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Faster aspart (Fiasp)

Novo Nordisk

An ultra-rapid mealtime insulin — insulin aspart reformulated with niacinamide (and L-arginine) to speed early absorption, appearing in the blood about twice as fast as standard aspart and trimming post-meal spikes.

Available nowRegulator-approvedrapidultra-rapidmealtime

The scorecard

Onset speed72

Among mealtime peers: insulin appears ~2.5 min after injection and glucose-lowering begins ~16-20 min — onset ~2x faster than standard aspart, but still not physiologic.[1]

Time to peak60

Mealtime convention (faster peak = better): time-to-peak effect ~91-133 min depending on dose; earlier and larger early action than aspart but maximum is still ~1.5-2 h out.[1]

Short tail58

Mealtime convention (shorter tail = better): duration ~5-7 h (dose-dependent) with earlier offset than aspart in pumps (~24 min sooner), but the tail is only modestly cleaner.[5]

Consistency64

Within-patient day-to-day variability in glucose-lowering is ~18-19%; predictable, though injection-site reactions are reported slightly more often than with aspart.[1]

Exercise flexibility56

Faster off-rate helps marginally around activity, but a multi-hour tail still complicates exercise and unannounced exertion.[4]

Access & cost58

Access convention (cheaper/more available = better): widely approved and pump-cleared, but brand-only with no biosimilar; high out-of-pocket cost without insurance though patient caps exist.[10]

Insulins are scored relative to their role peers (see tags: rapid, ultra-rapid, basal, inhaled). A basal insulin's onset score compares it to other basals, not to mealtime insulins.

Editor’s take

A real but incremental step. The pharmacology genuinely left-shifts versus aspart — fastest-in-class alongside Lyumjev — and it shines in pumps and closed-loop, where every saved minute compounds. But it doesn't erase the fundamental subcutaneous lag, which is exactly why the insulin-speed gap remains.

The full picture

Faster aspart is the rapid-acting analog insulin aspart reformulated with two excipients — niacinamide (vitamin B3), which speeds early absorption, and L-arginine, which stabilizes the formulation.1 It is a mealtime (bolus) insulin: you take it to cover the carbohydrate in a meal, alongside a separate long-acting basal insulin or as the bolus insulin in a pump.2

How fast, exactly? After a subcutaneous injection, insulin aspart appears in the bloodstream in about 2.5 minutes, with peak insulin concentration around 63 minutes.3 The glucose-lowering effect starts at roughly 16-20 minutes, reaches its peak at about 91-133 minutes (later and larger with bigger doses), and fades over 5-7 hours; the terminal half-life is about 1.1 hours.3 Compared with standard aspart, faster aspart roughly doubles the early insulin exposure and delivers up to 2.5-fold more glucose-lowering action in the first 30 minutes — the curve is shifted earlier at both ends.4 In a pump, it turns on about 11 minutes sooner and off about 24 minutes sooner than aspart.5 The speed comes from niacinamide: it increases the fraction of insulin present as fast-absorbing monomers by ~35%, boosts transport across blood-vessel walls by ~27%, and causes a brief local widening of small vessels.1

Does it help in real life? In the 26-week onset 1 trial in adults with type 1 diabetes, mealtime faster aspart matched aspart on overall HbA1c and was superior for the post-meal glucose rise at both 1 and 2 hours.6 In pumps (onset 5), it again held HbA1c non-inferior and improved 1-hour post-meal glucose, though investigators noted a numerical imbalance in severe hypoglycemia worth watching.7 In children and adolescents, onset was about twice as fast with greater early exposure, supporting use across ages.8

Consistency and exercise. Day-to-day variation in its glucose-lowering effect within a person is modest (~18-19%).3 The faster on/off profile is a marginal help around activity, but a multi-hour tail still means active insulin can drive lows during or after exercise — plan ahead.

Delivery, approvals, dosing. It comes in FlexTouch pens, vials, PenFill cartridges, and a PumpCart cartridge.3 The EU authorised it on 9 January 2017, later extended to children aged 1 year and older.9 The FDA approved it in 2017 and expanded the label for insulin-pump use in October 2019.10 A standout practical feature: it can be dosed at the start of a meal or up to 20 minutes after starting to eat — useful for unpredictable appetites in young children.2

Access and cost. It is approved across the US, UK, EU, Canada, Australia, and Japan, but remains brand-only — there is no biosimilar or generic (patent protection runs to about 2026), and US out-of-pocket costs are high without insurance, partly offset by manufacturer caps and insurance.11

What's coming. Faster aspart's real frontier is automation: because closed-loop systems must react to glucose through the insulin-action lag, even a few saved minutes matter, and faster aspart is increasingly used in hybrid closed-loop and fully-closed-loop research. But it does not remove the underlying subcutaneous delay — which is why the field is pursuing genuinely ultra-fast and intradermal formulations to close the insulin-speed gap.

References

  1. Kildegaard J, Buckley ST, Nielsen RH, et al. Elucidating the Mechanism of Absorption of Fast-Acting Insulin Aspart: The Role of Niacinamide. Pharm Res (2019). https://doi.org/10.1007/s11095-019-2578-7 ↩ ↩2

  2. Novo Nordisk. FIASP (insulin aspart injection) US Prescribing Information — Dosage and Administration. https://www.novo-pi.com/fiasp.pdf ↩ ↩2

  3. Novo Nordisk. FIASP (insulin aspart injection) US Prescribing Information — Clinical Pharmacology (12.2, 12.3). https://www.novo-pi.com/fiasp.pdf ↩ ↩2 ↩3 ↩4

  4. Haahr H, Heise T. Fast-Acting Insulin Aspart: A Review of its Pharmacokinetic and Pharmacodynamic Properties and the Clinical Consequences. Clin Pharmacokinet (2020). https://doi.org/10.1007/s40262-019-00834-5 ↩

  5. Biester T, Kordonouri O, Danne T. Pharmacological Properties of Faster-Acting Insulin Aspart. Curr Diab Rep (2017). https://doi.org/10.1007/s11892-017-0931-y ↩

  6. Russell-Jones D, Bode BW, De Block C, et al. Fast-Acting Insulin Aspart Improves Glycemic Control in Basal-Bolus Treatment for Type 1 Diabetes (onset 1). Diabetes Care (2017). https://doi.org/10.2337/dc16-1771 ↩

  7. Klonoff DC, Evans ML, Lane W, et al. A randomized, multicentre trial evaluating the efficacy and safety of fast-acting insulin aspart in continuous subcutaneous insulin infusion in adults with type 1 diabetes (onset 5). Diabetes Obes Metab (2019). https://doi.org/10.1111/dom.13610 ↩

  8. Fath M, Danne T, Biester T, et al. Faster-acting insulin aspart provides faster onset and greater early exposure vs insulin aspart in children and adolescents with type 1 diabetes mellitus. Pediatr Diabetes (2017). https://doi.org/10.1111/pedi.12506 ↩

  9. European Medicines Agency. Fiasp — European Public Assessment Report (EPAR). https://www.ema.europa.eu/en/medicines/human/EPAR/fiasp ↩

  10. Novo Nordisk. FDA approves Fiasp for use in insulin infusion pumps for adults with type 1 or type 2 diabetes (22 Oct 2019). https://www.prnewswire.com/news-releases/fda-approves-fiasp-for-use-in-insulin-infusion-pumps-for-adults-with-type-1-or-type-2-diabetes-300942998.html ↩

  11. SingleCare. How much does Fiasp cost without insurance? https://www.singlecare.com/blog/fiasp-without-insurance/ ↩

What's next for this

  • →Increasing use in hybrid and fully-closed-loop automated insulin delivery research, where faster onset benefits closed-loop control

Sources

  1. [1]FIASP (insulin aspart injection) US Prescribing Information · regulatory — PK/PD numbers — onset ~2.5 min, Tmax ~63 min, peak effect ~91-133 min, duration ~5-7 h, half-life ~1.1 h, variability ~18-19%; adult + pediatric indication; mealtime/within-20-min dosing; CSII use.
  2. [2]Fiasp — European Public Assessment Report (EPAR) · regulatory — EU marketing authorisation 9 Jan 2017; indication extended to children aged 1 year and above.
  3. [3]FDA approves Fiasp for use in insulin infusion pumps for adults with type 1 or type 2 diabetes · regulatory — US pump (CSII) label expansion, 22 Oct 2019, based on onset 5.
  4. [4]Haahr H, Heise T. Fast-Acting Insulin Aspart: A Review of its Pharmacokinetic and Pharmacodynamic Properties and the Clinical Consequences. Clin Pharmacokinet (2020) · peer-reviewed — Up to 2.5-fold greater glucose-lowering effect within first 30 min; left-shifted profile; PMC7007438.
  5. [5]Biester T, Kordonouri O, Danne T. Pharmacological Properties of Faster-Acting Insulin Aspart. Curr Diab Rep (2017) · peer-reviewed — In pump use, faster on (-11 min), faster off (-24 min), >100% greater action in first 30 min vs aspart.
  6. [6]Kildegaard J, et al. Elucidating the Mechanism of Absorption of Fast-Acting Insulin Aspart: The Role of Niacinamide. Pharm Res (2019) · peer-reviewed — Niacinamide raises monomer fraction ~35%, endothelial permeability ~27%, plus transient local vasodilation; PMC6373292.
  7. [7]Russell-Jones D, et al. Fast-Acting Insulin Aspart Improves Glycemic Control in Basal-Bolus Treatment for Type 1 Diabetes (onset 1). Diabetes Care (2017) · peer-reviewed — 26-week phase 3; HbA1c non-inferior, mealtime faster aspart superior on 1-h and 2-h postprandial glucose.
  8. [8]Klonoff DC, et al. A randomized, multicentre trial evaluating fast-acting insulin aspart in CSII in adults with type 1 diabetes (onset 5). Diabetes Obes Metab (2019) · peer-reviewed — 16-week pump trial; HbA1c non-inferior, superior 1-h postprandial glucose; numerical imbalance in severe hypos noted; PMC6590130.
  9. [9]Fath M, et al. Faster-acting insulin aspart provides faster onset and greater early exposure vs insulin aspart in children and adolescents with type 1 diabetes. Pediatr Diabetes (2017) · peer-reviewed — Onset ~2x faster (5-7 min earlier) across ages; early exposure greater by 78-147%.
  10. [10]How much does Fiasp cost without insurance? (SingleCare) · news — High out-of-pocket cost for vials and pen cartons without insurance; no generic/biosimilar; patent to ~2026.