form can do — for horses whose forage situation makes low status likely — is support antioxidant status in a more efficient way than synthetic alternatives. That is the honest claim, and it is a meaningful one.
Who Is Most at Risk for Low Vitamin E Status
Fresh pasture is the primary natural source of vitamin E for horses. Green grass is high in alpha-tocopherol; hay is not. The drying and storage process degrades vitamin E significantly, and hay that has been stored for months — which describes most hay fed in winter and late summer in northern climates — may retain very little. Horses with reliable year-round pasture access are in a different situation from horses on dry lots, in stalls, or fed hay exclusively.
The groups most commonly discussed in the context of low vitamin E status:
- Horses with no or limited pasture access (dry lots, full stall time, sacrifice paddocks)
- Horses on hay-only or hay-plus-grain diets with no supplemental vitamin E
- Horses under heavy oxidative stress — hard work, illness, recovery
- Horses with fat malabsorption issues, since vitamin E is fat-soluble and requires dietary fat for absorption
- Broodmares and growing horses, where status affects fetal and neonatal development
If your horse falls into one or more of these categories, it is worth discussing vitamin E testing with your vet before assuming supplementation is needed — and worth discussing which form to use if supplementation is warranted.
Mad Barn Natural Vitamin E: The Product
Mad Barn’s Natural Vitamin E is the lead recommendation for horses without consistent pasture access, and the reason is straightforward: it supplies natural-source (RRR) alpha-tocopherol, the form the research consistently identifies as more bioavailable than synthetic alternatives.
A few things worth knowing about this product specifically:
Form matters for fat-soluble vitamins. Vitamin E requires dietary fat for absorption. Feeding Natural Vitamin E alongside a meal that contains some fat — even a small amount of oil or fat-containing feed — supports uptake. If your horse is on a very low-fat diet, that is worth discussing with your vet or an equine nutritionist.
It is a targeted single-nutrient product. Mad Barn’s Natural Vitamin E is not a full vitamin and mineral balancer. If your horse also has gaps in trace minerals, zinc, copper, or other nutrients, a separate balancer like Omneity would be the appropriate addition — and many owners feed both. What you should not do is assume that adding vitamin E alone covers the rest of the diet. Forage analysis and professional guidance are the correct tools for that question.
Pricing starts at $74.99. For a natural-source vitamin E supplement, that is competitive. The cost-per-day depends on the amount you feed, which should come from the product label and your vet’s guidance — not from a blog post.
It stacks cleanly with the Mad Barn lineup. Natural Vitamin E layers onto Omneity or AminoTrace+ without conflict. If you are already running a Mad Barn balancer and want to add targeted vitamin E support, this is the appropriate product for that purpose.
Where Natural Vitamin E is not the right pick: if you also need to address selenium alongside vitamin E, Mad Barn makes a combined product — Natural E/Organic Se — that pairs natural vitamin E with organic selenium. Selenium has a genuinely narrow safe range, the gap between adequate and toxic is not wide, and selenium supplementation should only happen after testing confirms it is warranted. I would not recommend adding selenium without bloodwork and professional input, full stop.
Ready to try Mad Barn Natural Vitamin E? Use my link for reader benefits at Mad Barn → https://madbarn.com?ref=18219
Natural E/Organic Se: When You Need Both, With a Caution
Natural E/Organic Se is worth naming here because the question of whether to supplement vitamin E alone or vitamin E plus selenium comes up regularly, and the answer is not “add both to be safe.”
Selenium deficiency is a real concern in geographic regions where soils — and therefore forages — are low in selenium. Certain parts of the Pacific Northwest, Great Lakes region, and parts of the Northeast have well-documented low-selenium soils. Horses in those areas on forage-only or forage-plus-hay diets may not be meeting selenium requirements. But selenium toxicity is also a documented problem, and it can occur when supplementation is added on top of a forage that is already adequate. The only way to know which situation your horse is in is testing: hay analysis for selenium content and bloodwork for selenium status.
If your vet or nutritionist confirms that both vitamin E and selenium are warranted, the organic selenium form in Natural E/Organic Se is the more bioavailable and safer option compared to inorganic selenium sources. Organic selenium (selenomethionine) has better tissue retention and a wider safety margin than sodium selenite, which is the inorganic form common in many premix products.
But this is a case where I want to be explicit: do not guess on selenium. Test first, supplement to confirmed need, retest. Mad Barn’s research library addresses the selenium question in more depth, and if you want to understand the regional and forage-level context, their published materials are worth reading — link through the main site at https://madbarn.com?ref=18219 and look for their nutrition articles.
How to Think About the Buying Decision
The table below summarizes the relevant products and when each makes sense.
| Product | Starting Price | Best For | When to Skip It |
|---|---|---|---|
| Natural Vitamin E | $74.99 | Horses without pasture; hay-only diets; confirmed low vitamin E status | If selenium is also low — use Natural E/Organic Se instead |
| Natural E/Organic Se | See site | Horses where both vitamin E and selenium are confirmed low by testing | If selenium status is unknown — test first |
| AminoTrace+ | $64.99 | Metabolic horses who also need elevated trace minerals; includes natural vitamin E | Do not stack with Omneity |
| Omneity Premix | $54.99 | Broad vitamin/mineral coverage; can be fed alongside Natural Vitamin E | Does not provide standalone natural vitamin E at therapeutic levels |
The default recommendation for a hay-only horse with no metabolic concerns: Natural Vitamin E alongside Omneity, confirmed by bloodwork and reviewed with your vet or an equine nutritionist.
The default recommendation for a metabolic horse (EMS, IR, laminitis-prone): AminoTrace+ already includes natural vitamin E alongside elevated trace minerals. Do not add Natural Vitamin E on top of AminoTrace+ without checking in with a nutritionist on total vitamin E intake. And if your horse has a history of laminitis or is actively dealing with a metabolic condition, that is a veterinary conversation first — supplements are adjuncts to a vet-directed plan, not a plan in themselves.
I have talked through how to think about supplement stacking and what questions to actually ask your vet on the podcast — the short version is that most horses on hay-based diets are underserved on vitamin E specifically, and the form matters more than most label-reading guides acknowledge.
The Bottom Line
Natural vitamin E is not a marketing distinction. The structural difference between natural (RRR-alpha-tocopherol) and synthetic (all-rac-alpha-tocopherol) is chemically real, biologically meaningful, and well-documented in the equine research. For horses that lack reliable fresh pasture — which describes a significant portion of the horses I see discussed in the context of vitamin E concerns — natural-source supplementation is the more efficient choice.
Mad Barn’s Natural Vitamin E is the product I would point to first for hay-only and dry-lot horses where the goal is supporting antioxidant status with the most bioavailable form available. It is a clean, single-nutrient product, it layers onto their balancer lineup without conflict, and the price is reasonable for what it is.
The caveats bear repeating: confirm status with bloodwork before supplementing if you can, work with your vet or a qualified equine nutritionist on amounts, and if selenium is also a question, test before adding it. The research supports using natural vitamin E. It does not support guessing your way through it.
Ready to try Mad Barn Natural Vitamin E? Use my link for reader benefits at Mad Barn → https://madbarn.com?ref=18219
