Gut Health & Nutrition Library · Selection Guide
Betaine Anhydrous vs Betaine Hydrochloride vs Coated Betaine: A Buyer's Selection Guide
Three feed-grade forms, three very different economics. This guide walks through delivered-betaine content, the head-to-head trial record, handling behaviour, choline and methionine sparing rules, and the COA lines that actually discriminate between lots.
Author: Shouhui Chen — SKF (Beijing) Biotechnology Co., Ltd. · Last updated: 28 September 2026 · Reading time: ~9 min
Key takeaways
- Betaine hydrochloride is not "stronger": pure betaine HCl is only ~76% betaine by weight, so equal-betaine dosing needs 1.28 kg of HCl product per 1 kg of anhydrous product. [2],[6]
- Two international broiler trials on an equal-betaine basis favour anhydrous betaine for growth, meat quality and gut barrier function; one Chinese layer trial at equal product mass slightly favoured HCl. [2],[3],[4]
- Anhydrous betaine is strongly hygroscopic (it forms the monohydrate); HCl flows better but is a skin/respiratory sensitiser under EU user-safety assessment. [5],[10],[11]
- Practical sparing rules: 1 kg anhydrous betaine ≈ 0.6 kg DL-methionine; replace up to ~50% of added choline in broilers (≤25% conservative). [14],[16]
- For ruminants, buy coated (rumen-protected) betaine — uncoated betaine vanishes in the rumen within 4–6 h. [12],[13]
1. The three feed-grade forms at a glance
Feed buyers choose between betaine anhydrous (trimethylglycine, CAS 107-43-7), betaine hydrochloride (CAS 590-46-5) and coated/rumen-protected betaine. The anhydrous form carries the most active betaine per kilogram; HCl handles better but dilutes the actives; coated products exist mainly for ruminant diets.
Betaine (N,N,N-trimethylglycine) is a zwitterionic osmolyte and methyl donor used in feed to spare methionine and choline, support animals under heat or saline-water stress, and reduce carcass fat. [1],[15] Commercially it reaches the feed industry in three physical forms, and the differences that matter in procurement are chemistry, not marketing:
| Betaine anhydrous | Betaine hydrochloride | Coated / rumen-protected | |
|---|---|---|---|
| Identity | Trimethylglycine, C₅H₁₁NO₂, MW 117.15, CAS 107-43-7 | Betaine HCl, C₅H₁₁NO₂·HCl, MW 153.61, CAS 590-46-5 | Betaine (usually anhydrous) in a fatty or pH-sensitive matrix |
| Where it comes from | Extraction from sugar-beet molasses (2–5% betaine), or synthesis from trimethylamine + chloroacetic acid with electrodialysis desalting [9],[10] | Chemical synthesis; the residual-salt load of the sodium process drives the common "low ignition residue" upgrade [8],[10] | Anhydrous betaine + hydrogenated fat / stearates / bentonite; one commercial product: 55% betaine, 60% rumen bypass [12],[13] |
| Typical feed-grade assay | ≥96.0% (dry basis, GB 7300.203-2020); 98% grades also common [7] | ≥98.0% as betaine HCl (dry basis, GB 7300.204-2019) [6] | 25–55% betaine in the product [12],[13] |
| Betaine delivered per kg product | ≈960 g (96% grade) | ≈748 g (98% grade × 76.3% betaine content) | ≈330–550 g before rumen losses |
| Hygroscopicity / flow | Strongly hygroscopic, forms monohydrate C₅H₁₁NO₂·H₂O; flow was the historical weakness that led to the HCl salt [8],[10],[11] | Less hygroscopic, better flow; still labelled hygroscopic in the Chinese standard [6],[8] | Fat coating protects particles from moisture pick-up [12] |
| EU feed-additive status | Authorised, 3a920 (nutritional additive, all species) [5] | Authorised, 3a925 [5] | Authorised only as a preparation of the basic substance — check the exact entry |
Table 1. The three feed-grade betaine forms compared on the attributes that matter in procurement
The 76.3% betaine content of pure betaine HCl follows directly from the molecular weights (117.15/153.61). This is why the broiler trial by Chen et al. dosed 1,284.46 mg/kg of betaine HCl against 1,000 mg/kg of anhydrous betaine — a factor of 1.2845, essentially the stoichiometric correction. [2]
2. Anhydrous vs hydrochloride: what head-to-head trials actually show
The published head-to-head evidence is limited but consistent in one direction: when the two forms are dosed on an equal-betaine basis, anhydrous betaine matched or beat betaine HCl for broiler growth, meat quality and gut barrier function. One layer trial that dosed equal product masses slightly favoured HCl — a design difference buyers should notice.
Equal-betaine dosing: anhydrous wins on performance
In the most complete comparison, 400 male partridge-shank broilers received either anhydrous betaine (500 or 1,000 mg/kg) or betaine HCl (642.23 or 1,284.46 mg/kg — the stoichiometric equivalent). Anhydrous betaine significantly improved growth, breast-meat yield, muscle pH, water retention and antioxidant capacity; the HCl form was less effective. [2]
A second controlled study (105 broilers, 1 kg active betaine/t from either source) found that synthetic betaine HCl increased intestinal paracellular permeability in jejunum and caecum, disturbed villus architecture, and did not improve body weight, whereas natural (beet-derived) betaine improved BW and weight gain significantly. [3]
Equal-product-mass dosing: HCl slightly ahead in one layer trial
A Chinese layer trial (504 Hy-Line Brown hens, 48 weeks of age, 500 mg/kg of each product for 5 weeks) reported that betaine HCl was the only group to significantly raise lay rate (87.29% vs 82.79% control, P=0.044) and lower liver MDA (P=0.017); both forms equally improved feed/egg ratio, Haugh units and serum catalase. The authors concluded that HCl was "slightly superior" to anhydrous betaine. [4]
3. Hygroscopicity, caking and premix handling
Anhydrous betaine absorbs moisture readily and converts to the monohydrate, so it demands sealed liners and dry storage; betaine HCl was historically developed precisely to overcome betaine's poor flow, and coated products are the most moisture-tolerant of all.
The process literature is explicit about the origin of the HCl salt: "the flowability of betaine seriously limited its application, and to overcome this drawback betaine hydrochloride came into being" — with HCl being cheaper and less hygroscopic. [8] The other side of the coin: anhydrous betaine "has excellent moisture absorption and forms the hydrate C₅H₁₁NO₂·H₂O after absorbing water" [10], and its synthesis route must strip residual salt (electrodialysis to chloride <0.2%) precisely because salt impurities worsen caking. [9]
| Handling question | Anhydrous betaine | Betaine HCl | Coated betaine |
|---|---|---|---|
| Caking risk in summer transit | Higher — needs PE liners, sealed drums, dry warehouse | Lower, but the GB standard still labels it hygroscopic [6] | Lowest — fat matrix sheds moisture [12] |
| Premix compatibility | Good; less aggressive on vitamins than choline chloride (industry consensus, vendor-sourced) | Acidic (pH 0.8–1.2 in solution) — mind touch points with acid-sensitive actives [6] | Designed for feed milling; check coating melt point vs pelleting temperature |
| Worker safety | Skin/eye irritant; dust inhalation hazard [5] | Skin/eye irritant plus dermal and respiratory sensitiser (EU CLP-based assessment) [5] | Follow the SDS of the finished preparation |
Table 2. Handling and safety comparison across the three forms
Both Chinese national standards also cap trimethylamine-related impurities: total free amine ≤100 mg/kg for anhydrous betaine and free amine/ammonia ≤300 mg/kg (as (CH₃)₃N) for HCl — the fishy-odour indicator on a COA. [6],[7]
4. Converting betaine against choline chloride and methionine
Betaine covers only the methyl-donor job of choline and only part of methionine's requirement. Workable rules: 1 kg of anhydrous betaine ≈ 1.9 kg of 60% choline chloride on a molecule basis (replace at most half of added choline in broilers), and ≈ 0.6 kg of DL-methionine.
Choline chloride
Choline must first be oxidised to betaine in the liver before its methyl groups become available; betaine donates methyls directly. [1] But the conversion only runs one way — betaine cannot be turned back into choline, so it cannot cover choline's structural roles (phosphatidylcholine membranes, acetylcholine). [1],[14]
| Basis | Conversion | Source quality |
|---|---|---|
| Equal molecules (chemistry) | 1 kg anhydrous betaine 96% ≈ 1.9 kg choline chloride 60% (8.20 vs 4.30 mol/kg) | Stoichiometric calculation |
| Equal methyl-donor function, broilers | Betaine can substitute ~50% of added choline; ≤25% under a conservative approach | Industry guidance + reviewed trial evidence [14],[16] |
| Laying hens | Methyl-donor portion of choline can be covered more fully (up to 100% reported) | Industry guidance [14] |
| Chinese broiler trial, 42 d | 400 g/t anhydrous betaine matched or beat 480–960 g/t choline chloride on weight and FCR; betaine + natural choline gave the lowest cost of gain | Peer-group trial, 2,000 birds [17] |
Table 3. Betaine ↔ choline chloride conversion rules
Methionine
The practical bioavailability of betaine against supplemental methionine is about 60%: 1 kg anhydrous betaine replaces ≈ 0.6 kg DL-methionine. [14] A dose-controlled Chinese trial (192 AA broilers, 42 d) replaced 25%, 50% or 100% of added DL-Met with anhydrous betaine at a 1:1 weight ratio: growth was never harmed, 50% substitution even raised crude-protein digestibility (+11.5%, P<0.05), but 100% substitution reduced breast-muscle GPX activity, lowered 24 h pH and increased drip loss. The authors recommended replacing no more than 25% of added methionine. [11]
5. Coated and rumen-protected betaine: the ruminant decision
In cattle and sheep, uncoated betaine is degraded by rumen microbes within 4–6 hours. Coated betaine that releases most of its payload in the intestine delivered significantly better gain and feed conversion than the same betaine dose uncoated — so for ruminants, buy on measured release rates, not on betaine content alone.
"Betaine added to sheep diets disappears from the rumen within 4–6 h" — the sentence that opens every rumen-protection rationale. [12],[13] In a 36-head fattening-bull trial (80 d), coated betaine (CBT: 250 g/kg betaine in hydrogenated fat + stearates + bentonite, dosed to supply the same 6 g/d of betaine as the uncoated group) measurably released 28.3% of its betaine in the rumen and 69.2% in the small intestine. Against plain betaine at the same active dose, CBT significantly improved ADG (1.76 vs 1.68 kg/d, P=0.034), final body weight (P=0.032), FCR (5.28 vs 5.50, P=0.009), and DM and OM digestibility (P=0.001). [12] A commercial rumen-protected product used in a sheep trial contained 55% betaine with 60% rumen bypass. [13]
One honest caveat from the same bull trial: uncoated betaine beat the coated product on ADF digestibility and five fibrolytic microbial counts — the coating does keep betaine away from rumen fibre-digesters too. If the goal is rumen fermentation support rather than intestinal delivery, plain betaine is not automatically wrong. [12]
6. COA checklist: the numbers that actually matter
Assay on a dry basis is the headline, but the discriminating COA lines are loss on drying, ignition residue/NaCl, free amine (trimethylamine), arsenic and heavy metals. Secondary indicators separate premium lots from commodity lots far better than the assay floor does.
| COA parameter | Betaine anhydrous (GB 7300.203-2020) | Betaine HCl (GB 7300.204-2019) |
|---|---|---|
| Assay, dry basis | ≥96.0% betaine [7] | ≥98.0% betaine HCl [6] |
| Loss on drying | Low single digits — verify lot value against supplier spec | ≤0.5% [6] |
| Ignition residue | Low; watch NaCl (≤0.3% on premium specs) | ≤1.0%; sodium-process goods hover near the limit, upgraded calcium-process lots reach ~0.08% [8] |
| Free amine / TMA | ≤100 mg/kg total free amine [7] | ≤300 mg/kg as (CH₃)₃N [6] |
| pH (solution) | ~neutral | 0.8–1.2 (strongly acidic) [6] |
| As / Pb | ≤2 / ≤10 mg/kg | ≤2 / ≤10 mg/kg [6] |
| Betaine delivered per kg | ≈960 g (96% grade) | ≈748 g [2],[6] |
Table 4. COA parameters that discriminate between betaine lots
Red flags when comparing quotes: assay quoted "as is" instead of dry basis; ignition residue near 1% on HCl (sodium-process salt load, which worsens irritation and caking); no free-amine line (fishy-odour risk in finished feed); and for coated products, no measured rumen/intestinal release figures. [8],[12]
7. Regulatory status at a glance
In the EU both forms are authorised nutritional feed additives for all species (3a920 anhydrous, 3a925 HCl) with recommended maxima of 2,000 mg/kg complete feed; China governs the two forms under separate GB standards. Always confirm the destination-market status of the exact product type before contracting.
| Market | Anhydrous betaine | Betaine HCl |
|---|---|---|
| EU | Authorised, 3a920, nutritional additive (vitamins/provitamins and chemically well-defined substances having a similar effect), all species; 2025 renewal confirmed safety under authorised conditions; recommended maxima: 2,000 mg/kg complete feed, 1,000 mg/L drinking water (poultry), 700 mg/L (pigs), 250 mg/L (calves) [5] | Authorised, 3a925, same category and maxima; user safety stricter (skin/eye irritant, dermal and respiratory sensitiser) [5] |
| China | GB 7300.203-2020 (feed additive — betaine) [7] | GB 7300.204-2019 (feed additive — betaine hydrochloride) [6] |
Table 5. Regulatory status of the two main betaine forms in the EU and China
Frequently asked questions
Is betaine HCl 98% stronger than betaine anhydrous 96%?
No — the "98%" refers to betaine HCl content, not betaine content. Pure betaine HCl is only 76.3% betaine by weight, so 1 kg of 98% HCl product carries ≈748 g of betaine versus ≈960 g in 1 kg of 96% anhydrous product. Equal-betaine dosing needs a factor of ≈1.28 for the HCl form, exactly the ratio used in the Poultry Science comparison trial. [2],[6]
How much choline chloride can I replace with betaine anhydrous?
Chemistry says 1 kg of 96% anhydrous betaine ≈ 1.9 kg of 60% choline chloride molecule-for-molecule. Biology trims that: betaine covers only the methyl-donor function, so replace up to ~50% of added choline in broilers (≤25% conservative) and up to the full methyl-donor portion in layers. [14],[16]
Can betaine fully replace methionine in broiler feed?
No. Use 1 kg anhydrous betaine ≈ 0.6 kg DL-methionine and cap substitution at ~25% of added methionine. Full replacement did not hurt growth but degraded breast-muscle quality (GPX, 24 h pH, drip loss). [11],[14]
Which form should I buy for hot, humid climates?
For the same betaine payload, anhydrous betaine is the most hygroscopic (monohydrate formation) — buy it with moisture-tight liners and rotate stock; HCl flows better but acidifies solutions and carries sensitiser handling requirements; coated products are the most moisture-tolerant. [5],[8],[10] Betaine's osmolyte function is itself most valuable under heat stress. [15]
Do I need rumen-protected betaine for cattle and sheep?
If the target is intestinal delivery and animal performance, yes: uncoated betaine is gone from the rumen in 4–6 h, while a coated product releasing 28.3% rumen-side beat the same uncoated dose on ADG (P=0.034) and FCR (P=0.009) in fattening bulls. Ask suppliers for measured release rates, not just betaine content. [12],[13]
What should I check on a betaine COA before ordering?
Dry-basis assay (≥96% anhydrous / ≥98% HCl), loss on drying, ignition residue or NaCl, free amine/TMA, As and Pb, and — for coated goods — rumen and intestinal release rates. Remember the price-per-kg trap: compare cost per kilogram of delivered betaine, not per kilogram of product. [6],[7],[8],[12]
References
- Eklund M, Bauer E, Wamatu J, Mosenthin R. Potential nutritional and physiological functions of betaine in livestock. Nutrition Research Reviews. 2005;18(1):31–48. doi:10.1079/NRR200493
- Chen R, Yang M, Song YD, Wang RX, Wen C, Liu Q, Zhou YM, Zhuang S. Effect of anhydrous betaine and hydrochloride betaine on growth performance, meat quality, postmortem glycolysis, and antioxidant capacity of broilers. Poultry Science. 2022;101(4):101687. doi:10.1016/j.psj.2021.101687
- Awad WA, Ruhnau D, Gavrău A, Dublecz K, Hess M. Comparing effects of natural betaine and betaine hydrochloride on gut physiology in broiler chickens. Poultry Science. 2022;101(12):102173. doi:10.1016/j.psj.2022.102173
- Qiu X, et al. Effects of different types of betaine on production performance, egg quality and antioxidant function of laying hens [in Chinese]. China Poultry. 2025;47(5):55–61. (Chinese journal, no DOI; as indexed on CNKI.)
- EFSA FEEDAP Panel (Villa RE, et al.). Assessment of the feed additives betaine anhydrous (3a920) and betaine hydrochloride (3a925) for all animal species for the renewal of their authorisations (Orffa Additives B.V.). EFSA Journal. 2025;23(4):e9355. doi:10.2903/j.efsa.2025.9355
- GB 7300.204-2019 Feed additives — Part 2: Vitamins and provitamins — Betaine hydrochloride [in Chinese]. State Administration for Market Regulation. (Technical indicators verified against the standard text.)
- GB 7300.203-2020 Feed additives — Part 2: Vitamins and provitamins — Betaine [in Chinese]. State Administration for Market Regulation.
- Lu F, Wang W, Hu B, Feng W. Study on the synthesis of low-ignition-residue betaine hydrochloride [in Chinese]. Applied Chemical Industry. 2015;44(12):2230–2233. doi:10.16581/j.cnki.issn1671-3206.2015.12.017
- Wang X. Study on the synthesis and purification process of betaine [in Chinese]. Coal and Chemical Industry. 2024;47(9):138–141. doi:10.19286/j.cnki.cci.2024.09.028
- Chen H, Liu Y, Zhao S, Zhang H. Analysis of betaine product applications and market trends [in Chinese]. China Food Additives. 2025;(6):183–195. doi:10.19804/j.issn1006-2513.2025.6.024
- Fu Q, et al. Effects of replacing methionine with betaine on growth, nutrient metabolism and serum biochemical indices of broilers [in Chinese]. Journal of Fujian Agriculture and Forestry University (Natural Science Edition). 2015;44(4):396–401. (Thesis version of the same trial: Nanjing Agricultural University, 2015.)
- Lei W, Tian Y, Xu K, et al. Effects of betaine and coated betaine on growth performance, nutrient digestion and rumen fermentation of Holstein bulls [in Chinese]. Chinese Journal of Animal Nutrition. 2024;36(10):6422–6431. doi:10.12418/CJAN2024.546
- Li P. Effects of fermented bran polysaccharides and rumen-protected betaine on growth performance, nutrient digestibility, blood and rumen indices of meat sheep [master's thesis, in Chinese]. Inner Mongolia Agricultural University; 2021.
- Mavromichalis I. Making the best use of betaine in pig and poultry feed. Feed Strategy (industry expert commentary; not peer-reviewed).
- Saeed M, Babazadeh D, Naveed M, Arain MA, Hassan FU, Chao S. Reconsidering betaine as a natural anti-heat stress agent in poultry industry: a review. Tropical Animal Health and Production. 2017;49(7):1329–1338. doi:10.1007/s11250-017-1355-z
- Wang H, et al. Application of betaine in poultry and its mechanism of action [in Chinese]. China Feed. 2025;(9):80–86. (Citing the choline-replacement ratios of Dilger et al., 2007.)
- Jin D, et al. Effects of plant-derived natural choline and betaine, alone or in combination, as substitutes for choline chloride on production performance of broilers [in Chinese]. 2026;48(3):16–25. (Journal title to be confirmed against the final CNKI version.)
About the author. Shouhui Chen, SKF (Beijing) Biotechnology Co., Ltd — technical service for feed additives.
Data provenance. All performance and specification figures in this article are drawn from the peer-reviewed and standard documents cited above, except where marked as industry guidance or vendor-sourced consensus. Betaine-containing products are feed additives, not veterinary medicines; nothing here is a substitute for veterinary advice or a label-specific recommendation. Formulation decisions should be made on delivered betaine equivalents and confirmed against the COA and local regulations.
Last updated: 28 September 2026. Literature search cut-off: 28 September 2026; later publications are not included.
Sourcing betaine on delivered-betaine economics?
SKF Bio supplies betaine anhydrous 98% with dry-basis assay, free-amine and ignition-residue lines on every COA. Ask us for lot data, formulation equivalents, or a quote per kilogram of delivered betaine.