Home Ingredients D-Tagatose (Low-Calorie Sugar)
Metabolic Health

D-Tagatose (Low-Calorie Sugar)

Evidence Level
Limited
7 Clinical Trials
4 Documented Benefits
2/5 Evidence Score

D-tagatose is a rare sugar with the same chemical formula as fructose but a different shape. It is made commercially from galactose, fructose or starch-derived maltodextrin, is about 75 to 92 percent as sweet as table sugar, and is used as a reduced-calorie sweetener and bulking ingredient. In the US, FDA has had no questions about several GRAS notices for its use in foods, and the EU and UK authorize it as a novel food. Taken with or just before carbohydrate, it can lower the glucose and insulin rise that follows, and pooled trials report HbA1c slightly lower than with placebo or control, although the largest long trials were funded in part by a company that was developing it as a drug. Trials found no consistent benefit for blood lipids or body weight. At the doses used in those trials, gas, bloating and diarrhea were common, and single large doses briefly raise blood uric acid.

Studied Dose 5 to 10 g in a drink, or 10 to 75 g before a glucose load, in single-meal tests; 2.5 to 7.5 g three times daily for 6 months; 15 g three times daily before meals for up to 12 months. EU and UK rules set 15 g as a tolerable single serving.
Active Compound D-Tagatose, a ketohexose and C-4 epimer of D-fructose.

Benefits

Lower blood glucose and insulin rise after carbohydrate

A pooled analysis of 8 tagatose trials found lower post-meal glucose and insulin responses than with control, rated moderate certainty. An earlier pooled analysis of single-meal tests at up to 30 g found the insulin response about 25 percent lower than with the same meal alone, but only a 3 percent, nonsignificant, drop in glucose. Taken on its own, tagatose did not raise glucose or insulin.

Supported by Trial 7, Trial 4

HbA1c over 6 to 12 months of daily use

In a placebo-controlled trial of about one year in adults with type 2 diabetes not taking glucose-lowering medicine, 15 g three times daily lowered HbA1c slightly more than placebo (registry data at one year: 0.11 point down versus 0.09 up). A pooled analysis found HbA1c about 0.25 point lower than with control. The two largest long trials were funded in part by Spherix, which was developing tagatose as a drug.

Supported by Trial 1, Trial 2

Blood lipids and body weight in longer trials

In the largest trial, total and LDL cholesterol fell slightly more than with placebo in the main analysis but not in the per-protocol analysis, HDL fell more and triglycerides did worse in the main analysis, and body weight did not change. A one-year study in 8 people reported weight loss and higher HDL but had no control group. A pooled analysis found no lipid or body composition effect.

Supported by Trial 1, Trial 3

Sugar replacement covered by an FDA dental labeling rule

FDA's health claim rule for noncariogenic sweeteners (21 CFR 101.80) lets a qualifying sugar-free food sweetened with D-tagatose state that tagatose, unlike other sugars, does not promote tooth decay, along with the required note that frequent between-meal sugars and starches can promote it. This compares tagatose with sugar; it does not show that taking tagatose protects teeth.

Supported by Trial 1, Trial 3

Mechanism of action

1

Partly absorbed, the rest fermented in the colon

In people with an ileostomy, about 81 percent of a 15 g daily dose was absorbed in the small intestine. What is not absorbed reaches the colon, where gut bacteria ferment it into short-chain fatty acids and gas. This fermentation and the water drawn into the gut explain the bloating, flatulence and loose stools at higher doses.

2

May slow glucose uptake from the gut

Taken before a glucose or sucrose drink, tagatose blunted the blood glucose rise in a dose-dependent way while blood tagatose itself rose only slightly. The researchers proposed that it reduces glucose absorption in the intestine; the study did not measure glucose absorption directly.

3

Handled in the liver like fructose

The absorbed part is converted in the liver to tagatose-1-phosphate, which breaks down slowly. In a small human study this lowered blood phosphate and raised uric acid more than the same dose of fructose. A 30 g dose also raised the gut hormones GLP-1 and CCK.

Clinical trials

1
Phase 3 HbA1c trial with a sucralose placebo
PubMed

Phase 3, multicenter, randomized, double-blind, placebo-controlled trial of 15 g D-tagatose in water three times daily before meals versus a sweetness-matched sucralose placebo, supported in part by Spherix. (Ensor et al. 2015, J Endocrinol Diabetes Obes)

494 adults with type 2 diabetes managed by diet and exercise only, in the US and India (232 tagatose and 248 placebo treated).

HbA1c fell more than placebo at 2 months (p = 0.0198) and later visits in the main analysis; in the per-protocol analysis the difference was significant only from month 6, and the effect was mainly in US sites. Body weight did not change; in the main analysis HDL fell more and triglycerides did worse than placebo, with no significant difference per protocol. GI side effects were more frequent and more often severe with tagatose. The senior author was Spherix president.

2
Six-month dose-finding trial without placebo
PubMed

Randomized trial of three D-tagatose doses (2.5, 5.0 or 7.5 g three times daily) for 6 months, compared with each person's own baseline, supported in part by Spherix. (Ensor et al. 2014, J Endocrinol Diabetes Obes)

161 adults with mild type 2 diabetes managed by diet and exercise, at 18 sites in the US and India.

HbA1c fell most at 7.5 g three times daily, but differences between dose groups were not significant at any time point. Fasting glucose fell only at the highest dose and body weight fell more at the two higher doses. There was no placebo group, and about 37 percent of participants withdrew.

3
One-year open pilot in 8 people
PubMed

Open, uncontrolled pilot study of 15 g D-tagatose three times daily with food for 12 months after a 2-month run-in. (Donner et al. 2010, Nutr Res)

12 adults with type 2 diabetes recruited; results reported for 8, with fewer in some analyses.

In the 5 people without added diabetes medicine, body weight fell from 108.4 to 103.3 kg, and HDL rose in the 6 not given lipid medicine. HbA1c fell from 10.6 to 9.6 percent, which was not significant. Ten of the 12 recruited had mild, short-lived digestive side effects. With no control group, these changes cannot be attributed to tagatose.

4
Tagatose before a glucose drink: dose-response test
PubMed

Acute tolerance tests of 75 g D-tagatose alone or 30 minutes before a 75 g glucose or sucrose drink, plus 10 to 30 g doses before glucose. (Donner et al. 1999, Diabetes Obes Metab)

8 adults without and 8 with type 2 diabetes.

Tagatose alone did not change glucose or insulin. Taken before glucose, it lowered the glucose rise in the diabetes group in a dose-dependent way from 10 g upward, without a significant insulin change. A 75 g dose caused diarrhea, nausea or flatulence in every participant; at 10 to 30 g, 3 of 10 had milder symptoms.

5
Tagatose drink and post-meal glucose in Korean adults
PubMed

Randomized, double-blind crossover study of a tagatose-containing drink versus a sucralose and erythritol drink, one week apart. (Kwak et al. 2013, Food Funct)

94 Korean adults enrolled (54 with normal glucose, 40 with high fasting glucose or newly diagnosed type 2 diabetes); 85 completed.

With 5 g of tagatose, glucose at 120 minutes and the glucose area under the curve fell in the high-glucose group but not in the normal group. When ages were matched the two groups responded similarly. In normal participants, a 10 g drink lowered insulin and C-peptide responses.

6
5 g tagatose before a glucose load: no glucose change
PubMed

Randomized controlled crossover study of 5 g D-tagatose, stevia or water 10 minutes before a glucose drink. (Sambra et al. 2022, Clin Nutr ESPEN)

33 young women with insulin resistance but without type 2 diabetes.

Tagatose did not change the glucose response compared with water; only stevia differed, with higher glucose at 30 and 60 minutes. Women felt fuller at 60 minutes after tagatose than after water, but food eaten at a buffet 3 hours later did not differ.

7
30 g tagatose versus fructose: uric acid
PubMed

Double-blind crossover study of 30 g oral D-tagatose, 30 g D-fructose or plain water. (Buemann et al. 2000, Metabolism)

8 men.

Peak serum uric acid and the 4-hour uric acid area were significantly higher after tagatose than after fructose or water, and blood phosphate dropped more. Tagatose also lowered the glucose and insulin response to a meal eaten about 4 hours later and raised the gut hormones CCK and GLP-1.

Side effects and drug interactions

Common Potential side effects

Diarrhea, flatulence, bloating and stomach rumbling are common at higher doses. In the phase 3 trial at 15 g three times daily, registry data show diarrhea in 120 of 185 people on tagatose versus 51 of 207 on placebo.
In single-dose tests of about 30 g, 31.5 percent of 73 young men had diarrhea and 15.1 percent nausea, and flatulence did not fade over 15 days of daily use.
EU and UK rules treat 15 g as a tolerable single serving and require foods above that, and drinks above 1 percent tagatose, to warn that excessive consumption may have laxative effects.
A single 75 g dose raised blood uric acid for a short time, peaking at about an hour, and 30 g raised it more than the same amount of fructose; 75 g a day for 8 weeks did not raise fasting uric acid. People with gout or high uric acid should ask a doctor before regular use.
The longest controlled trial lasted about one year, so longer-term safety is not known.

Important Drug interactions

Insulin or other glucose-lowering medicines: tagatose can lower post-meal glucose, and the long trials enrolled people not taking these medicines; check with your prescriber and monitor your blood sugar.
Gout and uric acid-lowering medicines: no study has tested the combination, but large single doses of tagatose raise uric acid for a few hours.

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Frequently asked questions about D-Tagatose (Low-Calorie Sugar)

What is D-tagatose?

D-tagatose is a rare sugar with the same chemical formula as fructose but a different shape. It is made from galactose, fructose or starch, is about 75 to 92 percent as sweet as table sugar, and is used to replace part of the sugar in foods.

Does D-tagatose affect blood sugar?

On its own it does not raise blood glucose or insulin. Taken with or before carbohydrate, it lowered the glucose or insulin rise in several small studies, although one study at 5 g found no glucose change. Placebo-controlled trials of daily use found HbA1c slightly lower than with placebo, mainly in trials funded in part by a company developing it as a drug. It is a sweetener, not a treatment, and anyone on blood sugar medicine should talk to their prescriber first.

How many calories does D-tagatose provide?

Fewer than sugar, but how many depends on the rules. The UK committee that assessed it in the EU cited 1.5 kcal per gram, while EFSA later set 3 kcal per gram for EU labels, according to a UK Food Standards Agency assessment. In one study about 81 percent of a 15 g daily dose was absorbed in the small intestine and the rest is fermented in the colon.

How is D-tagatose different from allulose?

Both are rare sugars related to fructose. Tagatose is sweeter, closer to table sugar, and provides more calories (1.5 to 3 kcal per gram in European assessments, versus no more than 0.4 for allulose on US labels). In single-meal tests both lower the glucose or insulin rise after carbohydrate. Tagatose has longer trials reporting HbA1c slightly lower than with placebo, but it also causes more digestive symptoms at the doses studied and briefly raises uric acid at high doses.

What is D-Tagatose used for?

D-Tagatose is researched primarily for Metabolic Health. A pooled analysis of 8 tagatose trials found lower post-meal glucose and insulin responses than with control, rated moderate certainty.

What is the recommended dosage of D-Tagatose?

The clinically studied dose is 5 to 10 g in a drink, or 10 to 75 g before a glucose load, in single-meal tests; 2.5 to 7.5 g three times daily for 6 months; 15 g three times daily before meals for up to 12 months. EU and UK rules set 15 g as a tolerable single serving. Always follow the product label and check with a healthcare provider for personal advice.

Is D-Tagatose safe, and does it have side effects?

Side effects and cautions reported for D-Tagatose include: Diarrhea, flatulence, bloating and stomach rumbling are common at higher doses. In the phase 3 trial at 15 g three times daily, registry data show diarrhea in 120 of 185 people on tagatose versus 51 of 207 on placebo. In single-dose tests of about 30 g, 31. It may also interact with some medications. D-Tagatose is not right for everyone, so check with a healthcare provider first if you are pregnant or breastfeeding, have a medical condition, or take prescription medication.

Does D-Tagatose interact with any medications?

Possible interactions include: Insulin or other glucose-lowering medicines: tagatose can lower post-meal glucose, and the long trials enrolled people not taking these medicines; check with your prescriber and monitor your blood sugar. If you take prescription medication, check with a pharmacist or doctor before using it.

How strong is the scientific evidence for D-Tagatose?

NutraSmarts rates the evidence for D-Tagatose as Limited (2 out of 5). It is backed by 7 study summaries and 16 cited references summarized on this page. A higher rating reflects more, larger, and better-designed human studies.

References(16 citations)

Evidence ratings on NutraSmarts are based on the totality of human clinical research, with emphasis on randomized controlled trials, meta-analyses, and systematic reviews. The references below directly support claims made throughout this page.

  1. Osborn L, DuPuis K, Liu S, Della Corte D, Della Corte KA. Glycemic and cardiometabolic effects of rare sugars allulose and tagatose: a systematic review and meta-analysis of controlled human intervention trials. Am J Clin Nutr. 2026;123(6):101314. doi: 10.1016/j.ajcnut.2026.101314.PubMedUsed to support: Systematic review and meta-analysis of 20 controlled trials (8 of tagatose, 12 of allulose; 1033 participants): tagatose lowered post-meal glucose and insulin responses and HbA1c (mean difference -0.25) with moderate certainty, and fasting insulin with very low certainty; neither sugar improved blood lipids or body composition.
  2. Braunstein CR, Noronha JC, Khan TA, Mejia SB, Wolever TM, Josse RG, Kendall CW, Sievenpiper JL. Effect of fructose and its epimers on postprandial carbohydrate metabolism: A systematic review and meta-analysis. Clin Nutr. 2020;39(11):3308-3318. doi: 10.1016/j.clnu.2020.03.002.PubMedUsed to support: Systematic review and meta-analysis of single-meal trials adding up to 30 g of fructose or its epimers to a carbohydrate meal: tagatose reduced the insulin response by 25 percent but gave a nonsignificant 3 percent reduction in the glucose response, with low certainty of evidence.
  3. Ensor M, Banfield AB, Smith RR, Williams J, Lodder RA. Safety and Efficacy of D-Tagatose in Glycemic Control in Subjects with Type 2 Diabetes. J Endocrinol Diabetes Obes. 2015;3(1):1065..PubMedUsed to support: Phase 3, randomized, double-blind trial in 494 adults with type 2 diabetes on diet and exercise alone (US and India): 15 g D-tagatose three times daily lowered HbA1c more than a sucralose placebo in the intention-to-treat analysis (significant per-protocol only from month 6, mainly in US sites); LDL and total cholesterol fell in the main analysis only, HDL fell more and triglycerides did worse than placebo, body weight did not change, and GI adverse events were more frequent and more often severe. Supported in part by Spherix; the senior author was Spherix president.
  4. US National Library of Medicine, ClinicalTrials.gov. Naturlose (D-Tagatose) Efficacy Evaluation Trial (NCT00955747): study record and posted results ClinicalTrials.gov. 2026;NCT00955747. Accessed October 2026..SourceUsed to support: Not PubMed-indexed. Registry record of the phase 3 trial, sponsor-investigator Robert Lodder (Spherix): 241 started tagatose and 253 placebo, with 69 in each arm not completing; least-squares mean HbA1c change at one year was -0.11 with tagatose versus +0.09 with placebo; diarrhea was reported in 120 of 185 tagatose and 51 of 207 placebo participants, flatulence in 85 versus 47, and defecation urgency in 64 versus 25.
  5. Ensor M, Williams J, Smith R, Banfield A, Lodder RA. Effects of Three Low-Doses of D-Tagatose on Glycemic Control Over Six Months in Subjects with Mild Type 2 Diabetes Mellitus Under Control with Diet and Exercise. J Endocrinol Diabetes Obes. 2014;2(4):1057..PubMedUsed to support: Randomized six-month trial of 2.5, 5.0 or 7.5 g D-tagatose three times daily in 161 adults with mild type 2 diabetes, with no placebo group: HbA1c fell most at the highest dose but dose groups did not differ significantly; fasting glucose fell only at 7.5 g; about 37 percent withdrew. Supported in part by Spherix; the senior author was Spherix president.
  6. Donner TW, Magder LS, Zarbalian K. Dietary supplementation with d-tagatose in subjects with type 2 diabetes leads to weight loss and raises high-density lipoprotein cholesterol. Nutr Res. 2010;30(12):801-6. doi: 10.1016/j.nutres.2010.09.007.PubMedUsed to support: Uncontrolled one-year pilot of 15 g D-tagatose three times daily in adults with type 2 diabetes (12 recruited, 8 analyzed): body weight fell and HDL rose in those without medication changes, HbA1c fell nonsignificantly, and 10 of 12 had mild, transient GI side effects.
  7. Donner TW, Wilber JF, Ostrowski D. D-tagatose, a novel hexose: acute effects on carbohydrate tolerance in subjects with and without type 2 diabetes. Diabetes Obes Metab. 1999;1(5):285-91. doi: 10.1046/j.1463-1326.1999.00039.x.PubMedUsed to support: Acute tolerance tests in 8 adults without and 8 with type 2 diabetes: D-tagatose alone did not change glucose or insulin; taken before a glucose load it reduced the glucose response dose-dependently from 10 g in the diabetes group; 75 g caused GI symptoms in all participants.
  8. Kwak JH, Kim MS, Lee JH, Yang YJ, Lee KH, Kim OY, Lee JH. Beneficial effect of tagatose consumption on postprandial hyperglycemia in Koreans: a double-blind crossover designed study. Food Funct. 2013;4(8):1223-8. doi: 10.1039/c3fo00006k.PubMedUsed to support: Randomized, double-blind crossover study in 85 Korean adults who completed: 5 g tagatose in a drink lowered 120-minute glucose and glucose area under the curve in hyperglycemic but not normal participants, and 10 g lowered insulin and C-peptide responses in normal participants.
  9. Sambra V, Vicuña IA, Priken KM, Luna SL, Allendes DA, Godoy PM, Novik V, Vega CA. Acute responses of stevia and d-tagatose intake on metabolic parameters and appetite/satiety in insulin resistance. Clin Nutr ESPEN. 2022;49:217-224. doi: 10.1016/j.clnesp.2022.04.018.PubMedUsed to support: Randomized crossover study in 33 women with insulin resistance: 5 g D-tagatose before a glucose load did not change glucose compared with water, increased self-rated satiety at 60 minutes, and did not change later buffet food intake.
  10. Saunders JP, Donner TW, Sadler JH, Levin GV, Makris NG. Effects of acute and repeated oral doses of D-tagatose on plasma uric acid in normal and diabetic humans. Regul Toxicol Pharmacol. 1999;29(2 Pt 2):S57-65. doi: 10.1006/rtph.1998.1264.PubMedUsed to support: Two-phase study in 8 healthy and 8 type 2 diabetes participants: a single 75 g dose of D-tagatose caused a transient rise in plasma uric acid peaking at 60 minutes, while 75 g a day for 8 weeks did not raise fasting uric acid or change lipids, HbA1c, glucose or insulin; most participants had flatulence and many had diarrhea. The lead author was affiliated with Biospherics.
  11. Buemann B, Toubro S, Holst JJ, Rehfeld JF, Bibby BM, Astrup A. D-tagatose, a stereoisomer of D-fructose, increases blood uric acid concentration. Metabolism. 2000;49(8):969-76. doi: 10.1053/meta.2000.7724.PubMedUsed to support: Double-blind crossover study in 8 men: 30 g D-tagatose raised serum uric acid more than 30 g fructose or water, lowered blood phosphate more than fructose, blunted the glucose and insulin response to a later meal, and raised CCK and GLP-1.
  12. Buemann B, Toubro S, Astrup A. Human gastrointestinal tolerance to D-tagatose. Regul Toxicol Pharmacol. 1999;29(2 Pt 2):S71-7. doi: 10.1006/rtph.1998.1265.PubMedUsed to support: Series of studies of 29 or 30 g D-tagatose: nausea and diarrhea occurred in 15.1 and 31.5 percent of 73 healthy young men, flatulence was common and did not decline over 15 days, and the authors suggested 30 g at one time may exceed a dose for ordinary use.
  13. Normén L, Laerke HN, Jensen BB, Langkilde AM, Andersson H. Small-bowel absorption of D-tagatose and related effects on carbohydrate digestibility: an ileostomy study. Am J Clin Nutr. 2001;73(1):105-10. doi: 10.1093/ajcn/73.1.105.PubMedUsed to support: Controlled diet study in 6 people with an ileostomy: apparent small-bowel absorption of 15 g D-tagatose a day was 81 percent, with only minor effects on absorption of other nutrients.
  14. Food and Drug Administration, HHS. Food labeling: health claims; D-tagatose and dental caries. Final rule. Fed Regist. 2003;68(128):39831-3..PubMedUsed to support: FDA final rule (2003) confirming the interim rule that amended the authorized health claim on noncariogenic carbohydrate sweeteners and dental caries (21 CFR 101.80) to list the sugar D-tagatose as an eligible substance. Under the codified rule a qualifying sugar-free food may state that tagatose, unlike other sugars, does not promote tooth decay.
  15. US Food and Drug Administration. GRAS Notice No. GRN 000977: D-tagatose (response letter to Bonumose, LLC) FDA GRAS Notice Inventory. 2021;Letter dated October 21, 2021..SourceUsed to support: Not PubMed-indexed. FDA letter stating it had no questions about the notifier's conclusion that D-tagatose made from maltodextrin is GRAS as a nutritive sweetener and in other food uses; notes that FDA had earlier raised no questions about GRN 000078 and GRN 000352 for D-tagatose; describes D-tagatose as a C-4 epimer of D-fructose about 90 percent as sweet as sucrose; and summarizes human studies with mild, transient GI symptoms such as diarrhea, flatulence and bloating.
  16. Food Standards Agency, Food Standards Scotland. Assessment of the Novel Food D-tagatose for a Change to the Conditions of Use (RP1652) FSA Research and Evidence. 2025;Published February 28, 2025. doi: 10.46756/001c.129153.SourceUsed to support: Not PubMed-indexed. UK safety assessment stating that D-tagatose was first authorized as a novel food in 2005 (EU and UK) after an application on behalf of Arla Food Ingredients; that it is 75 to 92 percent as sweet as sucrose and is made from galactose or fructose; that it is incompletely absorbed and fermented in the colon; that a tolerable single dose of no more than 15 g per serving was agreed because of laxative effects, with a laxative warning required above 15 g per serving and for drinks above 1 percent; and that the 2005 assessment cited 1.5 kcal/g while EFSA in 2016 concluded 3 kcal/g for labeling.