Faster aspart (Fiasp)
Novo Nordisk
What it is
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.
Editorial review: .
Source dates appear in the references where available; this record has no dated citation metadata.
Trial status, labels and access can change between reviews. How we review the evidence · How to read the evidence
Evidence behind this assessment
Key evidence notes. Study results, product eligibility and access answer different questions.
- Who was studied?
- Study populations and analysis groups vary. Product age limits alone do not describe who was studied.See the linked studies and their populations →
- Benefit or performance
- Consistency: Within-patient day-to-day variability in glucose-lowering is reported as ~18-19% in pharmacology studies; predictable, though injection-site reactions are reported slightly more often than with aspart.[1]
- Important harms and treatment burden
- Read the safety discussion and original sources. A missing summary does not establish safety.
- Approval and country access
- Country-specific approval and access are not summarized in this record.Approval, trial recruitment, local supply and funding are separate. Check the cited label or access source.
- Follow-up and remaining uncertainty
- Read the full discussion and original sources for follow-up duration and study limitations.
Editorial score: calculation and evidence
A weighted editorial judgment on a 0–100 scale, not a probability of success or a measured treatment effect. Higher criterion scores mean more favorable assessments.
Default calculation: 72 × 20 + 60 × 25 + 58 × 15 + 64 × 20 + 56 × 10 + 58 × 10 = 6230; divide by total weight 100. Unrounded weighted result: 62.3.
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]
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]
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]
Within-patient day-to-day variability in glucose-lowering is reported as ~18-19% in pharmacology studies; predictable, though injection-site reactions are reported slightly more often than with aspart.[1]
Faster off-rate helps marginally around activity, but a multi-hour tail still complicates exercise and unannounced exertion.[4]
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 manufacturer caps sometimes reduce what patients pay.[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 — among the fastest in its 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.6 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.1
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.1 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.1 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.6
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.7 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.8 In children and adolescents, onset was about twice as fast with greater early exposure, supporting use across ages.9
Consistency and exercise. Day-to-day variation in its glucose-lowering effect within a person is reported as modest (~18-19%) in pharmacology studies.1 The faster on/off profile may be only 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.1 The EU authorised it on 9 January 2017, later extended to children aged 1 year and older.2 The FDA approved it in 2017 and expanded the label for insulin-pump use in adults in October 2019.3 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.1
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 was reported to run to about 2026), and US out-of-pocket costs are high without insurance, sometimes partly offset by manufacturer caps and insurance.10
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 may matter, and faster aspart is being studied for use 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.
What's next for this
- →Ongoing research use in hybrid and fully-closed-loop automated insulin delivery, where faster onset may benefit closed-loop control
Sources
- [1]FIASP (insulin aspart injection) US Prescribing Information · Regulatory decision — 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.
Novo Nordisk. FIASP (insulin aspart injection) US Prescribing Information — Dosage and Administration.
Novo Nordisk. FIASP (insulin aspart injection) US Prescribing Information — Clinical Pharmacology (12.2, 12.3).
- [2]Fiasp — European Public Assessment Report (EPAR) · Regulatory decision — EU marketing authorisation 9 Jan 2017; indication extended to children aged 1 year and above.
European Medicines Agency. Fiasp — European Public Assessment Report (EPAR).
- [3]FDA approves Fiasp for use in insulin infusion pumps for adults with type 1 or type 2 diabetes · Regulatory decision — US pump (CSII) label expansion, 22 Oct 2019, based on onset 5.
Novo Nordisk. FDA approves Fiasp for use in insulin infusion pumps for adults with type 1 or type 2 diabetes (22 Oct 2019).
- [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 study — Up to 2.5-fold greater glucose-lowering effect within first 30 min; left-shifted profile; PMC7007438.
- [5]Biester T, Kordonouri O, Danne T. Pharmacological Properties of Faster-Acting Insulin Aspart. Curr Diab Rep (2017) · Peer-reviewed study — In pump use, faster on (-11 min), faster off (-24 min), >100% greater action in first 30 min vs aspart.
- [6]Kildegaard J, et al. Elucidating the Mechanism of Absorption of Fast-Acting Insulin Aspart: The Role of Niacinamide. Pharm Res (2019) · Peer-reviewed study — Niacinamide raises monomer fraction ~35%, endothelial permeability ~27%, plus transient local vasodilation; PMC6373292.
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).
- [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 study — 26-week phase 3; HbA1c non-inferior, mealtime faster aspart superior on 1-h and 2-h postprandial glucose.
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).
- [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 study — 16-week pump trial; HbA1c non-inferior, superior 1-h postprandial glucose; numerical imbalance in severe hypos noted; PMC6590130.
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).
- [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 study — Onset ~2x faster (5-7 min earlier) across ages; early exposure greater by 78-147%.
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).
- [10]How much does Fiasp cost without insurance? (SingleCare) · Science journalism — High out-of-pocket cost for vials and pen cartons without insurance; no generic/biosimilar; patent to ~2026.
SingleCare. How much does Fiasp cost without insurance?