Ingredients & evidence
Every substance from the 7 nutrient groups we work with – and how well it is actually supported by evidence in horses. Because a list of ingredients only means something once it says what it is worth.
Here you will find the technical assessment including the order of magnitude of requirements. What each kilogram of product actually contains depends on the individual horse's ration and is stated in the declaration of its custom mix.
How we rate evidence
We rate every ingredient by the evidence in horses – not by the evidence in humans, dogs or rats, and not by how common it is on the market.
- Solid
- Solid evidence – Controlled studies in horses or a recognised, tabulated nutrient requirement.
- Moderate
- Moderate evidence – Individual controlled studies in horses or a well-founded, undisputed physiological function.
- Limited
- Limited evidence – The evidence in horses is thin, inconsistent or transferred from other species. We say so openly.
Of 11 ingredients, we rate 9 as solid, 2 as moderate and 0 as limited in terms of evidence. The third number being zero is not down to generous rating but to our scope: we only supplement nutrients with a tabulated requirement. Anything that sounds interesting but has thin evidence in horses is listed further down under “What we deliberately leave out”.
Forage base
Closes the gap in calcium, phosphorus and magnesium when, by calculation, the forage ration does not cover these macrominerals.
Claim: Supplements calcium, phosphorus and magnesium in forage rations.
Deliberately without selenium, iodine, iron and fat-soluble vitamins – a base module that supplies everything inevitably doses these substances blindly.
- Solid
Calcium
Calcium carbonate
Macromineral for bone substance, muscle contraction and nerve conduction; in hay it varies greatly depending on the sward and cut.
Evidence: The requirement is tabulated and backed by balance trials. A meta-analysis of quantitative Ca, P and Mg metabolism confirms the orders of magnitude and also shows that calcium losses via sweat are small.
Requirement & reference values: In the reference model, the maintenance requirement of a 500 kg horse is around 17 g of calcium per day. At least as important is the Ca:P ratio of the whole ration – it should not fall below 1:1.
More in the knowledge base - Solid
Phosphorus
Monocalcium phosphate
Partner of calcium in bone metabolism and a building block of energy metabolism.
Evidence: Requirement tabulated. Grass hay is often low in phosphorus while calcium is plentiful – which is why in a hay-only ration phosphorus is more often the limiting part than calcium. However, supplementing without analysis can just as easily shift the ratio in the wrong direction.
Requirement & reference values: Maintenance requirement around 35 mg per kg body weight per day, i.e. about 17 g at 500 kg. Ca:P of the whole ration usually in the range 1.5:1 to 2:1.
More in the knowledge base - Moderate
Magnesium
Magnesium oxide
Cofactor in hundreds of enzyme reactions and involved in neuromuscular signal transmission.
Evidence: The physiological function is undisputed, the requirement figure is not: the 2024 meta-analysis finds a higher requirement for horses and a lower one for ponies than earlier estimates. We therefore calculate with an increased reference value from 300 kg, unchanged below that, and state the uncertainty. To be equally honest: there is no reliable basis for the popular use “against nervousness”, and according to current evidence there is no work-related addition.
Requirement & reference values: Reference approach according to GfE (German Society of Nutrition Physiology), increased by a factor of 1.85 from 300 kg body weight (about 10.4 g per day at 500 kg, 3.6 g at 280 kg).
More in the knowledge base
Carriers and processing aids: dried brewer's yeast, linseed cake (as pelleting aid) – with no effect claim of their own.
Zinc-copper balance
Supplements zinc and copper together and in a fixed ratio – the two trace elements in which German forage most often falls short by calculation.
Claim: Supplements zinc and copper in a balanced ratio – for skin, coat and hoof horn.
Zinc and copper come from a certified premix – sensitive trace elements must be added via a premix. Both are contained only in this module so that levels do not add up across several packs.
- Solid
Zinc
Zinc oxide · EU additive 3b603
Essential for keratin formation, the skin barrier and numerous enzyme systems; a deficit often shows first in horn and coat.
Evidence: Requirement tabulated. But zinc does not act in isolation: without a suitable copper ratio, topping up zinc alone fizzles out because both elements share the same absorption pathways. That is why we do not offer a zinc-only product.
Requirement & reference values: Requirement around 50 mg per kg dry matter intake (about 500 mg per day at 500 kg body weight). Total statutory maximum level: 120 mg zinc per kg complete feed (88% DM) across all sources.
More in the knowledge base - Solid
Copper
Copper(II) sulphate pentahydrate · EU additive 3b405
Involved in the cross-linking of keratin and collagen, in pigment formation and in iron metabolism.
Evidence: Requirement tabulated. The skill lies in the ratio to zinc, iron and manganese, not in the absolute amount – iron-rich rations and high zinc doses reduce copper absorption. We therefore dose copper relatively generously in the module so that the Zn:Cu ratio of the whole ration reaches the target range.
Requirement & reference values: Requirement around 10 mg per kg dry matter intake (about 100 mg per day at 500 kg). Zn:Cu of the whole ration usually 3:1 to 5:1; total statutory maximum level 25 mg copper per kg complete feed.
More in the knowledge base
Carriers and processing aids: wheat middlings (carrier), linseed cake (as pelleting aid) – with no effect claim of their own.
Vitamin E
Covers vitamin E where it is systematically lacking: in rations consisting mainly of conserved forage rather than fresh grass.
Claim: Supplements vitamin E in rations based mainly on conserved forage.
Deliberately without added selenium. The vitamin E and selenium combination common on the market couples two substances that need to be dosed separately – we only offer selenium as a separate module that requires a lab value.
- Solid
Vitamin E
all-rac-alpha-tocopheryl acetate · EU additive 3a700
Fat-soluble vitamin that plays a role in protecting cell membranes from oxidative stress; stabilised as an acetate so that it survives storage.
Evidence: The requirement is tabulated, and the reason for supplementing is well documented: fresh grass is rich in vitamin E, while in hay the content falls markedly with drying and storage time. A ration of hay and straw alone is therefore structurally low. The reverse is not supported – a dose far above the requirement brings no additional benefit, and vitamin E is stored as a fat-soluble vitamin.
Requirement & reference values: Maintenance requirement around 1 IU per kg body weight per day (about 500 IU at 500 kg); roughly double for intensive work.
More in the knowledge base
Carriers and processing aids: wheat middlings (carrier) – with no effect claim of their own.
Amino acids (lysine, methionine+cystine, threonine)
Raises digestible crude protein as well as lysine, methionine+cystine and threonine when the ration shows gaps by calculation.
Claim: Supplements digestible crude protein and the three amino acids with a defined requirement where there are gaps by calculation.
- Solid
L-lysine
L-lysine monohydrochloride · EU additive 3c322
Amino acid for protein supply. The Compendium classifies threonine as first-limiting; lysine is the best supported.
Evidence: For maintenance, the Compendium puts lysine at 4.1%, methionine+cystine at 2.7% and threonine at 5.2% of DCP. Threonine is therefore above lysine and the highest driver of requirement.
Requirement & reference values: Our reference model links amino acid requirements to digestible crude protein: Lys 4.1%, Met+Cys 2.7% and Thr 5.2% for maintenance.
More in the knowledge base - Moderate
Soya protein concentrate
Feed material according to the DLG positive list
Protein source with a high content of digestible crude protein and a favourable amino acid profile – supplies the rest of the protein that pure lysine cannot replace.
Evidence: Composition and protein quality are well characterised. But the benefit depends entirely on the ration actually being short of protein: with adequately supplied hay, extra protein brings no advantage, only higher nitrogen excretion. That is why this module only goes into the pack when there is a gap by calculation.
Requirement & reference values: Maintenance requirement for digestible crude protein around 3 g per kg metabolic body weight (about 320 g per day at 500 kg).
More in the knowledge base
Salt (sodium & chloride)
Supplements sodium and chloride based on basic supply and additional work-related requirement.
Claim: Supplements sodium and chloride to match the calculated gap in the ration.
Without added potassium: forage is regularly rich in potassium, so a blanket addition would not solve a problem that existed beforehand.
- Solid
Sodium & chloride
Sodium chloride (table salt)
Maintain fluid balance and osmotic pressure; both are lost in considerable amounts through sweating and are hardly available in forage.
Evidence: The supply recommendation and the additional work-related requirement are tabulated in Coenen/Vervuert. A meta-analysis of Na, K and Cl metabolism also confirms that sodium and chloride are electrolytes relevant to sweating and must be considered together.
Requirement & reference values: Basic supply for adult horses follows the supply recommendation according to Coenen/Vervuert. The additional work-related requirement is added based on the amount of sweat; the specific amount to supplement results solely from the whole ration. Fresh water must always be available.
More in the knowledge base
Iodine
Only with lab valueCloses a calculated iodine gap – only when a reliable lab value is available.
Claim: Supplements iodine where a calculated undersupply has been established.
Lab value required: without an iodine value from the analysis, the ration calculation does not recommend this module – not even if a gap arises by calculation.
- Solid
Iodine
Calcium iodate, anhydrous · EU additive 3b202
Building block of thyroid hormones and therefore involved in regulating basal metabolism.
Evidence: The requirement is tabulated – that is not the problem. Iodine has a narrow window in both directions: both undersupply and oversupply disrupt thyroid hormone synthesis, and iodine sources such as seaweed or iodised licks are hard to quantify in practice. That is why this module is tied to a lab value rather than an estimate.
Requirement & reference values: Reference approach around 0.15 mg per kg dry matter intake (about 1.5 mg per day at 500 kg). Statutory maximum level for equines: 4 mg iodine per kg complete feed (12% moisture), 3 mg/kg recommended.
More in the knowledge base
Carriers and processing aids: wheat middlings (carrier) – with no effect claim of their own.
Selenium
Only with lab valueCloses a calculated selenium gap – only when a reliable lab value is available.
Claim: Supplements selenium where a calculated undersupply has been established.
Lab value required: without a selenium value from the analysis, the ration calculation does not recommend this module – not even if a gap arises by calculation.
- Solid
Selenium
Sodium selenite · EU additive 3b801
Component of selenium-dependent enzymes involved in antioxidant processes in muscle metabolism.
Evidence: Selenium has the narrowest safety margin of anything in horse feed: there is little room between meeting the requirement and oversupply. The real risk is rarely the single dose but double supply from mineral feed, muesli and licks – the statutory maximum level explicitly applies to all sources combined. That is exactly why we do not give selenium on suspicion.
Requirement & reference values: Reference approach around 0.15 mg per kg dry matter intake (about 1.5 mg per day at 500 kg). Total statutory maximum level: 0.5 mg selenium per kg complete feed (12% moisture) across all sources.
More in the knowledge base
Carriers and processing aids: wheat middlings (carrier) – with no effect claim of their own.
What we deliberately leave out
A list of ingredients says little as long as it is unclear what was rejected – and why. This applies especially to the substances found in almost every off-the-shelf product.
Selenium and iodine without a lab value
Both substances have the narrowest safety window in horse feed, and for both the statutory maximum level applies to all sources combined. Mixing them into a base module inevitably doses them blindly – without knowing what hay, muesli and licks already supply. We therefore offer them as separate modules that are only unlocked once an analysis value is available: without a lab result, neither selenium nor iodine goes into an automatically assembled pack.
Read the backgroundIron
Iron deficiency is rare in adult horses – forage and adhering soil practically always supply plenty. Extra iron, on the other hand, competes with copper and zinc for absorption, and the body can hardly excrete it actively. Our ration check has no statutory maximum level stored as a limit for iron, and we never add it automatically.
Read the backgroundVitamin A and vitamin D3
Both are fat-soluble and are stored, so an oversupply builds up over weeks instead of being excreted. Pasture and sunlight cover the requirement in most horses anyway. Vitamin E is our only fat-soluble vitamin – not for the sake of completeness, but because its content in conserved forage falls systematically and predictably.
Read the backgroundMethionine and threonine based on requirement
The Compendium lists methionine+cystine and threonine as requirement values. The module only supplements them when the ration balance shows a gap. For Met+Cys, coverage is often underestimated because feeds frequently declare only methionine; no hoof, coat or healing promises are derived from the amino acids.
Read the backgroundPotassium in the electrolyte mix
Potassium is traditionally in every electrolyte powder. But forage is regularly rich in potassium, and the work-related extra requirement rises much more slowly than that for sodium and chloride. A blanket potassium addition therefore solves a problem that usually did not exist.
Read the backgroundOmega-3 fatty acids in a powder sachet
The obstacle here is not the evidence but the format – and we would rather say so than declare a token amount. A sensible daily amount is in the range of several tablespoons of oil; encapsulated as a powder, the oil alone would be bulkier than the entire sachet. On top of that, linseed oil supplies ALA, while the evidence is based on EPA/DHA – and horses convert ALA only to a limited extent. Fish oil, in turn, oxidises in powder form and is poorly accepted. If you want to supplement omega-3, do it with an oil, not a sachet.
Read the backgroundCobalt (beyond the trace element requirement)
Used as a hypoxia mimetic to stimulate the body's own EPO release – with serious cardiovascular risks in overdose and clear doping relevance. Ruled out for us, regardless of whether a horse competes.
Read the backgroundMulti-strain probiotics with human lactic acid bacteria
Strains from human use are not adapted to the equine gut, and reliable efficacy data in horses are lacking. A long strain name on the label is no substitute for evidence.
Read the backgroundAggressive pH buffer combinations
In effect, they aim to treat acidosis. That is the domain of therapy and belongs in the hands of a vet, not in a daily feed.
Read the backgroundHigh-dose herbal mixtures
Contradictory research combined with a real risk: plant compounds can act pharmacologically and lead to positive test results in competition. Potent enough for a positive doping test, but too weakly supported for a promise – that is the worst combination.
Read the background“Detox” and detoxification concepts
“Detoxification” is not a permitted nutritional purpose under feed law and is not physiologically defined. The liver and kidneys take care of that without powder.
Read the backgroundHigh-dose antioxidants
No additional benefit beyond the requirement has been shown. For fat-soluble vitamins and selenium, a high dose worsens the safety profile instead of improving it.
Read the background
Why requirement values are listed here, not product amounts
The figures given are requirement values from reference works, values from studies or statutory maximum levels – not a product declaration. How much an individual horse actually needs depends on its ration: hay varies from batch to batch, and what already comes from the basic forage does not need to be supplemented. That is why our levels result from requirement calculation and analysis – not from a round marketing number.
Sources
The content is based on the references listed below. It does not replace individual veterinary or feeding advice.
Show list of sources (19)
- GfE (2014) – Empfehlungen zur Energie- und Nährstoffversorgung von PferdenSpecialist reference in German-speaking countries (GfE, German Society of Nutrition Physiology), Committee for Requirement Standards
- NRC – Nutrient Requirements of Horses, 6th ed.International reference for the nutrient requirements of horses (National Research Council)
- Maier I, Kienzle E (2024): A Meta-Analysis on Quantitative Calcium, Phosphorus and Magnesium Metabolism in Horses and Ponies. Animals 14(19):2765 (LMU München)Meta-analysis: sweat losses of Ca, P and Mg are so small that no additional work-related requirement is applied. For Mg it calculates the replacement of endogenous faecal losses and separates by weight (horses > 300 kg: 37, ponies < 300 kg: 11 mg/kg metabolic body mass; a pony that was temporarily heavier remained in the pony group); the comparison factors (horses around 1.9×, ponies around ½) refer to Kienzle & Burger (20 mg/kg), not to the GfE
- Durchführungsverordnung (EU) 2016/1095Authorisation of zinc acetate, zinc chloride, zinc oxide, zinc sulphate and zinc chelates (3b601 ff.); total maximum content of zinc 120 mg/kg complete feed (12% moisture) for “other species and categories”, in which horses are not listed separately. Consolidated version of 25 September 2022 (including Implementing Regulation (EU) 2022/1458); authorisation expires according to the Annex on 27 July 2026; renewal procedures are under way at EFSA. According to the EU Register of Feed Additives (as of 15 October 2026), an application for renewal under Art. 14 of Regulation (EC) No 1831/2003 has been submitted (checked for zinc acetate dihydrate, 3b601); the authorisation remains valid. Additionally Implementing Regulation (EU) 2024/265 (zinc(II) betaine complex, 120 for other species).
- Durchführungsverordnung (EU) 2018/1039Authorisation of copper compounds (3b401 ff.); total maximum content of copper 25 mg/kg complete feed (12% moisture) in the category “other animals”, in which horses are not listed separately. Consolidated version of 21 September 2022 (including Implementing Regulation (EU) 2022/1445); authorisation expires according to the Annex on 13 August 2028. Additionally Implementing Regulation (EU) 2025/2513 (copper(II) betaine complex, also 25 for other species).
- Coenen M, Vervuert I (2020): Pferdefütterung. Begründet von H. Meyer. 6., aktualisierte Aufl., Georg Thieme Verlag, Stuttgart. ISBN 978-3-13-241778-6Standard reference work on equine nutrition in German-speaking countries; Table 4.17 mineral recommendations (recommended supply and minimum requirement), Table 4.18 derived sweat volumes per work level and weight class, Table 4.19 electrolyte performance requirement per sweat volume (in addition to maintenance requirement)
- Verordnung (EG) Nr. 1831/2003Feed additives – authorisation and use; “daily ration” based on 12% moisture (Art. 2(2)(f)), renewal of authorisation and automatic continuation (Art. 14(4)), general conditions of use (Annex IV: natural plus added amount; complementary feed, diluted as specified, at most at the level for complete feed). Link to the current EUR-Lex consolidated version (as of 27 March 2021).
- Mok CH, Urschel KL (2020): Amino acid requirements in horses (Invited Review). Asian-Australasian Journal of Animal Sciences 33(5):679–695Review of amino acid requirements: in horses essentially only lysine is quantitatively established; there are no robust requirement figures for methionine/threonine
- Kienzle, Pankratz & Zeyner (2023) – Kompendium zur Rationsberechnung für PferdeAuthor group Pferdewissen (Kienzle/Pankratz, LMU Munich; Zeyner, University of Halle-Wittenberg); self-published, Oberschleißheim, ISBN 978-3-00-075668-9. No link – self-published, not freely accessible.
- DLG Positivliste für EinzelfuttermittelPractice standard for feed materials in Germany
- Maier I, Kienzle E (2025): A Meta-Analysis on Quantitative Sodium, Potassium and Chloride Metabolism in Horses and Ponies. Animals 15(2):191Meta-analysis of Na, K and Cl metabolism; sodium and chloride are the electrolytes relevant to sweat and are considered together. Chloride is almost completely absorbed (median 94% in horses, 98% in ponies); published sodium maintenance recommendations for a 500 kg horse range from 3 to 13 g per day
- Durchführungsverordnung (EU) 2015/861Authorisation of potassium iodide, anhydrous calcium iodate and coated granulated calcium iodate (identification numbers 3b201 to 3b203); total maximum content of iodine for equids 4 mg/kg complete feed (12% moisture). Under other provisions, the Annex additionally gives a recommended maximum content of 3 mg/kg (not the binding value). Authorisation expires according to the Annex on 24 June 2025; for the renewal procedure see the EFSA opinion. According to the EU Register of Feed Additives (as of 15 October 2026), an application for renewal under Art. 14 of Regulation (EC) No 1831/2003 has been submitted; the authorisation remains valid.
- Durchführungsverordnung (EU) 2020/2117Renewal of the authorisation of selenium yeast from Saccharomyces cerevisiae CNCM I-3399 (identification number 3b812) for all animal species; total maximum content of selenium 0.50 mg/kg complete feed (12% moisture) and at most 0.2 mg/kg of added organic selenium. Authorisation expires according to the Annex on 6 January 2031. Other selenium sources with the same total value: Implementing Regulations (EU) 2019/49, 2019/804 and 2024/3168.
- Merck Veterinary Manual: Nutritional Diseases of Horses (Eisen)Iron deficiency is rare in adult horses; forage practically always supplies plenty of iron, and supplementation is only indicated where there is a specific reason
- Towards the elimination of excessive cobalt supplementation in racing horses: A pharmacological reviewCobalt as a hypoxia mimetic (HIF-1α stabilisation, EPO release); serious cardiovascular side effects in overdose
- FEI Equine Prohibited Substances List (EPSL)International list of prohibited and controlled substances in equestrian sport (Banned Substances & Controlled Medication)
- Verordnung (EU) 2020/354Particular nutritional purposes for dietetic feeds
- Verordnung (EG) Nr. 767/2009Placing on the market and use of feed, labelling and claims; definitions of complete feed (Art. 3(2)(i)) and complementary feed (point (j)), content of feed additives (Art. 8), feeding instructions (Annex II No. 4). Link to the current EUR-Lex consolidated version (as of 26 December 2018).
- Prof. Dr. Ingrid Vervuert – Institut für Tierernährung, Universität LeipzigResearch on starch digestion, glycaemic/insulinaemic responses and phytotherapeutics in horses